Nokia TCSM2¶

Nokia is one of the major historical manufacturers of GSM infrastructure equipment. They made BTSes, they made BSCs and MSCs, and they had several generations of Transcoder and Submultiplexer (TCSM) equipment that sits between the BSC and the MSC. (Nokia used the term TRAU to refer only to individual channels, handling a single voice or data call, while the big rack full of TRAUs was called TCSM.)

According to the available docs, Nokia had 3 generations of TCSM: the original TCSME, followed by TCSM2, followed by TCSM3i. Out of these 3 Nokia TRAU generations, plus other vendors besides Nokia, TCSM2 is our lucky winner: we were able to find enough documentation to figure out which components to buy and how to put them together, we were then able to actually buy the set of parts needed for a minimal configuration, and the module that holds all of the on-board software (TRCO card) came loaded with everything we need. Very lucky indeed!

The project to put together a working TCSM2 system in Themyscira lab is still ongoing as of this writing, tracked in #6464.

Documentation¶

The body of documentation we've collected for TCSM2 (and some for TCSM3i) is gathered here:

https://www.freecalypso.org/pub/GSM/Nokia_TCSM/

Some of the most interesting docs are:

• This document (a slide presentation from Huawei - how they did get involved?) focuses mostly on TCSM3i, but it begins by covering the full evolutionary line and includes some useful tidbits about TCSM2.
• This document (tcsm2.pdf) contains a lot of technical details about the internal architecture of TCSM2 and interconnection between modules - invaluable for reconstructing a working system from pieces!
• This document (tcsm2-command.pdf) thoroughly describes the management interface that is accessible via the RS-232 port on the TRCO card - essential for configuration!