READING THE SID WITH THE MOTOROLA PHONE
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Written on March 19, 1995. A sunny, but still somewhat cold sunday.

The SID (System IDentification) of a control channel can be determined using
the test mode of the Motorola cellular phone. This document assumes the reader
understands cellular technology in general, and how to access Motorola's test
mode in specific.

Tune the phone to the desired control channel with 11xxx# where XXX is the 
channel number. Hit 39# to receive one control channel word. One should appear
in less than two seconds, filling up all ten digits on the display with hexa-
decimal digits. Do this repeatedly until one is found with the correct 
pattern. Digit places start at the left hand side and go to the right.

The first digit should be C, D, E, or F. This letter can be used to determine the
DCC/SAT of the cell. A "C" is SAT 0, D is 1, E is 2, and F is 3. Ignore digits
8, 9, and 10. They are parity bytes. Digit 7 should be "6" or "E", though I
have never found it to be other than "E". The hexidecimal value of represented
by digits 2 through 5 is then divided by two, and then 1 added if the carrier
is a "A" side, "non-wireline" carrier. The result is the System ID.

for example:

E00388EA08

E means this cell has an SAT/DCC of 3. The A08 is ignored. The E to the left of
it is proper and normal, so this is the right kind of message. Ignore the 8 in
position 6, that is, just to the left of the E. 0038 in hexadecimal translates
((3*16=48)+8))  to 56. 56/2 = 28. Looking up System ID 28 on my chart indicates
Nynex in Boston. This is correct.

Please be aware that the two SID charts I have seen around the net are very
outdated. I have a more recent version on paper which I may eventually type in,
when I have the time and energy.

The methods used above are only a very crude way to do what could be done
much more efficiently by computer. I am sure that programs will be written to
do exactly this, but I am holding off until I have thoroughly hacked the
meaning of all these types of messages before writing such a program. I am 
also contemplating the design of a cable to replace the handset, running 
from the 25 pin connector on the side of my Bag Phone to a computer.

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