> 5.2 | Activating a Siemens Multiplexer Protocol Version

> When the multiplexer is started, the host application (the TE) and the connected module (the MS) negotiate which multiplexer protocol version to use. If TE and MS do not support the same multiplexer protocol, the lower version will be agreed upon. In other words, the highest protocol version common to both sides will be used.
> If no version check is done the TE reverts, due to lack of version information, to multiplexer protocol 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 protocol version numbers can be traced on the serial interface. They are indicated in the following format:

> • | TE version (e.g. version 1): TEMUXVERSION001

> • | MS version (e.g. version 2): MSMUXVERSION002

> The firmware of the Siemens products and the ready-to-use Windows drivers delivered by Siemens integrate a version control. When designing the host application based on your own 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 protocol version available.