Fermex VDS BUS

Hi I am trying to install ten nuki opener on a fermex bus

It should be easy but it doesn’t work
+± are vcc 18V (maybe also some kind of bus)
L Dataport
T is the second door bell

I tried it for 6 hours up to now and no configuration from the net or from the nuki app is working

I would be very happy if anyone can send me a connection diagram

I get stuck at the point the nuki app is searching for pressing the door opener button

I have a oszi for collecting data, also a datalogger if necessary,…

best regards

Has anytone an idea?