yep, 200 and 20 doesn’t show any value so voltage is apparently not high enough.
Then maybe you really dont get to the trigger power for the opener, it needs 3volts for detecting the ring signal!? But on the other side, it should not show this measurings you have, and Digital bus system sometimes have really less power, but you said its all analogue!?
Can you make a picture of the bell and opener wiring?
phew … Don’t know, maybe I have a bus system, but don’t know how to find out. It’s an old multi family house and I couldn’t find any room or box with some bus-like configuration.
Bus should only have two wires out of the wall.
well, there are 4 cables, so I thought it must be analogue … you see them all on my drawing – it’s the ones coming from the left:
- yellow: (+), goes straight to the bell
- green: (-), pipes through the apartment ring button to the bell
- red: Ground, pipes through the buzzer button to the apartment ring button
- black: goes to the buzzer button
In my original post I posted pictures of all the cables (buzzer and bell).
You use wagos as I, I use the exactly same for the opener! The purple and black cable’s are the ground cable’s of the opener, its very important that they are connected right, and normally purple and black are going in the same gnd block, where are the purple and black connected? And for info, the purple is the buzzer gnd and the black the ring-detection gnd.
The Nuki purple goes into the red ground (because buzzer works), the Nuki black currently goes nowhere since it’s described as optional. But I had it also connected to red as well previously and it didn’t work. But honestly I never put it back when trying your solutions. I will re-connect it later and try it again. Will let you know if that changes anything.
Yes please, black gnd connected is completely necessary, for ring detection to work! Let me know!
I tried it now. Nuki’s black and violet on the same ground, yellow on -, green on +. Doesn’t work 
In my configuration I have from “-” bell to yellow of opener, and then with green of opener back to “-” of the bell, so that the “-” runs fully through the opener, before going to the bell.
yep, that’s what I have.
I am really going out of my Latin here!?
Know you the model number or type of your outdoor-part, where guests ringing and talking?
well, there’s a metal plate with some buttons. There is not even a talking option. Only ringing and opening 
So after consulting my uncle I’m a step further: he told me to connect the Nuki Ground to the ring line and the yellow Nuki cable to the power line for the bell. That works now. But for obvious reasons the buzzer doesn’t work anymore because the circuit for it is only closed if someone rings.
It also doesn’t work to connect the violett cable to the normal ground and the black to the bell line. In fact the black cable doesn’t have any effect doesn’t matter where I put it since the violet apparently serves for bell and buzzer.
Any idea from that point?
Makes sence, and do you mean the buzzer works no more without bell at all, or just the activation of the buzzer over nuki!?
Just the activation via Nuki. The buzzer setup itself is untouched.
And I found out that the configuration of the nuki wires can change with the setup you choose, and am I correct, that you choosed other doors when setting up the opener in the nuki app!?