PURPOSE: To reduce the power consumption and generated heat of the communication controller by controlling a power supply of a communication control section when an information processing unit makes a call with a command from the processing unit and controlling the power supply with a command from an incoming call detection means when a call reaches the processing unit.

CONSTITUTION: When an information processing unit 4 makes a call to a terminal equipment and the unit 4 gives a command of supplying a power to a communication control section 2 to a power supply control section 10, the means 10 supplies the power from a power supply line 6 to the control section 2. When a call reaches the unit 4 from the terminal equipment and the call reaches the control section 2 from the terminal equipment, an incoming call detection means 9 detects the arrival of the call and gives a command of supplying power to the control section 2 to the means 10. The means 10 supplies the power of the power supply line 6 to the control section 2, which reports the arrival of the call from the terminal equipment to the unit 4 to make data transmission reception. Thus, the power consumption and generated heat are reduced by supplying the power only to the incoming call detection means not in the communication state.