I want to synchronize two Xbus kits. How does that work?

With an Xbus Kit, you have the following options for synchronisation:
1.    Using one of the sync functions of the Xbus Master (sync in. sync out) to either trigger the external system or have that trigger the XM. see page 16 of the XM user manual, page 10 of the XM technical doc and pages 13-16 of the Low Level documentation. Note the RS232 levels:
            1: -3 to -25V
            0:  3 to  25V

2.    If the external system has an additional free analogue channel available, you may use the analogue channel of the last MTx on the chain to record a distinctive and recognizable pattern on both systems (see Low Level Communication Documentation pgs. 20-21 and 24 and the MTi/MTx User Manual and Technical Documentation pgs 42-43).

3.    If the external system has an additional free analogue channel available, this could also be used to record a sync-out signal of the XM or the RTS pin to the XM. The sync out will provide a pulse pattern, best will probably the toggle mode (see XM Manual pg 16). The RTS will be set from low to high by the MT Software with the 'Run' and 'Stop' commands of the MT software while it records data from the Xbus Master.

Note that the use of the MT SDK is required to implement some of these options.