PURPOSE: To improve the quality of picture and character to be received while eliminating the deviation of synchronization by sending a signal while a parallel signal is converted into a serial signal without fail.

CONSTITUTION: A sending computer 11 at the transmission side gives a paralleled data comprising picture elements to a serial/parallel data conversion controller 12. The serial/parallel data conversion controller 12 converts a parallel data into a serial data in case of transmission and sends the result to a sender MODEM. The converted serial data is sent to a transmission side line terminator 14 from the MODEM and sent to a MODEM 14' and the receiver side line terminator via a communication line 15. Then the serial data outputted from the line terminator and the MODEM 14' is sent to the serial/parallel data conversion controller 12', where the data is converted into the parallel data and sent directly to a receiver side printer 13', where the data is printed out.