When I was shopping for an intercom system for my 8 unit building I purposely went for the dumbest system I could find. I wanted it as a foundation and isolated from the rest of the world. I also wanted no cameras.

Here is the installation documentation I have the 4-wire system. I installed it using Cat-5 and standard 548B wiring layout. The rest of the electronic door locks uses the Identiv Liberty key fob system. This was the only system I could find that allowed self-hosting.

I wouldn't mind another layer of integration that would add smartphone access control. The way the 2 systems are currently deployed I could ignore the TekTone side and just integrate the key fobs with the smartphones. I think this might already be possible be possible as the key fob readers already react to the NFC radios on my smartphone.

https://www.tektone.com/pdf_files/manuals/IL826_PK543A_insta...