Comelit compatibility

I am considering giving it a try with the analogue option for a simplebus 2 system from Comelit (4700). I think I have identified what I need for the wiring. I need to solder the door opener contact (at the back of the PCB) and wire the second bell contact to the Nuki opener for ring detection. See pictures in reply for more details (I can only embed 1 media item per post).
Can anyone tell me if the below diagram (for Elvox system, so completely different) will be helpful? And for ring suppression, should I mute the 1st bell from the Comelit system and add a second bell with green and/or yellow wire from Nuki opener? Last question on the voltage: it seems to be working on 12V, what is the best way to confirm this? I need that to get the ring to open setting working by technical support I think. Thanks for helping me out! PS: If I am confident I am able to achieve the above, I will give it a try and report back with the working setup.

Edit: the extra bell contact as referred to in the Comelit manual seems to be also part of the bus system, so likely encrypted en of no use. I will have to look further for the buzzer contact. Any suggestions based on pics below?