PURPOSE: To call a terminal set just after end of communication and to respond thereto by allowing an exchange to confirm a calling state to the same terminal group and to send a call signal even to an idle terminal set when a signal of communication end or an idle state notice comes from a terminal set.

CONSTITUTION: When the communication of the terminal is finished and exchange 5 receiving the notice of idle state checks a groups state memory 6, and when a terminal 2 of a line A is idle and the line A confirms the calling state, a call signal is sent to all of same group terminal sets 1∼3 of the line A to receive an incoming reception signal. In case of the state of not calling, the exchange sets the terminal set in the idle state to finish the procedure. Thus, the exchange 5 does not make terminal sets in a group formed by multi- point connection completing its call before response into idle state but makes all terminal sets except for a busy set into the same calling state. Thus, a party whose call is finished can reply a call of the same terminal set immediately.