Units are NOT battery powered.
Each apartment unit is powered by a plug-in "wall wart" type transformer power pack, and the front door unit gets power (24VAC?) supplied over a single pair of wires. The door unit also hardwires to the electric door striker and a "door ajar" switch.
Only the COMMUNICATION between the units is handled without wires.
I was considering one of the telephone line units, but 2 of the tenants in the building don't have POTS service, relying on cellular phones and cable internet.
The original intercom wiring is in pretty sad shape, with a few buried junction boxes and other nasties. I shouldn't have a problem getting one good pair from the basement intercom panel area to the front door to use for power, but the rest of the wiring I would like to just abandon if possible.
[This message has been edited by NJwirenut (edited 10-26-2006).]
