AT&T Door Phone Controller Telephone Line In Use With Door When Incoming Call Arrives

Telephone Line In Use With Door When Incoming Call Arrives

If there is a call in progress between the door speaker and a person inside the building and a C.O. call comes in, the person inside the building (not the door speaker) will hear a call waiting tone. The person inside the building can hook-flash the phone (or dial 9) and communicate with the incoming caller. When the call is complete, the person inside the building hangs up the phone or to speak with the person at the door speaker again, the person inside the building must hook-flash the phone (within 4 seconds after picking up the receiver).