> 5.4 | Implementing Version Control

> The TE initiates the version check by sending the Test command via the multiplexer control channel DLCI 0 (with TEMUX_Version).
> As specified in the GSM recommendation 07.10 (Chapter 5.4.6.3.4) the opposite entity shall respond with exactly the same value bytes.
> The MS shall return the Test command response with the same contents for the verification pattern. Hereafter the MS shall send a Test command message (with MSMUX_Version) to the TE, and the TE shall respond with the same contents. After sending the response a version compare is made on both sides. As a result, both sides shall agree upon the same multiplexer protocol version.