marantz remote control (M-BUS)?

I have marantz ST-48 tuner, which has no ir remote. However it can be controlled by marantz preamplifier or integrated amplifier, thru M-BUS. I have tried to find any information about this protocol, but foud nothing.

Does anyone here know anything about this protol? any information is needed. What I want to do is to add this control feature to my preamp...