PURPOSE: To make it possible to answer automatically to an incoming circuit only by lifting the handset by supplying power to the incoming line by an incoming signal from the circuit and by providing several relays and contacts which connect and maintain the incoming circuit.

CONSTITUTION: When incoming arrives at circuits 1L1 and 1L2, for example, among circuits 1L1, 1L2...nL1, and nL2, incoming relay R operates to supply power to incoming line RL via contact (r), and lifting the handset of the telephone set operates hook switches HS1 to HS3 while connection relay A1 is operated by busy relay B in process of operation. As a result, contact (a11) makes connections between circuits 1L1 and 1L2, and talking network N.W and contact (a12) connects the power supply to control line CL; while contact (a14) is broken, contact (a13) is made so as to supply relay A1 with the power continuously, so that answering to circuits 1L1 and 1L2 will be possible. For the originating operation, key (push button) LK1, for example, is depressed and switches HS1 to HS3 are only operated to operate relay A1, thereby allowing a call.