PURPOSE: To attain sure response to an incoming call at night by providing a night/day switch means and a transfer identification circuit to attain transfer connection from a decentralized response to a specific extension when the extension subscriber of the decentralized response system does not respond for a prescribed time at night.

CONSTITUTION: When an incoming call comes to atrunk line trunk CBWT00, a signal representing it is transmitted to a decentralized response display device TASU and displayed via a control circuit CONT. A central controller CCU transmits the number of the said trunk so as to allow a transfer identification circuit 1 to supervise the time of decentralized response. When the decetralized response is not responded to for a prescribed time, the circuit 1 transmits nonresponse information and the said trunk number to the CCU. The CCU discriminates that the system is switched to a specific extension connecting system from the decentralized response, connects the specific extension subscriber STA.A and the said trunk so as to call the said subscriber by using the said information.