I know the fault code but what is meant by riser? The LCEFCB boards??

If so, they all have a green led and all have power on the plugs.

It's not just the hoistway comms though, it's the car comms as well. I'm trying to figure out whether it's the dallas chip causing the issues or whether it's worth performing a drive setup from scratch.

It's just strange that we've replaced all floor boards, LCECPU, KNX board and the ADO board and still no comms.

Comms comes from the CPU and fed individually to the car, shaft and map panel.