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TUCoPS :: Phreaking Cellular - Misc. :: celltest.txt

Cellular phone codes not in your manual... how to bypass security etc.

The following file is a verbatim transcript of an article by the same name
appearing in the January, 1993 issue of NUTS & VOLTS Magazine.  The six (6)
accompanying photographs detailing construction have been omitted.
Copyright (c) 1992 Damien Thorn and T & L Publications.  Permission is
granted to freely distribute this file in unmodified form.  Identifying
board headers may be added as desired.


                   How to Build and Use Programming Aids

                              By Damien Thorn

Over the last few months in Nuts & Volts we've taken a close look at
cellular technology.  From an overview of the network to a "hands-on"
tutorial covering cellular telephone reprogramming.
This article introduces the construction and use of a manual test adapter
to assist in reprogramming or diagnosing problems in various cellular

You can build this device in about five minutes with one part from your
local computer store or Radio Shack.  The simplicity is elegant, and belies
the powerful control you can achieve over your cellular hardware.  Need to
bypass the security code usually required for programming, or display the
relative signal strength indication (RSSI) on a specific cellular channel?
With a manual test adapter you're just a few keystrokes away from this and


As I mentioned last month, there is little money to be made by cellular
dealers in the sales of equipment.  Hardware prices are so competitive that
most dealers sell new equipment at close to cost.  Dealers make their
profit through commissions for signing up subscribers for cellular service,
and by installation and repair.

Installing cellular phones is comparable to installing a CB radio, and less
difficult than wiring a car stereo.  Modern cellular phones are so reliable
that the phone itself rarely needs to be serviced.  Ancillary equipment
such as wiring and antennas are usually the cause of any malfunction.
Probably the most common service operation is programming.

Whether you are activating cellular service for the first time, or moving
to another city, your cellular phone must be reprogrammed with specific
data supplied by the cellular service provider (carrier).  Even changing
the unlock code on the phone requires reprogramming in many instances,
often associated with a fee ranging from $15-50.00.

The vast majority of contemporary cellular phones are programmed by
punching in the data right on the keypad without the aid of any external
programming device.  And this service is often performed by shop personnel
with little technical skill.  With a programming manual in front of her, I
watched the receptionist at a local dealer program a phone that was being
exchanged by a customer.

I use this example to illustrate how easy it is to reprogram a phone.
There is really no reason you or I cannot perform this task ourselves and
save money.  Reprogramming can also become a profitable additional service
offered by independent technicians.

                          "Motorola's Test Mode"

Motorola is probably the largest manufacturer of cellular phones.  In
addition to their own brands, they make phones for a plethora of other
companies.  I've always admired the quality of Motorola communications
equipment, and the test mode engineered into their cellular firmware
has scored them a few more points in my book.

The test mode is designed to be of assistance to cellular technicians in
the field, and is entered by grounding a specific pin on one of the phone's
connectors.  Once in test mode, the technician has manual control over many
of the functions normally automated by the firmware. The phone display can
now be used to indicate the status of various operational parameters.

The most useful functions to the hobbyist and professional programmer alike
are those which allow the data stored in the Numeric Assignment Module
(NAM) to be reviewed and changed.
This is not much different from using the standard programming mode, except
no special keyboard sequences and security codes are required for access.
The manual test mode effectively bypasses the software "front door" 
commonly used to enter programming mode, and is invaluable when the security 
code is unknown or has long since been forgotten.

The rest of this article details the construction of a test adapter and
explains its use as applicable to cellular programming.  From this point on
I'm assuming you've read my previous article or otherwise have at least a
basic knowledge of cellular programming.

The basic style of the Motorola-manufactured phone will determine how you
go about placing the unit in test mode.  Palm-size folded phones and the
one-piece hand held devices do not require and adapter.  A jumper between
the contact designated as the "test line" and ground is all that is

                 "Activating Test Mode:  Hand held Phones"

If your phone is one of the hand held types, slide the battery pack off the
unit.  The battery pack also serves as the rear of the phone's external
case.  On the top rear of the phone you should see twelve contacts arranged
in two horizonal rows as depicted in Photo #1.

Before you go any further, you should look at the model number of the phone
located on the back of the handset.   A typical model number is
"F09FSF9797."  The fourth letter (underlined) in this string is important.
This indicates the phone is of the Motorola "F" series and contains
firmware that is programmed to allow us to use the manual test mode.  The
older "D" series phones do not contain the appropriate firmware, and are
not even programmable from the keypad.
Do not attempt this procedure on a "D" series phone.

Another way to make sure the phone is of the "F"  or higher (G, H, I, etc.)
series as opposed to the older "D" series is to examine the plastic shroud
which extends from the top of the phone and partly covers the RF
switch/antenna connector housing.  The "F" (and newer) series phones have
various notches molded into the plastic shroud as can be seen in the photo.

To reiterate, if the model number contains the letter "D" as the fourth
character, it does not have a test mode, and cannot be reprogrammed from
the keypad.  Do not attempt to place it in test mode or you may damage the
phone.  Once you are certain the phone is of the "F" or higher series, you
may proceed.

The contact which serves as the test line is #6.  This is the contact to
the far right in the upper row, and should be the last (and sixth) of the
contacts comprising the top row of contacts.
Making a connection between this contact and ground will cause the phone to
enter the test mode when powered up.

The most convenient way I've found to accomplish this in lieu of a special
adapter or modified battery pack is to use a small piece of wire as a
jumper.  The short lengths that come with the Radio Shack RS-232 jumper box
we'll be discussing later work perfectly, right out of the package!

To jump contact #6 to ground, I use a very small jewelers screwdriver to
carefully wedge one of the solder-tinned ends of my jumper into the space
between the contact and the plastic edge to the right.  The snug fit
assures decent electrical contact and helps keep the jumper in place.
The other end of the jumper is gently inserted in the crevice on the RF
switch housing.  This bare metal area is the most convenient ground and
will even hold the end of the jumper.

Once you have the jumper connected, you need to flatten it against the
phone so that you can slide the battery back on without dislodging it.
Photo #2 depicts the jumper in the proper position to clear the battery

                         "Palm-size Folded Phones"

The "Micro TAC" variety of miniature folded phones ("Flip-Fones")
manufactured by Motorola usually require a special battery to activate the
test mode.  You can simulate this battery with your standard battery,

After removing the battery from the phone, you should see three contacts in
a row located in the lower right area of the phone.  The two outer contacts
are the battery connections.  Positive "+" is to the left, and negative "-"
is to the right.

The center contact is somewhat recessed and does not make contact with the
standard battery.
Your battery however, should have a mating third contact present.  To place
the phone in test mode, you need to get the center contact to mate with the
center contact on the battery.  Strategic use of a small piece of folded
metal foil, solder wick or similar conductive material can be used to
extend the center contact on the phone so that it will make contact with
the third terminal of the battery.

If you attempt this procedure, immediately power up the phone to make sure
you have not shorted the battery terminals.  If the phone does not come on
at all or feels warm to the touch, quickly remove the battery.  A shorted
NiCad battery can explode, causing serious injury.

                    "MINI-TR or Silver MiniTac phones"

Two specific phones - Motorola's MINI-TR or Silver MiniTac units can be
placed in programming mode by shorting the two contacts of the hands-free
microphone connector.

               "Mobile Installations & Transportable Phones"

These common phones are the type that consist of a handset connected to a
separate transceiver unit by a coiled cable resembling the receiver cord of
a standard landline telephone.  The handset cable is terminated with a
modular connector and plugged in to a jack.  The control cable from the
jack carries the handset, power and options wiring.  This control cable is
connected to the transceiver with a 25-pin DB25 connector as depicted in
Photo #3.

These phones are also placed in manual test mode by grounding the test
line.  The easiest way to accomplish this is by building a small test
adapter (also known as a "programming aid").  This device is placed between
the control cable and transceiver DB25 connectors allowing all the signals
to pass through unaffected with the exception of jumping the test line to
audio ground.

                        "Building the Test Adapter"

Construction of the test adapter is pretty straight forward.  The same DB25
connectors used by Motorola have been used for years as the standard
RS-232-C connector on computer equipment.
You can easily pick up a serial RS-232 inline jumper box from your local
computer, electronics or Radio Shack store.  The part number at Radio Shack
is #276-1403 and lists for $9.95 in their 1993 catalog.

The Radio Shack jumper box is designed for maximum flexibility and as such
does not have any of the pins preconnected.  Each trace on the circuit
board connecting the pins has a small break which you will need to bridge
with solder to allow the signals to pass through.  Examine the PC board
before beginning and follow a few of the traces.  Note the difference
between the break in each trace and the small solder pads used for
connecting jumpers.  You only need to bridge the traces.

Once you've applied a small dab of solder to restore the integrity of each
trace, you are ready to install the jumper.  The test line on these
Motorola phones is pin #21.  Pin #20 is the audio ground line.  You want to
jumper (short) these two pins.

Small numbers etched on the PC board indicate the jumper point for each
pin.  Locate the numbers 20 and 21 next to the small solder pads.  Using
one of the short jumper wires provided with the device, place the ends
through these two holes and solder them down on the opposite side of the
board.  Photo #4 depicts proper jumper installation, although I left one
end of the jumper unsoldered to illustrate it going through the board to be
soldered on the other side.

That completes the construction of a handy programming aid for Motorola
cellular phones, and you have a small packet of left over jumpers that are
perfect for jumpering the test line contact on the hand held units.  Be
sure to save them.

To use the test adapter, place it between the control (handset) cable and
the transceiver as shown in Photo #5.

                           "Test Mode Commands"

Once you've jumpered the appropriate contact or applied the test adapter,
it's time to turn on the phone.  When the phone powers up, a series of
digits should appear in the display similar to those shown in Photo #6.
They should alternate with another series of digits.  This indicates your
phone is in the manual test mode.

One display consists of two numbers, each three digits in length.  The set
to the right is the channel number designator for the specific cellular
frequency the phone is receiving from your local cell site (tower).  The
right-most trio is the relative signal strength indication (RSSI) of the
received frequency.

The seven-digit number alternating with the channel/RSSI display provides
the technician with additional status information.  Each individual digit
in the field is actually an independent status register.  With a letter
substituted for each of the seven digits, this is what they represent:

                               A B C D E F G

Position A - SAT Frequency.  Indicates which of the three SAT lock
frequencies is being used by the phone.
In this position a "0" = 5970Hz, "1" = 6000Hz, "2" = 6030Hz, "3" = No SAT
Position B - Carrier Status indication.  "0" = carrier off, "1" = carrier
Position C - Signalling Tone.  "0" = tone off, "1" = tone on.
Position D - RF Power Attenuation Level.  "0" through "7" are valid values.
Position E - Channel designation.  A "0" = voice channel, "1" = control
data channel.
Position F - Audio Mute (receive).  "1" = received audio is muted, "0" =
Position G - Audio Mute (transmit).  "1" = transmitted audio is muted.  "0"
= unmuted.

The meaning of all these status registers is fairly complex and has no
bearing on cellular reprogramming.  This display, like the majority of the
test commands, are only of value to an engineer placing the phone under
test with a cellular service monitor.

Table "A" lists the test commands that can be of assistance in
reprogramming.  I have omitted the test commands designed for use with a
service monitor, as issuing them without the phone connected to a monitor
may cause interference to the cellular network.  You may own the phone,
but the cellular provider owns the FCC license that allows you to use it.
Operating the transmitter in the phone in a manner inconsistent with this
license could subject you to loss of service and possible legal trouble.

                            "Issuing Commands"

If your phone did not come up with the status display described above, you
may need to manually instruct the phone to do so.  Pressing "#" enters the
test command mode, and "02#" is the command to display the status
registers.  If you enter a command improperly, the phone will
scroll the word "error" across the display.

If you need to review the current programming data stored in the NAM, enter
"55#" which instructs the phone to enter the programming mode.  You can
scroll through the contents of NAM displaying the stored values by
repeatedly pressing the "*" key.  Actual reprogramming through this mode is
considerably more difficult than through the standard programming mode.
The test mode does not display a step number to let you know what
programming step you are at, and the information is stored and displayed in
a different order.

Many programmers simply use this mode to obtain the security code, exit
test mode and program the phone in the normal fashion.  As you step through
the NAM contents with the "*" key, the security code is the only six-digit
number you'll see that isn't binary.  Once you've written it down, continue
to step through NAM until you see the "tick mark" in the display (it looks
like an apostrophe) and exit test mode by turning off the phone.

Motorola designed their phones so that they could only be programmed three
times.  I don't now the rationale for this, but a firmware counter
increments each time the phone is reprogrammed, and after the third time it
will no longer enter programming mode.  The instruction booklet that
accompanies the phone instructs you to take it to the dealer where you
bought it.

If you took the phone to a dealer, they would put the phone in test mode
(just like we're doing) and enter the command "32#" which resets the
counter to zero, allowing the phone to be reprogrammed three more times.
Do it yourself and save!

Many phones also have a cumulative call timer that counts the total number
of minutes the phone has been used for calls (actively transmitting).  This
"autonomous timer" (that you were told was not resetable) can be cleared
and reset to zero by punching in "03#" while in test mode.

Another useful command is "38#" which causes the phone to display the
Electronic Serial Number (ESN) that is burned in ROM.  The phone will
display the ESN one hex byte at a time.
Press "*" to increment to the next byte.  Note that the display shows four
numbers.  The two to the left indicate which byte you are viewing (00, 01,
02 or 03), and the actual value of that byte is at the right of the

You can punch in "19#" if you'd like to view the software version number
resident in your phone.


You should now have an understanding of the test mode inherent in cellular
phones manufactured by Motorola, and if you've followed this series of
articles in recent issues of Nuts & Volts, the operation of the cellular
network and reprogramming procedures are no longer so mysterious.

Your questions and comments are always welcome, and you can write or send
E-mail directly to me as mentioned below.  If plan to do much programming
or would like detailed information on the cellular network, you would
benefit greatly by investing in one of the detailed technical publications
offered in these very pages.  I've listed the publishers of several good
volumes in a sidebar, and you'll find their ads scattered throughout this

As a final note, you should be aware that the use of this information is
undertaken at your own risk.  Although most of this information was
triple-checked against available technical documentation, none of it
originated directly from Motorola.  I doubt you'll have a problem, but
you never know when a manufacturer might change their specifications.


                        "TEST MODE COMMAND SUMMARY"

The following is a summary of some of the commands available from within
the test mode on most cellular phones manufactured by Motorola.


     #             Initial keystroke to enter test command mode.
   01#        Reboot phone (begin power-up routine).
   02#        Display status registers.
   03#        Reset "autonomous timer" to zero minutes.
   04#        Initialize transceiver.
   07#        Mute audio (received).
   08#        Unmute audio (received).
11XXX#        Load frequency synthesizer with specific cellular channel
              (XXX = 3-digit decimal channel designator).
   13#        Power down the phone (off).
   19#        Display software version number.
   32#        Initialize NAM.  Erases all programmed data!
36XXX#        Activate channel scanning.  Pauses on each channel for XXX     

              milliseconds. Keying "#" aborts scanning.
   38#        Display Electronic Serial Number (ESN).
   45#        Display current relative signal strength (RSSI) of currently   

              loaded channel.
   53#        Enables scrambler option if phone is equipped.
   54#        Disables scrambler option if phone is equipped.
   55#        Programming mode - display/change NAM contents.


                    "Sources of Additional Information"

The following companies distribute publications that offer detailed
instructions and information
pertaining to cellular programming and various aspects of cellular

Spy Supply
7 Colby Court, Suite 215
Bedford, NH 03110
(617) 327-7272

P.O. Box 6426
Yuma, AZ 85366-6426
(602) 782-2316

2011 Crescent Drive
P.O. Box 88310
Alamogordo, NM 88310
(505) 434-0234


                             AUTHOR BIOGRAPHY

                             (For publication)

Damien Thorn's interest in electronics has deep roots.  A noted "hacker" 
and "phone phreak" by age sixteen, he contributed regularly to the 
underground newsletter "TAP."   Today Damien is an on-air radio personality 
and FCC licensed engineer in California's San Joaquin Valley.  His 
interests include computers, communications, security and privacy issues.  
He welcomes questions and comments.  You can reach him at 6333 Pacific Ave. 
#203, Stockton, CA 95207-3713 or via E-Mail at one of the following: via Internet mail, on CompuServe at 75720,2104,  or on 
Delphi as DrDamien.

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