an electronic equipment has a transmission / reception circuit for optical communication , and a cpu which is operated by programs and can be switched to either an operation mode or a standby mode involving less power consumption than the operation mode . the electronic equipment includes measuring instrument for , in the standby mode of the cpu , measuring frequency of light inputted from the transmission / reception circuit by using a clock which is operating in the standby mode , and frequency discriminating instrument for discriminating whether or not the measured frequency is a desired frequency . the cpu is changed from the standby mode to the operation mode depending on a discrimination result of the frequency discriminating instrument , and optical communication is executed by the transmission / reception circuit . thereby , standby cancellation with an optical input is enabled with low power consumption maintained , by which the load on the cpu is reduced .