PURPOSE: To surely and quickly inform the end state of communication to an operator at a remote location by calling a preset telephone set after the end of data communication to send a voice message of the end of communication.

CONSTITUTION: When transmission command is given to an input/output section 4, a central control section 5 sends a signal to a line control section 3 to acquire the line automatically and to allow an opposite composite telephone set to send its own telephone number and when the opposite party replies, data is sent via a data transmission/reception section 2. When the transmission of data is finished, the line is opened once, a line control section 3 acquires the line again by a signal from the central control section 5 to dial a set telephone number. When the telephone set replies, the line control section 3 connects the line to a voice message snding section 1 to send the end of communication message to a telephone set (operator) at a remote location from the composite telephone set.