PURPOSE: To attain the entry of data inputted during talking without changeover operation of a selection signal when the key telephone system is used for a terminal equipment as a voice reply device.

CONSTITUTION: A selection circuit 4 is provided with a switch 41 switched by the operation of the operator and with a relay 42 switched by a busy signal 104. The switch 41 selects either a dial pulse signal 102 or a PB signal 103. When the relay 42 outputs the signal selected by the switch 41 to a telephone system main body side 1 as it is when the busy signal 104 is inactive and the relay 42 is activated when the busy signal 104 is active and the PB signal 103 is outputted to the telephone system main body side 1 independently of the state of the switch 41.