Thanks for the quick reply. Just to be clear.... The 3line tele is in the house. The talkback horn is located in the garage. I want to add a telephone (no dial?) in the garage so a private conversation can be had if needed. Right now my setup is is with a Valcom V-2900 which is vasically a door control. Works great. Want to have the telephone in the garage for privacy if needed. 2900 does not support this. I do not have a phone yet for the garage. Anything I said help me? Thanks again