Abstract: A communication system of the present invention is provided in electric devices such as refrigerators including a plurality of output units such as electric fans, electric dampers, and output units such as sensors, thermistors, etc. The communication system is provided in the vicinity of the input and output units. The communication system includes a plurality of sub-control sections for controlling operations of the output units, a main control section for controlling the electric device by controlling operations of each sub-control section, a single communication-use cable for connecting the main control section and the sub-control sections so as to permit communications between them. Bidirectional communications between the main control section and each sub-control section are carried out through the communication-use cable.