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TUCoPS :: Phreaking General Information :: phonebox.txt

Methods of Phreaking and Telephone Security Methods

<*>    Joe Cosmo Presents.....
<*>          Methods of Phreaking and Telco Security
Measures           <*>
<*>                                       June 16, 1988
1:30 am       <*>

(formatted to 80 Columns)

   Dedication:  This phile is dedicated to all those great
phreakers who
taught me all of this, and to all of the newcomers being
born to the phreak
world. For the legends, it is here as their legacy, and for
the newcomers, I
hope they will use it as their guide in times of trouble,
and may there
always be phreakers in the world.

   I.  Introduction: What Telephone Fraud Is

  II.  Who Does It and Why

 III.  The Systems That Are Fooled

  IV.  Electronic Toll Fraud

       How Boxes Work

       The Blue Box

       Operation of a Blue Box

       Pink Noise

       The Black Box

       The Red Box

       The Cheese Box
   V.  Divertors
  VI.  Private Branch Exchanges
 VII.  Specialized Common Carriers
       SCC Extenders List
VIII.  PC Pursuit
       How to Originate a PC Pursuit Call
  IX.  Cellular Phone Fraud
       ESN Tampering
       Obtaining ESN's
   X.  CN/A's
       CN/A List
  XI.  Loops
 XII.  Alliance Teleconferencing
       Billing an Alliance Conference
       Starting a Conference
XIII.  Telephone System Security Measure
       ESS Detection Devices
       Automatic Number Identification and Centralized
            Automatic Message Accounting Tapes
       Dialed Number Recorders
       Trap Codes
       Stopping an FBI Trace
       Common Channel Inter-office Signaling
 XIV.  Laws Governing the Rights of Phreakers
  XV.  Conclusion

                I. Introduction: What Telephone Fraud Is
     Telephone fraud is illegally using the communication
facilities of
telephone companies. This is commonly known as "phreaking."
The writer's
purpose is to explore the methods of phreaking, and the
various security
measures of telephone companies.

                           II. Who Does It and Why
     The majority of people who phreak are owners of modems
DEModulators, devices which allow computers to communicate
over telephone
lines) and are usually between the ages of twelve and
seventeen. When the
person reaches age eighteen, he or she usually stops, since
after that age,
if the person in caught, the penalty can become very
serious, such as time in
prison, and fines starting at $8000.
     Scattered throughout the country are many different
computer bulletin
board systems, or BBS's. These are computer systems
established by private
users or large organizations for the exchange of public and
private messages
and software. Most are not a local call, though. Since the
normal user calls
about ten different BBS's, with even the lowest
long-distance rates, the
phone bill each month can range from $100 to $1000. The
solution is to
phreak. When these people learn how to phreak, they also
realize that besides
making free long-distance calls from their home, they can
also make free
calls from payphones. They also find that there are many
other facilities
that they can used without paying.

                         III. The Systems That Are Fooled
     Their are three types of telephone operating systems in
the U.S., Step
by Step (SxS), Crossbar (XB), and Electronic Switching
System (ESS). They are
described in detail in the following paragraphs.

                               Step by Step
     Step by Step (SxS) was the first switching system used
in America,
adopted in 1918 and until 1978 Bell had over 53% of all
exchanges using Step
by Step.  A long, and confusing train of switches is used
for SxS switching.

A. The switch train may become jammed, blocking calls.
B. No DTMF (Dual-Tone Multi-Frequency), to be discussed
C. Much maintenance and much electricity.
D. No "Touch-Tone" dialing.

A. No pulsing digits after dialing or "Touch Tone".
B. Much static in the connections.
C. No Speed calling, Call forwarding, and other services.
D. Pay-phone wants money first before dial-tone.

      Crossbar has been Bell's primary switcher after 1960.
Three types of
Crossbar switchings exist, Number 1 Crossbar (1XB), Number 4
Crossbar (4XB),
and Number 5 Crossbar (5XB). A switching matrix is used for
all of the phones
in an area. When someone calls, the route is determined and
is connected with
the other phone. The matrix is positioned in horizontal and
vertical paths,
organizing the train of switches more effectively, and
therefore, stopping
the equipment from jamming. There are no definite
distinguishing features of
Crossbar switchings from Step by Step.

                         Electronic Switching System
     ESS is the most advanced system employed, and has gone
through many
kinds of revisions. The latest system to date is ESS 11a,
which is used in
Washington D.C. for security reasons. ESS is the country's
most advanced
switching system, and has the highest security system of
all. With its many
special features, it is truly the phreaker's nightmare.

A. Dialing 911 for emergencies.
B. Dial-tone first for pay-phones.
C. Calling services, including Call forwarding, Speed
dialing, and Call
D. Automatic Number Identification for long-distance calls
(ANI), to be
   discussed later.
E. "Touch Tone"

                             IV. Electronic Toll Fraud
     The ETF's are electrical devices used to get free
long-distance calls.
The devices are more commonly known as colored boxes, and
using them is known
as "boxing." Boxing is one of the oldest way to phreak, and
therefore, it is
also the most dangerous, since the telephone companies are
very much aware of
their existence. Colored boxes are not used only for
phreaking. There are
many types which have other uses (such as the Tron Box,
which lowers your
electric bill), so only those used in telephone fraud will
be discussed.

                                 How Boxes Work
     In the beginning, all long distance calls were
connected manually by
operators who passed on the called number verbally to other
operators in
series. This is because pulse (rotary) digits are created by
causing breaks
in the DC current.  Since long distance calls call for
routing through
various switching equipment and AC voice amplifiers, pulse
dialing cannot be
used to send the destination number to the end local office
     Eventually, the demand for faster and more efficient
long distance
service caused Bell to make a multi-billion dollar decision.
They had to
create a signaling system that could be used on the LD
Network. They had two

[1] To send all the signaling and supervisory information
(eg., ON and OFF
HOOK) over separate data links.  This type of signaling is
referred to as
out-of-band signaling.

[2] To send all the signaling information along with the
conversation using
tones to represent digits.  This type of signaling is called

The second seemed to be the most economical choice, and so,
it was
incorporated in ESS.
     Then, in the 1960's, when the first ESS systems were
employed, a toy
whistle was put in each box of Captain Crunch Cereal as a
premium. A young
radio technician in the United States Air Force became
fascinated with the
whistle when he discovered that by blowing it into the
telephone after
dialing any long distance number, the trunk line would
remain open without
toll charges accounting. From then on, any number could be
dialed for free.
The truth was that the whistle produced a perfect-pitch 2600
Hz tone, the one
used to signify a disconnect in ESS switching equipment. To
overcome the
initial charge for the for the long distance call, he later
used toll-free
800 numbers.
     Being a skilled technician, Captain Crunch (he began to
use the name as
an alias) soon went beyond the simple whistle and
experimented with other
frequencies, creating many of the boxes discussed in the

                                 The Blue Box
     The "Blue Box" was so named because of the color of the
first one
discovered by the authorities. The design and hardware used
in the Blue Box
is very sophisticated, and its size varies from a large
piece of apparatus to
a miniaturized unit that is approximately the size of a
"king size" package
of cigarettes.
     The Blue Box contains 12 or 13 buttons or switches that
emit the
multi-frequency tones used in the normal operation of the
telephone toll
(long distance) switching network. In effect, the the Blue
Box can let a
person become the operator of a phone line. The Blue Box
enables its user to
originate fraudulent toll calls by circumventing (fooling)
toll billing
equipment. The Blue Box may be directly connected to a phone
line, or it may
be acoustically coupled to a telephone handset by placing
the Blue Box's
speaker next to the transmitter, or the telephone handset.

                           Operation of a Blue Box
     To understand the steps of a fraudulent Blue Box call,
it is necessary
to understand the basic operation of the Direct Distance
Dialing (DDD)
telephone network. When a DDD call is originated, the
calling number is
identified as an integral part of establishing the
connection. This may be
done either automatically by ANI in ESS, or in some cases,
by an operator
asking the calling party for his telephone number. This
information is
entered on a tape in the Centralized Automatic Message
Accounting (CAMA)
office. This tape also contains the number assigned to the
trunk line over
which the call is to be made. The information relating to
the call contained
on the tape includes the called number's identification,
time of origination
of the call, and if the called number answered the call. The
time of
disconnect is also recorded. The various data entries with
of the call are
correlated to provide billing information for use by the
caller's telephone
company's accounting department.
     The typical Blue Box user usually dials a number that
will route the
call into the telephone network without charge. For example,
the user will
very often call a well-known INWATS (toll-free) number. The
Blue Box user,
after gaining this access to the network when somebody picks
up and in
effect, "seizing" control of the line, operates a key on the
Blue Box which
emits a 2600 Hertz (cycles per second, abbreviated as Hz)
tone. This tone
causes the switching equipment to release the connection to
customer's line. The 2600 Hz tone is the signal to the
switching system that
the calling party has hung up. In fact though, the local
trunk on the calling
party's end is still connected to the toll network. The Blue
Box user now
operates the "KP" (Key Pulse) key on the Blue Box to notify
the toll
switching equipment that switching signals are about to be
emitted. The user
then pushes the "number" buttons on the Blue Box
corresponding to the
telephone number being called. After doing so, he/she
operates the "ST"
(Start) key to tell the switching equipment that signaling
is complete. If
the call is completed, only the portion of the original call
prior to the
operation of the 2600 Hz tone is recorded on the CAMA tape.
The tones emitted
by the Blue Box are not recorded on the CAMA tape.
Therefore, because the
original call to the INWATS number is toll-free, no billing
is rendered in
connection with the call.

     The above are the steps in a normal operation of a Blue
Box, but they
may vary in any one of the following ways:

A. The Blue Box may include a rotary dial to apply the
2600Hz tone and the
switching signals. This type of Blue Box is called a "dial
pulser" or "rotary
SF" Blue box.

B. A magnetic tape recording may be used to record the Blue
Box tones. Such a
tape recording could be used in lieu of a Blue Box to
fraudulently place
calls to the phone numbers recorded on the magnetic tape.

     All Blue Boxes, except "dial pulse" or "Rotary SF" Blue
must have the following four common operating capabilities:

A. It be able to emit the 2600 Hz tone. This tone is used by
the toll network
to indicate, either by its presence or its absence, an "on
hook" (idle) or
"off hook" (busy) condition of a trunk line.

B. The Blue Box must have a "KP" tones that unlocks or
the multi-frequency receiver at the called end to receive
tones corresponding to the called phone number.

C. The Blue Box must be able to emit DTMF, tones used to
transmit phone
numbers over the toll network. Each digit of a phone number
is represented by
a combination of two tones. For example, the 2 is 700 Hz and
900 Hz.

D. The Blue Box must have an "ST" key which consists of a
combination of two
tones that tell the equipment at the called end that all
digits have been
sent and that the equipment should start connecting the call
to the called

     The following is a chart of the multi-frequency (MF)
tones produced by
the normal Blue Box.

700  :   1   :   2   :   4   :   7   :  11   :    2600 X
900  :   +   :   3   :   5   :   8   :  12   :
1100 :   +   :   +   :   6   :   9   :  KP   :
1300 :   +   :   +   :   +   :  10   :  KP2  :
1500 :   +   :   +   :   +   :   +   :  ST   :
     : 700   : 900   :1100   :1300   :1500   :

     The "Dial Pulser" or "Rotary SF" Blue Box requires only
a dial
with a signalling capability to produce a 2600 Hz tone.

                                Pink Noise
     Since telephone companies have such advanced equipment
to detect Blue
Boxes, to help avoid detection "pink noise" is sometimes
added to the 2600 Hz
     Since 2600 Hz tones can be simulated in speech, the
detection equipment
of the switching system must be attentive not to
misinterpret speech as a
disconnect signal. Thus, a virtually
pure 2600 Hz tone is required for disconnect. This is also
the reason why the
2600 Hz tone must be sent rapidly; sometimes, it will not
work when the
person called is speaking. It is feasible, though, to send
some "pink noise"
along with the 2600 Hz.  Most of this energy should be above
3000 Hz.  The
pink noise will not reach the toll network, where we want
our pure 2600 Hz to
hit, but it will go through the local CO and thus, the fraud

                               The Black Box
     The Black Box is the easiest type to build. The box
stops a call from
being charged to some one only if it is hooked to the line
of the person
being called.
     In the normal telephone cable, there are four wires: a
red, a green, a
black, and a yellow. The red & green wires are often
referred to as tip (T)
and ring (R).
     When a telephone is on-hook (hung up) there is
approximately 48 volts of
DC current (VDC) flowing through the tip and ring. When the
handset of a
phone is lifted, switches close, causing a loop to be
connected (which is
known as the "local loop,") between the telephone and the
CO.  Once this
happens DC current is able to flow through the telephone
with less
resistance.  This causes a relay to energize and signal to
other CO equipment
that service is being requested. Eventually, a dial tone is
emitted. This
also causes the 48 VDC to drop down into the vicinity of 13
volts. The
resistance of the loop also drops below the 2500 ohm level.
Considering that
this voltage and resistance drop is how the CO detects that
a telephone was
taken off hook, how a Black Box works is by allowing the
voltage to drop
enough to allow talking, but not enough to signal to the CO
equipment to
start billing. To do this, a 10,000 Ohm, .5 Watt resistor is
incorporated in
the local loop on the called party's line.

                                    The Red Box
     A Red Box is a device that simulates the sound of a
coin being accepted
by a payphone. When a coin is put in the slot of a payphone,
the first
obstacle is the magnetic trap. This will stop any
light-weight magnetic
slugs. If it passes this, the coin is then classed as a
nickel, dime, or
quarter. Each coin is then checked for appropriate size and
weight. If these
tests are passed, it will then travel through a nickel,
dime, or quarter
magnet as proper. These magnets start an eddy current effect
which causes
coins of the appropriate characteristics to slow down so
they will follow the
correct trajectory.
     If all goes well, the coin will follow the correct
path, striking the
appropriate totalizer arm, causing a ratchet wheel to rotate
once for every
5-cent increment (eg, a quarter will cause it to rotate 5
times). The
totalizer then causes the coin signal oscillator to readout
a dual-frequency
signal indicating the value deposited to the Automated Coin
Toll Service
computer (ACTS) or the Traffic Service Position System
(TSPS) operator. These
are the tones emitted by the Red Box.
     For a quarter, five beep tones are outpulsed for 66
milliseconds (ms). A
dime causes two beep tones for 33 ms, while a nickel causes
one beep tone at
also  33 ms. A beep consists of two frequencies, 2200 Hz and
1700 Hz. As with
a Blue Box, Red Box tones can be recorded on a magnetic
     Since any call from a payphone is originated with a
"ground test," in
which the TSPS operator or the ACTS computer checks for the
presence of the
first coin inserted into the phone, by verifying use of the
magnetic, weight,
and size traps, when using a Red Box, it is necessary to put
in at least one

                                   The Cheese Box
     A Cheese Box lets a normal telephone emulate a
payphone. By emulating a
payphone, using a blue box now becomes safe, because if the
CO equipment
recognizes the call as one from a payphone, it does not
record it on a CAMA
tape. Since a normal telephone does not have a slot to enter
coins, a Red Box
is needed to generate the sound of a coin dropping.

                                  V. Divertors
     A divertor is a special service that allows businesses
to "divert" calls
if no one answers after a certain number of rings. For
example, a person
calls a company, and nobody answers. After about three
rings, a few clicks
are heard, then a few fainter rings are heard. The building
receiving the
call has changed from the company to another building,
usually somebody's
house. What has happened is that the call has been re-routed
from building A
to building B. In effect, the number called is not really
changed, but
instead, building A has answered the call, called building
B, and connected
the two lines together. If the person in building B
disconnects, the caller
is still connected to building A. With the way the divertor
equipment works
in the telephone company, the phone line of building A will
then emit a dial
tone and the caller has total control of the line, and can
originate another
call, charging it to building A.

                            VI. Private Branch Exchanges
     A Private Branch Exchange (PBX) is a system of out-WATS
(Wide Area
Telephone Service) lines and in-WATS lines. An out-WATS line
allows a
business to make as long-distance calls each month for a
flat rate. An
in-WATS line is a toll-free number (800 number) that is also
leased to
businesses for flat rates. PBX's save corporations much
money when their
salesmen, distributors, and franchisees must make many calls
from different
parts of the country. It works much like specialized common
carriers (to be
discussed later).
     First, the employee calls the company on the in-WATS
line. The switching
equipment picks up the phone, and send a tone to the
employee indicating for
him to enter the access code of the PBX. If the access code
is correct, then
the line is connected to the out-WATS line, and the employee
can make a call.
     To use PBX's, phreakers must find the access code of
the PBX. This can
be done very easily, since the code is usually only a few
digits. One way is
to dial different combinations manually on the telephone
keypad. The other
way is of the phreaker is the owner of a modem. A simple
program can be
easily written to continuously dial digit combinations
randomly or

                          VII. Specialized Common Carriers
     Ever since the break up of AT&T's monopoly on
long-distance service,
there have been many other corporations that compete with
AT&T in the
long-distance market, including Sprint, MCI, All-net, ITT,
and Metrophone.
These all boast opportunities for large savings on
long-distance calls. These
companies are called specialized common carriers (SCC's).
     SCC's cost less because they do not use the AT&T's
cable-based systems,
but instead use microwave links. Some have also added
fiber-optic lines to
their networks.
     Another way they can save consumers money is by using
AT&T's lines.
Instead of connecting calls by the shortest route, the
carrier will use a
different route, so the call goes through places where the
traffic is heavy, and the rate is lower. The companies that
do this are known
as "resellers."
     Most SCC's work nearly the same as PBX's. The 800
number is called, a
tone is heard, the private identification number (PIN) is
entered, and then
the call can be made. The length of the PIN number can range
from four digit
to fourteen digits.
     Besides 800 toll free numbers, in some areas, a 950 can
be used. A 950
works exactly the same as an 800 number, the only difference
is that the
consumer must enter only seven digits before dialing his PIN
number instead
of ten with a toll-free number. 950's are free of charge and
can be used both
at home and at pay phones.
     The PIN numbers can be found the same way as PBX access
codes. Since the
number of digits in a PIN is so great, using a computer is
much more common
practice than manual dialing.
     The following pages are lists of SCC's and their
dialups, formats, and
special points. Note that some have many different dialups.

[                           SCC Extenders List
[                      0-9 - Number of digits in code
[                      [ ] - Dial that exact number
[                      #   - Area code + Prefix + Suffix
[                      :   - Dial tone
[                      +   - ontinue dialing
|   Extender   |  Dialing Format  |        Company        |
Comments    |
| 800-223-0548 | 8+[1]+#          | TDX                   |
| 800-241-1129 | 8+[1]+#          | TDX                   |
| 800-248-6248 | 6+[1]+#          | SumNet Systems        |
(800)824-3000   |
| 800-288-8845 | 7:[1]+#          | TMC Watts             |
(800)999-3339   |
| 800-325-0192 | [1]+#+6          | MCI                   |
950-1986       |
| 800-325-1337 | 7:[1]+#          | TMC Watts             |
| 800-325-7222 | 6+[1]+#          | Max                   |
(800)982-4422   |
| 800-325-7970 | 6+[1]+#          | Max                   |
(800)982-4422   |
| 800-327-4532 | 8+#              | All-TelCo             |
| 800-327-9488 | #:13             | ITT                   |
950-0488       |
| 800-334-0193 | [9]+#            | Piedmont              |
| 800-345-0008 | [0]+#:14         | US Sprint FON Cards
|950-1033 also 9+#|
| 800-368-4222 | 8+#              | Congress Watts Lines  |
| 800-437-7010 | 13               | GCI                   |
| 800-448-8989 | 14+[1]+#         | Call US               |
| 800-521-8400 | 8:#              | TravelNet             |
950-1088 (voice)|
| 800-541-2255 | 10               | MicroTel              |
| 800-547-1784 | 13               | AmericaNet            |
| 800-621-5640 | 6+[1]+#          | ExpressTel            |
| 800-637-4663 | 5+[1]+#          | TeleSave              |
| 800-821-6511 | 5+[1]+#          | American Pioneer      |
(800)852-4154   |
| 800-821-6629 | 6+[1]+#          | Max                   |
(800)982-4422   |
| 800-821-7961 | 6+[1]+#          | Max                   |
(800)982-4422   |
| 800-826-7397 | 6:[1]+#          | Call U.S.             |
| 800-858-4009 | 6+[1]+#          | NTS                   |
Voice           |
| 800-862-2345 | 7:[1]+#          | TMC                   |
| 800-877-8000 | [0]+#:14         | US Sprint Calling
Card|950-1033 also 9+#|
| 800-882-2255 | 6:[1]+#          | AmeriCall             |
False Carrier   |
| 800-950-1022 | [0]+#:14         | MCI Calling Card      |
| 800-992-1444 | 9+#              | AllNet                |
950-1444        |

                              VIII. PC Pursuit
     Many modem users know Telenet as a packet-switching
network through
which they can connect to different telecommunication
services throughout the
country for an hourly rate of $2. With PC Pursuit, Telenet
uses the same
method as SCC's, but instead of using microwave links, the
call is routed
through computers. Since it is routed through computers, the
service can be
used by only owners of modems. Instead of paying the hourly
rate, the
consumer needs only to pay a flat monthly rate of $25.
     Using PC Pursuit is a little more difficult than using
SCC's, because
now instead of combinations of only ten different characters
(0-9), the whole
alphabet can be used in the access code. The following is a
chart showing the
steps to originate a typical PC Pursuit call.

                    How to Originate a PC Pursuit Call
     First, the users dials the local Telenet Access Center,
which can be
found by dialing Telenet customer service at 1-800-336-0437.


Note: (cr) signifies the carriage return on a computer

Network Shows     | User Types                 | Explanation
                  | (cr) (cr)                  |
TELENET           |                            | Telenet
network called and
XXX XXX           |                            | your
network address.
TERMINAL=         | "D1" (cr)                  | Enter "D1"
or press (cr)
@                 | For 300 bps:               | CONNECT
command.  To access
                  | "C(sp)DIALXXX/3,XXXX(cr)"  | a PC
Pursuit city type a PC
                  |                            | Pursuit
access code and
                  | For 1200 bps:              | your user
                  | "C(sp)DIALXXX/12,XXXX(cr)" |
PASSWORD=         | "XXXXXX" (cr)              | Type the
DIALXXX/X         | "ATZ" (cr)                 | You are now
connected to the
CONNECTED         |                            | PCP city.
Type ATZ (upper).
OK                | "ATDTXXXXXXX" (cr)         | Dials a
number in PCP city
CONNECT           |                            | Your are
now connected to
                  |                            | your
destination computer.

     If the number dialed is busy, the user will see BUSY.
To call another
number in the same city, the user types "ATZ." The network
will answer OK.
The user then types "ATDTXXXXXXX" (cr) to dial the next
     To connect to a different PC Pursuit City, when the
user sees BUSY, he
types "@" (cr). When a @ appears, "D" (cr) is entered. This
disconnects the
user from the previous city. The  user then follows the
above procedures to
dial another city.

                         IX. Cellular Phone Fraud
     Cellular phones have evolved considerably from previous
Signaling between mobile and base stations uses high-speed
digital techniques
and involves many different types of digital messages. The
cellular phone
contains its own Mobile Identification Number (MIN), which
is programmed by
the seller or service shop and can be changed when, for
example, the phone is
sold to a new user.  In addition, the U.S. cellular standard
incorporates a
second number, the Electronic Serial Number (ESN), which is
intended to
uniquely and permanently identify the mobile unit.
     According to the Electronic Industries Association
(EIA) Interim
Standard IS-3-B, Cellular System Mobile Station Land Station
Specification, the serial number is a 32-bit binary number
that uniquely
identifies a mobile station to any cellular system.  It must
be factory-set
and not readily alterable in the field.  The circuitry that
provides the
serial number must be isolated from fraudulent contact and
Attempts to change the serial number circuitry should render
the mobile
station inoperative.
     The ESN was intended to solve two problems the industry
observed with
its older systems. First, the number of subscribers that
older systems could
support fell far short of the demand in some areas, leading
groups of users
to share a single mobile number (fraudulently) by setting
several phones to
send the same identification.  Carriers lost individual user
and their means of predicting and controlling traffic on
their systems.
     Second, systems had no way of automatically detecting
use of stolen
equipment because thieves could easily change the
transmitted identification.
    In theory, the required properties of the ESN allow
cellular systems to
check to ensure that only the correctly registered unit uses
a particular
MIN, and the ESNs of stolen units can be permanently denied
("hot-listed"). This measure is an improvement over the
older systems, but
vulnerabilities remain.

                                ESN Tampering
     Although the concept of the unalterable ESN is laudable
in theory,
weaknesses are apparent in practice.  Many cellular phones
are not
constructed so that attempts to change the serial number
circuitry renders
the mobile station inoperative.  Contrary to this statement,
swapping of one
ESN chip for another in a unit that has been found to
functione flawlessly
after the switch was made.

                                 Obtaining ESN's
     Since most manufacturers are using industry standard
Read-Only Memory
(ROM) chips for their ESNs, the chips are easily bought and
programmed or
copied.  In programming the ESN with a valid code is another
Remembering that to obtain service from a system, a cellular
unit must
transmit a valid MIN (telephone number) and (usually) the
serial number stored in the cellular switch's database. With
the right
equipment, the ESN/MIN pair can be read right off the air
because the mobile
transmits it each time it originates a call.  Service shops
can capture this
information using test gear that automatically receives and
decodes the
reverse, or mobile-to-base, channels.
     Another way to obtain the numbers is from service
shops. Service shops
keep ESN/MIN records on file for units they have sold or
serviced, and the
carriers also have these data on all of their subscribers.
employees could compromise the security of their customers'
telephones by
obtaining these records.
     In many ways, trade in illegally obtained ESN/MIN pairs
could, in the
future, resemble what currently transpires in the long
distance telephone
business with AT&T credit card numbers and alternate
long-distance carrier
(such as MCI, Sprint and Alltel) account codes. Code numbers
are swapped
among friends, published on computer bulletin boards and
trafficked by career
criminal enterprises.

                                X. CN/A's
     CN/A's, which stands for Customer Names and Addresses,
are bureaus that
exist so that authorized Bell employees can find out the
name and address of
any customer in the Bell System.  All phone numbers are
maintained on file
including unlisted numbers.
     To find the owner of any number, the person first must
call the local
CN/A during business hours. Then he must pretend to be from
a registered
business, and ask for the owner of the number. In some
states, though, the
operator will ask for an ID number. In these cases, one must
be guessed at.
     There is also a type of reverse CN/A bureau, which is
usually called a
NON PUB DA or TOLL LIB. With these numbers, somebody can
find unpublished
numbers if the caller gives the operator the name and
locality. These are
considerably harder to use, since the operator will then
request the caller's
name, supervisors name, etc.
     The following is a list of current CN/A's.


                  1988 CN/A List  (subject to change)

Area: CN/A            Area: CN/A               Area: CN/A
 201:  Classified      202: 304-343-7016        203:
 204: 204-949-0900     206: 206-345-4082        207:
 208: 303-293-8777     209: 415-781-5271        212:
 213: 415-781-5271     214: 214-464-7400        215:
 216: 614-464-0519     217: 217-789-8290        218:
 219: 317-265-4834     301: 304-343-1401        302:
 303: 303-293-8777     304: 304-344-8041        305:
 307: 303-293-8777     308: 402-221-7199        312:
 313: 313-424-0900     314: 816-275-8460        316:
 317: 317-265-4834     318: 504-245-5330        319:
 401: 617-787-5300     402: 402-221-7199        404:
 405: 405-236-6121     406: 303-293-8777        412:
 413: 617-787-5300     414: 608-252-6932        415:
 416: 416-443-0542     417: 816-275-8460        418:
 419: 614-464-0519     501: 405-236-6121        502:
 503: 206-345-4082     504: 504-245-5330        505:
 509: 206-345-4082     512: 512-828-2501        513:
 514: 514-394-7440     515: 402-221-7199        517:
 518: 518-471-8111     519: 416-443-0542        601:
 602: 303-293-8777     603: 617-787-5300        605:
 606: 502-583-2861     607: 518-471-8111        608:
 609:  Classified      612: 402-221-7199        613:
 614: 614-464-0519     615: 615-373-5791        616:
 617: 617-787-5300     619: 415-781-5271        701:
 702: 415-543-2861     703: 304-344-7935        704:
 705: 416-443-0542     707: 415-781-5271        712:
 713: 713-961-2397     715: 608-252-6932        716:
 717: 412-633-5600     718: 518-471-8111        801:
 802: 617-787-5300     804: 304-344-7935        805:
 806: 512-828-2501     809: 404-751-8871        812:
 813: 813-228-7871     814: 412-633-5600        815:
 816: 816-275-8460     817: 214-464-7400        901:
 904: 912-752-2000     906: 313-424-0900        912:
                       914: 518-471-8111        916:
                       918: 405-236-6121        912:

                                XI. Loops
       The loop is an alternative communication medium that
has many
potential uses. Loops are phone lines that are connected
when they are called
simultaneously. One use is when somebody wants another
person to call them
back but is reluctant to give out their home phone number
(eg., if they were
on a party line).
        Loops are found in pairs that are usually close to
each other (eg.,
718-492-9996 and 718-492-9997). On a loop, one line is the
high end, and the
other is the low end. The high end is always silent.  The
tone disappears on
the low end when somebody calls the high end.
     It is truly only safe to use a loop during non-business
hours. During
business, loops are used to test equipment by various
telephone companies and
local CO's.

                      XII. Alliance Teleconferencing
     Alliance Teleconferencing is an independent company
which allows the
general public to access and use its conferencing equipment.

                     Billing an Alliance Conference
     Alliance Teleconferencing is accessed by dialing
0-700-456-1000 in most
states. In some states, the first and last digits of the
suffix vary. There
are four main ways to use Alliance illegally. The first is
through a PBX.
Some allow use of the 700 exchange, but many do not.
     The second way is with a Blue Box. After seizing the
KP-0-700-456-1000-ST is dialed. The equipment now thinks
that Alliance has
been dialed from a switchboard and bills the conference to
     The third way is to a loop. After being connected to
Alliance, the
caller contacts the operator by pressing 0. The caller then
can ask for the
conference to billed to another number, giving the operator
the number of the
high-end of a loop. The operator will then call the loop. A
friend of the
phreaker must be prepared to answer the call by calling the
low-end. When the
friend answers and accepts the billing, the conference will
be billed to the
     The fourth way is from a divertor. Since the divertor
is a normal,
home-type line, the phreaker should not have any problems
starting a

                        Starting a Conference
     When Alliance answers, a two-tone combination is
emitted. The caller
then types a two digit combination to tell the equipment how
many people will
be in the conference, including the originator. Then either
# is pressed to
continue or * is pressed to cancel the conference. To dial a
each conferee,
the phreaker simply answers each prompt with the phone
number of the
corresponding person.
     To join the conference, the originator enters #, and to
return to
control mode, he enters # again. To transfer control of the
#+6+1+ the phone number of the person you wish to transfer
the control to. To
end the conference, the phreaker presses the * button.

                 XIII. Telephone System Security Measures
     To stop telephone fraud, there are many measures which
companies can apply to identify and convict the phone

                          ESS Detection Devices
     Telephone companies have had twenty years to work on
detection devices;
therefore, they are well refined.  Basically, the detection
devices will look
for the presence of 2600 Hz where it does not belong, which
is in the local
CO. It then records the calling number and all activity
after the 2600 Hz.

     Automatic Number Identification and the Centralized
Automatic Message
                           Accounting Tapes
     Automatic Number Identification (ANI) is an implement
in ESS that can
instantly identify the calling party. For every call that is
information including the numbers of the calling and
receiving parties, the
time of origination of the call, if the called party
answered the call, and
the time when the caller has hung-up is recorded on a tape
in the Centralized
Automatic Message Accounting (CAMA) office. This includes
wrong numbers,
toll-free numbers, and local calls. This tape is then
processed for billing
     Normally, all free calls are ignored, but the billing
equipment has been
programmed to recognize many different types of unusual
activity. One checks
if a certain 800 number is called excessively. If the number
is an SCC, the
equipment can instantly check if the caller is a subscriber
of the SCC. If it
is not, it will alert the company of the illegal activity.
Another is if
there is a call where the calling party has stayed off-hook
for a large
amount of time, but the called party never answers. The
equipment recognizes
this as possible use of a Black Box.

                       Dialed Number Recorders
     Placing a Dialed Number Recorders (DNR) on a telephone
line is standard
procedure when telephone fraud is suspected. The most common
DNR's can do the
following: print all touch tone digits sent (in suspected
illegal use of an
SCC), print out all MF and record the presence of 2600hz on
the line (in
suspected use of a Blue Box), and activate a tape recorder
for a specific
amount of time.

                             Trap Codes
     Trap codes are decoy PIN numbers. If a telephone
company find that a
certain PIN number is being used illegally, it will call the
real owner and
notify him of the change in his account number. The company
will then contact
the FBI to bring their telephone "lock in" trace equipment.
     A lock in trace is a device used by the FBI to lock
into the phone
user's location. Since all phone connections are held open
by a certain
voltage of electricity,
the lock in trace works by patching into the line and
generate the same
voltage into the lines. If the caller tries to hang up,
voltage is retained.
The phone will continue to ring as if someone was calling
even after the call
is disconnected. The trunk then remains open and the call
can be traced. The
FBI sets its equipment so that the next time the PIN number
is illegally
used, the call goes through, but while the communication is
proceeding, the
FBI traces the call.

                        Stopping an FBI Trace.
     Stopping a trace is quite simple. If the voltage in the
line could be
lowered, the trace could not function, since lowering the
voltage would also
probably short out the FBI voltage generator. Therefore, any
appliance which
uses many volt can be connected to the red and green wires
in a wall jack,
and the trace should be removed.

              Common Channel Inter-office Signaling
     Besides detection devices, Bell has begun to gradually
redesign the
network using out-of-band signaling.  This is known as
Common Channel
Inter-office Signaling (CCIS).  Since this signaling method
sends all the
signaling information over separate data lines, and does not
use any form of
DTMF, all colored boxes do not work under it. Of course,
until this
multi-million dollar project is totally complete, boxing
will still be
possible. It will become progressively harder to find places
to "box" off of,

             XIV. Laws Governing the Rights of Phreakers
     Since phreaking is one-hundred percent illegal, once
discovered, there
are not many laws protecting the phreaker. There are,
however some laws
governing steps government agents may take to convict him.
     The first law is the Section 605 of Title 47 of the
United States Code.
This section forbids interception of communications, except
by persons
outlined in Chapter 119, Title 18, which is a portion of the
Omnibus Crime
Control and Safe Streets Act of 1968.
     In this chapter, Section 2511 (2) (a) (i) says "It
shall not be unlawful
under this chapter for an operator of a switchboard, or an
officer, employee,
or agent of any communications carrier, whose facilities are
used in the
transmission of a wire communication, to intercept,
disclose, or use that
communication in the normal course of his employment, while
engaged in any
activity which is a necessary incident to the rendition of
his service of the
protection of the rights or property of the carrier of such
This means that agents of telephone companies are allowed
not only allowed to
tap lines without a warrant, but also allowed to disclose
the recording of a
     In the case United States vs. Sugden, the following
ruling was made:
"For an unreasonable search and seizure to result from the
interception of
the defendant's communication, he must have exhibited a
expectation of privacy. Where, as here, one uses a
communication facility
illegally, no such expectation is required." This simply
means that when you
make an illegal call, you have waved your right to privacy.


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