Connection issues with digital intercom (2 wires bus system?)

Hey guys, I tried already a lot but its not working.

I have a digital intercom
This is the model:
and this is how it looks like on the backside:

the titles on the backside are:
NC, GND, RING, SW+ and SW-

this is not in the compatibility list of Nukis opener but I wanna try it anyway.

do you have any ideas how to connect the different cables?

thanks a lot in advance

OK, I tried nearly any possible wireconnection but nothing works.

So, before I return the Nuki stuff, I would like to know how to connect the Opener as “OTHER DOOR” to my intercom?

Can anybody please help me?