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TUCoPS :: Networks :: itapac.txt

What is ITAPAC




_______________________________________________________________________________ 
 
 
                         ItaPac - A Brief Introduction 
 
                   A Telecom Computer Security Bulletin File 
_______________________________________________________________________________ 
 
 
 
Prologue 
-------- 
This text will represent a very complete tutorial about a packet switching 
network used in Italy: ItaPac.  The purpose of this file is to supply very 
interesting information to have secure use and VERY LONG ItaPac password 
lifetime.  It includes also a brief summary of what (shit) ItaPac is, techincal
terms, various news. 
 
 
What's ItaPac 
------------- 
ItaPac is the Italian Packet Switched Network.  The "packet" protocol is called
as it is because the data which travels through the network is assembled in 
255 char groups (packets), with an address physically in the net towards which 
data is sent at fixed time intervals.  Packets can thus contain different 
source data, and in this way they divide the cost of transmission and optimize 
net traffic.  All of which runs transparent to the users, which doesn't remark 
of commutation, and works in an apparent "real time". 
 
In order to support all available protocols, the Packet Switch needs gestional 
software.  As for definition, all terminals able to support the switching are 
called PADs (packet assembly-disassembly) and work following the CCITT X.25 
recommendations. 
 
A PAD is very expensive to run.  It is not the software or hardware that is so 
expensive, but rather the continuous maintenance and supervision required to 
keep the system running.  Normally, most of the users prefer have the switching
handled by an ACP Server which makes his call and transforms the packet proto- 
col from X.25 to an X.28 asycronous, that is compatable with the normal modems 
that we use. 
 
The user becomes like a DTE (Data Terminal Equipment), he connects to an ACP 
(Adapter/Concentretor of Packets) and can operate in trasparency without 
any kind of problems. 
 
The user can login to a pad in either of two ways: 
 
1) DIRECTLY: by dedicated wire installed by Italcable.  The cost is higher, 
     but that guarantees a much higher transmission quality. 
 
2) SWITCHED: by phone (switched line, not to be confused with ACP, even if 
     there are similarities); the cost is much lower, but the transmission 
     quality is unacceptable at times. 

The direct X.28 user has his own network user address (NUA).  Some users have 
only one NUA while others have a multiplexed system.  This system generally 
consists of one NUA and a variable number of subaddresses.  The actual number 
of subaddresses depends on the number of doors he has into his pad. 
 
The switched user (poor) can only call others DTE, but he cannot receive calls,
because he doesn't a network user address.  In effect the only address where he
can answer is that of the PAD on which he is logged on.  Thus the DTE call from
a phone number (of home, office, etc), if he can receive calls from another 
DTE, means that the hardware is able to scan the call, and we will all be in 
the shit (sorry for the hard expression). 
 
Taking apart the quality in trasmission, there is no difference between the two
X.28 types: both need a modem.  The first, connected to a standard phone line, 
and the second to dedicated one. 
 
For the rest of this file we will talk about the X.28 terminals of the second 
type: the dedicated ItaPac PADs. 
 
The ACP at their time, are connected to NCP (Nodes of Commutation of Packets) 
with transit functions or access for DTE X.25 and of local commutation.  The 
NCP are connected between them at high speed (64k/second), and ACP are conn- 
ected to NCP at 9600 bit/second. 
 
 ___________________________________________________________________________ 
|              |                |          |             |                  | 
|  User Class  |  Xmit Methods  |  Speeds  |  Protocols  |  Access Methods  | 
|______________|________________|__________|_____________|__________________| 
|              |                |          |             |                  | 
| Char by Char |   Start/Stop   | 300/1200 |     X28     |   Via Phone or   | 
|   Terminal   | Full/Half Dup. |   baud   |             |      Direct      | 
|______________|________________|__________|_____________|__________________| 
|              |                |          |             |                  | 
|    Packet    |      HDLC      | 2400 and |     X25     |      Direct      | 
|  Terminals   |  Full Duplex   | 9600 bps |             |       Only       | 
|______________|________________|__________|_____________|__________________| 
 
 
The CCITT standard makes it possible to interface ItaPac with other networks 
around the world.  In effect, the NCPs are connected as big telephonic centers.
Anyway, it seems that all European traffic to the USA and other countries, such
as Australia, Argentina, Japan, etc, will transmit by the centers that are in 
Paris, France.  Maybe from Paris data is sent via satellite, but I don't know. 
 
 
NUIs, NUAs, and DNICs 
--------------------- 
Well, when you connect to one of ItaPac's entry points (of which there are 41 
ACP sites on Italian terrain at 300/200 baud and full duplex (V21, V22)), 
ItaPac responds: 
 
     ACP:** I T A P A C ** GENOVA 32 PORTA: 4 
 
The above is an example of the herald for an entry node in Genoa.  In the
example you can note that the number "32:" is really the node (the phone number 
you have called).  Larger cities generally have more than one node.  The PORTA
is the port to the node (the physical entry point to the node).  "PORTA: 4"
means that you are connected to the fourth port of this particular Genoa
ItaPac node. 
You can also see from the above example that there are 3 other people connected
to the same node as you.  Every ItaPac node can support at greatest a finite 
number of ports.  If all the ports of a node are in use then the PAD will 
reject all new DTE calls. 
 
Frequently most (or all) of the ports until Friday night will not answer at 
all.  Until one logs you off you cannot enter a port that is in use.  Very 
often the first 2 or 3 ports will be busy from an internal console, or these 
will be reserved as an "emergency lane" for internal-use-only.  A good way to 
use a free door is to send to people that are probably the callers an Urgent 
Call Income (UCI; in the States it is known as a BVC -- Busy Verification 
Signal -- AKA emergency interrupt).  The you can redial the node.  This time 
ItaPac will answer.  The message "Beware, please, Urgent Urban Call Incoming" 
will appear on the screen.  This will blow our friend from the port, thus 
freeing it for our use.  Eh eh.  Now for some definitions. 
 
1) NUI 
2) NUA 
3) CUG (optional) 
 
NUI - Network User Identification: Nothing other than an ItaPac password. 
Every time you call an NUA, ItaPac will charge the account of owner of the 
password.  Often NUIs are valid only for certain nodes.  That is if the 
contract signed with Italcable will allow a 300 baud at Genova on 2697, this 
NUI will not work on the 2564 node.  SYNTAX: the NUI must be preceded by 
UPPERCASE "N" and finished by a minus "-".  The NUI MUST BE TYPED IN UPPERCASE.
Between "N" and "-" the NUI will not be displayed (echoed).  You will obtain 
only "N-" on display. 
 
NUA-Network User Address: the physical address of a remote DTE.  Similar to a 
phone number, you understand.  Must be typed without blank inside and soon 
after the NUI (or a timeout will occur and ItaPac will hang up on you). 
 
CUG - Close User Group: this is basically a high-security NUI.  CUG stands for 
Close User Group.  CUG users have access to optional parameters that are used 
for user recognition (and you know what that means).  Having a CUG account is 
very handy.  CUG users have the ability to inibit hackers (after all, they are 
there for network security, right?).  There are less CUG users in Italy than 
the USA and are generally rare (but I know of one).  A typical example would 
be the US Tymnet NUAs (03106nnnnnn).  The PAS response will be ACP:CLR NA or 
Call Not Accepted and shut down.  Makes hacking on a CUG account a good way to 
waste your time. 
 
Now we will take a closer look at an ItaPac NUAs structure (the numbers are 
examples only): 
 
    DCC  NC 
    |  __| 
   / \|
   12345678901234 
   \_ / 
     | 
    DNIC 
 
DNIC = Data Network Identification Code; it contains the address of the country
to be called and the code for the network chosen.  It is then divided into two 
parts: DCC and NC. 
 
DCC is the Data Country Code; a three digit number that is the phone prefix. 
Every country has different one. 
 
NC is the Network Code; a country can have more than one data network.  In 
Italy there is ONLY packet switched network, the code is "2" and it is Dardo. 
 
Follow with: the prefix of the called city, the DTE number, an eventual suffix 
that is the "phone particular" (max 4 digit). 
 
Note: The DCC is used only to call outside.  DCC must be preceded by a zero. 
ItaPac, in this case, is different from other countries. 
 
Let's show a pratical example: The Cilea of Milan (Segrate). 
 
The NUA is:  2220208 
             |||______ local address of DTE 
             ||_______ 2 (02) = Milano 
             |________ NC: 2  = ItaPac 
 
Now, another example: the Altos Unix (altger) in Munich, West Germany (note: 
a favorite hangout of Xtension). 
 
The NUA is: 026245890040004 
            |\ /|\_ _/| 
            | | |  |  |____ 40004: network address 
            | | |  |_______ 5 8900: munich prefix 
            | | |__________ 4: DATEX-P (germany ItaPac) 
            | |____________ 262: DCC West Germany 
            |______________ foreign call 
 
The NUA's structure isn't so all the time.  NUAs can exist that don't appear to
have countries or cities.  This because the address is sent to an indicated ACP
that will provide the rerouting of the call.  If the NCP has been instructed to
consider a certain address like another, the DTE can have a Rome NUA and be 
located in Genoa.  As call with the account to called... 
 
It's very important to be able to read an NUA.  Many times you can find systems
like VAXs and UNIXs and some refer to not-interactive logins; NUAs are not 
often completed.  An NUA without a DNIC is like a phone number without an area 
code: its meaning is nothing.  Usually the system makes references to a subject
network, or it supplies other info in a less clear fashion.  At this need I 
will supply a very short list of world wide DNICs I've found (notice that they 
are old hat, the new stuff is only for friends)... 
 
Beware: many countries own more than one national network (GB, USA, etc) then
you will probably hear a thousand cries of "In USA where?  On Tymnet, or 
Autonet?  or Telenet?  or RCA?  EtherNet?"  And I can continue... 
 
  
DNIC   Network Name    Country 
_______________________________________________________________________________ 
 
 
2041   Datanet 1       Netherlands 
2062   DCS             Belgium 
2080   Transpac        France 
2284   Telepac         Switzerland 
2322   Datex-P         Austria 
2329   Radaus          Austria 
2342   PSS             UK 
2382   Datapak         Denmark 
2402   Datapak         Sweden 
2405   Telepak         Sweden 
2442   Finpak          Finland 
2624   Datex-P         West Germany 
2704   Luxpac          Luxembourg 
2724   Eirpak          Ireland 
3020   Datapac         Canada 
3028   Infogram        Canada 
3103   ITT/UDTS        USA 
3106   Tymnet          USA 
3110   Telenet         USA 
3340   Telepac         Mexico 
3400   UDTS-Curacau    Curacau 
4251   Isranet         Israel 
4401   DDX-P           Japan 
4408   Venus-P         Japan 
4501   Dacom-Net       South Korea 
4542   Intelpak        Singapore 
5052   Austpac         Australia 
5053   Midas           Australia 
5252   Telepac         Hong Kong 
5301   Pacnet          New Zealand 
6550   Saponet         South Africa 
7240   Interdata       Brazil 
7241   Renpac          Brazil 
9000   Dialnet         USA 
7421   Dompac          French Guiana 
 
 
This list may be in the hands of hackers everywhere.  And, because the bread 
for a hacker is done with ItaPac's floor, the minimum I suggest is to learn by 
memory the main International DNICs.  Not these for French Guiana, but the main
European and American ones. 
 
Let's return to ItaPac.  When you are connected to a remote system, the network
sends an ACP: COM and it leaves the field and lets you join the host.  To clear
call and return in command mode (the star "*" prompt) must make some
differences.
 
1 - for the most part, the host leaves the possibility to user to talk with his
    PAD, either to setup his parameters, close, reset or confirm the call.  In 
    this case, often frequently, with the sequence CTRL-P ItaPac will reappear 
    with its "*" prompt and it accepts commands.  Typing "CLR" ItaPac will 
    close the virtual call to host and answer "ACP: CLR CONF". 
 
2 - Some Hosts, usually those with internal PADs, won't allow to ItaPac control
    to the user.  CTRL-P is not recognized, and the only way to logoff or catch
    the control of the PAD is send a ten LONG-BREAK sequences.  The BREAK, not 
    to be confused with CTRL-C, that is not in this site, is an INTERNAL signal
    whic(BFs not an ASCII code.  It is used by the communication program you 
    use to send that acknowledgment.  If you don't have the capability to send 
    BREAK (short or long); beware not to use these black holes from where the 
    only way to exit will be the physical disconnect from the PAD (ie, drop 
    carrier on the modem). 
 
3 - The use of CLR is not correct and in most cases it will cause serious 
    problems to host machines.  In effect, their software (or perhaps hardware)
    is not able to translate correctly the loss of carrier and enters into a 
    "Wait-State Pending", that will finish only before a well-defined interval.
    In the mean time, this door is unavailable.  Network administratons never 
    like CTRL-P CLR. 
 
 
Network Signals, Profiles (Outline, Shapes, Sketch), Parameters 
--------------------------------------------------------------- 
A detailed description about all net signals, standard outlines and parameter 
sets, is supplied from a "manual about ItaPac access from X28 start-stop 
terminals" 
 
This manual can easily be "thieved" at kermesses in Italcables stands, in more 
desperate cases, you can ask that to your friends. 
 
What is not written therein into from Italcable is the meaning about parameters
14,15,16,17,18,19.  Official guide stops at the 13th.  But command ^P PAR? 
gives a full list with 19 entries!  Now here are the descriptions: 
 
14: Padding after Line feed (LF) 
    0  No padding inserted 
 1-15  When it is in the Data Transfer state, the pad inserts a time delay from
       1 to 15 chars times the length after each LF that it inserts.  The 
       normal setting is determined by the terminal in use. 
 
15: Editing of data 
       This parameter and the following parameters (16, 17, and 18) determines 
       how editing of data is perfomed when the pad is in the Data Transfer 
       State 
    0  editing of data is not possible 
    1  Must be set to this value if the editing facility required 
 
16: Charachter delete character 
    0  characted deletion is not possible 
1-255  This is the IA5 decimal code of the choosen delete character.  The
       normal setting is 127 (for RUBOUT or DEL) 
 
17: Buffer delete character 
    0  Buffer deletion is not possible 
1-255  This is IA5 decimal code of the choosen buffer delete char.  The normal 
       setting is 24 (CTRL-X) or (CAN) 
 
18: Buffer display character 
    0  Buffer display is not possible 
1-255  This is the IA5 decimal code of the choosen buffer display char.  The 
       normal setting is 18 (CTRL-R) or (TAPE-ON) 
 
Parameter 19 is unknown.  One word about Delete.  It's possible to correct what
is typed in command mode via the DEL key.  If you use the Backspace (ASCII 8) 
key ItaPac will not accept corrections but it will translate these as true 
chars. 
 
 
PAD SPEED 
--------- 
If your modem will colloquiate with a PAD at a defined baud rate (300 or 1200, 
full duplex) the packet transmission will slow in a drastic way the number of 
incoming and outgoing characters from your DTE. 
 
PADs send a continuous stream of clear-to-send and Ready-to-send signals that 
are really macro rests between packets.  At lower transmission speeds (ie, 300 
baud) the switching does not feel right, but at 1200 it does.  We have computed
that the speed of real transfers and receiving can, at maximum performance, 
raise to 450 baud.  It is slower when you transfer a file, when the PADs work 
is very heavy.  Via Xmodem, the PAD will try to destroy time-out signals, or 
confuse all.  Public computer systems such as Delphi know that also.  If you 
aren't able to download correctly using the Xmodem protocol then that means 
that only the remote host isn't detecting the differences between packets 
and asybchronous terminals. 
 
The question is: will it happen only on ItaPac (not new) or is a common 
problem to all NCPs? 
 
 
"NC" Nights 
----------- 
There are nights in which every address you call is "NC".  The Network Conges- 
tion state is very frequent on ItaPac, and will disallow the use of the network
used from NCP.  The causes are very mysterious.  At night Firms aren't using 
ItaPac, and it seems the network is used only by hobbists.  Then what?  At the 
Service center they negate all, but this is reality.  ItaPac, at the end, is an
asshole.
 
It has very high rates but they will add a joke to the classical thief: some- 
times it doesn't work.  How does it not work?  Ha!  To them everything is 
always ok.  And then someone will cry scandal if you try to bypass them! 
 
 
NUIs USED
--------- 
Usually, NUIs that are used (or had been used) are demo NUIs.  It hasn't an 
account, and then -in theory- cannot exaust.  Operators cannot ever notify 
their use, because they don't have a record of calls...If a demo NUI will die, 
the cause can be one of only two: 
 
1) ItaPac has changed codes due to normal administration 
 
2) ItaPac was warning about the happening, or from their techician who had 
   noted abnormal traffic and has controlled, or from an external (a son of 
   a bitch spy!) 
 
 
     +2-15-87 
        +-+ 
        | | 
     +--+ +--+ 
     +--+ +--+ 
        | | 
        | | 
        |_| 
      53ST6R 
 
 
  An historical NUA- it has been working for over 2 years, and for a SPY...   
 
 
HOW GET AN NUI 
-------------- 
The more simple and safe method is to copy that from kermesses where Italcable,
or otherwise, use X.28 wires.  The dedicated X28 DOESN'T NEED AN NUI because 
they are directly connected. 
 
Go near the operator and ask "That is a MODEM?" 
 
Operator (if they have the time) will be moved to pity, in front of so much 
ingnorance, and he feels so relaxed, types in his pw.  You, with an optimum 
eye, must read the keyboard and memorize the NUI.  This is called shoulder 
surfing. 
 
It is well, in the case of big kermesses, to try to catch ANY booklet, agenda, 
block notes left near terminals.  If the stand is owned by Italcable, ALL you 
can catch, must BE, without differences. 
 
A new scanning technique, based on trying statistically calculated, is in exam 
between DTE222.  This technique may guarantee, if applied to a long scan time, 
posithives results in NUI research.  The minimum number of NUI tried cannot be 
less than to 100,000 (1 hundred thousand), causing cost and time problems. 
 
At large lines, that rule is like: a NUI generator will provide to create a 
very likely NUI following the same criteria.  A scanner will try all in an 
automatic manner.  It tries 8, then it uses a valid NUI to connect to 22000 
(Echo pad), immediatly it logs off (CLR CONF), putting zero thanks to ACP:COM 
the ACP:ERR ILL counter (how we know, to 10th ERR ILL the pad will logoff
physical call [hangs]).  The 9th try is as security margin.  Then the scanning 
will restart.  At 1200 baud - therefore - we had a 1400 hours tested NUI 
average.  This, is all talk!  In addition, it seems that before 700 ERR ILL, 
not looking counter reset, ItaPac will hang up.  That will make it more diff- 
icult for our computer; it araises at times (will redial number) and make the 
search more expensive. 
 
 
NETWORK SIGNALS 
--------------- 
Net can send several mesages: 
    - as answer to a command 
    - for his own decision 
    - following an action performed byt remote terminal 
 
1.  Errors messages 
 
ERR CNA  syntax of command is correct, but not allowed in this state 
ERR ILL  command is not syntactically correct or the hit is not recognized 
ERR EXP  timeout and command was not completed 
ERR PNA  the requested outline is not assigned yet 
 
2.  Logoff messages 
 
CLR OCC  the called number is busy 
CLR NC   Network congestion or temporaly failure of hardaware cannot allow new 
         calls 
CLR INV  Requested performance is not valid 
CLR NA   The calling number cannot have connection to DTE (ex: Close User 
         Group not compatable) 
CLR ERR  Call is hung for a local procedure error 
CLR RPE  Call is hung for a remote DTE error 
CLR NP   Called NUA is not assigned 
CLR DER  Called NUA is out of order 
CLR PAD  PAD has hung the call because he had received am invitation to  
         "clear" from DTE 
CLR DTE  Remote DTE hung call 
CLR RNA  Remote DTE cannot accept charged calls 
 
3.  Reset Messages 
 
RESET DTE  Remote has resetted virtual circuit 
RESET RPE  Call is putt in reset state for remote DTE error 
RESET ERR  Call is reset for a local error 
RESET NC   Call is hung for a network congestion 
 
 
RATES AND DUTIES 
---------------- 
For whoever wants to subscribe ItaPac, here are the rates.  For whoever uses it
as Portoguese it might be interesting to have an idea about how much it costs 
the real owner of an NUI.  The, if you have one, don't abuse and don't tell it 
to the four winds. Remember that real owner can, at any moment, change it! 

 
BY X.28 Switched Phone 
---------------------- 
  Class (baud)     Lire/Month 
       300           12,150 
      1200            7,100 
 
NUI duties: 7,200 / month 
 
to these must be added: 
 
  modem duties 
  mail and telegraph duties 
  contributions and trafic (counter turns!) 
 
The amount of the first two isn't clearly specified on the rates-sheets, but it
is marked as: 
 
Following the current rates.  Last, is so divided: they will consider the 
distance betweenyouser site and the centre of relhative area phone code. 
 
 
X.25-X.28 Direct Connection 
--------------------------- 
Class (baud)    Lire/Month 
     300         108,000 
    1200         139,500 
    2400         208,800 
    4800         275,400 
    9600         311,400 
 
To these must be added: 
 
  modem duties 
  duties foryouse of area to area circuitery 
  duties for new wires 
 
 
Time rates for Ports Taken 
-------------------------- 
class (baud)    Lire/Minute (or fract) 
     300         13.50 
    1200         18.00 
 
 
Time Rates 
---------- 
  6.80 Lire/minute or fraction 
 
 
Volume rates 
------------ 
  1.78 Lire/segment or fraction thereof (1 segment= 64 octets) 

 
Rates to call 
------------- 
  30 lire / call 
 
 
Addings per NUI 
--------------- 
  7,200 / month 
 
For time and volume rates there is a 30% discount from 9 PM to 8 AM every day, 
including Saturday and non-working days 
 
 
PVC Rates 
--------- 
 54,000 Lire / Month 
 
 
Class of Max Charge of line 
--------------------------- 
 9,000 * KB / Month 
 
 
CUG 
--- 
 Master    56,700 Lire / Month 
Users         900 Lire / Month 
 
 
Payment to Called 
----------------- 
  8,100 / Month 
 
 
Change Options Parms 
-------------------- 
  45,000 Lire 
 
 
Speed Class Change 
------------------ 
  90,000 lire 
 
 
Calls List 
---------- 
  Lire 30 each voice in list 
 
International Trafic [The rates are in Gold Francs (GF)] 
 
 
Europe 
------
  GF 0.107 / min or fraction thereof 
 
 
Extra Europe 
------------ 
  GF 0.3333 / min or fract (1) 
  GF 0.4    / min or fract (2) 
  GF 0.5    / min or fract (3) 
 
(1) North America or Middle East directly connected to Italy 
(2) Other countries out from Europe directly connected to Italy 
(3) All others 
 
In a few words, if you aren't a Multinational Company, but an hobbist, you must
charge a 20 years money loan to be able to afford ItaPac. 
 
The Network is also able to receive characters following international Alphabet
from CCITT No. 5 (IA5) with 1 or 2 stop bits and it will produce even chars 
with the #2 stop bit.  In the exchange of control chars between terminals and 
net, ItaPac will translate characters dropping out the parity and send chars 
with even parity.  Characters are exchanged in transparent way to user regard- 
ing parity and bits. 
 
 
TO CONNECT VIA THE SWITCHED WAY 
------------------------------- 
1) Dial the ItaPac node phone number.  Whoever doesn't have an automatic modem 
   must switch to data within 10 seconds from the first ItaPac tone. 
 
2) send two <CR> to build the phisycal connection (within 30 seconds) 
 
3) ItaPac will send the network herald, ACP identification and entry port (as 
   explained) 
 
4) At you're request: enter the virtual call state by typing ACP: FREE 
 
5) send call request by issuing the NUI, the NUA and the data field (max 12 
characters optional).  E.g: if the NUI is AAAAAA and the NUA is 2345678 you 
must type: NAAAAAA-2345678 <CR>.  The NUI is never echoed on screen.  All 
sequences must blank free and entered within 120 seconds from first keypress. 
If you type a wrong NUI, net will answer ACP: ERR ILL.  If you also need to 
send a data string, (e.g.  ABCD) send: NAAAAAA-2345678 D or P ABCD <CR>. 
Typing 'D' before string the following data will be echoed, with 'P'. 
 
6) net give ACP: COM if call is done. 
 
From this moment starts the data exchange phase and, until you disconnect, all 
commands to the net must be preceded with the ^P sequence.  If the call is not 
correct, the net will answer by sending a disconnect signal to specify the 
cause of it.  After 10 times of unsuccessfully placed calls, the net will hang 
up the carrier.  If the call is possible, the NUA will receive an ACP: (caller 
address) COM. 
 

COMMANDS 
-------- 
The following commands can be issued prior to having a connection, meanwhile 
data transfer.  In the last case, type a ^P before to exit data session (either
it's considered as data itself).  At end of command send <CR>.  Beware that in 
a start-stop terminals calls (X.28) commands must sent also from TH in packet 
way, following X.29 procedures. 
 
1) Virtual call state request: 
     STAT <CR> 
     will answer: 
     - if call is on : ACP: ENGAGED 
     - if call is off : ACP: FREE 
 
2) Shape Choose 
  
    PROF <CR> 
    network will put on that (see later).  At start the #3 is default outline. 
 
3) Commands to send only during the data exchange (preceded by ^P) 
    reset request: ^P RESET <CR> 
    That command will cancel call followings data on line. 
 
4) Interrupt send to remote DTE: 
    ^P INT <CR> 
   This packet will go over travelling data.  Then, the action taked by host 
is software depending on. 
 
 
THE EDITING FEATURE. 
 
By the Editing Feature, you can delete a char or a line to make editing the PAD
provide buffered characters.  The editing function is ever in use during X.28 
and the ACP xmit.  To have it meanwhile data transfer you must choose parm 15. 
In this case, the user can choose between parms 16,17 and 18 the usable chars 
to request editing function and he can, via par 19, editing signals send by 
PAD. 
 
1) Delete a char 
 
To make the deletion of the last type character you must send parm 16 defines 
the character (default DEL) before receving this char, the PAD will erase last 
character in the editing buffer, and, if parm 16 is different from 0, it send 
the signal about the erased char as said from par 19: 
 
     if parm 19 is set to 0, no signal sent 
     if parm 19 is set to 1, pad sent IA5 signal; this procedure is suggested 
        for printer like terminals 
     If parm 19 is set to 2, pad will sent a BS SP BS sequence of IA5.  This 
        procedure will locate cursor at inserting point of new char and is 
        therefore suggested for video terminals. 
 
2) Erase a line 

To erase a line you must send the char set into parm 17 (def: CAN).  Before 
receving this character, the PAD will erase the buffer and, if parm 6 is set 
to anything save 0, it will send the line deletion character, following par- 
ameter 19: 
 
     if parm 19 is set to 0 : nothing sent 
     if parm 19 is set to 1 : pad send XXX 
     if parm 19 is set to 2 : pad will send SP BS SP of IA5 for a number times 
        as the number of chars in the buffer 
 
3) Display a line 
 
To obtain a line display you must send char defined by parm 12 (def: DC2). 
Before receive this char pad will sent to terminal all chars stored in the 
buffer. 
 
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Downloaded From P-80 Systems 304-744-2253


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