PURPOSE: To realize high-speed transmission with an interruption simplified when transmitting a large amount of continuous data and a small amount of discrete data both mixed, by allowing a control part to set and reset a parallel line and specific bit and to shift a shift register.

CONSTITUTION: Transmission part 601 modulates and sends data to a transmission line, and reception part 602 demodulates the data to generate reception pulses. Here, repeated data are stored temperarily in shift register 603, and through the control of control part 603, the shift of shift register and the set and reset of a parallel line and specific bit are made. Consequently, when a large amount of continuous data and a small amount of discrete data are both mixed and transmitted, the interruption is simplified and high-speed transmission can be made possible.