This is information related to the Dobiss protocols that I have discovered by probing various things on my devices. My installation is a pair of modules marked "Dobiss Domotics Relay Module single pole 8 channel Model DO4511" connected by a black CAN cable. The button bus is connected to the first module.
WARNING Assume that anything you can touch or probe or poke a wire into is on LIVE VOLTAGE and will kill you if you touch it. I'm not responsible for whatever you decide to do with this information.
In particular make sure of the following: Measure that there is no voltage between the ground and your earch connection.