Sorry, it's not a telephone, so it won't work on a POTS line.
It's an intercom, and uses low voltage DC for talk, and low voltage AC to make the buzzers buzz.
Generally, the lobby instrument and any apartment instrument that goes off-hook are in series.
Signalling is over a third lead, via a button/buzzer arrangement.
The receiver units crop up from time to time on the ATCA or TCI forums.
You might try contacting a company who maintains these intercom systems, for advice and spares. There are many in NYC, and I would assume that they are also in other large cities.
These guys might be able to help:
LeeDan
