STATION ID - 7047/3.12

9x Datakit Network
FOR OFFICIAL USE ONLY

This is a 9x system, restricted to authorized persons and for
official 9x business only. Anyone using this system, network or data
is subject to being monitored at any time for system administration and
for identifying unauthorized users or system misuse. Anyone using this
system expressly consents to such monitoring and is advised that any
evidence of criminal activity revealed through such monitoring may be
provided to law enforcement for prosecution.

 
                        &$&$&$&$&$&$&$&$&$&$&$&$&$&$
                       &$&$&$&$&$&$&$&$&$&$&$&$&$&$&$
                     &$&$                          &$&$
                      &$             The            &$
                    &$&$  Analogue Cellular System &$&$
                     &$                             &$
                    &$&$                           &$&$
                     &$          by: Ardist         &$
                    &$&$                           &$&$
                      &$&$&$&$&$&$&$&$&$&$&$&$&$&$&$&
                        &$&$&$&$&$&$&$&$&$&$&$&$&$&$

       This TxT file is for    ...... 9x.....    --- 9x Release only.


Introduction:
~~~~~~~~~~~~~

Even though we are at the age of digital technology, the majority of people
still are not familiar with the analogue system.  This text file has been
put out for a better understanding of the differences between AMPS (Automatic
Mobile Phone Service) - TACS ( Total Access Communications System ) - and
NAMPS ( Narrowband Automatic Mobile Phone Service).  Before I continue I
would like to thank my good friend AngieB for typing this file out for me.
Now that I have explained my purpose for writing this text file I have one
more thing to say before we get started:

Disclaimer:
~~~~~~~~~~~

This file is for educational purposes only, and anything derived from this
file, especially illegal uses of the analogue cellular structure are NOT my
responsibility.  This file does not contain any information of illegal use
of cellular phones or cloning methods. This file is simply for a better
understanding of the analogue cellular system.

Three Regions of the Analogue System:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Before I begin explaining the three analogue cellular systems I would like
to give you a very simple understanding of the three regions the analogue
system is divided into.  There are three regions.  To make this short I am
just going to talk about region two. Region two includes North America,
South America, and Canada.  The three region system is recognized by the
International Telecommunications Union ( ITU ).  The region two radio
frequencies give us the North American AMPS system, which is also known as
Nordic Mobile Telephone ( NMT ).  Where as in the United Kingdom, TACS
system is used in other radio regions.  They are all very similar to each
other in the sense that they all use Bi-Phase signaling.

AMPS and NAMPS systems:
~~~~~~~~~~~~~~~~~~~~~~~

Narrowband AMPS known as NAMPS takes each 30Khz AMPS channel and splits it
into three 10Khz channels, the resulting three for one split results in an
increase for system capacity.  Without the overhead for cell splitting and
other complexities that the AMPS system has.  NAMPS is compatible with the
AMPS system in that the 30Khz control channel is still used,and cellphones
can be built to handle both standards. NAMPS has other additional features
which makes it a better system.    The NAMPS and the AMPS systems are both
compatible with the dual mode operation allowing AMPS customers to  switch
back and forth between the systems,and allowing them to hand over the AMPS
channels to NAMPS channels or vice versa.       It is possible only if the
customer is using a dual mode cellular phone.

ARQ ( Automatic Request for Retransmission Signaling ) Signaling:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Automatic Request for Retransmission Signaling.    The signaling is at the
speed of 200bps, which does away with the 10Khz tone AMPS uses which makes
the  cellular  phone acknowledge orders that it receives from the cellular
tower.  This is especially important when a handover takes place.  Where
the AMPS handover order confirmation of 50ms of 10Khz signaling tone is
often missed due to interference.

Improved Call Control:
~~~~~~~~~~~~~~~~~~~~~~

This is the next feature I will be talking about.  The NAMPS specification
provides for a feature known as Mobile Reported Interference ( MRI ).  The
base station (cell site) can request that the cellular phone can send in a
measure of the forward Traffic Channel ( TCH ) signal strength. As well as
the measure of the number of the errors of the 200bps signaling stream.

Alpha-Numeric Message:
~~~~~~~~~~~~~~~~~~~~~~

Alpha-Numeric Message allows the NAMPS system to send fourteen characters
or less on the forward channel in a point to point or point to multi-point
mode.  It also allows you to combine paging functions with your cellular
phone service allowing you to send your service provider to charge you more
and rip you off, considering that it is a built in system and doesn't cost
them anything.

Pre-Loading:
~~~~~~~~~~~~

Since cellular phones are dual mode they allow an AMPS phone to support
NAMPS technology, without supporting NAMPS service.

Sub Audio Signaling:
~~~~~~~~~~~~~~~~~~~~

The key to the 10Khz channel spectrum is the Sub Audio Signaling scheme
employed between the cellular tower and the cellular phone.  A 200bps
continuous data stream is sent.  The hacker using the cloned phone, errrr....
the user of the cellular phone does not hear the signaling :o).  Because
the frequency resides well below the usable portion of the audio spectrum.

Superior Audio Tone ( SAT ) and Digital Superior Audio Tone ( DSAT ):
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Taking the place of SAT and signaling tone, is a sequence of digital words
in the 200bps stream.  NAMPS provides for seven DSAT sequences that have
cross correlation properties.  Digital Signal Tone ( DST ) consists of the
logical inverses of the seven DSAT sequences.

Total Access Communications System ( TACS ):
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In the above I didn't mention any specifications of the TACS system.  TACS
and AMPS are very similar, in fact almost the same.  The only major
differences in a TACS to AMPS system is Reverse Channel Frequencies (RCF's)
and Forward Channel Frequencies   ( FCF's ). In AMPS the RCF is 824Mhz-849Mhz
and the FCF for AMPS is 869Mhz - 894Mhz.  Compared to TACS where the RCF is
872Mhz - 905Mhz and the FCF is 917Mhz - 950Mhz.  The number of channels in
AMPS is 832 where in TACS it is 1000.  AMPS - TACS are the same compared to
NAMPS.  That is why I discussed AMPS - NAMPS.

More Differences Between AMPS - TACS - NAMPS:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

All real differences in the AMPS - TACS - NAMPS systems are very few, which
can be broken down into fewer parameters starting with the number of channels.
AMPS have 832 channels, TACS have 1000 channels, which is in greater difference
with the NAMPS system, which has 832 * 3 possible channels !! 

There are a few more major differences that I am going to mention, leaving
out several.  The SAT tones are three at 6Khz for the AMPS and TACS system.
Seven DSAT data rate channels is 10Kbps in NAMPS, 8Kbps for TACS, and 200bps
on TCH for NAMPS. The TACS system that I have mentioned above is referred to
ETACS ( Enhanced Total Access Communications System ).

Acronyms and Abbreviations:
~~~~~~~~~~~~~~~~~~~~~~~

AMPS            -               Automatic Mobile Phone Service
DSAT            -               Digital Superior Audio Tone
ETACS           -               Enhanced Total Access Communications System
FCF             -               Forward Channel Frequencies
ITU             -               International Telecommunications Union
MRI             -               Mobile Reported Interference
NAMPS           -               Narrowband Automatic Mobile Phone Service
NMT             -               Nordic Mobile Telephone
RCF             -               Reverse Channel Frequencies
SAT             -               Superior Audio Tone
TACS            -               Total Access Communications System

Disclaimer:
~~~~~~~~~~

This file is for educational purposes only, and anything derived from
this file, especially illegal uses of the analogue cellular structure
are NOT my responsibility. This file does not contain any information
of illegal use of cellular phones or cloning methods.    This file is
simply for a better understanding of the analogue cellular system.

Hope you enjoyed this text file !!  If you have any questions you can
usually find me on Efnet ( IRC ) in #Cellular, #9x and #IUA :).

(IUA) International Underground Alliance --- www.iua.nu --- Be
reconized by IUA and be wanted everywhere in the world by Interpol
