PURPOSE: To recognize who is a new visitor without interrupting talking when a person at home in a master set receives a call from other slave set by the new visitor while the person is busy with a visitor of one slave set.

CONSTITUTION: While a video signal changeover circuit 24 and an audio signal changeover circuit 26 are switched to a slave set 1a by a system control section 20, when a person at home uses a handset 8 to be talking with a visitor of a slave set 1a and other visitor comes to a slave set 1b and a call pushbutton 6 is depressed, a call signal detection circuit 21 detects it. The system control section 20 operates a call tone generating circuit 22 to allow a speaker 23 to sound a call tone thereby switching the video signal changeover circuit 24 to be the position of the slave set 1b for a prescribed time.