Visit our newest sister site!
Hundreds of free aircraft flight manuals
Civilian • Historical • Military • Declassified • FREE!


TUCoPS :: Networks :: c30e_int.txt

C/30 Interface Guide




[ netinfo/c30e-interface-guide.doc ]


                                          CDRL Item: B006-3
                                               Date: 15 July 1987











                   C/30E PHYSICAL LAYER INTERFACE GUIDE




                               Prepared for:

                       Defense Communications Agency
                Defense Communications Systems Organization
                         Washington, DC 20305-2000



                       Contract No: DCA200-85-C-0023
                            Task Order No: 5-44
                         DCAC No: DCAC-350-180-()


                               Prepared by:

                      BBN Communications Corporation
                             50 Moulton Street
                            Cambridge, MA 02238







               Copyright 1987 BBN Communications Corporation




DCAC-350-180-( )                                                     i

                            GENERAL INFORMATION
                   C/30E Physical Level Interface Guide

1.  Purpose.  This Instruction prescribes the policy, assigns the 
responsibility, and identifies the requirements for connecting an  X.25 
host to a C/30E PSN by means of a MIL-STD-188-114 (balanced), EIA-232-D, 
or V.35 interface.  This Instruction also identifies the requirements for 
connecting one C/30E PSN to another by means of a MIL-STD-188-114 
(balanced), EIA-232-D, or V.35 interface, as well as for the BELL 303 
interface.

2.  Applicability.  This Circular applies to Headquarters, DCA, and all 
subordinate and affiliate activities, and all military departments and 
Government agencies using or requesting DDN access.

3.  References.

    a.  Military Standard 188-114; "Electrical Characteristics of Digital 
Interface Circuits," 24 March 1976.

    b.  EIA Standard 449;  "General Purpose 37-Position and 9-Position 
Interface for Data Terminal Equipment and Data Circuit-Terminating 
Equipment Employing Serial Binary Data Interchange," November 1977.
DCAC-350-180-( )                                                     ii

    c.  EIA Standard 232-D;   "Interface between Data  Terminal Equipment 
and Data Circuit-Terminating Equipment Employing Serial Binary Data 
Interchange," December 1985.

    d.  International  Standard  ISO  2593;   "Connector   Pin 
Allocations  for  Use with High-Speed Data  Terminal  Equipment," 
1973-03-01 (First Edition).

    e.  Bell  System  Technical  Reference;  "Wideband  Data Stations 
303-Type," August 1966.

4.  Policy.

    a.  The current DDN standard node supports only MIL-STD-188-114 
balanced serial host interfaces.  The EIA-232 and V.35 interfaces are not 
recommended for future installations, but they may be found where they are 
provided by an existing installation, and it is not feasible to install a 
MIL-STD-188-114 balanced interface prior to upgrading the entire node to 
DDN standard.

    b.  DDN policy is that the C/30E minimum host bit rate be 9.6 kb/s for 
MIL-STD-188-114, EIA-232-D, and V.35 interfaces.  DDN also supports 
Extended Modem Looping (XMOD).

5.  Responsibility.  DCA, Code B611, will ensure that this Circular is 
updated to reflect current DDN standard node.
DCAC-350-180-( )                                              iii

                            CONTENTS

                                            Paragraph         Page

BASIC CIRCULAR

    Purpose  . . . . . . . . . . . . . . .      1              i
    Applicability  . . . . . . . . . . . .      2              i
    References . . . . . . . . . . . . . .      3              i
    Policy . . . . . . . . . . . . . . . .      4             ii
    Responsibility . . . . . . . . . . . .      5             ii

DEFINITIONS. . . . . . . . . . . . . . . .                   vii

Chapter                                     Paragraph         Page

1.  MIL-STD-188-114 NEIGHBOR OR NEARBY
      HOST INTERFACE

        Overview . . . . . . . . . . . . .      1             1-1
        Electrical Characteristics . . . .      2             1-1
        Mechanical Characteristics . . . .      3             1-9
        Interconnecting Cables . . . . . .      4            1-11

2.  MIL-STD-188-114 REMOTE HOST INTERFACE

        Overview . . . . . . . . . . . . .      1             2-1
        Electrical Characteristics . . . .      2             2-1
        Mechanical Characteristics . . . .      3             2-6
        Interconnecting Cables . . . . . .      4            2-11

3.  EIA-232-D HOST INTERFACE

        Overview . . . . . . . . . . . . .      1             3-1
        Electrical Characteristics . . . .      2             3-1
        Mechanical Characteristics . . . .      3             3-8
        Interconnecting Cables . . . . . .      4            3-10

4.  V.35 HOST INTERFACE

        Overview . . . . . . . . . . . . .      1             4-1
        Electrical Characteristics . . . .      2             4-1
        Mechanical Characteristics . . . .      3             4-7
        Interconnecting Cables . . . . . .      4             4-9

5.  MIL-STD-188-114 NEIGHBOR OR NEARBY
      TRUNK INTERFACE

        Overview . . . . . . . . . . . . .      1             5-1
        Electrical Characteristics . . . .      2             5-1
        Mechanical Characteristics . . . .      3            5-11
        Interconnecting Cables . . . . . .      4            5-13
DCAC-350-180-()                                                  iv

Chapter                                     Paragraph           Page

6.  MIL-STD-188-114 REMOTE TRUNK INTERFACE

        Overview . . . . . . . . . . . . .      1                6-1
        Electrical Characteristics . . . .      2                6-1
        Mechanical Characteristics . . . .      3                6-5
        Interconnecting Cables  .  . . . .      4               6-11

7.  EIA-232-D NEIGHBOR OR NEARBY TRUNK INTERFACE

        Overview . . . . . . . . . . . . .      1                7-1
        Electrical Characteristics . . . .      2                7-1
        Mechanical Characteristics . . . .      3                7-7
        Interconnecting Cables . . . . . .      4                7-9

8.  V.35 REMOTE TRUNK INTERFACE

        Overview . . . . . . . . . . . . .      1                8-1
        Electrical Characteristics . . . .      2                8-1
        Mechanical Characteristics . . . .      3                8-6
        Interconnecting Cables . . . . . .      4                8-8

9.   BELL 303 NEIGHBOR OR NEARBY TRUNK INTERFACE

        Overview . . . . . . . . . . . . .      1                9-1
        Electrical Characteristics . . . .      2                9-1
        Mechanical Characteristics . . . .      3                9-8
        Interconnecting Cables . . . . . .      4               9-10

10.  BELL 303 REMOTE TRUNK INTERFACE

        Overview . . . . . . . . . . . . .      1               10-1
        Electrical Characteristics . . . .      2               10-1
        Mechanical Characteristics . . . .      3               10-3
        Interconnecting Cables . . . . . .      4               10-9






DCAC-350-180-( )                                             v

                          ILLUSTRATIONS

Table                                                         Page


1-1     Signal Name Equivalency Table . . . . . . . . .        1-2
1-2     Frequencies Provided by the FDBCLK Fantail  . .        1-3
1-3     DDN Standard Node Interchange Circuit Use . . .        1-8
1-4     DDN Standard Node EIA-449 (DTE)
          Connector Pinout  . . . . . . . . . . . . . .       1-10
2-1     Remote-Modem DTE Interface Connector Pinout . .        2-8
2-2     KGAB - Remote Host Connector Pinout . . . . . .        2-9
2-3     KGAB - Remote Modem Connector Pinout  . . . . .       2-10
2-4     Remote Interface Cables . . . . . . . . . . . .       2-11
3-1     Signal Name Equivalency Table . . . . . . . . .        3-3
3-2     EIA-232-D Interchange Circuit Use . . . . . . .        3-7
3-3     EIA-232-D Connector Pinout  . . . . . . . . . .        3-9
4-1     V.35 Interchange Circuit Use  . . . . . . . . .        4-6
4-2     V.35 34-Pin and 37-pin Connector Pinout . . . .        4-8
5-1     Signal Name Equivalency Table . . . . . . . . .        5-2
5-2     Frequencies Provided by the MMBC Fantail. . . .        5-3
5-3     DDN Standard Node MMB*/MMBC                           
          Interchange Circuit Use  . . . .  . . . . . .       5-10
5-4     DDN Standard Node EIA-449 (DTE)
          Connector Pinout  . . . . . . . . . . . . . .       5-12
6-1     Remote-Modem DCE Interface Connector Pinout . .        6-8
6-2     KGAB - Remote C/30E Connector Pinout. . . . . .        6-9
6-3     KGAB - Remote Modem Connector Pinout  . . . . .       6-10
6-4     Remote Interface Cables . . . . . . . . . . . .       6-11
7-1     Signal Name Equivalency Table . . . . . . . . .        7-3
7-2     EIA-232-D Interchange Circuit Use . . . . . . .        7-6
7-3     EIA-232-D Connector Pinout  . . . . . . . . . .        7-8
8-1     V.35 Trunk Interchange Circuit Use  . . . . . .        8-5
8-2     V.35 34-Pin and 37-pin Connector Pinout . . . .        8-7
9-1     Signal Name Equivalency Table   . . . . . . . .        9-3
9-2     BELL 303 Trunk Interface Circuit Use  . . . . .        9-7
9-3     DDN Standard Node EIA-449 (DTE) Connector Pinout       9-9
10-1    DTE Interface Connector Pinout  . . . . . . . .       10-6
10-2    DCE BELL 303 Interface Connector Pinout . . . .       10-7
10-3    KGAB-Remote Modem Connector Pinout. . . . . . .       10-8
10-4    Remote Interface Cables . . . . . . . . . . . .       10-9
DCAC-350-180-( )                                                 vi

Figure                                                           Page

1-1     C/30E PSN and Nearby EIA-449 Host Cabling
          Diagram (C/30E Sources Clock). . . . . . . . . .       1-12
1-2     Cable Example: C/30E PSN to EIA-449 Nearby
          Host (C/30E Sources Clock) . . . . . . . . . . .       1-13
2-1     Demarcation Point "A" Between the C/30E and
          Remote Host. . . . . . . . . . . . . . . . . . .        2-3
2-2     Demarcation Point "B" Between the KGAB and
          Remote Host. . . . . . . . . . . . . . . . . . .        2-3
2-3     Functional Signal Flow Between a Nearby Modem and
          C/30E, or a KGAB and a Remote Host . . . . . . .        2-7
2-4     C/30E and Remote Host Cabling Diagram. . . . . . .       2-12
2-5     C/30E and Remote Host Cabling Diagram
          (with Cryptographic Devices) . . . . . . . . . .       2-12
3-1     C/30E PSN and Nearby EIA-232-D Host Cabling
          Diagram. . . . . . . . . . . . . . . . . . . . .       3-10
3-2     Cable Example: C/30E PSN to Nearby EIA-232-D
          Host . . . . . . . . . . . . . . . . . . . . . .       3-11
4-1     C/30E PSN and Nearby V.35 Host Cabling Diagram . .        4-9
4-2     Cable Example: C/30E PSN to Nearby V.35 Host . . .       4-10
5-1     C/30E EIA-449 PSN and Nearby EIA-449 PSN Cabling
          Diagram MMBC (C/30E Sources Clock) . . . . . . .       5-15
5-2     C/30E PSN with MMBC to EIA-449 Nearby PSN Cabling 
          Diagram with MMBC-MMBC (C/30E Sources Clock) . .       5-15
5-3     Cabling Example: C/30E with MMB to EIA-449 Nearby
          PSN with MMBC (C/30E Sources Clock). . . . . . .       5-16
5-4     Cabling Example: C/30E with MMBC to EIA-449 Nearby
          PSN with MMBC (C/30E Sources Clock). . . . . . .       5-17
6-1     Demarcation Point "A" Between the C/30E and
          Remote C/30E . . . . . . . . . . . . . . . . . .        6-3
6-2     Demarcation Point "B" Between the KGAB and
          Remote C/30E PSN  . . . .  . . . . . . . . . . .        6-3
6-3     Functional Signal Flow Between a Nearby Modem and
          C/30E, or an SR(ON) NS(OFF) KGAB and a Remote PSN.      6-7
6-4     C/30E and Remote Host Cabling Diagram. . . . . . .       6-12
6-5     C/30E and Remote Trunk Cabling Diagram
          (with Cryptographic Devices) . . . . . . . . . .       6-12
7-1     C/30E PSN and Nearby EIA-232-D PSN Cabling
          Diagram  . . . . . . . . . . . . . . . . . . . .        7-9
8-1     C/30E PSN and Remote V.35 PSN Cabling Diagram  . .        8-8
8-2     Cable Example: C/30E PSN to Remote V.35 PSN  . . .        8-9
9-1     BELL 303 MMI to BELL 303 MML Cabling Example . . .       9-11
9-2     BELL 303 Trunk Interface Cabling Example . . . . .       9-12
10-1    Demarcation Point "A" Between the C/30E and
          Remote C/30E . . . . . . . . . . . . . . . . . .       10-2
10-2    BELL 303 Remote Trunk Interchange Circuit Use. . .       10-5


DCAC-350-180-( )                                                 vii

                                DEFINITIONS

C/30E.  X.25-based communication processor made by BBN Communications 
Corporation.  Used in Packet-Switching Network applications.

DCE.  Data Circuit-Terminating Equipment.

DC-37P.  37-pin male connector.

DC-37S.  37-pin female connector.

DDN.  Defense Data Network.

DPPC.  Digital Patch Panel connected between the DCE and the encryption 
device.

DPPE.  Digital Patch Panel connected between the DTE and the encryption 
device.

DTE.  Data Terminal Equipment.

EIA.  Electronic Industries Association.

EMI.  Electromagnetic Interference.
        
DCAC-350-180-( )                                                 viii

FDBCLK.  MSYNC-driven clock-sourcing MIL-STD-188-114 adapter  (fantail)  
containing EIA-449  connectors.   The  FDBCLK fantail can be used to 
source clock.

FDB3.  MSYNC-driven MIL-STD-188-114 fantail containing EIA-449 
connectors.  FDB3 cannot provide clock.

FD4.  Fantail containing EIA-232-D connectors.

FPA.  Fixed Plant Adapters: Complete assembly consisting of two KGABs, 
space for two KG-84As, and one FPA shelf that supports the assembly in the 
encryption cabinet.

KGAB.  Interfaces a KG-84A with a communications line by providing for 
cable termination, filter isolation, and update counter support.

KG-84A.  Provides standard link encryption to all interswitch trunks and 
host access lines on the MILNET.  Not used for collocated equipment.

MII Board.  Input/output motherboard used in C/30E PSNs to interface with 
communications lines leading to other DDN PSNs.

MMBC Board.  Daughterboard emulating a MIL-STD-188-114 DCE, thus providing 
clock. Its DTE counterpart is the MMB board.

MMI Board. Daughterboard emulating a BELL 303 DTE.

DCAC-350-180-( )                                                 ix

MML Board. Daughterboard emulating a BELL 303 DCE.

MS Connection.  KGAB Connectors.

MSYNC.  Input/output motherboard that is used in C/30E PSNs to interface 
with synchronous host access lines.

PSN.  Packet Switch Node used in the DDN to provide full service network 
access ports for hosts and trunks.  PSN and C/30E are used interchangeably 
in this document.

Synchronous Devices.   Require a clock signal to operate the 
communications interface.

TEMPEST.  Limits compromising electromagnetic emanations from  
communications  equipment.

Trunk. Communications link providing an interface between two nearby or 
remote PSNs, hence a PSN-to-PSN interface.

DCAC-350-180-( )                                                     1-1


      CHAPTER 1.  MIL-STD-188-114  NEIGHBOR OR NEARBY HOST INTERFACE

1.  Overview.  This chapter describes the electrical and mechanical 
characteristics of the MIL-STD-188-114 balanced DTE interface that 
connects the C/30E PSN with a neighbor/nearby host or a modem.  This 
interface is largely in conformance with the EIA-449/422 standard 
considered the general commercial equivalent to MIL-STD-188-114.  
Exceptions to the standard include the required signal states for Clear to 
Send and Receiver Ready as well as the open circuit voltage.  For ease of 
reference, table 1-1 equates the EIA-449, EIA-232, and CCITT interface 
signal names.  However, in the rest of chapters 1 and 2, only the EIA-449 
signal name will be used.

2.  Electrical Characteristics.

    a.  Voltage Levels.  The electrical measurements of the C/30E 188-114 
interface circuits are in accordance with MIL-STD-188-114, chapter 5, 
except with regard to subsection 5.1.1.2: Open Circuit Measurement.  The 
C/30E open circuit driver voltage, measured in   accordance with 5.1.1.2, 
is less than +9.0V for balanced drivers and +4.5V for unbalanced drivers.

DCAC-350-180-( )                                                     1-2


                 TABLE 1-1.  SIGNAL NAME EQUIVALENCY TABLE



SG   Signal Ground                 AB     Signal Ground                      102      Signal Ground
SC   Send Common                   --                                        102a     DTE Common
RC   Receive Common                --                                        102b     DCE Common
SD   Send Data                     BA     Transmitted Data                   103      Transmitted Data
RD   Receive Data                  BB     Received Data                      104      Received Data
RS   Request To Send               CA     Request To Send                    105      Request To Send
CS   Clear To Send                 CB     Clear To Send                      106      Ready For Sending
DM   Data Mode                     CC     Data Set Ready (DCE Ready)         107      Data Set Ready
TR   Terminal Ready                CD     Data Terminal Ready (DTE Ready)    108/2    Data         Terminal Ready
RR   Receiver Ready                CF     Received Line Signal Detector      109      Data Channel Received Line
                                                                                      Signal Detector
IS   Terminal In Service           --                                        ---
SQ   Signal Quality                CG     Signal Quality Detector            110      Data Signal Quality
                                                                                                   Detector
SR   Signaling Rate Selector       CH     Data Signal Rate Selector          111      Data Signaling Rate
                                           (DTE Source)                                Selector (DTE Source)
SI   Signaling Rate                CI     Data Signal Rate Selector          112      Data Signaling Rate
      Indicator                            (DCE Source)                                Selector (DCE Source)
NS   New Signal                    --                                        ---
TT   Terminal Timing               DA     Transmitter Signal Element Timing  113      Transmitter Signal Element
                                           (DTE Source)                                Timing (DTE Source)
ST   Send Timing                   DB     Transmitter Signal Element Timing  114      Transmitter Signal Element
                                           (DCE Source)                                Timing (DCE Source)
RT   Receive Timing                DD     Receiver Signal Element Timing     115      Receiver Signal Element
                                                                                                    Timing (DCE Source)
SS   Select Standby                --                                        116      Select Standby
SB   Standby Indicator             --                                        117      Standby Indicator

IC   Incoming Call                 CE     Ring Indicator                     125      Calling Indicator
SF   Select Frequency              --                                        126      Select Transmit Frequency
LL   Local Loopback                LL     Local Loopback                     141      Local Loopback
RL   Remote Loopback               RL     Remote Loopback                    140      Remote Loopback
TM   Test Mode                     TM     Test Mode                          142      Test Indicator
AT   Alternate Timing*             --                                        142


*  Alternate Timing is provided on spare pins 3 and 21 when
   the FDBCLK clock-sourcing fantail is providing clock.
DCAC-350-180-( )                                                     1-3

    b.  Clocking.  Two fantails, FDB3 and FDBCLK, provide the EIA-449 
connectors that terminate cables from all I/O interfaces.  The fantail 
connectors are configured as DTEs.  When the FDB3 fantail is used, the DCE 
must provide clock because the FDB3 fantail does not support 
clock-sourcing capability.  When FDBCLK, a clock-sourcing enhanced 
fantail, is used, either the DTE or DCE can provide clock.

        (1)  FDB Fantail Clock Rates.  FDBCLK and FDB3 interface hardware 
support any external clock between 1.2 kb/s and 112 kb/s.  However, DDN 
policy is that the minimum PSN host bit rate be 9.6 kb/s.  When FDBCLK 
clock-sourcing capability is used, the FDBCLK on-board clock generator 
provides the frequencies described in table 1-2.


          TABLE 1-2.  FREQUENCIES PROVIDED BY THE FDBCLK FANTAIL
        
                                                                          

Clock Frequency                                  Accuracy* 

112kHz, 56kHz, 19.2kHz,9.6kHz, 4.8kHz, 2.4kHz    +0.05% (500 ppm**)

64kHz, 50kHz                                     +0.005% (50 ppm)

                                                                          

*  Accuracy over a temperature range of 10 to 30 degrees C.
** PPM = Parts Per Million
DCAC-350-180-( )                                                     1-4

        (2)  Signaling Sense.  Signaling sense for balanced and unbalanced 
circuits is in accordance with EIA-422-A with the exception that the 
differential voltage applied to the interconnecting cable is in the range 
of 2 volts to 9 volts for the C/30E.  As defined in RS-422-A, ON (0, 
Space, or +) is generated when A terminal is positive with respect to the 
B terminal, and OFF (1,  MARK, or -) is generated when A terminal is 
negative with respect to the B terminal.

    c.  Bit Rate and Cable Length.  Interconnecting cable length and its 
relation to data signaling rates is in accordance with EIA Standard 449, 
section 6.10, and EIA Standard 422-A, section 4.3 and the appendix.

        (1)  Maximum Cable Length.  The maximum length of the cable is 
1000 feet.

        (2)  Slew Rate Limiting.  Signal rise time is set to 1 microsecond 
(100 kb/s value).

    d.  Interchange  Circuits.  The EIA-449 interface for the C/30E is 
provided by the  MSYNC motherboard in conjunction  with the appropriate 
daughterboards to fulfill the MIL-STD-188-114 I/O option.

        (1)  Electrical Use of Interchange Circuits.  The DDN electrical 
use of interchange circuits is either static or active.  Static circuits 
are tied by the hardware so that the signal state remains constant on the 
line, either ON or OFF.  Active circuits change their state under program 
control.  DDN use of the interchange circuits is shown in table 1-3.
DCAC-350-180-( )                                                     1-5

        (2)  Software Use of Interchange Circuits.  Interchange circuit 
signals are used by the software in different ways.  Active circuits are 
under program control: either the software reacts to the circuit signal 
when it changes, or the software can assert a circuit when necessary (such 
as LL which can be used by operations personnel for testing connections).  
Unsupported circuits either are not read by the software or a value is 
written to the circuit by the software and that value does not change 
during operation.  Table 1-3 provides a list of circuits and their use.

        (3)  Interchange Circuit Definitions.  For additional information 
about these interchange circuits, see EIA Standard 449.  The following 
descriptions assume use of full period/full duplex circuits, with flow 
control handled at higher levels.

             (a)  Signal Ground.  See EIA Standard EIA-449.

             (b)  Send Common.  See EIA Standard EIA-449.

             (c)  Receive Common.  See EIA Standard EIA-449.

             (d)  Terminal in Service.  IS is tied ON by the hardware.

             (e)  Incoming Call.  IC is reported to the Monitoring Center; 
however, its value has no software effect.

             (f)  Terminal Ready.  TR is asserted ON by PSN software when 
the link is initialized.
DCAC-350-180-( )                                                     1-6

             (g)  Data Mode.  DM must be asserted ON by the DCE and is 
monitored by the PSN software.

             (h)  Send Data.  See EIA Standard EIA-449.

             (i)  Receive Data.  See EIA Standard EIA-449.

             (j)  Terminal Timing.  See EIA Standard EIA-449.

             (k)  Send Timing.  See EIA Standard EIA-449.

             (l)  Receive Timing.  See EIA Standard EIA-449.

             (m)  Request to Send.  RS is asserted ON by PSN software when 
the link is initialized.

             (n)  Clear to Send.  CS must be asserted ON by the DCE and is 
monitored by PSN software.  If the signal state on this line changes to 
OFF, the software macrocode will stop data transmission.

             (o)  Receiver Ready .  RR must be asserted ON by the DCE and 
is monitored by PSN software.  If the signal state on this line changes to 
OFF, the software macrocode will stop receiving data.

             (p)  Signal Quality.  SQ is reported to the Monitoring 
Center; however, its value has no software effect.

DCAC-350-180-( )                                                     1-7

             (q)  New Signal.  Ns is tied OFF by the hardware.

             (r)  Select Frequency.  SF/SR is electrically active and 
asserted OFF by the PSN software when the link is initialized.

             (s)  Signaling Rate Selector.  See Select Frequency, 2.d.3.r 
above for a description.

             (t)  Signaling Rate Indicator.  SI is reported to the 
Monitoring Center; however, its value has no software effect.

             (u)  Local Loopback.  LL is electrically active, but asserted 
OFF by PSN software when the link is initialized.  LL can be controlled by 
the Monitoring Center.

             (v)  Remote Loopback.  RL is electrically active, but 
asserted OFF by PSN software when the link is initialized.  RL is 
available for Monitoring Center control.

             (w)  Test Mode.  TM is reported to the Monitoring Center; 
however, its value has no software effect.

             (x)  Select Standby.  SS is tied OFF by hardware.

             (y)  Standby Indicator.  SB is not connected.

DCAC-350-180-( )                                                     1-8

           TABLE 1-3.  DDN STANDARD NODE INTERCHANGE CIRCUIT USE



449                                            Electrical        Required State of     Comments
ID      EIA-449 Name          Source           Circuit         Control/Status Sigals

SG      Signal Ground         DTE/DCE          Ground                   N/A            Ground
SC      Send Common           DTE              Ground                   N/A            Common
RC      Receive Common        DCE              Ground                   N/A            Common
SD      Send Data             DTE              Active                   N/A            Data Circuit
RD      Receive Data          DCE              Active                   N/A            Data Circuit
RS      Request to Send       DTE              Active                   ON             Asserted On by PSN software.
CS      Clear to Send         DCE              Active                   ON             Asserted On by DCE, and
                                                                                       monitored by PSN software to
                                                                                       determine line status.
DM      Data Mode             DCE              Active                   ON             Asserted ON by DCE, and
                                                                                       monitor by PSN sofware.
TR      Terminal Ready        DTE              Active                   ON             Asserted ON by PSN sofware.
RR      Receiver Ready        DCE              Active                   ON             Asserted ON by DCE, and
                                                                                       monitor by PSN software to
                                                                                       determine line status.
SQ      Signal Quality        DCE              Active                   Don't Care     Monitored by PSN software, but
                                                                                       no action is taken.
SF/SR   Select Frequency/     DTE              Active                   OFF            Asserted OFF by PSN software.
         Signaling Rate Sel.
SI      Signaling Rate        DCE              Active                   Don't Care     Monitored by PSN software,but
         indicator                                                                     no action is taken.
TT      Terminal Timing       DTE              Active                   N/A            Timing circuit for Transmitted
                                                                                       Data when PSN supplies timing.
ST      Send Timing           DCE              Active                   N/A            Timing circuit for Received
                                                                                       Data when DCE provides timing.
RT      Receive Timing        DCE              Active                   N/A            Timing circuit for Received
                                                                                       Data when DCE provides timing.
SS      Select Standby        DTE              Static                   OFF            Tied OFF by hardware.
SB      Standby Indicator     DCE              Not Connected            Don't Care     Not connected in PSN.
IC      Incoming Call         DCE              Active                   Don't Care     Monitored by PSN software, but
                                                                                       no action is taken.
LL      Local Loopback        DTE              Active                   OFF            Initialized to OFF by
                                                                                       software.  Available for
                                                                                       Monitoring Center control.
RL      Remote Loopback       DTE              Active                   OFF            Initialized to OFF by
                                                                                       software.  Available for 
                                                                                       Monitoring Center control.
TM      Test Mode             DCE              Active                   Don't Care     Monitored by PSN software, but
                                                                                       no action is taken.
NS      New Signal            DTE              Static                   OFF            Tied OFF by hardware.
IS      Terminal in Service   DTE              Static                   ON             Tied ON by hardware.
AT      Alternative Timing    DTE              Active                   N/A            Special timing circuit for
                                                                                       Received Data when the PSN
                                                                                       supplies timing.




NOTE:  N/A = Not Applicable
DCAC-350-180-( )                                                     1-9

3.  Mechanical Characteristics.  All EIA-449/422 connectors offered for 
the C/30E meet the following specifications.
    
    a.  Interface Connectors.  All C/30E EIA-449 connectors are DC-37P 
type (male) connectors.

        (1)  Intermating dimensions are in accordance with EIA-449, 
section 3.3.1.

        (2)  The means for C/30E DTE connectors to latch and unlatch from 
the latching blocks on the DCE connector are within the dimensions 
specified in EIA-449, section 3.3.2.  DDN uses the English 4-40 thread 
latching block.
    
    b.  Connector Contact Assignments.  All C/30E EIA-449/422 contact 
assignments are in accordance with EIA-449, section 3.4.  Table 1-4 
provides the DDN standard node connector pinout.   The signals are used as 
specified in section 2.d.3.
DCAC-350-180-( )                                                     1-10

       TABLE 1-4.  DDN STANDARD NODE EIA-449 (DTE) CONNECTOR PINOUT

                                                                          

Pin     EIA     CCITT         Name
        ID      ID

1       FG                    Frame Ground           
2       SI      111           Signaling Rate Indicator
20      RC      102b          Receive Common
3       AT      ---           Alternate Timing +     
21      AT      ---           Alternate Timing -
4       SD      103           Send Data +            
22      SD      103           Send Data -
5       ST      114           Send Timing +          
23      ST      114           Send Timing -
6       RD      104           Receive Data +                  
24      RD      104           Receive Data -         
7       RS      105           Request to Send +      
25      RS      105           Request to Send -
8       RT      115           Receive Timing +       
26      RT      115           Receive Timing -
9       CS      106           Clear to Send +
27      CS      106           Clear to Send -
10      LL      141           Local Loopback
28      IS      ---           Terminal in Service    
11      DM      107           Data Mode +
29      DM      107           Data Mode -
12      TR      108.2         Terminal Ready +       
30      TR      108.2         Terminal Ready -
13      RR      109           Receiver Ready +       
31      RR      109           Receiver Ready -
14      RL      140           Remote Loopback
32      SS      116           Select Standby         
15      IC      125           Incoming Call
33      SQ      110           Signal Quality
16      SF/SR   126           Select Frequency/Signaling Rate
                               Selector
34      NS      ---           New Signal             
17      TT      113           Terminal Timing +      
35      TT      113           Terminal Timing -
18      TM      142           Test Mode
36      SB      117           Standby Indicator
19      SG      102           Signal Ground          
37      SC      102a          Send Common

                                                                          
DCAC-350-180-( )                                                     1-11

4.  Interconnecting Cables.

    a.  Interconnecting cables are in accordance with MIL-STD-188-114.  
They must be low capacitance, multiple twisted pair that meet the 
following specifications resulting in  a transmission line with a nominal 
characteristic impedance on the order of 100 ohms to frequencies greater 
than 100 kHz, and a dc series loop resistance not exceeding 240 ohms.  The 
overall braid shield must have at least 85% coverage.

        (1)  Conductor Size.   Interconnecting cables should be in 
accordance with MIL-STD-188-114, Appendix 10, with regard to conductor 
size (subsection 10.1.1).  Interconnecting cables or wires should be 
composed of wires of a 24 AWG or larger conductor for solid or stranded 
copper wires, or for non-copper conductors a sufficient size to yield a dc 
wire resistance not to exceed 30 ohms/1000 feet per conductor.

        (2)  Mutual Pair Capacitance.   In accordance with 
MIL-STD-188-114, the capacitance between one wire in the pair to the other 
wire in the pair should not exceed 20 picofarads/foot, and the value 
should be reasonably uniform over the length of the wire or cable.

        (3)  Stray Capacitance.   In accordance with MIL-STD-188-114, the 
capacitance between one wire in the cable to all others in the cable 
sheath, with all others connected to ground, should not exceed 40 
picofarads/foot, and should be reasonably uniform for a given conductor 
over the length of the wire or cable.

DCAC-350-180-( )                                                     1-12

             (4)  Pair-to-Pair Balanced Crosstalk.  In accordance with 
MIL-STD-188-114, Appendix 10, with regard to pair-to-pair balanced 
crosstalk (subsection 10.1.4), the crosstalk from on pair of wires to any 
other pair in the same cable sheath should have a minimum value of 40 dB 
of attenuation measured at 150 kHz.

          (b)  Figure 1-1 is a cabling diagram of a C/30E PSN connected to 
a nearby EIA-449 host, and figure 1-2 is an example of a cable (BBNCC P/N# 
2409313G01) that could be used to interconnect them.




     +---------------------------------------------------------------+
     |                                                               |
     |               DC-37S                    DC-37S                |
     |                 /                           \                 |
     | +----------+  /                               \  +----------+ |
     | | EIA-449  |--+            2409318G01         +--| EIA-449  | |
     | | DTE Host |P1|===============================|P2|  C/30E   | |
     | |          |--+                               +--|  (DTE)   | |
     | +----------+                                     +----------+ |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     +---------------------------------------------------------------+

      FIGURE 1-1.  C/30E PSN AND NEARBY EIA-449 HOST CABLING DIAGRAM
                   (C/30E SOURCES CLOCK)
DCAC-350-180-( )                                                     1-13


       +-----------------------------------------------------------+
       |     DTE Host                                    C/30E     |
       |        P1                                         P2      |
       |      DC-37S                                     DC-37S    |
       | Pin#     Signal                            Signal    Pin# |
       |  +/-       +/-   Shield             Shield   +/-      +/- |
       |  1         FG  >--------+         +-------<  FG       1   |
       |                                                           |
       |                                    +------<  AT      3/21 |
       |                                    |                      |
       |                  Pair #            |                      |
       |  4/22      SD  >-(1)------\   /----|------<  SD      4/22 |
       |                             /      |                      |
       |  5/23      ST  >-(2)------/---\----+---+--<  ST      5/23 |
       |                         /       \      |                  |
       |  6/24      RD  >-(3)--/           \----|--<  RD      6/24 |
       |                                        |                  |
       |  8/26      RT  >-(4)-\                 +--<  RT      8/26 |
       |                       \                                   |
       |  7/25      RS  >-(5)---\-------\   /------<  RS      7/25 |
       |                         \        \                        |
       |  11/29     DM  >-(6)--+--\-----/   \--+---<  DM     11/29 |
       |                       |   \           |                   |
       |  9/27      CS  >------+    \          +---<  CS      9/27 |
       |                       |     \         |                   |
       |  13/31     RR  >------+       \       +---<  RR     13/31 |
       |                                 \                         |
       |  19/37  SG/SC  >-(7)-+------------\-------<  SG/SC  19/37 |
       |                      |              \                     |
       |  17/35     TT  >-----|--(12)---No     \---<  TT     17/35 |
       |                      |         Connection (NC)            |
       |                      +--(8)----NC                         |
       |                      |                                    |
       |                      +--(9)----NC                         |
       |                      |                                    |
       |                      +--(10)---NC                         |
       |                      |                                    |
       |                      +--(11)---NC                         |
       |                      |                                    |
       |                      +--(sp)---NC                         |
       |                                                           |
       +-----------------------------------------------------------+
     
       FIGURE 1-2.  CABLE EXAMPLE: C/30E PSN TO EIA-449 NEARBY HOST
                    (C/30E SOURCES CLOCK)


DCAC-350-180-( )                                                     1-14


       +-----------------------------------------------------------+
       |     DTE Host                                    C/30E     |
       |        P1                                         P2      |
       |      DC-37S                                     DC-37S    |
       | Pin#     Signal                            Signal    Pin# |
       |  +/-       +/-   Shield             Shield   +/-      +/- |
       |  1         FG  >--------+         +-------<  FG       1   |
       |                                                           |
       |                                    +------<  AT      3/21 |
       |                                    |                      |
       |                  Pair #            |                      |
       |  4/22      SD  >-(1)------\   /----|------<  SD      4/22 |
       |                             /      |                      |
       |  5/23      ST  >-(2)------/---\----+---+--<  ST      5/23 |
       |                         /       \      |                  |
       |  6/24      RD  >-(3)--/           \----|--<  RD      6/24 |
       |                                        |                  |
       |  8/26      RT  >-(4)-\                 +--<  RT      8/26 |
       |                       \                                   |
       |  7/25      RS  >-(5)---\-------\   /------<  RS      7/25 |
       |                         \        \                        |
       |  11/29     DM  >-(6)--+--\-----/   \--+---<  DM     11/29 |
       |                       |   \           |                   |
       |  9/27      CS  >------+    \          +---<  CS      9/27 |
       |                       |     \         |                   |
       |  13/31     RR  >------+       \       +---<  RR     13/31 |
       |                                 \                         |
       |  19/37  SG/SC  >-(7)-+------------\-------<  SG/SC  19/37 |
       |                      |              \                     |
       |  17/35     TT  >-----|--(12)---No     \---<  TT     17/35 |
       |                      |         Connection (NC)            |
       |                      +--(8)----NC                         |
       |                      |                                    |
       |                      +--(9)----NC                         |
       |                      |                                    |
       |                      +--(10)---NC                         |
       |                      |                                    |
       |                      +--(11)---NC                         |
       |                      |                                    |
       |                      +--(sp)---NC                         |
       |                                                           |
       +-----------------------------------------------------------+
     
       FIGURE 1-2.  CABLE EXAMPLE: C/30E PSN TO EIA-449 NEARBY HOST
                    (C/30E SOURCES CLOCK)


DCAC-350-180-( )                                                     2-1


             CHAPTER 2.  MIL-STD-188-114  REMOTE HOST INTERFACE

1.  Overview.  This chapter describes the electrical and mechanical 
characteristics of the MIL-STD-188-114 balanced remote host interface.     
This chapter documents the interface between the remote modem and the      
host (demarcation point A in figure 2-1) with no intervening       
cryptographic devices (KG-84As).  Eventually KG-84As will be required      
for all host access circuits; therefore, chapter 2 also provides an      
example of the cabling that connects from the remote modem to the remote   
Fixed Plant Adapter (FPA) and then to the host (demarcation point B in    
figure 2-2).

2.  Electrical Characteristics.

    a.  Voltage Levels.  The modems used will conform to EIA-449.  The 
electrical interface of the KG-84A is in accordance with MIL-STD-188-114, 
chapter 5, except with regard to subsection 5.1.1.2: Open Circuit   
Measurement.  The open circuit driver voltage, measured in accordance      
with 5.1.1.2, is less than +10.0V for balanced drivers and +5.0V for  
unbalanced drivers.

DCAC-350-180-( )                                                     2-2


    b.  Clocking.

        (1)  Modem Clocking.  The modem supplies timing on the Send       
Timing and Receive Timing circuits.  Terminal Timing isnot supported       
for remote host interfaces.  While the DDN hardware will support         
between 1.2 kb/s and 64 kb/s, DDN policy is that the minimum host         
access rate be 9.6 kb/s.
DCAC-350-180-( )                                                     2-3



     +--------------------------------------------------------------+
     |                                                              |
     |                                                              |
     | C/30E PSN                                         Host       |
     | +-----------+   +-----------+ +-----------+    +-----------+ |
     | |           |   |           | |           |A   |           | |
     | |118-114 Bal|---|188-114 Bal|-|188-114 Bal|----|118-114 Bal| |
     | |   DTE     |   |   DCE     | |   DCE     |    |   DTE     | |
     | |           |   |           | +           |    |           | |
     | +-----------+   +-----------+ +-----------+    +-----------+ |
     |                                                              |
     |                                                              |
     |                                                              |
     +--------------------------------------------------------------+

    FIGURE 2-1.  DEMERCATION POINT "A" BETWEEN THE C/30 AND REMOTE HOST



   +-------------------------------------------------------------------+
   |   C/30E PSN                                              Host     |
   | +-----------+                                       +-----------+ |
   | |118-114 Bal|                                       |           | |
   | |   DTE     |                                       |118-114 Bal| |
   | |           |                                       |   DTE     | |
   | |           |                                       |           | |
   | +-----+-----+                                       +-----+-----+ |
   |       |                                                   |       |
   |       |                                                   |       |
   |   +---+---+                                           +---+---+   |
   |   | DPPE  |                                           | DPPE  |   |
   |   +---+---+                                           +---+---+   |
   |       |                                                   |       |
   |       |                                                   |       |
   |       |      +--+ +-----------+ +-----------+  +---+      |B      |
   |   +---+---+  |D | |           | |           |  |D  |  +---+---+   |
   |   | KGAB  |--|P |-|188-114 Bal|-|188-114 Bal|--|P  |--| KGAB  |   |
   |   |       |  |P | |           | |   DCE     |  |P  |  |       |   |
   |   +-------+  |C | |           | |           |  |C  |  +-------+   |
   |              +--+ +-----------+ +-----------+  +---+              |
   |                                                                   |
   |                                                                   |
   +-------------------------------------------------------------------+

       FIGURE 2-2.  DEMARCATION POINT "B" BETWEEN THE KGAB AND HOST

DCAC-350-180-( )                                                     2-4


        (2)  Signaling Sense.  Signaling sense for balanced and       
unbalanced circuits is in accordance with EIA-422-A with the exception     
of the differential voltage, which applied to the interconnecting         
cable, is in the C/30E range of 2 volts to 9 volts.  As defined in     
RS-232-A, ON (0, Space, or +) is generated when the A terminal is       
positive with respect to the B terminal, and OFF (1, MARK, or -) is    
generated when the A terminal is negative with respect to the B terminal.

    c.  Bit Rate and Cable Length.

        (1)  EIA-449 Compliance.  Interconnecting cable length and its   
relation to data signaling rates is in accordance with EIA Standard 449, 
section 6.10, and EIA Standard 422-A, section 4.3 and the appendix.

        (2)  Maximum Cable Length.  The maximum cable length between the   
remote modem and the host including the intervening FPA is 1000 feet;   
however, cable lengths less than 200 feet are preferred.

    d.  Interchange Circuits.

        (1)  C/30E Local Modem Interface.

             (a)  Signal flow between the C/30E and the local modem is     
shown in figure 2-3.  This interface and associated hardware are        
provided by DDN.  The signal flow is the same when a KG-84A is used.       
This interface uses EIA-449 pin assignments.
DCAC-350-180-( )                                                     2-5


             (b)  As shown in figure 2-3, the supported signals are        
Send Data (SD), Send Timing (ST), Receive Data (RD), Receive Timing (RT),  
and Terminal Ready (TR).  Clear to Send (CS), Data Mode (DM), and       
Receiver Ready (RR) are tied ON by the cable connected to the fantail.    
Remote Loopback (RL) and Local Loopback (LL) are to be used for those  
functions and they are connected at the DCE interface.   Terminal Timing   
(TT) is not supported from the PSN.

             (c)  Two special DDN-specific loopback signals, CL and DL,    
are provided as shown in figure 2-3.  The Signaling Rate Selector (SR)    
signal is used by the PSN to loop the local KG-84A and is designated as    
"C" loop or CL (standing for COMSEC Loopback) in figure 2-3 after it      
leaves the C/30E fantail.  SR is not connected to the DCE interface.  The 
Request To Send (RS) signal is reserved for future use within the FPA     
KG-84A and  is designated as "D" loop or DL.  RS is not connected at the   
DCE interface.  The Terminal Ready (TR) signal from the PSN provides 
both    the Terminal Ready and Request to Send (RS) to the DCE.

        (2)  Host-Remote Modem Interface.  The cable functional signal    
flow between the remote modem and the DTE host is also shown in figure     
2-3.  The signal flow is the same as that described in 1.d.1, above.      
The KGAB uses MS connectors with the pinout shown in figure 2-3 and       
tables 2-2 and 2-3.  Figure 2-3 shows DDN standard cables.  Figure 2-2     
is provided as an example of one way to connect to a remote host.  If      
DDN standard cables are not used, only the signals shown as mandatory      
in table 2-2 are required.  The optional signals are used by the PSN end   
of the circuit.
DCAC-350-180-( )                                                     2-6


3.  Mechanical Characteristics.  All EIA-449/422 connectors offered for    
the C/30E meet the specifications provided in this section.

    a.  Interface Connectors.  DDN MIL-STD-188-114 DCE connectors are     
DC-37S type (female) connectors.  The DDN FPA uses an MS connector on      
the KGAB counter assemblies.

    b.  Connector Contact Assignments.

        (1)  C/30E Connectors.  All DDN EIA-449/422 contact assignments    
are in accordance with EIA-449, section 3.4.  In chapter 1, table 1-5   
provides the standard DTE pinouts and section 2.d.3 provides circuit 
descriptions.

        (2)  KGAB Connectors.  KGAB connectors to the remote host and the 
remote modem are shown in tables 2-2 and 2-3, respectively.
DCAC-350-180-( )                                                     2-7



 PSN/                  Patch                                        Patch                DCE
 Host        Cable #   Panel   Cable #         KGAB       Cable #   Panel   Cable #       
             6847              6817                       6812              7835         
                       Pin #                                        Pin #                 
 +--+ Pin #  +-----+  +-----+ +-----+   Pin #  +--+  Pin #  +----+ +-----+ +----+  Pin # +--+
 |  |  +/-   |     |  | +/- | |     |    +/-   |  |   +/-   |    | | +/- | |    |   +/-  |  |
 |SD|  4/22 --------->| 2/14|---(1)---> 24/25  |SD|  2/3  -------->| 2/14|--------> 4/22 |SD|
 |  |                 |     |                  |  |                |     |               |  |
 |ST|  5/23 --------->|15/16|<--(2)----  4/5   |ST|  4/5  <--------|15/16|<-------- 5/23 |ST|
 |  |                 |     |                  |  |                |     |               |  |
 |RD|  6/24 --------->| 3/19|<--(3)----  6/7   |RD|  6/7  <--------| 3/19|<-------- 6/24 |RD|
 |  |                 |     |                  |  |                |     |               |  |
 |RT|  8/26 --------->|17/18|<--(4)----  8/9   |RT|  8/9  <--------|17/18|<-------- 8/26 |RT|
 |  |                 |     |                  |  |                |     |               |  |
 |TR| 12/30 --------->|20/10|---(5)---> 10/11  |TR| 10/11  ------->|20/10|----+--->12/30 |TR|
 |  |                 |     |                  |  |                |     |    |          |  |
 |  |                 |     |                  |  |                |     |    +---> 7/25 |RS|
 |  |                 |     |                  |  |                |     |               |  |
 |  |       NC<-------| 5/6 |<--(6)---- 14/15  |CS| 12/13  <-------| 5/6 |<-------- 9/27 |CS|
 |  |                 |     |                  |  |                |     |               |  |
 |SG| 19/37 ------+---| 7/8 |---(7)---> 12/13  |SG| 14/15  --------| 7/8 |--------- 19/37|SG|
 |  |             |   |     |                  |  |                |     |               |  |
 |SR| 16/37 ------|-->|12/13|---(8)---> 16/17  |CL| 16/17  ------->|12/13|------> NC     |  |
 |  |             |   |     |                  |  |                |     |               |  |
 |RL| 14/37 ------|-->|11/21|---(9)---> 18/19  |RL| 18/19  ------->|11/21|-------->14/37 |RL|
 |  |             |   |     |                  |  |                |     |               |  |
 |RS|  7/37 ------|-->| 4/9 |---(10)--> 20/21  |DL| 20/21  ------->| 4/9 |------> NC     |  |
 |  |             |   |     |                  |  |                |     |               |  |
 |LL| 10/37 ------|-->|22/25|---(11)--> 22/23  |LL| 22/23  ------->|22/25|-------->10/37 |LL|
 |  |             |   |     |                  |  |                |     |               |  |
 |ON| 28/32 --->+ +-->|24/23|---(12)-->  2/3   |TT| 24/25  ------->|24/23|-------->17/35 |TT|
 |CS|  9/27 <---|     +-----+                  +--+                +-----+               |  |
 |DM| 11/29 <---|                                                                        |  |
 |RR| 13/31 <---|                                                                        |  |
 +--+                                                                                    +--+

    Notes:  1.  Pin numbers are the same on both sides of Patch Panel.
            2.  Encircled numbers are the cable pair numbers.

      FIGURE 2-3.  FUNCTIONAL SIGNAL FLOW BETWEEN A NEARBY MODEM AND
                   C/30E OR A KGAB AND A REMOTE HOST

DCAC-350-180-( )                                                     2-8


          TABLE 2-1.  REMOTE-MODEM DTE INTERFACE CONNECTOR PINOUT

                                                                           

        Pin     EIA     CCITT     Name                    
                ID      ID                           

Mandatory

        1       FG                 Frame Ground      
        4       SD +    103        Send Data         
        22      SD -    103        Send Data         
        5       ST +    114        Send Timing       
        23      ST -    114        Send Timing       
        6       RD +    104        Receive Data      
        24      RD -    104        Receive Data      
        7       RS +    105        Request to Send        
        25      RS -    105        Request to Send
        8       RT +    115        Receive Timing         
        26      RT -    115        Receive Timing
        9       CS +    106        Clear to Send
        27      CS -    106        Clear to Send
        12      TR +    108.2      Terminal Ready         
        30      TR -    108.2      Terminal Ready
        17      TT +    113        Terminal Timing        
        35      TT -    113        Terminal Timing
        19      SG      102        Signal Ground          
        37      SC      102a       Send Common

Optional

        2       SI      112        Signaling Rate Indicator
        10      LL      141        Local Loopback
        11      DM +    107        Data Mode
        13      RR      109        Receiver Ready
        14      RL      140        Remote Loopback
        15      IC      125        Incoming Call
        16      SF/SR   126/111    Select Frequency/Signaling Rate Selector 
        18      TM      142        Test Mode
        20      RC      102b       Receive Common
        28      IS      ---        Terminal In Service
        29      DM -    107        Data Mode
        31      RR -    109        Receiver Ready
        32      SS      116        Select Standby
        33      SQ      110        Signal Quality
        34      NS      ---        New Signal
        36      SB      117        Standby Indicator
                                                                 
                                                                           

DCAC-350-180-( )                                                     2-9


              TABLE 2-2.  KGAB - REMOTE HOST CONNECTOR PINOUT
                                                                 
                                                                           

        Pin     EIA     CCITT      Name
                ID      ID            

Mandatory

        1       FG                    Frame Ground           
        24      SD +    103           Send Data              
        25      SD -    103           Send Data
        4       ST +    114           Send Timing
        5       ST -    114           Send Timing
        6       RD +    104           Receive Data           
        7       RD -    104           Receive Data
        8       RT +    115           Receive Timing         
        9       RT -    115           Receive Timing
        10      TR +    108.2         Terminal Ready         
        11      TR -    108.2         Terminal Ready
        12      SG      102           Signal Ground          
        13      SC      102a          Send Common            
        19      SS      116           Select Standby

Optional

        14      CS +    106           Clear to Send
        15      CS -    106           Clear to Send
        22      LL      141           Local Loopback
        20      DL +    105           "D" Loop (Reserved)    
        21      DL -    105           "D" Loop (Reserved)
        18      RL      140           Remote Loopback
        2       TT +    113           Terminal Timing        
        3       TT -    113           Terminal Timing
        16      CL +    126           "C" Loop (KG-84A Loop)
        17      CL -    126           "C" Loop (KG-84A Loop)
                                                                 
                                                                           


DCAC-350-180-( )                                                     2-10


              TABLE 2-3  KGAB - REMOTE MODEM CONNECTOR PINOUT

                                                                           

        Pin     EIA     CCITT     Name
                ID      ID         

Mandatory


        1       FG                 Frame Ground
        2       SD +    103        Send Data
        3       SD -    103        Send Data
        4       ST +    114        Send Timing
        5       ST -    114        Send Timing
        6       RD +    104        Receive Data
        7       RD -    104        Receive Data
        8       RT +    115        Receive Timing
        9       RT -    115        Receive Timing
        10      TR +    108.2      Terminal Ready
        11      TR -    108.2      Terminal Ready
        14      SG      102        Signal Ground
        15      SG      102        Signal Ground
        24      TT +    113        Terminal Timing
        25      TT -    113        Terminal Timing

Optional

        12      CS +    106        Clear To Send
        13      CS -    106        Clear To Send
        16      CL      ---        "C" Loop (KG-84A Loop)
        17      CL -    ---        "C" Loop (KG-84A Loop)
        18      RL +    140        Remote Loopback
        19      RL -    140        Remote Loopback
        20      DL +    ---        "D" Loop (Reserved)
        21      DL -    ---        "D" Loop (Reserved)
        22      LL +    141        Local Loopback
        23      LL -    141        Local Loopback
                                                                 
                                                                           
DCAC-350-180-( )                                                     2-11


4.  Interconnecting Cables.  Figures 2-4 and 2-5 provide a cabling       
diagram of a configuration with a C/30E, modems, and FPAs.  Table 2-4  
describes the cables used for interconnecting these devices.  See        
chapter 1, section 4, for specifications on interconnecting cables.


                     TABLE 2-4. REMOTE INTERFACE CABLES
                                  
                                                                           

Connection         BBNCC           Description
                   P/N#

PSN/Host to DPPE   2406847GO1      12-pr, PSN/MSYNC 188-114
                                    Bal Host to DB25P

DPPE to KGAB       2406817GO1      12-pr, DB25S to FPA-J1

KGAB to DPPC       2406812GO1      12-pr, FPA-J2 to DB25P

DPPC to DCE        2407835GO1      12-pr, DB25S to 188-114 DCE
                                  
                                                                           
DCAC-350-180-( )                                                     2-12



   +------------------------------------------------------------------------+
   |                                                                        |
   |                                                                        |
   |                                                                        |
   |         Cable # +-+ Cable #                 Cable # +-+  Cable #       |
   | +-----+2406847- | |2407835-                 2407835-| | 240687-        |
   | |C/30E|   G01   |D|  G01   +-----+   +-----+  G01   |D|   G01   +----+ |
   | | PSN |---------|P|--------| DCE |---| DCE |--------|P|---------|DTE | |
   | |(DTE)|         |P|        +-----+   +-----+        |P|         |HOST| |
   | +-----+         |E|                                 |E|         +----+ |
   |                 +-+                                 +-+                |
   |                                                                        |
   |                                                                        |
   |                                                                        |
   |                                                                        |
   +------------------------------------------------------------------------+

               FIGURE 2-4.  C/30E AND REMOTE HOST CABLING DIAGRAM




   +------------------------------------------------------------------------+
   |                                                                        |
   | +-----+                                                        +-----+ |
   | |C/30E|                                                        | DTE | |
   | | PSN |                                                        | HOST| |
   | |(DTE)|                                                        |     | |
   | +--+--+                                                        +--+--+ |
   |    | Cable #                                              Cable # |    |
   |    | 2406847G01                                        2406847G01 |    |
   | +--+--+                                                        +--+--+ |
   | | DPPE|                                                        | DPPE| |
   | +--+--+                                                        +--+--+ |
   |    | Cable #                                              Cable # |    |
   |    | 2406817G01                                        2406817G01 |    |
   |    |                                                              |    |
   |    |   Cable #      Cable #                 Cable #     Cable #   |    |
   | +--+--+2406812-+-+ 2407835-                2407835- +-+2406812-+--+--+ |
   | |     |  G01   |D|   G01  +-----+    +-----+  G01   |D|  G01   |     | |
   | | KGAB|--------|P|--------| DCE |----| DCE |--------|P|--------| KGAB| |
   | |     |        |P|        +-----+    +-----+        |P|        |     | |
   | +-----+        |C|                                  |C|        +-----+ |
   |                +-+                                  +-+                |
   |                                                                        |
   |                                                                        |
   +------------------------------------------------------------------------+

               FIGURE 2-5.  C/30E AND REMOTE HOST CABLING DIAGRAM
                            (WITH CRYPTOGRAPHIC DEVICES)

DCAC-350-180-( )                                                 3-1

                    CHAPTER 3.  EIA-232-D HOST INTERFACE

1.  Overview.  This chapter describes the electrical and mechanical 
characteristics of the obsolete DDN EIA-232-D connection at the neighbor  
or nearby host.  For ease of reference, table 3-1 equates the EIA-232-D, 
EIA-449, and CCITT interface signal names.  However, in the rest of this 
chapter, only the EIA-232-D signal name will be used.  DDN uses the    
EIA-232-D interface only where an existing non-DDN standard PSN provides   
such an interface, and it is not feasible to install a MIL-STD-188-114  
balanced interface prior to upgrading the entire node to DDN standard 
(MIL-STD-188-114 balanced serial host interfaces).

2.  Electrical Characteristics.

    a.  Voltage Levels.  The electrical measurements of the C/30E      
EIA-232-D interface circuits are in accordance with EIA Standard 232-D,  
section 2.1.  For normal operation, the open circuit driver voltage shall  
be no more than +15 V.

    b.  Clocking.

        (1)  Supported Clock Rates.  The FD4 fantail contains the     
connectors that terminate cables from all I/O interfaces.  The FD4 
DCAC-350-180-( )                                                 3-2

fantail contains four EIA-232-D connectors configured as DTEs.  This   
interface has clock-sourcing capability allowing either the DTE or DCE     
to provide the clock.  The hardware can support external clock rates     
between 1.2 kb/s and 112 kb/s.  However, DDN policy is 9.6 kb/s for the  
minimum PSN host bit rate, and 19.2 kb/s for the maximum rate.

        (2)  Signaling Sense.  Signaling sense is in accordance with EIA 
Standard 232-D, subsection 2.1.3.  The signal is considered marking (OFF)  
when the voltage on the interchange circuit is more negative than -3 V     
with respect to signal ground, and spacing (ON) when the voltage is more 
positive than +3 V with respect to signal ground.

    c.  Bit Rate and Cable Length.  Interconnecting cable length is in 
accordance with EIA-232-D, section 3.1.  The recommended maximum cable    
length between an EIA-232-D DCE and DTE is 200 feet when overall       
shielded, low capacitance, twisted pair cable is used.

    d.  Interchange Circuits.

        (1)  Electrical Use of Interchange Circuits.  The DDN electrical   
use of interchange circuits is either static or active.  Static circuits   
are tied by the hardware so that the signal state remains constant on the  
line, either ON or OFF.  Active circuits change their state under program 
control.  DDN use of the interchange circuits is shown in table 3-2.

DCAC-350-180-( )                                                 3-3

                 TABLE 3-1.  SIGNAL NAME EQUIVALENCY TABLE

                                                                          


     EIA-232-D                                      EIA-449                        CCITT
     ID     Name                                    ID     Name                    ID     Name
             
     AB     Signal Ground                           SG     Signal Ground           102    Signal Ground
     CE     Ring Indicator                          IC     Incoming Call           125    Calling Indicator
     CD     DTE Ready                               TR     Terminal Ready          108/2  Data Terminal Ready
     CC     DCE Ready                               DM     Data Mode               107    Data Set Ready
     BA     Transmitted Data                        SD     Send Data               103    Transmitted Data
     BB     Received Data                           RD     Receive Data            104    Received Data
     DA     Transmitter Signal Element Timing       TT     Terminal Timing         113    Transmitter Signal Element
             (DTE Source)                                                                  Timing (DTE Source)
     DB     Transmitter Signal Element Timing       ST     Send Timing             114    Transmitter Signal Element
             (DCE Source)                                                                  Timing (DCE Source)
     DD     Receiver Signal Element Timing          RT     Receive Timing          115    Receiver Signal Element
             (DCE Source)                                                                  Timing (DCE Source)
     CA     Request To Send                         RS     Request To Send         105    Request To Send
     CB     Clear To Send                           CS     Clear To Send           106    Ready For Sending
     CF     Received Line Signal Detector           RR     Receiver Ready          109    Data Channel Received Line
                                                                                           Signal Detector
     CG     Signal Quality Detector                 SQ     Signal Quality          110    Data Signal Quality
                                                                                           Detector
     CH     Data Signal Rate Selector               SR     Signaling Rate Selector 111    Data Signaling Rate
             (DTE Source)                                                                  Selector (DTE Source)
     CI     Data Signal Rate Selector               SI     Signaling Rate          112    Data Signaling Rate
             (DCE Source)                                   Indicator                      Selector (DCE Source)
     LL     Local Loopback                          LL     Local Loopback          141    Local Loopback
     RL     Remote Loopback                         RL     Remote Loopback         140    Remote Loopback
     TM     Test Mode                               TM     Test Mode               142    Test Indicator
    

                                                                          
DCAC-350-180-( )                                                 3-4

        (2)  Software Use of Interchange Circuits.  Interchange circuit  
signals are used by the software in different ways.  Active circuits are   
under program control: either the software reacts to the circuit signal    
when it changes, or the software can assert a circuit when necessary       
(such as LL which can be used by operations personnel for testing 
connections).  Unsupported circuits either are not read by the software    
or a value is written to the circuit by the software, and that value does  
not change during operation.  Table 3-2 provides a list of circuits and    
their use.

        (3)  Interchange Circuit Definitions.

             (a)  Signal Ground.  See EIA Standard 232-D.

             (b)  Ring Indicator.  RI is reported to the Monitoring      
Center; however, its value has no software effect.

             (c)  DCE Ready.  This circuit must be asserted ON by the      
DCE, and it is monitored by the PSN software.

             (d)  DTE Ready.  This circuit is asserted ON by PSN 
software   when the link is initialized.

             (e)  Transmitted Data.  See EIA Standard 232-D.

             (f)  Received Data.  See EIA Standard 232-D.
DCAC-350-180-( )                                                 3-5

             (g)  Transmitter Signal Element Timing (DTE Source).  See EIA 
Standard 232-D.  Also see subsection 2.b of this guide.  This circuit 
provides the clock for Transmitted Data when the PSN sources timing.  The 
frequency of this circuit should be equal to that of DTE-Sourced Receiver 
Signal Element Timing.

             (h)  Transmitter Signal Element Timing (DCE Source).  See EIA 
Standard 232-D.  This circuit provides the clock for Transmitted Data when 
the clock for Transmitted Data when the DCE sources timing.

             (i)  Receiver Signal Element Timing (DTE Source).  This 
circuit provides the clock for Received Data when the PSN sources timing.  
The frequency of this circuit should be equal to that of DTE-Sourced 
Transmitter Signal Element Timing.

             (j)  Receiver Signal Element Timing (DCE Source).  See EIA 
Standard 232-D.  This circuit provides clock for Received Data when the 
DCE sources timing.

             (k)  Request to Send.  This circuit is asserted ON by PSN 
software when the link is initialized.

             (l)  Clear to Send.  CS must be asserted ON by the DCE 
because it is monitored to determine line status.  If the signal state on 
this line changes to OFF, the software macrocode will stop data 
transmission.
DCAC-350-180-( )                                                 3-6

             (m)  Received Line Signal Detector.  This circuit must be 
asserted ON by the DCE because it is monitored to determine line status.  
If the signal state on this line changes to OFF, the software macrocode 
will stop receiving data.

             (n)  Signal Quality Detector.  This circuit is reported to 
the Monitoring Center; however, its value has no software effect.

             (o)  Data Signal Rate Selector (DTE Source).  This circuit is 
asserted OFF by the PSN software when the link is initialized.

             (p)  Data Signal Rate Selector (DCE Source).  This circuit is 
electrically active; however, its value has no software effect.

             (q)  Local Loopback.  LL is electrically active, but asserted 
OFF by PSN software when the link is initialized.  LL can be controlled by 
the Monitoring Center.

             (r)  Remote Loopback.  RL is electrically active, but 
asserted OFF by PSN software when the link is initialized.  This circuit 
is available for Monitoring Center control.

             (s)  Test Mode.  TM is reported to the Monitoring Center; 
however, its value has no software effect.

DCAC-350-180-( )                                                 3-7

               TABLE 3-2. EIA-232-D INTERCHANGE CIRCUIT USE

                                                                          


232                                               Electrical       Required State of             Comments
ID     EIA-232-D Name             Source          State         Control/Status Signals

AB     Signal Ground              DTE/DCE         Ground                 N/A*          
BA     Transmitted Data           DTE             Active                 N/A           Data Circuit
BB     Received Data              DCE             Active                 N/A           Data Circuit
CA     Request to Send            DTE             Active                 ON            Asserted ON by PSN software.
CB     Clear to Send              DCE             Active                 ON            Asserted ON by DCE, and
                                                                                       monitored by PSN software to 
                                                                                       determine line status.
CD     DTE Ready                  DTE             Active                 ON            Asserted ON by PSN software.
CF     Received Line Signal       DCE             Active                 ON            Asserted ON by DCE, and
        Detector                                                                       monitored by PSN software to
                                                                                       determine line status.
CG     Signal Quality             DCE             Active                 Don't Care    Monitored by PSN software, but
        Detector                                                                       no action is taken.
CH     Data Signal Rate           DTE             Active                 OFF           Asserted OFF by PSN software.
       Selector
CI     Data Signal Rate           DCE             Active                 Don't Care    Not monitored by PSN software.
        Selector                                                                       
DA     Transmitter Signal         DTE             Active                 N/A           Timing circuit for Transmitted
        Element Timing                                                                 Data when the PSN supplies
                                                                                       timing.
DB     Transmitter Signal         DCE             Active                 N/A           Timing circuit for Transmitted
        Element Timing                                                                 Data when the DCE supplies
                                                                                       timing.
DC**   Receive Signal             DTE             Active                 N/A           Timing circuit used for
        Element Timing                                                                 Received Data when the PSN
                                                                                       supplies timing.
DD     Receive Signal             DCE             Active                 N/A           Timing circuit used for
        Element Timing                                                                 Received Data when the DCE
                                                                                       supplies timing.
CE     Ring Indicator             DCE             Active                 Don't Care    Monitored by PSN software, but
                                                                                       no action is taken.
LL     Local Loopback             DTE             Active                 OFF           Initialized to OFF by
                                                                                       software.  Available for
                                                                                       Monitoring Center control.
RL     Remote Loopback            DTE             Active                 OFF           Initialized to OFF by
                                                                                       software.  Available for
                                                                                       Monitoring Center control.
TM     Test Mode                  DCE             Active                 Don't Care    Monitored by PSN software, but
                                                                                       no action is taken.


                                                                          

* N/A = Not Applicable
** The circuit name "DC" is from an earlier version of EIA-232.
DCAC-350-180-( )                                                 3-8

3.  Mechanical Characteristics.  All EIA-232-D connectors on the C/30E 
meet the specifications provided in this section.

    a.  Interface Connectors.    All C/30E fantail MSYNC EIA-232-D 
connectors are DB-25P type (male) connectors.  Intermating dimensions are 
in accordance with EIA-232-D, section 3.2.1.

    b.  Connector Contact Assignments.  DDN standard node EIA-232-D 
connector contact assignments are in accordance with EIA-232-D, section 
3.3.1.  Table 3-3 provides DDN EIA-232-D connector pin assignments.  
Signal use is specified in section 2.d.3.

DCAC-350-180-( )                                                 3-9

                   TABLE 3-3.  EIA-232-D CONNECTOR PINOUT
                                                                 
                                                                          

Pin     EIA     CCITT         Name
        ID      ID            

1       --      --            Shield
2       BA      103           Transmitted Data
3       BB      104           Received Data
4       CA      105           Request To Send
5       CB      106           Clear To Send
6       CC      107           DCE Ready
7       AB      102           Signal Ground (Common Return)
8       CF      109           Received Line Signal Detector
11      --      126           Select Transmit Frequency
15      DB      114           Transmitted Signal Element Timing
                               (DCE Source)
17      DD      115           Receiver Signal Element Timing
                               (DCE Source)
18      LL      141           Local Loopback
19      DC*     ---           Receiver Signal Element Timing
                               (DTE Source)
20      CD      108/2         DTE Ready
21      CG      110           Signal Quality Detector
22      CE      125           Ring Indicator
23      CH/CI   111/112       Data Rate Selector
24      DA      113           Transmit Signal Element Timing
                               (DTE Source)
25      --      142           Test Indicator

                                                                          

* The circuit name "DC" is from an earlier version of EIA-232.

DCAC-350-180-( )                                                 3-10

4.  Interconnecting Cables.

    a.  For interconnecting cable specifications, see chapter 1, section 
4, of this guide.

    b.  Figure 3-1 is a cabling diagram of a C/30E PSN connected to a 
nearby EIA-232 host, and figure 3-2 is an example of an interconnecting 
cable (BBNCC P/N# 2409318G01).






     +---------------------------------------------------------------+
     |                                                               |
     |               DB-25S                    DB-25S                |
     |                 /                           \                 |
     | +----------+  /                               \  +----------+ |
     | | EIA-232  |--+            2409318G01         +--| EIA-232  | |
     | | DTE Host |P1|===============================|P2|  C/30E   | |
     | |          |--+                               +--|  (DTE)   | |
     | +----------+                                     +----------+ |
     |                                                               |
     |                                                               |
     |                                                               |
     |                                                               |
     +---------------------------------------------------------------+

      FIGURE 3-1.  C/30 PSN AND NEARBY EIA-232-D HOST CABLING DIAGRAM

DCAC-350-180-( )                                                 3-11


       +-----------------------------------------------------------+
       |     DTE Host                                    C/30E     |
       |        P1                                         P2      |
       |      DC-37S                                     DC-37S    |
       | Pin#     Signal                            Signal    Pin# |
       |  +/-       +/-   Shield             Shield   +/-      +/- |
       |  1         FG  >--------+         +-------<  FG       1   |
       |                                                           |
       |                 Pair #                                    |
       |  2/7       SD  >-(1)------\   /-----------<  SD       2/7 |
       |                             \                             |
       |  15/NC     ST  >-(2)---\  /   \ /---------<  TT      24/7 |
       |                         /     / \                         |
       |  3/NC      RD  >-(3)--/   \ /     \-------<  RD      3/NC |
       |                           / \                             |
       |  17/NC     RT  >-(4)----/     \-----------<  TRT     19/7 |
       |                                                           |
       |  4/7       RS  >-(5)-----------\   /------<  RS       4/7 |
       |                                  \                        |
       |  6/NC      DM  >-(6)--+--------/   \--+---<  DM      6/NC |
       |                       |               |                   |
       |  5/NC      CS  >------+               +---<  CS      5/NC |
       |                       |               |                   |
       |  8/NC      RR  >------+               +---<  RR      8/NC |
       |                                                           |
       |  7/7       SG  >-(7)-+--------------------<  SG       7/7 |
       |                      |                                    |
       |                      +--(8)----No Connection (NC)         |
       |                      |                                    |
       |                      +--(9)----NC                         |
       |                      |                                    |
       |                      +--(10)---NC                         |
       |                      |                                    |
       |                      +--(11)---NC                         |
       |                      |                                    |
       |                      +--(12)---NC                         |
       |                      |                                    |
       |                      +--(sp)---NC                         |
       |                                                           |
       +-----------------------------------------------------------+
     
       FIGURE 3-2.  CABLE EXAMPLE: C/30E PSN TO NEARBY EIA-232-D HOST

 DCAC-350-180-( )                                                     4-1

                      CHAPTER 4.  V.35 HOST INTERFACE

1.  Overview.  This chapter describes the electrical and mechanical 
characteristics of the obsolete DDN V.35 connection at the neighbor or 
nearby host.  All control signals have electrical characteristics of 
EIA-232-D, and EIA-232-D signal names are used in the rest of this 
chapter.  The data and timing signals conform to Recommendation V.35.  
Like the EIA-232 interface, the V.35 interface is used only where an 
existing non-DDN-standard PSN provides such an interface, and it is not 
feasible to install a MIL-STD-188-114 balanced interface prior to 
upgrading the entire node to DDN-standard (MIL-STD-188-114 balanced serial 
host interfaces).

2.  Electrical Characteristics.

    a.  Voltage Levels.  The electrical measurements of the C/30E V.35 
interface circuits are in accordance with CCITT Recommendation V.35.
    
    b.  Clocking.  The FD4 fantail contains the connectors that terminate 
the cables from all I/O interfaces.  The FD4 fantail contains four V.35 
connectors configured as DTEs.  This interface has clock-sourcing 
capability allowing either the DCE or C/30E to provide 
DCAC-350-180-( )                                                     4-2

the clock.  The hardware can support external clock rates between 300 b/s 
and 100 kb/s.  Three internal clocks are provided at the following rates:  
76.8 kb/s, 57.6 kb/s, 9.6 kb/s.

        (1)  Signaling Sense.   Signaling sense is in accordance with 
CCITT Recommendation V.35.  A binary "0"  (space) is transmitted when 
terminal "A" is positive (+.55v +20%) to terminal "B" (-.55V +20%).  A 
binary 1 is transmitted when terminal "A" is negative (-.55v +20%) to 
terminal "B" (+.55v +20%).  The drivers produce a nominal 1.1 volts 
peak-to-peak signal balanced with respect to ground.

    c.  Bit Rate/Cable Length.

        (1)  Maximum Cable Length.  The recommended maximum cable length 
between a V.35 DCE and DTE is 30 feet when overall shielded, low 
capacitance, twisted pair cable is used.  Cable lengths of 100 feet are 
also possible.

    d.  Interchange  Circuits.

        (1)  Electrical Use of Interchange Circuits.  The DDN electrical 
use of interchange circuits is either static or active.  Static circuits 
are tied by the hardware so that the signal state remains constant on the 
line, either ON or OFF.  Active circuits change their state under program 
control.  DDN use of the interchange circuits is shown in table 4-1.

DCAC-350-180-( )                                                     4-3

         (2)  Software Use of Interchange Circuits.  Interchange circuit 
signals are used by the software in different ways.  Active circuits are 
under program control: either the software reacts to the circuit signal 
when it changes, or the software can assert a circuit when necessary (such 
as LL which can be used byoperations personnel for testing connections).  
Unsupported circuits either are not read by the software or a value is 
written to the circuit by the software, and that value does not change 
during operation.  Table 4-1 describes circuit use.

          (3)  Interchange Circuit Definitions.  EIA-232-D signal names 
are used throughout this chapter.

               (a)  Signal Ground.  See EIA-232-D.

               (b)  DCE Ready.  This circuit must be asserted ON by the 
DCE, and it is monitored by the PSN software.

               (c)  Data Set Ready.  This circuit must be asserted on by 
the DCE, and it is monitored by the PSN.

               (d)  Transmitted Data.  See EIA-232-D.

               (e)  Received Data.  See EIA-232-D.

               (f)  Transmitter Signal Element Timing (DTE Source).  See 
EIA-232-D.  Also see subsection 2.b of this guide.  This circuit 
DCAC-350-180-( )                                                     4-4

provides the clock for Transmitted Data when the PSN sources timing.  The 
frequency of this circuit should be equal to that of Terminal Receive 
Timing.

               (g)  Transmitter Signal Element Timing (DCE Source).  See 
EIA-232-D.  This circuit provides the clock for Transmitted Data when the 
DCE sources timing.

               (h)  Receiver Signal Element Timing (DCE Source).  See 
EIA-232-D.  This circuit provides clock for Received Data when the DCE 
sources timing.

               (i)  Request to Send.  This circuit is asserted ON by PSN 
software when the link is initialized.

               (j)  Clear to Send.  This circuit must be asserted ON by 
the DCE and is monitored by PSN software to determine line status.  If the 
signal state on this line changes to OFF, the software macrocode will stop 
data transmission.

               (k)  Received Line Signal Detector.  This circuit must be 
asserted ON by the DCE, and is monitored by PSN software to determine line 
status.  If the signal state on this line changes to OFF, the software 
macrocode will stop receiving data.

               (l)  Terminal Receive Timing.  This circuit is received by 
another DTE via a crossover cable when the C/30E sources 
DCAC-350-180-( )                                                     4-5

timing, providing clock for Received Data.  The frequency of this circuit 
should be equal to that of DTE-Sourced Transmitter Signal Element Timing.  
This circuit is equivalent to DC in older versions of EIA-232, as 
referenced in chapter 3.
DCAC-350-180-( )                                                     4-6

                   TABLE 4-1. V.35 INTERCHANGE CIRCUIT USE

                                                                           


CCITT                                Electrical      Required State of     Comments
ID    Name                Source       State      Control/Status Signals

101   Protective Ground   DTE/DCE    Ground          N/A                   
102   Signal Ground       DCE/DTE    Ground          N/A
103   Transmitted Data    DTE        Active          N/A                   Data Circuit
104   Received Data       DCE        Active          N/A                   Data Circuit
105   Request to Send     DTE        Active          ON                    Asserted ON by PSN software.
106   Clear to Send       DCE        Active          ON                    Asserted ON by DCE and
                                                                            monitored by PSN software to
                                                                            determine line status.
107   Data Set Ready      DCE        Active          ON                    Asserted ON by DCE, and
                                                                            monitored by PSN software.
109   Received Line       DCE        Active          ON                    Asserted ON by DCE, and
      Signal Detector                                                      monitored by PSN software to
                                                                            determine line status.
113   Transmitter Signal  DTE        Active          N/A                   Timing circuit for Transmitted
      Element Timing                                                       Data when the PSN supplies
                                                                            timing.
---   Terminal Receive    DTE        Active          N/A                   Timing circuit for Received
      Timing                                                                Data when the PSN supplies
                                                                            timing.
114   Transmitter Signal  DCE        Active          N/A                   Timing circuit for Transmitted
      Element Timing                                                       Data when the DCE supplies
                                                                            timing.
115   Receiver Signal     DCE        Active          N/A                   Timing circuit for Received
      Element Timing                                                       Data when the DCE supplies
                                                                            timing.

                                                                          

NOTES:  N/A = Not Applicable


DCAC-350-180-( )                                                     4-7

3.  Mechanical Characteristics.  All V.35 connectors offered for the C/30E 
meet the specifications provided in this section.  Cables for this 
interface, supplied by DDN, are equipped with an EIA-449 connector at one 
end to mate with the EIA-449 connector on the C/30E fantail; the other end 
provides a MIL-C-28748 34-pin connector to mate with the V.35 DCE.

    a.  Interface Connectors.  All V.35 connectors on the C/30E fantail 
are DC-37P type (male) connectors.  They are wired as described in table 
4-2.

        (1)  Intermating dimensions are in accordance with EIA-449-D.

        (2)  The means for C/30E DTE connectors to latch and unlatch from 
the latching blocks on the DCE connector are within the dimensions 
specified in EIA-449, section 3.3.1.  DDN uses the English 4-40 thread 
latching block.

    b.  Connector Contact Assignments.  DDN standard node V.35 connector 
contact assignments are in accordance with CCITT Recommendation V.35 and 
ISO 2593.  Table 4-2 provides DDN V.35 connector pin assignments.  The 
signals are used as specified in section 2.d.3.

DCAC-350-180-( )                                                     4-8

            TABLE 4-2.  V.35 34-PIN AND 37-PIN CONNECTOR PINOUT

                                                                          

34-pin   37-pin* CCITT      Signal Name                    449
 #        #      ID                                        Name

A        1       101        Shield                         FG
P        4       103        Transmitted Data               SD+
S        22      103        Transmitted Data               SD- **
Y        5       114        Transmitter Signal Element     ST+
                             Timing (DCE Source)
a/AA     23      114        Transmitter Signal Element     ST-
                             Timing (DCE Source)
R        6       104        Received Data                  RD+
T        24      104        Received Data                  RD-
C        7       105        Request to Send                RS+
-        25      102        Signal Ground                  SG
V        8       115        Receiver Signal Element Timing RT+
                             (DCE Source)
X        26      115        Receiver Signal Element Timing RT-
                             (DCE Source)
D        9       106        Clear to Send +                CS+
-        27      102        Signal Ground                  SG
K        10      141        Local Test Loopback            LL (LT)
E        11      107        Data Set Ready +               DM+
-        29      102        Signal Ground                  SG-
-        31      102        Signal Ground                  SG-
F        13      109        Received Line Signal Detector  RR
U        17      ---        Terminal Timing                TT+ ***
W        35      ---        Terminal Timing                TT- ***
L        16      ---        Terminal Receive Timing        TRT+ ***
N        34      ---        Terminal Receive Timing        TRT- ***
B        19      102        Signal Ground                  SG
B        37      102        Signal Ground                  SG
                                                                   
                                                                          

* This information represents a straight cable to a V.35 DCE.
** The + and - symbols, used in EIA-449, correspond to A and B,
   respectively, in V.35 terminology.
*** Internally generated clocks are supplied on pins TT and TRT.

DCAC-350-180-( )                                                     4-9

4.  Interconnecting Cables.

    a.  For interconnecting cable specifications, see chapter 1, section 
4, of this guide.

    b.  Figure 4-1 is a cabling diagram of a V.35 PSN and nearby V.35 
host, and figure 4-2 provides an example of an interconnecting cable 
(BBNCC P/N# 2409320G01).



   +-------------------------------------------------------------------+
   |                                                                   |
   |              V.35S                             DC-37S             |
   |               /                                  \                |
   | +--------+  /                                      \  +---------+ |
   | |  V.35  |--+               2409320G01             +--|  V.35   | |
   | |  DTE   |P1|======================================|P2|  C/30E  | |
   | |  Host  |--+                                      +--|  (DTE)  | |
   | +--------+                                            +---------+ |
   |                                                                   |
   |                                                                   |
   |                                                                   |
   |                                                                   |
   +-------------------------------------------------------------------+

        FIGURE 4-1.  C/30E PSN AND NEARBY V.35 HOST CABLING DIAGRAM

DCAC-350-180-( )                                                     4-10


       +-----------------------------------------------------------+
       |     DTE Host                                    C/30E     |
       |        P1                                         P2      |
       |      V.35S                                      DC-37S    |
       | Pin#     Signal                            Signal    Pin# |
       |  +/-       +/-   Shield             Shield   +/-      +/- |
       |  A         FG  >--------+         +-------<  FG       1   |
       |                                                           |
       |                 Pair #                                    |
       |  P/S       SD  >-(1)------\   /-----------<  SD      4/22 |
       |                             \                             |
       |  Y/AA      ST  >-(2)---\  /   \ /---------<  TT     17/35 |
       |                         /     / \                         |
       |  R/T       RD  >-(3)--/   \ /     \-------<  RD      6/24 |
       |                           / \                             |
       |  V/X       RT  >-(4)----/     \-----------<  TRT    16/34 |
       |                                                           |
       |  C/NC      RS  >-(5)-----------\   /------<  RS      7/25 |
       |                                  \                        |
       |  E/NC      DM  >-(6)--+--------/   \--+---<  DM     11/29 |
       |                       |               |                   |
       |  D/NC      CS  >------+               +---<  CS      9/27 |
       |                       |               |                   |
       |  F/NC      RR  >------+               +---<  RR     13/31 |
       |                                                           |
       |  B/B       SG  >-(7)-+--------------------<  SG/SC  19/37 |
       |                      |                                    |
       |                      +--(8)----No Connection (NC)         |
       |                      |                                    |
       |                      +--(9)----NC                         |
       |                      |                                    |
       |                      +--(10)---NC                         |
       |                      |                                    |
       |                      +--(11)---NC                         |
       |                      |                                    |
       |                      +--(12)---NC                         |
       |                      |                                    |
       |                      +--(sp)---NC                         |
       |                                                           |
       +-----------------------------------------------------------+
    
         FIGURE 4-2.  CABLE EXAMPLE: C/30E PSN TO NEARBY V.35 HOST

DCAC-350-180-( )                                                     5-1

      CHAPTER 5.  MIL-STD-188-114  NEIGHBOR OR NEARBY TRUNK INTERFACE

1.  Overview.  This chapter describes the electrical and mechanical 
characteristics of the MIL-STD-188-114 balanced DTE interface that 
connects the C/30E PSN with a modem.  DDN supports Extended Modem  Looping 
(XMOD) through the MIL-STD-188-114 interface. This interface is largely in 
conformance with the EIA-Standard 449/422, considered the general 
commercial equivalent to MIL-STD-188-114.  For ease of reference, Table 
5-1 equates the EIA-449, EIA-232-D, and CCITT interface signal names.  
However, in the rest of chapters 5 and 6, only the EIA-449 signal names 
will be used.

2.  Electrical Characteristics.

    a.  Voltage Levels.  The electrical measurements of the C/30E 188-114 
interface circuits are in accordance with MIL-STD-188-114, chapter 5, 
except with regard to subsection 5.1.1.2: Open Circuit Measurement.  The 
C/30E open circuit driver voltage, measured in accordance with 5.1.1.2, is 
less than  +9.0V  for balanced drivers and +4.5V for unbalanced drivers.

DCAC-350-180-( )                                                     5-2

                 TABLE 5-1.  SIGNAL NAME EQUIVALENCY TABLE

                                                                          


EIA-449                             EIA-232-D                                 CCITT
ID    Name                          ID     Name                               ID      Name

SG    Signal Ground                 AB     Signal Ground                      102    Signal Ground
SC    Send Common                   --                                        102a   DTE Common
RC    Receive Common                --                                        102b   DCE Common
SD    Send Data                     BA     Transmitted Data                   103    Transmitted Data
RD    Receive Data                  BB     Received Data                      104    Received Data
RS    Request To Send               CA     Request To Send                    105    Request To Send
CS    Clear To Send                 CB     Clear To Send                      106    Ready For Sending
DM    Data Mode                     CC     Data Set Ready (DCE Ready)         107    Data Set Ready
TR    Terminal Ready                CD     Data Terminal Ready (DTE Ready)    108/2  Data Terminal Ready
RR    Receiver Ready                CF     Received Line Signal Detector      109    Data Channel Received Line
                                                                                      Signal Detector
IS    Terminal In Service           --                                        ---
SR    Signaling Rate Selector       CH     Data Signal Rate Selector          111    Data Signaling Rate
                                            (DTE Source)                              Selector (DTE Source)
SI    Signaling Rate                CI     Data Signal Rate Selector          112    Data Signaling Rate
       Indicator                            (DCE Source)                              Selector (DCE Source)
NS    New Signal                    --                                        ---
TT    Terminal Timing               DA     Transmitter Signal Element Timing  113    Transmitter Signal Element
                                            (DTE Source)                              Timing (DTE Source)
ST    Send Timing                   DB     Transmitter Signal Element Timing  114    Transmitter Signal Element
                                            (DCE Source)                              Timing (DCE Source)
RT    Receive Timing                DD     Receiver Signal Element Timing     115    Receiver Signal Element
                                                                                       Timing (DCE Source)
SS    Select Standby                --                                        116    Select Standby
SF    Select Frequency              --                                        126    Select Transmit Frequency
LL    Local Loopback                LL     Local Loopback                     141    Local Loopback
RL    Remote Loopback               RL     Remote  Loopback                   140    Remote Loopback


                                                                          
DCAC-350-180-( )                                                     5-3

    b.  Clocking.  Two fantails, MMB and MMBC, provide the EIA-449 
connectors that terminate cables from all I/O interfaces.  The MMB fantail 
connector is configured as a DTE.  When the MMB fantail is used, the DCE 
must provide clock because the MMB fantail does not support clock-sourcing 
capability.  TheMMBC, a clock-sourcing enhanced fantail, is configured as 
a DCE and can provide clock.

        (1)  MMBC Clock Rates.  MMBC and MMB interface hardware support 
any external clock between 1.2 kb/s and 112 kb/s.  However, DDN policy is 
that the minimum PSN bit rate be 9.6 kb/s.  When MMBC  clock-sourcing 
capability is used, the MMBC on-board clock generator provides the 
frequencies described in Table 5-2.


           TABLE 5-2.  FREQUENCIES PROVIDED BY THE MMBC FANTAIL

                                                                          

Clock Frequency                                Accuracy*

112kHz, 64kHz,                                 
56kHz, 50kHz                                   +0.005% (50 ppm**) 

                                                                          

*  Accuracy over a temperature range of 10 to 30 degrees C.
** PPM = Parts Per Million
DCAC-350-180-( )                                                     5-4

        (2)  Signaling Sense.  Signaling sense for balanced and unbalanced 
circuits is in accordance with EIA-422-A with the exception that the 
differential voltage applied to the interconnecting cable is in the range 
of 2 volts to 9 volts for the C/30E.  As defined in EIA-422-A, ON (0, 
Space, or +) is generated when A terminal is positive with respect to the 
B terminal,  and OFF (1,  MARK, or -) is generated when A terminal is 
negative with respect to the B terminal.

        (3)  On-Board Jumpers.  There are three jumper option pairs on the 
MMB:

    --1  Used for RS-422 mode (balanced Category I cirduits)
    --2  Used for RS-423 mode (unbalanced Category I circuits)
    --3  Used for normal (univerted) data operation
    --4  Used to invert transmit and receive data
    --5  Used for invert data in RS-423 mode
    --6  Used for RS-422 mode or normal data in RS-423 mode

Boards are shipped from the factory with steps 1, 3, 6 selected.

    c.  Bit Rate and Cable Length.  Interconnecting cable length and its 
relation to data signaling rates are in accordance with EIA Standard 449, 
section 6.10, and EIA Standard 422-A, section 4.3 and the appendix.

DCAC-350-180-( )                                                     5-5

        (1)  Maximum Cable Length.  The maximum length of the cable is 
1000 feet.

        (2)  Slew Rate Limiting.  Signal rise time is set to 1 microsecond 
(100 kb/s value).

    d.  Interchange Circuits.  There are two EIA-449 trunk interfaces: a 
non-clock-sourcing interface provided by the MMB daughterboard, and a 
clock-sourcing interface provided by the MMBC daughterboard.  The 
difference in the implementation of these two interfaces is described in 
this section, as well as in tables 5-3 and 5-4.

        (1)  Electrical Use of Interchange Circuits.  The DDN electrical 
use of interchange circuits is either static or active.  Static circuits 
are tied by the hardware so that the signal state remains constant on the 
line, either ON or OFF.  Active circuits change their state under program 
control.  DDN use of the interchange circuits is shown in Tables 5-3 and 
5-4.

        (2)  Software Use of Interchange Circuits.  Interchange circuit 
signals are used by the software in different ways.  Active circuits are 
under program control:  the software canreact to a received signal when it 
changes, and the software can assert a transmitted signal when necessary 
(such as RS, TR, and LL which can be used by operations personnel for 
testing connections).  Unsupported circuits are either not read by the 
software or a value is written to the circuit by the software and that 
DCAC-350-180-( )                                                     5-6

value does not change during operation.  Tables 5-3 and 5-4 provides a 
list of circuits and their use.

        (3)  Interchange Circuit Definitions.  For additional information 
about these interchange circuits, see EIA Standard 449.  The following 
descriptions assume use of full period/full duplex circuits, with flow 
control handled at higher levels.

             (a)  Signal Ground.  See EIA Standard EIA-449.

             (b)  Send Common.  See EIA Standard EIA-449.

             (c)  Receive Common.  See EIA Standard EIA-449.

             (d)  Terminal in Service.  For the non-clock-sourcing 
interface, IS is tied ON by the hardware.  For the clock-sourcing 
interface, this circuit is not connected.

             (e)  Incoming Call.  IC is not connected. 
             
             (f)  Terminal Ready.  For the non-clock-sourcing interface, 
TR is asserted OFF by PSN software when the link is initialized and allows 
Monitoring Center control.  For the clock-sourcing interface, TR is not 
connected.

             (g)  Data Mode.  For the non-clock-sourcing interface, 
DCAC-350-180-( )                                                     5-7

DM is not monitored by the PSN software.  For the clock-sourcing 
interface, DM is asserted ON by hardware.

             (h)  Send Data.  See EIA Standard EIA-449.

             (i)  Receive Data.  See EIA Standard EIA-449.

             (j)  Terminal Timing.   See EIA Standard EIA-449. TT is 
supported as a "reflected clock" in phase with ST.

             (k)  Send Timing.  See EIA Standard EIA-449.

             (l)  Receive Timing.  See EIA Standard EIA-449.

             (m)  Request to Send.  For the non-clock-sourcing interface, 
RS is asserted OFF by the PSN software when the link is initialized. RS 
allows Monitoring Center control.  For the clock-sourcing interface, RS is 
not connected.

             (n)  Clear to Send. For the non-clock-sourcing interface, CS 
is not monitored by the PSN software.  For the clock-sourcing interface, 
CS is asserted ON by hardware.

             (o)  Receiver Ready.  For the non-clock-sourcing interface, 
RR is not monitored by PSN software.  For the clock-sourcing interface, RR 
is asserted ON by hardware.
DCAC-350-180-( )                                                     5-8

             (p)  New Signal.  For the non-clock-sourcing interface, NS is 
tied OFF by the hardware.  For the clock-sourcing interface, NS is not 
connected.

             (q)  Select Frequency.  For the non-clock-sourcing interface, 
SF/SR is electrically active and asserted OFF by the hardware when the 
link is initialized.  For the clock-sourcing interface, SF/SR is not 
connected.

             (r)  Signaling Rate Selector.  See Select Frequency, 2.d.3.q 
above for a description.

             (s)  Signaling Rate Indicator.  SI is not connected.

             (t)  Local Loopback.  For the non-clock-sourcing interfaces, 
LL is electrically active, but asserted OFF by PSN software when the link 
is initialized.  LL can be controlled by the Monitoring Center.  For the 
clock-sourcing interface, LL is not connected.

             (u)  Remote Loopback.  RL is electrically active, but 
asserted OFF by PSN software when the link is initialized.  For the 
non-clock-sourcing interface, RL is not available for Monitoring Center 
control.  For the clock-sourcing interface, RL is asserted when another 
DCE requests the PSN to enter remote loopback.

             (v)  Test Mode. For the non-clock-sourcing interface, TM 
DCAC-350-180-( )                                                     5-9

is not connected.  For the clock-sourcing interface, TM is OFF during 
normal operations but ON during loopback operations to acknowledge the 
loopback request from another DCE.

             (w)  Select Standby.  For the non-clock-sourcing interface, 
SS is tied OFF by hardware.  For the clock-sourcing interface, SS is not 
monitored by PSN software but it is used as the remote loop indicator when 
the PSN requests another DCE to enter remote loopback.
        
             (x)  Standby Indicator.  For the non-clock-sourcing 
interface, SB is not connected.  For the clock-sourcing interface, SB is 
OFF during normal operations, and it is used as the remote loop request 
signal for loopback operations when the PSN requests another DCE to enter 
remote loopback.
DCAC-350-180-( )                                                     5-10

      TABLE 5-3. DDN STANDARD NODE MMB*/MMBC INTERCHANGE CIRCUIT USE

                                                                          


449                                            Electrical       Required State of   Comments
ID     EIA-449 Name            Source          Circuit       Control/Status Signals

SG     Signal Ground           DTE/DCE         Ground                 N/A           Ground
SC     Send Common             DTE             Ground                 N/A           Common
RC     Receive Common          DCE             Ground                 N/A           Common
SD     Send Data               DTE             Active                 N/A           Data Circuit
RD     Receive Data            DCE             Active                 N/A           Data Circuit
RS     Request to Send         DTE             Active                 OFF           Asserted OFF by PSN software.
                                                                                     Treated as LL for XMOD.
CS     Clear to Send           DCE             Active                 Don't Care    Not monitored by PSN software. 
DM     Data Mode               DCE             Active                 Don't Care    Not monitored by PSN software.
TR     Terminal Ready          DTE             Active                 OFF           Asserted OFF by PSN software.
                                                                                     Treated as RL for XMOD.
RR     Receiver Ready          DCE             Active                 Don't Care    Not monitored by PSN software. 
SQ     Signal Quality          DCE             Not Connected          Don't Care    Not connected in PSN. 
SF/SR  Select Frequency/       DTE             Static                 OFF           Tied OFF by hardware.
        Signaling Rate Sel.
SI     Signaling Rate          DCE             Not Connected          Don't Care    Not connected in PSN.
TT     Terminal Timing         DTE             Active                 N/A           Timing circuit for Transmitted
                                                                                    Data when PSN supplies timing.
ST     Send Timing             DCE             Active                 N/A           Timing circuit for Transmitted
                                                                                    Data when DCE provides timing.
RT     Receive Timing          DCE             Active                 N/A           Timing circuit for Received
                                                                                    Data when DCE provides timing.
SS     Select Standby          DTE             Static                 OFF           Tied OFF by hardware.
SB     Standby Indicator       DCE             Not Connected          Don't Care    Not connected in PSN.
IC     Incoming Call           DCE             Not Connected          Don't Care    Not connected in PSN. 
LL     Local Loopback          DTE             Active                 OFF           Tied to OFF by PSN software.
                                                                                     Treated as CL for XMOD.
RL     Remote Loopback         DTE             Static                 OFF           Tied OFF by hardware. 
TM     Test Mode               DCE             Not Connected          Don't Care    Not connected in PSN.
NS     New Signal              DTE             Static                 OFF           Tied OFF by hardware.
IS     Terminal in Service     DTE             Static                 ON            Tied ON by hardware.
AT     Alternate Timing        DTE             Not Connected          N/A           Not monitored by PSN software.


                                                                          

NOTE:  N/A = Not Applicalbe 
* MMB provides a non-clock-sourcing (DTE) interface.
    
DCAC-350-180-( )                                                     5-11

3.  Mechanical Characteristics.  All EIA-449/422 connectors offered for 
the C/30E meet the following specifications.

    a.  Interface Connectors.  All C/30E EIA-449 connectors interfacing an 
MMB with an MMBC have DC-37P type (male) connectors for  the  MMB side and 
a DC-37S type (female) connectors for the MMBC side.  Two interfacing 
MMBC-configured PSNs use two DC-37P connectors.

        (1)  Intermating dimensions are in accordance with EIA-449, 
section 3.3.1.

        (2)  The means for C/30E DTE connectors to latch and unlatch from 
the latching blocks on the DCE connector are within the dimensions 
specified in EIA-449, section 3.3.2.  DDN uses the English 4-40 thread 
latching block.

    b.  Connector Contact Assignments.  All C/30E EIA-449/422 contact 
assignments are in accordance with EIA-449, section 3.4.  Table 5-4 
provides the DDN standard node connector pinout.  The signals are used as 
specified in section 2.d.3 of the Standard.
DCAC-350-180-( )                                                     5-12

       TABLE 5-4.   DDN STANDARD NODE EIA-449 (DTE) CONNECTOR PINOUT

                                                                          

Pin     EIA     CCITT   Name
        ID      ID

1       FG              Frame Ground
2       SI      111     Not Connected
20      RC      102b    Receive Common
3       AT      ---     Not Connected
21      AT      ---     Not Connected
4       SD      103     Send Data +
22      SD      103     Send Data -
5       ST      114     Send Timing +
23      ST      114     Send Timing -
6       RD      104     Receive Data +
24      RD      104     Receive Data -
7       RS      105     Request to Send +
25      RS      105     Request to Send -
8       RT      115     Receive Timing +
26      RT      115     Receive Timing -
9       CS      106     Clear to Send +
27      CS      106     Clear to Send -
10      LL      141     Local Loopback
28      IS      ---     Tied to "1" on MMB, Not Connected on MMBC
11      DM      107     Data Mode +
29      DM      107     Data Mode -
12      TR      108.2   Terminal Ready +
30      TR      108.2   Terminal Ready -
13      RR      109     Receiver Ready +
31      RR      109     Receiver Ready 
14      RL      140     Remote Loopback - Tied to "0" on MMB,
                          Active on MMBC
32      SS      116     Select Standby - Tied to "0"
15      IC      125     Incoming Call
33      SQ      110     Signal Quality
16      SF/SR   126     Select Frequency/Signaling Rate
                         Tied to "1"
34      NS      ---     New Signal - Tied to "0"
17      TT      113     Terminal Timing +
35      TT      113     Terminal Timing -
18      TM      142     Not Connected - MMBC Has This
36      SB      117     Not Connected - MMBC Has This
19      SG      102     Signal Ground
37      SC      102a    Send Common

                                                                          
DCAC-350-180-( )                                                     5-13

4.  Interconnecting Cables.

    a.  For interconnecting cable specifications, see chapter 1, section 
4, of this guide.

    b.  Figure 5-1 is a cabling diagram of a C/30E PSN connected to a 
nearby EIA-449 PSN via an MMB-MMBC configuration.  Figure  5-2  is a 
cabling diagram of a C/30E PSN connected to a nearby EIA-449 PSN via an 
MMBC-MMBC configuration, the preferred configuration for the DDN. Figure 
5-3 is an example of a cable used to interconnect the MMB-MMBC 
configuration, whereas  figure  5-4 illustrates the MMBC-MMBC nearby 
EIA-449 PSN connection.

        (1)  Conductor Size.  Interconnecting cables should be in 
accordance with MIL-STD-188-114, Appendix 10, with regard to conductor 
size 
(subsection 10.1.1).  Interconnecting cables or wires should be composed 
of wires of a 24 AWG or larger conductor for solid or stranded copper 
wires, or for non-copper conductors a sufficient size to yield a dc wire 
resistance not to exceed 30 ohms/1000 feet per conductor.

        (2)  Mutual Pair Capacitance.  In accordance with MIL-STD-188-114, 
the capacitance between one wire in the pair to the other wire in the pair 
should not exceed 20 picofarads/foot, and the value should be reasonably 
uniform over the length of the wire or cable.
DCAC-350-180-( )                                                     5-14

        (3)  Stray Capacitance.  In accordance with MIL-STD-188-144, the 
capacitance between ome wire in the cable to all others in the cable 
sheath, with all others connected to ground, should not exceed 40 
picofarads/foot, and should be reasonably uniform for a given conductor 
over the lenght of the wire or cable.

        (4)  Pair-to-Pair Balanced Crosstalk.  In accordance with 
MIL-STD-188-144, Appendix 10, with regard to pair-to-pair balanced 
crosstalk (subsection 10.1.4), the crosstalk from one pair of wires to any 
other pair in the same cable sheath should have a minimun value of 40 dB 
attenuation measured at 150 kHz.

DCAC-350-180-( )                                                     5-15


      +-------------------------------------------------------------+
      |                                                             |
      |                DC-37PS                  DC-37P              |
      | +----------+    /                         \    +----------+ |
      | | EIA-499  |  /                             \  |  C/30E   | |
      | |  C/30E   |--+        2409327G01           +--| EIA-449  | |
      | |   DTE    |P1|=============================|P2|   DCE    | |
      | |  (MMB)   |--+                             +--|  (MMBC)  | |
      | |          |                                   |          | |
      | +----------+                                   +----------+ |
      |                                                             |
      +-------------------------------------------------------------+

      FIGURE 5-1.  C/30E EIA-449 PSN AND NEARBY EIA-449 PSN CABLING 
                   DIAGRAM (C/30E SOURCES CLOCK)




      +-------------------------------------------------------------+
      |                                                             |
      |                DC-37P                   DC-37P              |
      | +----------+    /                         \    +----------+ |
      | |          |  /                             \  |          | |
      | |  C/30E   |--+        2409328G01           +--|  C/30E   | |
      | |  MMBC    |P1|=============================|P2|  MMBC    | |
      | |   DCE    |--+                             +--|   DCE    | |
      | |          |                                   |          | |
      | +----------+                                   +----------+ |
      |                                                             |
      +-------------------------------------------------------------+

      FIGURE 5-2.  C/30E PSN WITH MMBC TO EIA-449 NEARBY PSN CABLING
                   DIAGRAM WITH MMBC (C/30E SOURCES CLOCK)

DCAC-350-180-( )                                                     5-16


      +-----------------------------------------------------------+
      |       MMB                                        MMBC     |
      |      C/30E                                       C/30E    |
      |        P1                                         P2      |
      |      DC-37S                                      DC-37S   |
      | Pin#     Signal                            Signal    Pin# |
      |  +/-       +/-   Shield             Shield   +/-      +/- |
      |  1         FG  >--------+         +-------<  FG       1   |
      |                                                           |
      |                                                           |
      |                 Pair #                                    |
      |  4/22      SD  >-(1)----------------------<  SD      4/22 |
      |                                                           |
      |  5/23      ST  >-(2)----------------------<  ST      5/23 |
      |                                                           |
      |  6/24      RD  >-(3)----------------------<  RD      6/24 |
      |                                                           |
      |  8/26      RT  >-(4)----------------------<  RT      8/26 |
      |                                                           |
      |  12/30     TR  >-(5)----------------------<  TR     12/30 |
      |                                                           |
      |  9/27      CS  >-(6)----------------------<  CS      9/27 |
      |                                                           |
      |  19/37   SG\SC >-(7)----------------------<  SG/SC  19/37 |
      |                                                           |
      |  11/29     DM  >-(8)----------------------<  TM     20/18 |
      |                                                           |
      |  13/31     RR  >-(10)-+-------------------<  RR     13/31 |
      |                       |                                   |
      |  7/SC      RS  >-(11)-|-------------------<  RL     14/NC |
      |                       |                                   |
      |  17/35     TT  >-(12)-|-------------------<  TT     17/35 |
      |                       |                                   |
      |                       +-(9)--- NO CONNECTION              |
      |                                     (NC)                  |
      |                                                           |
      |                                                           |
      +-----------------------------------------------------------+

      FIGURE 5-3.  CABLING EXAMPLE: C/30E WITH MMB TO EIA-449 NEARBY
                   PSN WITH MMBC (C/30E SOURCES CLOCK)
DCAC-350-180-( )                                                     5-17


       +-----------------------------------------------------------+
       |      MMBC                                        MMBC     |
       |      C/30E                                       C/30E    |
       |       P1                                          P2      |
       |      DC-37P                                      DC-37P   |
       | Pin#     Signal                            Signal    Pin# |
       |  +/-       +/-   Shield             Shield   +/-      +/- |
       |  1         FG  >--------+         +-------<  FG       1   |
       |                                                           |
       |                                                           |
       |                 Pair #                                    |
       |  4/22      SD  >-(1)-------\  /----------->  SD      4/22 |
       |                              \                            |
       |  6/24      RD  >-(3)-------/   \---------->  RD      6/24 |
       |                                                           |
       |  8/26      RT  >-(4)----\              /--<  RT      8/26 |
       |                          \            /                   |
       |  12/30     TR  >-(5)------\----------/----<  TR     12/30 |
       |                            \        /                     |
       |  9/27      CS  >-(6)--------\------/------<  CS      9/27 |
       |                              \    /                       |
       |  19/37   SG\SC >-(7)----------\--/--------<  SG/SC  19/37 |
       |                                \/                         |
       |  32/NC     DM  >-(8)-----------/\---------<  TM     18/SG |
       |                               /  \                        |
       |  18/SG     TM  >-(10)--------/----\-------<  SS     32/NC |
       |                             /      \                      |
       |  14/NC     RL  >-(11)------/--------\-----<  SB     36/SG |
       |                           /          \                    |
       |  17/35     TT  >-(12)-+--/            \---<  TT     17/35 |
       |                       |                                   |
       |                >------|-(2)--- NO CONNECTION              |
       |                       |             (NC)                  |
       |                       +-(5)--- NC                         |
       |                       |                                   |
       |                       +-(9)--- NC                         |
       |                                                           |
       +-----------------------------------------------------------+

      FIGURE 5-4.  CABLING EXAMPLE: C/30E WITH MMBC TO EIA-449 NEARBY
                   PSN WITH MMBC (C/30E SOURCES CLOCK)

DCAC-350-180-( )                                                     6-1

            CHAPTER 6.  MIL-STD-188-114  REMOTE TRUNK INTERFACE

1.  Overview.  This chapter describes the electrical and mechanical 
characteristics of the MIL-STD-188-114 balanced remote trunk interface.  
DDN supports Extended Modem Looping (XMOD) through the MIL-STD-188-114 
interface. This chapter also documents the interface between the remote 
modem and the PSN (demarcation point A in figure 6-1) with no intervening 
cryptographic devices (KG-84As).  Eventually KG-84As will be required for 
all trunk circuits; therefore, chapter 6 also provides an example of the 
cabling that connects from the remote modem to the remote Fixed Plant 
Adapter (FPA) and then to the PSN (demarcation point B in figure 6-2).

2.  Electrical Characteristics.

    a.  Voltage  Levels.   The  modems used will conform  to  EIA Standard 
449.  The electrical interface of the KG-84A is in accordance with 
MIL-STD-188-114, chapter 5, except with regard to subsection 5.1.1.2: Open 
Circuit Measurement.  The open circuit driver voltage, measured in 
accordance with section 5.1.1.2 of this 

DCAC-350-180-( )                                                     6-2

statement, is less than +9.0V for balanced drivers and +4.50V for 
unbalanced drivers.

    b.  Clocking.

        (1)  Modem Clocking.  The modem supplies timing on the Send Timing 
and Receive Timing circuits.  Terminal Timing isnot supported for remote 
PSN interfaces.  While the DDN hardware will support between 1.2 kb/s and 
64 kb/s, DDN policy states that the minimum PSN access rate be 9.6 kb/s.
DCAC-350-180-( )                                                     6-3


     +--------------------------------------------------------------+
     |                                                              |
     |                                                              |
     | C/30E PSN                                      C/30E PSN     |
     | +-----------+   +-----------+ +-----------+    +-----------+ |
     | |           |   |           | |           |A   |           | |
     | |118-114 Bal|---|188-114 Bal|-|188-114 Bal|----|118-114 Bal| |
     | |   DTE     |   |   DCE     | |   DCE     |    |   DTE     | |
     | |           |   |           | +           |    |           | |
     | +-----------+   +-----------+ +-----------+    +-----------+ |
     |                                                              |
     |                                                              |
     |                                                              |
     +--------------------------------------------------------------+

      FIGURE 6-1.  DEMERCATION POINT "A" BETWEEN THE C/30 AND REMOTE 
                   C/30E



   +-------------------------------------------------------------------+
   |   C/30E PSN                                           C/30E PSN   |
   | +-----------+                                       +-----------+ |
   | |118-114 Bal|                                       |           | |
   | |   DTE     |                                       |118-114 Bal| |
   | |           |                                       |   DTE     | |
   | |           |                                       |           | |
   | +-----+-----+                                       +-----+-----+ |
   |       |                                                   |       |
   |       |                                                   |       |
   |   +---+---+                                           +---+---+   |
   |   | DPPE  |                                           | DPPE  |   |
   |   +---+---+                                           +---+---+   |
   |       |                                                   |       |
   |       |                                                   |       |
   |       |      +--+ +-----------+ +-----------+  +---+      |B      |
   |   +---+---+  |D | |           | |           |  |D  |  +---+---+   |
   |   | KGAB  |--|P |-|188-114 Bal|-|188-114 Bal|--|P  |--| KGAB  |   |
   |   |       |  |P | |           | |   DCE     |  |P  |  |       |   |
   |   +-------+  |C | |           | |           |  |C  |  +-------+   |
   |              +--+ +-----------+ +-----------+  +---+              |
   |                                                                   |
   |                                                                   |
   +-------------------------------------------------------------------+

     FIGURE 6-2.  DEMERCATION POINT "B" BETWEEN THE KGAB AND C/30E PSN
DCAC-350-180-( )                                                     6-4

        (2)  Signaling Sense.  Signaling sense for balanced and unbalanced 
circuits is in accordance with EIA Standard 422-A with  the exception of 
the differential voltage, which applied to the interconnecting cable, is 
in the C/30E range of 2 volts to 9 volts.  As defined in EIA Standard 
422-A, ON (0, Space, or +) is generated when the A terminal is positive 
with respect to the B terminal, and OFF (1, MARK, or -) is generated when 
the A terminal is negative with respect to the B terminal.

    c.  Bit Rate and Cable Length.

        (1)  EIA-449 Compliance.  Interconnecting cable length and its 
relation to data signaling rates are in accordance with EIA Standard 449, 
section 6.10, and EIA Standard 422-A, section 4.3 and the Appendix.

        (2)  Maximum Cable Length.  The maximum cable length between the 
remote modem and the PSN, including the intervening FPA is 1000 feet; 
however, cable lengths less than 200 feet are preferred.

    d.  Interchange Circuits.

        (1)  C/30E Local Modem Interface.

             (a)  Signal flow between the C/30E and the local modem is 
shown in figure 6-3.  This interface and associated hardware are provided 
by DDN.  The signal flow is the same when a KG-84A is used.  This 
interface uses EIA-449 pin assignments.
             
DCAC-350-180-( )                                                     6-5

             (b)  As shown in figure 6-3, the supported signals are Send 
Data (SD), Send Timing (ST), Receive Data (RD), and Receive Timing (RT).  
Clear to Send (CS), Data Mode (DM), and ReceiverReady (RR) are tied ON by 
the cable connected to the fantail.Terminal Ready (TR) is being used for 
the Remote Loopback (RL) function.  Request to Send (RS) is being used for 
the Local Loopback (LL) function.  The signal LL is being used for the 
COMSEC Loopback (CL) described below.

             (c)  A special DDN-specific loopback signal, CL, is provided 
as shown in figure 6-3.  The Local Loopback (LL) signal is used by the PSN 
to loop the local KG-84A and is designated as  "C" loop or CL (standing 
for COMSEC Loopback) in figure 6-3 after it leaves the C/30E fantail.  

3.  Mechanical Characteristics.  All EIA-449/422 connectors offered for 
the C/30E meet the specifications of this section.

    a.  Interface Connectors.  DDN MIL-STD-188-114 DCE connectors are 
DC-37S type (female) and DC-37P type (male) connectors.  The DDN FPA uses 
an MS connector on the KGAB counter assemblies.

    b.  Connector Contact Assignments.

        (1)  C/30E Connectors.  All DDN EIA-449/422 contact assignments 
are in accordance with EIA Standard 449, section 3.4.  In chapter 1, Table 
DCAC-350-180-( )                                                     6-6

5-4 provides the standard DTE pinouts and section 2.d.3 of the Standard 
provides circuit descriptions.

        (2)  KGAB Connectors.  KGAB connectors to the remote C/30E and the 
remote modem are shown in Tables 6-2 and 6-3, respectively.
DCAC-350-180-( )                                                     6-7



PSN/                  Patch                                        Patch                DCE
MII         Cable #   Panel   Cable #         KGAB       Cable #   Panel   Cable #       
             6833              6817                       6812              7835         
                      Pin #                                        Pin #                 
+--+ Pin #  +-----+  +-----+ +-----+   Pin #  +--+  Pin #  +----+ +-----+ +----+  Pin # +--+
|  |  +/-   |     |  | +/- | |     |    +/-   |  |   +/-   |    | | +/- | |    |   +/-  |  |
|SD|  4/22 --------->| 2/14|---(1)---> 24/25  |SD|  2/3  -------->| 2/14|--------> 4/22 |SD|
|  |                 |     |                  |  |                |     |               |  |
|ST|  5/23 --------->|15/16|<--(2)----  4/5   |ST|  4/5  <--------|15/16|<-------- 5/23 |ST|
|  |                 |     |                  |  |                |     |               |  |
|RD|  6/24 --------->| 3/19|<--(3)----  6/7   |RD|  6/7  <--------| 3/19|<-------- 6/24 |RD|
|  |                 |     |                  |  |                |     |               |  |
|RT|  8/26 --------->|17/18|<--(4)----  8/9   |RT|  8/9  <--------|17/18|<-------- 8/26 |RT|
|  |                 |     |                  |  |                |     |               |  |
|SR/ 12/30 --------->|20/10|---(5)---> 10/11  |TR| 10/11  ------->|20/10|----+--->12/30 |TR|
|NS|                 |     |                  |  |                |     |    |          |  |
|  |                 |     |                  |  |                |     |    +---> 7/25 |RS|
|  |                 |     |                  |  |                |     |               |  |
|  |       NC<-------| 5/6 |<--(6)---- 14/15  |CS| 12/13  <-------| 5/6 |<-------- 9/27 |CS|
|  |                 |     |                  |  |                |     |               |  |
|SG| 19/37 ------+---| 7/8 |---(7)---> 12/13  |SG| 14/15  --------| 7/8 |--------- 19/37|SG|
|  |             |   |     |                  |  |                |     |               |  |
|SR| 16/37 ------|-->|12/13|---(8)---> 16/17  |CL| 16/17  ------->|12/13|------> NC     |  |
|  |             |   |     |                  |  |                |     |               |  |
|RL| 14/37 ------|-->|11/21|---(9)---> 18/19  |RL| 18/19  ------->|11/21|-------->14/37 |RL|
|  |             |   |     |                  |  |                |     |               |  |
|RS|  7/37 ------|-->| 4/9 |---(10)--> 20/21  |DL| 20/21  ------->| 4/9 |------> NC     |  |
|  |             |   |     |                  |  |                |     |               |  |
|LL| 10/37 ------|-->|22/25|---(11)--> 22/23  |LL| 22/23  ------->|22/25|-------->10/37 |LL|
|  |             |   |     |                  |  |                |     |               |  |
|ON| 28/32 --->+ +-->|24/23|---(12)-->  2/3   |TT| 24/25  ------->|24/23|-------->17/35 |TT|
|CS|  9/27 <---|     +-----+                  +--+                +-----+               |  |
|DM| 11/29 <---|                                                                        |  |
|RR| 13/31 <---|                                                                        |  |
+--+                                                                                    +--+
   Notes:  1.  Pin numbers are the same on both sides of Patch Panel.
           2.  Encircled numbers are the cable pair numbers.


    FIGURE 6-3.  FUNCTIONAL SIGNAL FLOW BETWEEN A NEARBY MODEM AND 
                 C/30E, OR A SR(ON) NS(OFF) KGAB AND A REMOTE PSN
DCAC-350-180-( )                                                     6-8

          TABLE 6-1.  REMOTE-MODEM DCE INTERFACE CONNECTOR PINOUT

                                                                          

        Pin     EIA     CCITT       Name                  
                ID      ID    

Mandatory

        1       FG                 Frame Ground      
        4       SD +    103        Send Data         
        22      SD -    103        Send Data         
        5       ST +    114        Send Timing       
        23      ST -    114        Send Timing       
        6       RD +    104        Receive Data      
        24      RD -    104        Receive Data      
        7       RS +    105        Request to Send        
        25      RS -    105        Request to Send
        8       RT +    115        Receive Timing         
        26      RT -    115        Receive Timing
        9       CS +    106        Clear to Send
        27      CS -    106        Clear to Send
        12      TR +    108.2      Terminal Ready         
        30      TR -    108.2      Terminal Ready
        17      TT +    113        Terminal Timing        
        35      TT -    113        Terminal Timing
        19      SG      102        Signal Ground          
        37      SC      102a       Send Common

Optional

        2       SI      112        Signaling Rate Indicator
        10      LL      141        Local Loopback
        11      DM +    107        Data Mode
        13      RR      109        Receiver Ready
        14      RL      140        Remote Loopback
        15      IC      125        Incoming Call
        16      SF/SR   126/111    Select Frequency/Signaling Rate 
                                   Selector          
        18      TM      142        Test Mode
        20      RC      102b       Receive Common
        28      IS      ---        Terminal In Service
        29      DM -    107        Data Mode
        31      RR -    109        Receiver Ready
        32      SS      116        Select Standby
        33      SQ      110        Signal Quality
        34      NS      ---        New Signal
        36      SB      117        Standby Indicator

                                                                          
DCAC-350-180-( )                                                     6-9

             TABLE 6-2.  KGAB - REMOTE C/30E CONNECTOR PINOUT

                                                                          

        Pin     EIA     CCITT      Name
                ID      ID            

Mandatory

        1       FG                    Frame Ground           
        24      SD +    103           Send Data              
        25      SD -    103           Send Data
        4       ST +    114           Send Timing
        5       ST -    114           Send Timing
        6       RD +    104           Receive Data           
        7       RD -    104           Receive Data
        8       RT +    115           Receive Timing         
        9       RT -    115           Receive Timing
        10      TR +    108.2         Terminal Ready         
        11      TR -    108.2         Terminal Ready
        12      SG      102           Signal Ground          
        13      SC      102a          Send Common            
        19      SS      116           Select Standby

Optional

        14      CS +    106           Clear to Send
        15      CS -    106           Clear to Send
        22      LL      141           Local Loopback
        20      DL +    105           "D" Loop (Reserved)    
        21      DL -    105           "D" Loop (Reserved)
        18      RL      140           Remote Loopback
        2       TT +    113           Terminal Timing        
        3       TT -    113           Terminal Timing
        16      CL +    126           "C" Loop (KG-84A Loop)
        17      CL -    126           "C" Loop (KG-84A Loop)

                                                                          

DCAC-350-180-( )                                                     6-10

              TABLE 6-3  KGAB - REMOTE MODEM CONNECTOR PINOUT

                                                                          

        Pin     EIA     CCITT      Name
                ID      ID         

Mandatory

        1       FG                 Frame Ground
        2       SD +    103        Send Data
        3       SD -    103        Send Data
        4       ST +    114        Send Timing
        5       ST -    114        Send Timing
        6       RD +    104        Receive Data
        7       RD -    104        Receive Data
        8       RT +    115        Receive Timing
        9       RT -    115        Receive Timing
        10      TR +    108.2      Terminal Ready
        11      TR -    108.2      Terminal Ready
        14      SG      102        Signal Ground
        15      SG      102        Signal Ground
        24      TT +    113        Terminal Timing
        25      TT -    113        Terminal Timing

Optional

        12      CS +    106        Clear To Send
        13      CS -    106        Clear To Send
        16      CL      ---        "C" Loop (KG-84A Loop)
        17      CL -    ---        "C" Loop (KG-84A Loop)
        18      RL +    140        Remote Loopback
        19      RL -    140        Remote Loopback
        20      DL +    ---        "D" Loop (Reserved)
        21      DL -    ---        "D" Loop (Reserved)
        22      LL +    141        Local Loopback
        23      LL -    141        Local Loopback

                                                                          

DCAC-350-180-( )                                                     6-11

4.  Interconnecting Cables.   Figures 6-4 and 6-5 provide a cabling 
diagram of a configuration with a C/30E, modems, and FPAs.  Table 6-4 
describes the cables used for interconnecting these devices.  See chapter 
1, section 4, for specifications on interconnecting cables.


                    TABLE 6-4. REMOTE INTERFACE CABLES

                                                                          

Connection             BBNCC         Description
                       P/N#

PSN IMP/MII to DPPE    2406833G01    12-pr, PSN/MSYNC 188-114 Bal
                                     Host to DB25P

DPPE to KGAB           2406817GO1    12-pr, DB25S to FPA-J1

KGAB to DPPC           2406812GO1    12-pr, FPA-J2 to DB25P

DPPC to DCE            2407835GO1    12-pr, DB25S to 188-114 DCE

                                                                          
DCAC-350-180-( )                                                     6-12


+------------------------------------------------------------------------+
|                                                                        |
|                                                                        |
|                                                                        |
|         Cable # +-+ Cable #                 Cable # +-+  Cable #       |
| +-----+2406833- | |2407835-                 2407835-| | 2406833-       |
| |C/30E|   G01   |D|  G01   +-----+   +-----+  G01   |D|   G01   +----+ |
| | PSN |---------|P|--------| DCE |---| DCE |--------|P|---------|DTE | |
| |(DTE)|         |P|        +-----+   +-----+        |P|         |HOST| |
| +-----+         |E|                                 |E|         +----+ |
|                 +-+                                 +-+                |
|                                                                        |
|                                                                        |
|                                                                        |
|                                                                        |
+------------------------------------------------------------------------+

            FIGURE 6-4.  C/30E AND REMOTE HOST CABLING DIAGRAM



+------------------------------------------------------------------------+
|                                                                        |
| +-----+                                                        +-----+ |
| |C/30E|                                                        |C/30E| |
| | PSN |                                                        | PSN | |
| |(DTE)|                                                        |     | |
| +--+--+                                                        +--+--+ |
|    | Cable #                                              Cable # |    |
|    | 2406833G01                                        2406833G01 |    |
| +--+--+                                                        +--+--+ |
| | DPPE|                                                        | DPPE| |
| +--+--+                                                        +--+--+ |
|    | Cable #                                              Cable # |    |
|    | 2406817G01                                        2406817G01 |    |
|    |                                                              |    |
|    |   Cable #      Cable #                 Cable #     Cable #   |    |
| +--+--+2406812-+-+ 2407835-                2407835- +-+2406812-+--+--+ |
| |     |  G01   |D|   G01  +-----+    +-----+  G01   |D|  G01   |     | |
| | KGAB|--------|P|--------| DCE |----| DCE |--------|P|--------| KGAB| |
| |     |        |P|        +-----+    +-----+        |P|        |     | |
| +-----+        |C|                                  |C|        +-----+ |
|                +-+                                  +-+                |
|                                                                        |
|                                                                        |
+------------------------------------------------------------------------+

            FIGURE 6-5.  C/30E AND REMOTE TRUNK CABLING DIAGRAM
                         (WITH CRYPTOGRAPHIC DEVICES)

DCAC-350-180-( )                                                     7-1

         CHAPTER 7.  EIA-232-D NEIGHBOR OR NEARBY TRUNK INTERFACE

1.  Overview.  This chapter describes the electrical and mechanical 
characteristics of the obsolete DDN EIA-232-D  PSNconnection at the 
neighbor or nearby PSN.   DDN supports Extended Modem Looping (XMOD) 
through the EIA-232-D interface. For ease of reference, Table 7-1 equates 
the EIA-232-D, EIA-449, and CCITT interface signal names.  However, in the 
rest of this chapter, only the EIA-232-D signal name will be used.  DDN 
uses the EIA-232-D interface only where an existing non-DDN standard PSN 
provides such an interface, and it is not feasible to install a 
MIL-STD-188-114 balanced interface prior to upgrading the entire node to 
DDN standard (MIL-STD-188-114 balanced serial trunk interfaces).

2.  Electrical Characteristics.

    a.  Voltage Levels.  The electrical measurements of the C/30E 
EIA-232-D interface circuits are in accordance with EIA Standard 232-D, 
section 2.1.  For normal operation, the open circuit driver voltage shall 
be no more than +15 V.

    b.  Clocking.

        (1)  Supported Clock Rates.  The MMR fantail contains the
DCAC-350-180-( )                                                     7-2

connector that terminates a cable from all the DTE.  The fantail contains 
one EIA-232-D connector configured as a DTE.  This interface has no 
clock-sourcing capability.  The hardware can support external clock rates 
between 1.2 kb/s and 112 kb/s.  However, DDN policy is 9.6 kb/s for the 
minimum  PSN bit rate and 19.2 kb/s for the maximum rate.

        (2)  Signaling Sense.   Signaling sense is in accordance with EIA 
Standard 232-D, subsection 2.1.3.  The signal is considered marking (OFF) 
when the voltage on the interchange circuit is more negative than -3 V 
with respect to signal ground, and spacing (ON) when the voltage is more 
positive than +3 V with respect to signal ground.

    c.  Bit Rate and Cable Length.  Interconnecting cable length  is in 
accordance with EIA-232-D, section 3.1.  The recommended maximum cable 
length between an EIA-232-D DCE and DTE is 200 feet when overall shielded, 
low capacitance, twisted pair cable is used.

    d.  Interchange  Circuits.

        (1)  Electrical Use of Interchange Circuits.  The DDN electrical 
use of interchange circuits is either static or active.  Static circuits 
are tied by the hardware so that the signal state remains constant on the 
line, either ON or OFF.  Active circuits change their state under program 
control.  DDN use of the interchange circuits is shown in Table 7-2.

DCAC-350-180-( )                                                     7-3

                 TABLE 7-1.  SIGNAL NAME EQUIVALENCY TABLE

                                                                          


EIA-232-D                                      EIA-449                        CCITT
ID          Name                               ID     Name                    ID     Name

AB         Signal Ground                       SG     Signal Ground           102    Signal Ground
CE         Ring Indicator                      IC     Incoming Call           125    Calling Indicator
CD         DTE Ready                           TR     Terminal Ready          108/2  Data Terminal Ready
CC         DCE Ready                           DM     Data Mode               107    Data Set Ready
BA         Transmitted Data                    SD     Send Data               103    Transmitted Data
BB         Received Data                       RD     Receive Data            104    Received Data
DA         Transmitter Signal Element Timing   TT     Terminal Timing         113    Transmitter Signal Element
            (DTE Source)                                                              Timing (DTE Source)
DB         Transmitter Signal Element Timing   ST     Send Timing             114    Transmitter Signal Element
            (DCE Source)                                                              Timing (DCE Source)
DD         Receiver Signal Element Timing      RT     Receive Timing          115    Receiver Signal Element
            (DCE Source)                                                              Timing (DCE Source)
CA         Request To Send                     RS     Request To Send         105    Request To Send
CB         Clear To Send                       CS     Clear To Send           106    Ready For Sending
CF         Received Line Signal Detector       RR     Receiver Ready          109    Data Channel Received Line
                                                                                      Signal Detector
CG         Signal Quality Detector             SQ     Signal Quality          110    Data Signal Quality
                                                                                      Detector
CH         Data Signal Rate Selector           SR     Signaling Rate Selector 111    Data Signaling Rate
            (DTE Source)                                                              Selector (DTE Source)
CI         Data Signal Rate Selector           SI     Signaling Rate          112    Data Signaling Rate
            (DCE Source)                               Indicator                      Selector (DCE Source)
LL         Local Loopback                      LL     Local Loopback          141    Local Loopback
RL         Remote Loopback                     RL     Remote Loopback         140    Remote Loopback
TM         Test Mode                           TM     Test Mode               142    Test Indicator


                                                                          
DCAC-350-180-( )                                                     7-4

        (2)  Software Use of Interchange Circuits.  Interchange circuit 
signals are used by the software in different ways.  Active circuits are 
under program control: either the software reacts to a received signal 
when it changes, or the software can assert a transmitted signal when 
necessary (such as LL which can be used by operations personnel for 
testing connections).  Unsupported circuits are either not read by the 
software or a value is written to the circuit by the software, and that 
value does not change during operation.  Table 7-2 provides a list of 
circuits and their use.

        (3)  Interchange Circuit Definitions.

             (a)  Signal Ground.  See EIA Standard 232-D.

             (b)  DCE Ready.  This circuit is not monitored by the PSN 
software.
             (c)  DTE Ready.  This circuit is asserted OFF by PSN software 
when the link is initialized.  Available for Monitoring Center control.

             (d)  Transmitted Data.  See EIA Standard 232-D.

             (e)  Received Data.  See EIA Standard 232-D.

             (f)  Transmitter Signal Element Timing (DCE Source).  See EIA 
Standard 232-D.  This circuit provides the clock for Transmitted Data when 
the DCE sources timing.


DCAC-350-180-( )                                                     7-5

             (g)  Receiver Signal Element Timing (DCE Source).  See EIA 
Standard 232-D.  This circuit provides clock for Received Data when the 
DCE sources timing.

             (h)  Request to Send.  This circuit is asserted OFFby  PSN  
software  when the link is  initialized.  Available  for Monitoring Center 
control.

             (i)  Clear to Send.  This circuit must be asserted ON by the 
DCE, but it is not monitored by the PSN software.

             (j)  Received Line Signal Detector.  This circuit must  be 
asserted ON by the DCE, but it is not monitored by  the PSN software.
DCAC-350-180-( )                                                     7-6

            TABLE 7-2. EIA-232-D INTERCHANGE TRUNK CIRCUIT USE

                                                                          


232                                               Electrical       Required State of   Comments
ID     EIA-232-D Name         Source              State         Control/Status Signals

AB     Signal Ground          DTE/DCE             Ground                 N/A*          
BA     Transmitted Data       DTE                 Active                 N/A           Data Circuit
BB     Received Data          DCE                 Active                 N/A           Data Circuit
CA     Request to Send        DTE                 Active                 OFF           Asserted OFF by PSN software.
                                                                                       Treated as LL for XMOD.
CB     Clear to Send          DCE                 Active                 Don't Care    Not monitored by PSN software.
CC     DCE Ready              DCE                 Active                 Don't Care    Not monitored by PSN software.
CD     DTE Ready              DTE                 Active                 OFF           Asserted OFF by PSN software.
                                                                                       Treated as RL for XMOD.
CF     Received Line Signal   DCE                 Active                 Don't Care    Not monitored by PSN software.
DB     Transmitter Signal     DCE                 Active                 N/A           Timing circuit for Transmitted
                                                                                       Data when the DCE supplies
                                                                                       timing 
DD     Receive Signal         DCE                 Active                 N/A           Timing circuit used for
        Element Timing                                                                 Received Data when the DCE supplies
                                                                                       timing.
                                                                                       No action is taken.


                                                                          

* N/A = Not Applicable
DCAC-350-180-( )                                                     7-7

3.  Mechanical Characteristics.  The MMR EIA-232-D connectors on the C/30E 
meets the specifications provided in this section.

    a.  Interface Connectors.  The MMR C/30E fantail EIA-232-D connector 
is a DB-25P type (male) connectors.  Intermating dimensions are in 
accordance with EIA-232-D, section 3.2.1.

    b.  Connector Contact Assignments.  DDN standard node EIA-232-D 
connector contact assignments are in accordance with EIA-232-D, section 
3.3.1.  Table 7-3 provides DDN EIA-232-D connector pin assignments.  
Signal use is specified in section 2.d.3. of this Standard.
DCAC-350-180-( )                                                     7-8

                  TABLE 7-3.  EIA-232-D CONNECTOR PINOUT

                                                                          

Pin     EIA     CCITT         Name
        ID      ID            

1       --      --            Shield
2       BA      103           Transmitted Data
3       BB      104           Received Data
4       CA      105           Request To Send
5       CB      106           Clear To Send
6       CC      107           DCE Ready
7       AB      102           Signal Ground (Common Return)
8       CF      109           Received Line Signal Detector
9       --      ---           + DC Test Voltage (+8VDC)
10      --      ---           - DC Test Voltage (-8VDC)
11      DB      114           Transmitted Signal Element Timing
                               (DCE Source)
12      DD      115           Receiver Signal Element Timing
                               (DCE Source)
13      CD      108/2         DTE Ready

                                                                          

* The circuit name "DC" is from and earlier version of EIA-232.

DCAC-350-180-( )                                                     7-9

4.  Interconnecting Cables.

    a.  For interconnecting cable specifications,  see chapter 1 and 
section 4, of this guide.

    b.  Figure 7-1 is a cabling diagram of a C/30E PSN connected to a 
nearby EIA-232 PSN, and figure 7-2 is an example of an interconnecting 
cable (BBNCC P/N# 2405535GO1).




   +------------------------------------------------------------------+
   |                                                                  |
   |             DB-25S                            DB-25S             |
   |               /                                  \               |
   | +--------+  /                +-----+               \  +--------+ |
   | |EIA-232 |--+ 2405535G01  +--|RS232|--+ 2405535G01 +--|EIA-232 | |
   | | C/30E  |P1|=============|P2| SME |P1|============|P2| C/30E  | |
   | |  PSN   |--+             +--|     |--+            +--|  PSN   | |
   | | (DTE)  |                /  +-----+  \               | (DTE)  | |
   | +--------+              /               \             +--------+ |
   |                     DB-25P            DB-25P                     |
   |                                                                  |
   +------------------------------------------------------------------+

      FIGURE 7-1.  C/30E PSN AND NEARBY EIA-232-D PSN CABLING DIAGRAM
 DCAC-350-180-( )                                                     8-1

                  CHAPTER 8.  V.35 REMOTE TRUNK INTERFACE

1.  Overview.  This chapter describes the electrical and mechanical  
characteristics of the obsolete DDN V.35 connection between two remote 
PSNs.  DDN standard does not support neighbor or nearby V.35 PSN-PSN 
connections.   Like the EIA-232 interface, the V.35 interface is used only 
where an existing non-DDN-standard PSN provides such an interface, and it 
is not feasible to install a MIL-STD-188-114 balanced interface prior to 
upgrading the entire node to DDN-standard (MIL-STD-188-114 balanced serial 
PSN interfaces). All control signals have electrical characteristics of 
EIA-232-D, and EIA-232-D signal names are used in the rest of this 
chapter.  The data and timing signals conform to Recommendation V.35. DDN 
supports Extended Modem Looping (XMOD) through the V.35 interface.

2.  Electrical Characteristics.

     a.  Voltage Levels.  The electrical measurements of the C/30E V.35 
interface circuits are in accordance with CCITT Recommendation V.35.

     b.  Clocking.  The MMV interface hardware contains the connectors 
that terminate the cables from all I/O interfaces.  The MMV fantail 
contains one V.35 connector configured as a DTE.  This interface has no 
clock-sourcing capability.  The hardware  can support external clock rates 
between 300 b/s and 100 kb/s.
DCAC-350-180-( )                                                     8-2

         (1)  Signaling Sense.  Signaling sense is in accordance with 
CCITT Recommendation V.35.  A binary "0" (space) is transmitted when 
terminal "A" is positive (+.55v +20%) to terminal "B" (-.55V +20%).  A 
binary 1 is transmitted when terminal "A" is negative (-.55v +20%) to 
terminal "B" (+.55v +20%).  The drivers produce a nominal 1.1 volts 
peak-to-peak signal balanced with respect to ground.

     c.  Bit Rate/Cable Length.

         (1)  Maximum Cable Length.  The recommended maximum cable length 
between a V.35 DCE and DTE is 30 feet when overall shielded, low 
capacitance, twisted pair cable is used.  Cable  lengths  of  up to 2000 
feet are also  possible with the proper cables, see LOR-0023-003 for more 
details.

     d.   Interchange  Circuits.

          (1)  Electrical Use of Interchange Circuits.  The DDN electrical 
use of interchange circuits is either static or active.  Static circuits 
are tied by the hardware so that the signal state remains constant on the 
line, either ON or OFF.  Active circuits change their state under program 
control.  DDN use of the interchange circuits is shown in Table 8-1.

          (2)  Software Use of Interchange Circuits.  Interchange circuit 
signals are used by the software in different ways.  Active circuits are 
DCAC-350-180-( )                                                     8-3

under program control: either the software reacts to the circuit signal 
when it changes, or the software can assert a circuit when necessary (such 
as LL which can be used by operations personnel for testing connections).  
Unsupported circuits either are not read by the software or a value is 
written to the circuit by the software, and that value does not change 
during operation.  Table 8-1 describes circuit use.

          (3)  Interchange Circuit Definitions.  EIA-232-D signal names 
are used throughout this chapter.

               (a)  Signal Ground.  See EIA-232-D.

               (b)  DCE Ready.  This circuit must be asserted ON by the 
DCE, but it is not monitored by the PSN software.

               (c)  Transmitted Data.  See EIA-232-D.

               (d)  Received Data.  See EIA-232-D.

               (e)  Transmitter Signal Element Timing (DTE Source).  See 
EIA-232-D.  Also see subsection 2.b of this guide.  This circuit provides 
the clock for Transmitted Data when the PSN sources timing.  The frequency 
of this circuit is equal to that of Transmitter Signal Element Timing.

               (f)  Transmitter Signal Element Timing (DCE Source).  See  
EIA-232-D.   This  circuit  optionally provides the clock for Transmitted 
Data when the DCE sources timing.
DCAC-350-180-( )                                                     8-4

               (g)  Receive Signal Element Timing (DCE).  This circuit  
optimally provides the clock for received data when the DCE sources 
timing.

               (h)  Request to Send.  This circuit is asserted OFF by the 
PSN software. Available for Monitoring Center control.

               (i)  Clear to Send.  This circuit must be asserted ON by 
the DCE, but it is not monitored by PSN software.

               (j)  Received Line Signal Detector.  This circuit must be 
asserted ON by the DCE, but it is not monitored by PSN software.

               (k)  Data Terminal Ready.  This circuit is asserted OFF by 
the PSN software. Available for Monitoring Center control.

               (l)  Local Test Loopback.  This circuit is asserted OFF by 
the PSN software. Available for Monitoring Center control.

DCAC-350-180-( )                                                     8-5

               TABLE 8-1. V.35 TRUNK INTERCHANGE CIRCUIT USE

                                                                          


CCITT                                             Electrical       Required State of    Comments
ID     Name                       Source          State         Control/Status Signals

101    Protective Ground          DTE/DCE         Ground                N/A                   
102    Signal Ground              DCE/DTE         Ground                N/A
103    Transmitted Data           DTE             Active                N/A                   Data Circuit
104    Received Data              DCE             Active                N/A                   Data Circuit
105    Request to Send            DTE             Active                OFF                   Asserted OFF by PSN software.
                                                                                              Treated as LL for XMOD.
106    Clear to Send              DCE             Active                ON                    Not monitored by PSN software.
107    DCE Ready                  DCE             Active                Don't Care            Not monitored by PSN software.
108/2  DTE Ready                  DTE             Active                OFF                   Asserted OFF by PSN software.
                                                                                              Treated as RL for XMOD.
109    Received Line              DCE             Active                ON                    Not monitored by PSN software.
113    Transmitter Signal         DTE             Active                N/A                   Reflected timing circuit
        Element Timing                                                                        for Transmitted Data
                                                                                              timing.
114    Transmitter Signal         DCE             Active                N/A                   Timing circuit for Transmitted
        Element Timing                                                                        Data when the DCE supplies
                                                                                              timing.
115    Receiver Signal            DCE             Active                N/A                   Timing circuit for Received
        Element Timing                                                                        Data when the DCE supplies
                                                                                              timing.
141    Local Test                 DCE             Active                OFF                   Asserted OFF by PSN software.
        Loopback                                                                              Treated as CL by XMOD.


                                                                          

NOTES:  N/A = Not Applicable

DCAC-350-180-( )                                                     8-6

3.  Mechanical Characteristics.  All V.35 connectors offered for the C/30E 
meet the specifications provided in this section.  Cables for this 
interface, supplied by DDN, are equipped with an EIA-449 connector on one 
end to mate with the EIA-449 connector on the C/30E fantail; the other end 
provides a MIL-C-28748 34-pin connector to mate with the V.35 DCE.

    a.  Interface Connectors.  The V.35 connectors on the C/30E fantail is 
a DC-37P type (male) connector.  It is wired as described in Table 8-2.

        (1)  Intermating dimensions are in accordance with EIA-449-D.

        (2)  The means for C/30E DTE connectors to latch and unlatch from 
the latching blocks on the DCE connector are within the dimensions 
specified in EIA-449, section 3.3.1.  DDN uses the English 4-40 thread 
latching block.

    b.  Connector Contact Assignments.  DDN standard node V.35 connector 
contact assignments are in accordance with CCITT Recommendation V.35 and 
ISO 2593.  Table 8-2 provides DDN V.35 connector pin assignments.  The 
signals are used as specified in section 2.d.3.

DCAC-350-180-( )                                                     8-7

            TABLE 8-2.  V.35 34-PIN AND 37-PIN CONNECTOR PINOUT

                                                                          

34-pin   37-pin*  CCITT  Signal Name                      449
 #         #      ID                                      Name

A        1        101    Shield                           FG
P        4        103    Transmitted Data                 SD+
S        22       103    Transmitted Data                 SD-**
Y        5        114    Transmitter Signal Element       ST+
                          Timing (DCE Source)
a/AA     23       114    Transmitter Signal Element       ST-
                          Timing (DCE Source)
R        6        104    Received Data                    RD+
T        24       104    Received Data                    RD-
V        8        115    Receiver Signal Element Timing   RT+
                          (DCE Source)
X        26       115    Receiver Signal Element Timing   RT-
                          (DCE Source)
H        30       108/2  DTE Ready                        TR
B        12       102    Signal Ground                    SG
C         7       105    Request to Send                  RS
B***     25       102    Signal Ground                    SG
K        10       141    Local Test Loopback              LL(LT)
B        28       102    Signal Ground                    SG
U        17       113    Transmitter Signal Elem Timing   SG-
                          (DTE Source)
W        35       113    Transmitter Signal Elem Timing SG-
                          (DTE Source)
E        11       107    DCE Ready                        RR
B        29       102    Signal Ground                    SG
D        9        106    Clear to Send                    CS
B****    27       102    Signal Ground                    SG
F        13       109    Received Ready                   RR
B        31       102    Signal Ground                    SG
B        19       102    Signal Ground                    SG
B        37       102    Signal Ground                    SG

                                                                          

* This information represents a straight cable to a V.35 DCE.
** The + and - symbols, used in EIA-449, correspond to A and B,
   respectively, in V.35 terminology.
*** Internally reflected clocks are supplied on pins TT.
**** V.35 in 34 pin connector is labeled as pin B Signal Ground.

DCAC-350-180-( )                                                     8-8

4.  Interconnecting Cables.

    (a)  For interconnecting cable specifications, see chapter 1, section 
4, of this guide.

    (b)  Figure 8-1 is a cabling diagram of a V.35 PSN and remote V.35 
PSN, and figure 8-2 provides an example of an interconnecting cable (BBNCC 
P/N# 2405510G01). 






  +------------------------------------------------------------------+
  |                                                                  |
  |            V.35P                              DC-37P             |
  |              /                                    \              |
  | +-------+  /            +-----+  +-----+            \  +-------+ |
  | |  V.35 |--+ 2405540G01 |     |  |     | 2405540G01 +--|  V.35 | |
  | | C/30E |P1|========================================|P2| C/30E | |
  | | (DTE) |--+            | DCE |  | DCE |            +--| (DTE) | |
  | +-------+               +-----+  +-----+               +-------+ |
  |                                                                  |
  +------------------------------------------------------------------+

        FIGURE 8-1.  C/30E PSN AND REMOTE V.35 PSN CABLING DIAGRAM

DCAC-350-180-( )                                                     8-9


       +-----------------------------------------------------------+
       |      C/30E                                       C/30E    |
       |        P1                                         P2      |
       |      DC-37S                                      DC-37S   |
       | Pin#     Signal                            Signal    Pin# |
       |  +/-       +/-   Shield             Shield   +/-      +/- |
       |  1         FG  >--------+         +-------<  FG       1   |
       |                                                           |
       |                                                           |
       |  P/S       SD   Pair #                       SD      4/22 |
       |                >-(1)----------------------<               |
       |  Y/AA      ST                                ST      5/23 |
       |                >-(2)----------------------<               |
       |  R/T       RD                                RD      6/24 |
       |                >-(3)----------------------<               |
       |  V/X       RT                                RT      8/26 |
       |  H/B       TR  >-(4)----------------------<  TR     30/12 |
       |                                                           |
       |  C/B       RS  >-(5)----------------------<  RS      7/25 |
       |  K/B       LL                                LL     10/28 |
       |                >-(6)----------------------<               |
       |  U/W       TT                                TT     17/35 |
       |                >-(7)----------------------<               |
       |  E/B                                         DM     11/29 |
       |                >-(8)----------------------<               |
       |  D/B       OS                                CS      9/27 |
       |            DM  >-(9)----------------------<               |
       |  F/B       RR                                RR     13/31 |
       |                >-(10)---------------------<               |
       |  B/B       SG                                SG     19/37 |
       |                >-(11)---------------------<               |
       |                                                           |
       |                >-(12)---------------------<               |
       |                                                           |
       +-----------------------------------------------------------+
     
        FIGURE  8-2.  CABLE EXAMPLE:  C/30E PSN TO REMOTE V.35 PSN

 DCAC-350-180-( )                                                     9-1

          CHAPTER 9. BELL 303  NEIGHBOR OR NEARBY TRUNK INTERFACE

1.  Overview.  This chapter describes the electrical and mechanical 
characteristics of the BELL 303 DTE interface that connects the C/30E PSN 
with a modem. This interface is in conformance with the  BELL 303 
standard, cited in chapter of this guide.  The BELL 303 interface is used 
only where an existing non-DDN-standard PSN provides such an interface, 
and it is not feasible to install a MIL-STD-188-114 balanced interface 
prior to upgrading the entire node to DDN-standard (MIL-STD-188-114 
balanced serial PSN interfaces). DDN supports Extended Modem Looping 
(XMOD) through the BELL 303 interface. For ease of reference, table 9-1 
equates the EIA-449, BELL 303, and CCITT interface signal names.  In the 
remainder of the BELL 303 discussion, the EIA-449 signal name will be 
used.

2.  Electrical Characteristics.

    a.  Voltage Levels and Signaling Sense.  The electrical measurements 
of the C/30E interface circuits are in accordance with Bell 303.  The 
cable drivers operate into, and the cable terminators operate from coaxial 
cables, with 75 ohms to  120 ohms characteristic impedance.  The high 
speed interface is provided on a current switching basis. A binary "1", 
Control "OFF" or "marking" signal is represented by a current less than 5 
DCAC-350-180-( )                                                     9-2

ma into 100 ohms.  A binary "0", Control "ON" or "spacing" signal is 
represented by a current greater than 23 ma into 100 ohms.  All 
interchange circuits are fail-safe in that an open circuit is considered a 
control OFF or Mark Hold condition.

The above-mentioned currents are supplied at the output of the cable 
drivers.  The open circuit voltage of the terminator will range between 
-1.3 and -0.8 volts. The negative voltage is added by a bias in the 
terminator.  With greater than 23 ma into 100 ohms supplied to a cable 
terminator, the terminator input voltage is more positive than +1.0 
volts.  An open circuit must be recognized by a terminator as OFF, as 
mentioned above.
DCAC-350-180-( )                                                     9-3

                 TABLE 9-1.  SIGNAL NAME EQUIVALENCY TABLE

                                                                          


EIA-449                                  BELL 303                                  CCITT
ID    Name                               ID     Name                               ID     Name

SG    Signal Ground                      --     Ground in Sleeves                  102    Signal Ground
SC    Send Common                        --                                        102a   DTE Common
RC    Receive Common                     --                                        102b   DCE Common
SD    Send Data                          E      Send Data                          103    Transmitted Data
RD    Receive Data                       K      Received Data                      104    Received Data
RS    Request To Send                                                              105    Request To Send
CS    Clear To Send                                                                106    Ready For Sending
DM    Data Mode                                                                    107    Data Set Ready
TR    Terminal Ready                                                               
                                                                                   108/2  Data Terminal Ready
RR    Receiver Ready                                                               109    Data Channel Received Line
                                                                                           Signal Detector
IS    Terminal In Service                --                                        ---
SR    Signaling Rate Selector                                                      111    Data Signaling Rate
                                                                                           Selector (DTE Source)
SI    Signaling Rate                                                               112    Data Signaling Rate
       Indicator                                                                           Selector (DCE Source)
NS    New Signal                         --                                        ---
TT    Terminal Timing                                                              113    Transmitter Signal Element
                                                                                           
ST    Send  Timing                       J   Serial Clock                          114    Transmitter Signal Element
                                              Transmit                                     Timing (DCE Source)
RT    Receive  Timing                    L   Serial Clock Receive                  115    Receiver Signal Element
                                              (DCE Source)                                 Timing (DCE Source)
SS    Select Standby                     --                                        116    Select Standby
SF    Select Frequency                   --                                        126    Select Transmit Frequency
LL    Local Loopback                     G   Local Test                            141    Local Loopback
RL    Remote Loopback                                                              140    Remote Loopback


                                                                          

DCAC-350-180-( )                                                     9-4

    b.  Clocking.  Two fantails, MMI and MML, provide the connectors that 
terminate cables from all I/O interfaces.  The MMI fantail connector is 
configured as a DTE.  When the MMI fantail is used, the DCE must provide 
clock because the MMI fantail does not support clock-sourcing capability.  
The MML, a clock-sourcing enhanced fantail, is configured as a DCE and 
provides clock.

        (1)  MML Clock Rates.  MML and MMI interface hardware support any 
external clock between  1.2 kb/s and 112 kb/s.  However, DDN policy states 
that the minimum  PSN bit rate be 9.6 kb/s.  When MML clock-sourcing 
capability  is used, the MML on-board clock generator provides the 
following frequencies: 230.4 kb, 50 kb, 19.2 kb.  The 230.4 kb rate is not 
supported by operational software.

        (2)  Maximum Cable Length. The maximum length of the cable is 50 
feet. The MMI-configured PSN connector has a DC-37P type  (male) as the 
DTE and the  MML-configured  PSN  connector has a DC-37S (female) as the 
DCE.  Cable lengths greater than 200 feet may be possible.  The BELL 303 
specification, section 7, should be consulted.

     d.  Interchange Circuits.  The BELL 303 interface is provided by the 
MMI motherboard upon which is attached an MMI/MML daughterboard.

         (1)  Electrical Use of Interchange Circuits.  The DDN electrical 
use of interchange circuits is either static or active.  Static circuits 
are tied by the hardware so that the signal state remains constant on the 
DCAC-350-180-( )                                                     9-5

line, either ON or OFF. Active circuits change their state under program 
control.  DDN use of the interchange circuits is shown in table 9-2.

        (2)  Software Use of Interchange Circuits.  Interchange circuit 
signals are used by the software in different ways.  Active circuits are 
under program control: the software can react to a received signal when it 
changes, and the software can assert a transmitted signal when necessary 
(such as LL, which can be used by operations personnel for testing 
connections).  Unsupported circuits either are not read by the software or 
a value is written to the circuit by the software.  That value does not 
change during operation.  Table 9-2 provides a list of circuits and their 
use.

        (3)  Interchange Circuit Definitions.  For additional information 
about these interchange circuits, see EIA Standard 449.  The following 
descriptions assume use of full period/full duplex circuits, with flow 
control handled at higher levels.

             (a)  Signal Ground.  See EIA Standard 449.

             (b)  Send Data.  See EIA Standard 449.

             (c)  Receive Data.  See EIA Standard 449.

             (d)  Send Timing.  See EIA Standard 449.

             (e)  Receive Timing.  See EIA Standard 449.

DCAC-350-180-( )                                                     9-6

             (f)  Local Loopback.  LL is asserted OFF by PSN software when 
the link is initialized.   LL can be controlled by the Monitoring Center.
DCAC-350-180-( )                                                     9-7

             TABLE 9-2. BELL 303 TRUNK INTERCHANGE CIRCUIT USE

                                                                          


449                               Electrical       Required State of   Comments
ID     EIA-449 Name     Source    Circuit       Control/Status Signals

SG     Signal  Ground   DTE/DCE   Ground in Sleeve        N/A            Ground
SD     Send Data        DTE       Active                  N/A            Data Circuit
RD     Receive Data     DCE       Active                  N/A            Data Circuit
ST     Send Timing      DCE       Active                  N/A            Timing circuit for Transmitted
                                                                         Data when DCE provides timing.
RT     Receive Timing   DCE       Active          N/A                    Timing circuit for Received
                                                                         Data when DCE provides timing.
LL     Local Loopback   DTE       Active          OFF                    Initialized to OFF by PSN software.
                                                                         Available for Monitoring Center
                                                                         Control through XMOD.


                                                                          

NOTE:  N/A = Not Applicable
DCAC-350-180-( )                                                     9-8

3.  Mechanical Characteristics.  All BELL 303 connectors offered for the 
C/30E meet the following specifications.

    a.  Interface Connectors.  The C/30E MMI/MML BELL 303 connector DC-37P 
type (male) connectors.

        (1)  Intermating dimensions are in accordance with EIA Standard 
449, section 3.3.1.

        (2)  The means for C/30E DTE connectors to latch and unlatch from 
the latching blocks on the DCE connector are within the dimensions 
specified in EIA Standard 449, section 3.3.2.  DDN uses the English 4-40 
thread latching block.

    b.  Connector Contact Assignments.  All C/30E BELL 303 contact 
assignments, as shown in table 9-3, provide the DDN
standard node connector pinout.   The signals are used asspecified in EIA 
Standard 449 section 2.d.3.
DCAC-350-180-( )                                                     9-9

       TABLE 9-3.  DDN STANDARD NODE EIA-449 (DTE) CONNECTOR PINOUT

                                                                          

Pin     EIA     CCITT   Name
        ID      ID    

8       SD      103     Send Data
27      SG      102     Signal Ground
12      ST      114     Send Timing
31      SG      102     Signal Ground
10      RD      104     Receive Data
29      SG      102     Signal Ground
6       RT      115     Receive Timing
25      SG      102     Signal Ground
11      LL      141     Local Loopback
30      SG      102     Signal Ground

                                                                          
DCAC-350-180-( )                                                     9-10

4.  Interconnecting Cables.

    a.  Interconnecting cables must be low capacitance, multiple twisted 
pair that result in  a transmission line with a nominal characteristic 
impedance on the order of 100 ohms to frequencies greater than 100 kHz, 
and a dc series loop resistance not exceeding 240 ohms.  The overall braid 
shield must have at least 85% coverage.

        (1)  Conductor Size.  Interconnecting cables or wires should be 
composed of wires of a 24 AWG or larger conductor for solid or stranded 
copper wires, or for non-copper conductors a sufficient size to yield a dc 
wire resistance not to exceed 30 ohms/1000 feet per conductor.

        (2)  Mutual Pair Capacitance.  The capacitance between one  wire  
in the pair to the other wire in the pair  should  not exceed  20 
picofarads/foot,  and the value should  be  reasonably uniform over the 
length of the wire or cable. 

        (3)  Stray Capacitance.  The capacitance between one wire  in  the 
cable to all others in the cable sheath,  with  all others connected to 
ground, should not exceed 40 picofarads/foot,and should be reasonably 
uniform for a given conductor over the length of the wire or cable.

        (4)  Pair-to-Pair Balanced Crosstalk.  The crosstalk from on pair 
of wires to any other pair in the same cable sheath should have a minimum 
value of 40 dB attenuation measured at 150 kHz.
DCAC-350-180-( )                                                     9-11

    b.  Figure 9-1 is a cabling diagram of a C/30E PSN connected to a 
nearby BELL 303 PSN, and figure 9-2 is an example of a cable used to 
interconnect them.









   +-------------------------------------------------------------------+
   |                                                                   |
   |   C/30E PSN                                          C/30E PSN    |
   | +------------+                                     +------------+ |
   | |    MMI     |                                     |     MML    | |
   | |            |2405538601              R 2405538601 |            | |
   | | BELL - 303 |-------------------------------------| BELL - 303 | |
   | |            |                                     |            | |
   | |    DTE     |                                     |            | |
   | +------------+                                     +------------+ |
   |                                                                   |
   +-------------------------------------------------------------------+

         FIGURE 9-1.  BELL 303 MMI TO BELL 303 MML CABLING EXAMPLE
DCAC-350-180-( )                                                     9-12









       +-----------------------------------------------------------+
       |      C/30E                                       C/30E    |
       |        P1                                         P2      |
       |      DC-37S                                      DC-37P   |
       | Pin#     Signal                            Signal    Pin# |
       |  +/-       +/-   Shield             Shield   +/-      +/- |
       |  1         FG  >--------+         +-------<  FG       1   |
       |                                                           |
       |                                                           |
       |                 Pair #                                    |
       |  8/27      SD  >-(1)----------------------<  SD      8/27 |
       |                                                           |
       |  12/31     ST  >-(2)----------------------<  ST     12/31 |
       |                                                           |
       |  10/29     RD  >-(3)----------------------<  RD     10/29 |
       |                                                           |
       |  6/25      RC  >-(4)----------------------<  RC      6/25 |
       |                                                           |
       |  11/30     LL  >-(5)----------------------<  LL     11/30 |
       |                                                           |
       +-----------------------------------------------------------+

           FIGURE 9-2.  BELL 303 TRUNK INTERFACE CABLING EXAMPLE
 DCAC-350-180-( )                                                     10-1

               CHAPTER 10.  BELL 303 REMOTE TRUNK INTERFACE

1.  Overview.  This chapter describes the electrical and mechanical
characteristics of the BELL 303 balanced remote trunk interface.  This
chapter documents the interface between the remote modem and the PSN
(demarcation point A in figure 10-1) with no intervening cryptographic
devices (KG-84As).  The DDN standard is a MIL-STD-188-114 balanced
interface, and the BELL 303 is used only when it is not feasible to
install the standard. DDN supports Extended Modem Looping (XMOD)
through the BELL 303 interface.

2.  Electrical Characteristics.

    a. Voltage Levels and Signaling Sense.  The modems used will conform 
to BELL 303.

    b.  Clocking.

        (1)  Modem Clocking.  The modem supplies timing on the Send Timing 
and Receive Timing circuits.  Terminal Timing is not supported for remote 
PSN interfaces.  While the DDN hardware will support between 1.2 kb/s and 
64 kb/s, DDN policy is that the minimum PSN access rate be 9.6 kb/s.

DCAC-350-180-( )                                                     10-2









     +--------------------------------------------------------------+
     |                                                              |
     |                                                              |
     | C/30E PSN                                          PSN       |
     | +----------+     +----------+  +---------+     +-----------+ |
     | |          |     |          |  |         |     |           | |
     | |BELL - 303|-----|BELL -303 |--|BELL -303|-----| BELL -303 | |
     | |   DTE    | /|\ |  DCE     |  |  DCE    | /|\ |           | |
     | |          |  |  |          |  |         |  |  |           | |
     | +----------+  |  +----------+  +---------+  |  +-----------+ |
     |               |                             |                |
     |               |                             |                |
     |         2405537601                    R 2405537601           |
     |                                                              |
     +--------------------------------------------------------------+

     FIGURE 10-1.  DEMARCATION POINT "A" BETWEEN THE C/30E AND REMOTE
                   C/30E  
DCAC-350-180-( )                                                     10-3

    c.  Bit Rate and Cable Length.

        (1)  Maximum Cable Length.  The maximum cable length between the 
remote modem and the PSN is 50 feet; however, in some special applications 
cable lengths more  than  200 feet are possible.   Refer to the BELL 303  
specification section 7.0 for details. 

    d.  Interchange Circuits.

        (1)  C/30E Local Modem Interface.

             (a)  Signal flow between the C/30E and the local modem is 
shown in figure 6-3.  This interface and associated hardware are provided 
by DDN.  This DCE interface uses BELL 303 pin assignments.

             (b)  As shown in figure 10-2, the supported signals are Send 
Data (SD), Serial Clock Transmit (ST), Receive Data (RD), and Serial Clock 
Receive (SR) and Local Test (LL).

3.  Mechanical Characteristics.

    a.  Interface Connectors.  The PSN end of the cable has a connector  
of  the DC-37S type (female) and the DCE  end  of  the cable  connector  
has  a  Burndy MD12MXP-17TC  plug  with a  Burndy M2H50RC-1P2 protective 
shield.

DCAC-350-180-( )                                                     10-4

    b.  Connector Contact Assignments.  Table 10-1 provides the standard 
DTE pinouts.  Table 10-2 provides the standard  DCE pinouts, and section 
2.d.3 of the EIA Standard 449 provides circuit descriptions.
DCAC-350-180-( )                                                     10-5









       +-----------------------------------------------------------+
       |      C/30E                                       C/30E    |
       |        P1                                         P2      |
       |      DC-37S                                      DC-37P   |
       | Pin#     Signal                            Signal    Pin# |
       |  +/-       +/-   Shield             Shield   +/-      +/- |
       |  1             >--------+         +-------<           1   |
       |                                                           |
       |                                                           |
       |                 Pair #                                    |
       |  8/27      SD  >-(1)----------------------<  SD  E/SLEEVE |
       |                                                           |
       |  12/31     ST  >-(2)----------------------<  ST  J/SLEEVE |
       |                                                           |
       |  10/29     RD  >-(3)----------------------<  RD  K/SLEEVE |
       |                                                           |
       |  6/25      RC  >-(4)----------------------<  RC  L/SLEEVE |
       |                                                           |
       |  11/30     LL  >-(5)----------------------<  LL  G/SLEEVE |
       |                                                           |
       +-----------------------------------------------------------+

        FIGURE 10-2.  BELL 303 REMOTE TRUNK INTERCHANGE CIRCUIT USE
DCAC-350-180-( )                                                     10-6

                TABLE 10-1.  DTE INTERFACE CONNECTOR PINOUT

                                                                          

        Pin     EIA     CCITT      Name   
                ID      ID    

        8       SD      103        Send Data
        27      SG      102        Signal Ground
        12      ST      114        Send Timing
        31      SG      102        Signal Ground
        10      RD      104        Receive Data
        29      SG      102        Signal Ground
        6       RT      115        Receive Timing
        25      SG      102        Signal Ground
        11      LL      141        Local Loopback
        30      SG      102        Signal Ground

                                                                          

DCAC-350-180-( )                                                     10-7

            TABLE 10-2.  DCE BELL 303 INTERFACE CONECTOR PINOUT

                                                                          

        Pin         EIA     CCITT         Name
                    ID      ID            

Mandatory

        E           SD      103           Send Data             
        SLEEVE      SG      102           Signal Ground         
        J           ST      114           Send Timing           
        SLEEVE      SG      102           Signal Ground
        K           RD      104           Receive Data          
        SLEEVE      SG      102           Signal Ground         
        L           RT      115           Receive Timing        
        SLEEVE      SG      102           Signal Ground

Optional

        G           LL      141           Local Loopback
        SLEEVE      SG      102           "D" Loop (Reserved)   

                                                                          

DCAC-350-180-( )                                                     10-8

             TABLE 10-3  KGAB - REMOTE MODEM CONNECTOR PINOUT

                                                                          

        Pin         EIA     CCITT         Name
                    ID      ID

Mandatory

        1           FG                    Frame Ground
        2           SD +    103           Send Data
        3           SD -    103           Send Data
        4           ST +    114           Send Timing
        5           ST -    114           Send Timing
        6           RD +    104           Receive Data
        7           RD -    104           Receive Data
        8           RT +    115           Receive Timing
        9           RT -    115           Receive Timing
        10          TR +    108.2         Terminal Ready
        11          TR -    108.2         Terminal Ready
        14          SG      102           Signal Ground
        15          SG      102           Signal Ground
        24          TT +    113           Terminal Timing
        25          TT -    113           Terminal Timing

Optional

        12          CS +    106           Clear to Send
        13          CS -    106           Clear to Send
        16          CL +    ---           "C" Loop (KG-84A Loop)
        17          CL -    ---           "C" Loop (KG-84A Loop)
        18          RL +    140           Remote Loopback
        19          RL -    140           Remote Loopback
        20          DL +    ---           "D" Loop (Reserved)
        21          DL -    ---           "D" Loop (Reserved)
        22          LL +    141           Local Loopback
        23          LL -    141           Local Loopback

                                                                          

DCAC-350-180-( )                                                     10-9

4.  Interconnecting Cables.  Figure 10-1 provides a cabling diagram of a 
configuration with a C/30E and a BELL 303 modem. Table 10-3 describes the 
cable used for interconnecting these devices.




                    TABLE 10-3. REMOTE INTERFACE CABLES

                                                                          

Connection               BBNCC         Description
                         P/N#

PSN IMP/MII to BELL 303  2405537G01    5-pr, PSN/MII BELL 303
                                       to BELL 303 Modem

                                                                          
 



TUCoPS is optimized to look best in Firefox® on a widescreen monitor (1440x900 or better).
Site design & layout copyright © 1986-2014 AOH