For the RJ-45 the documentation it says:
2x RJ45 connector for remote panel and/or parallel and 3-phase operation.
Nothing about protocol.
It then says about how to configure:
A MK3-USB (VE.Bus to USB) interface. Alternatively, the Interface MK2.2b (VE.Bus to RS232) can be used (RJ45 UTP cable needed).
I cannot from pictures/descriptions figure out exactly what cable to use and where to connect it.