Multiplexer User's Guide
Confidential / Released
5 Multiplexer protocol version control
The multiplexer protocol offers a version control to ensure that TE and MS support the same
extent of functionality and to maintain upward and downward compatibility when later
firmware versions of the GSM engines are released. The implementation of version control is
a subset of the GSM 07.10 standards.
When the multiplexer is started, the MS and the application negotiate which MP version to
use. If TE and MS do not support the same multiplexer protocol, the lower version will be
agreed upon. If no version check is done the TE reverts, due to lack of version information, to
multiplexer version 1. This means that both sides only agree on version 1, even though they
may have the same and even higher version.
The TE and MS multiplexer version numbers can be traced on the serial interface.
They appear as follows:
• TE version (e.g. version 1):
• MS version (e.g. version 2):
In multiplexer protocol sources delivered by Siemens AG version control is integrated. When
designing an application based on other sources take care to implement the version check
as well, especially if you wish to upgrade to later firmware releases. It is strongly
recommended to implement the latest multiplexer version available.
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