The telephone interface module is cool but I have a LOVE/HATE relationship with it.
It is an Elan Z600 communications controller with the speakercraft name on it.

You can have 2 doorbells ring through BG msuic system. Pick up any phone and talk to front door, have paging over BG music system, Use phones as intercom, ulock/open doors/gates. Put source music into phones so that if you put someone on hold the get to listen to music. List goes on and on.

The 2 things I HATE MOST are the nasty sounding dial tone and the fact that the dial tone will not work with the phone companies voice mailbox system. You can bypass the system dialtone and get to a standard tone and then listen for the beeps to see if you have any messages.

Other than that I love it.

Robbie S