PURPOSE: To reduce the instaneous interruption time of a call tone of other telephone set in a incoming state by restarting other call tone in the timing of a replay notice of a replied subscriber circuit even when the call tones of telephone sets of all subscriber circuits are stopped by one replay of plural subscriber circuits in the incoming state.
CONSTITUTION: An incoming call replay detection means is provided, which detects that one or more of subscriber circuits (12-1) - (12-n) of the same number as plural telephone sets(11-1) - (11-n) and controlling them respectively is in the call receiving stat and at least one of them replies. When the incoming call replay detection means detects the incoming replay from any subscriber circuit, the call tone of the telephone sets of all the subscriber circuits (12-1) - (12-n) including the replied subscriber circuit is stopped. When the incoming reply of the replied subscriber circuit is informed, the call tone is restarted from the telephone set of other subscriber circuits than the replied subscriber circuit is restarted. Thus, the instaneous interruption period of the call tone of other incoming telephone sets is reduced when one telephone set of the simultaneous call receiving telephone sets is replied.