PURPOSE: To dispense with re-dialing by performing automatic connection after completing speech even when the speech is being performed and to improve operability by enabling incoming from a dial-in central office to an extension subscriber during the speech to be connected.

CONSTITUTION: When the incoming from a dial-in central office trunk 4 arrives at the extension subscriber 1 performing the speech via a central office trunk 3 and a network 2, a central control unit 6 informs the incoming by connecting the extension subscriber 1 to an audible voice device 5 in a short time by controlling the network 2. Then, a state is returned to an original state again, and also, the incoming from the trunk 4 to the extension subscriber 1 is stored in a memory device 7. The central control unit 6 calls the extension subscriber 1 after identifying the completion of the speech by performing on-hook by the extension subscriber 1. When the extension subscriber 1 performs off-hook, the central control unit 6 connects the incoming from the dial-in trunk to the extension subscriber 1 performing the speech.