PURPOSE: To attain high speed data transmission with a few signal lines by connecting a facsimile device and a personal coputer with plural two-way data lines and two-way control signal lines.

CONSTITUTION: A facsimile 10 consists of a network controller NCU controlling the connection with a communication line, modulators-demodulators (MODEM) converting a picture signal and a commnication signal, data compressing reproducer DCR reproducing a picture data from a compressed code data, read/write buffer RWB storing temporarily picture data, scanner ISA reading a picture data of an original, plotter REC copying the picture data on a recording paper sheet, and a controller SCU for them. The device 10 is connected with an interface IFP of a personal computer 1 via an interface IFF and a cable CAB. The consists of plural two-way data lines and control lines and the direction of the signal is decided by controlling the gate of the IFP and IFF.