CONTROL DEVICE AND INPUT-OUTPUT INTERFACE UNIT

A timer circuit switches a second changeover switch and a third changeover switch to a pulse output unit for a certain period of time when power supply is started, and causes the pulse output unit to output a code pulse to a second communication line. An input-output control unit switches a first changeover switch to a first terminal for the certain period of time when the power supply is started, determines whether a code indicated by the code pulse received from the first terminal is a regular code, and cuts off electric power supplied from a first power supply line to a second power supply line when the code is not the regular code.