PURPOSE: To attain transmission/reception of a character data even during talking by providing the 1st changeover means connecting a telephone set and a MODEM switchingly to a communication line and the 2nd changeover means connecting a keyboard output to either a word processor or the telephone set switchingly.

CONSTITUTION: In making a call at first from the sending side (hereinafter A) to the reception side (hereinafter B), a switch 11 is connected to a terminal X so as to attain talking, but when a character data from a word processor 13 at the A is sent to the B, the B allows the switch 11 at the B to throw a terminal Y at the voice talking mode. In sending the data from the A, the A side is switched into the data communication mode, the data is sent and the B side applies parallel-serial conversion to the received data to display the character on a display device or to make a hard copy. When the data communication from the A is finished, an end command is sent from the A, and both the A and B become the voice talking mode. Then the character data is sent or received freely even during talking to improve the density of communication.