Electronic equipment for optical communication capable of saving power

Electronic equipment having 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 comprising:

• a first clock which is halted during the stand-by mode and a second clock which is operational during both the stand-by mode and the operation mode;
• a measuring instrument for, in the standby mode of the CPU, measuring frequency of light inputted from the transmission/reception circuit, wherein power control for a light reception circuit is turned ON and OFF during the stand-by mode using the second clock;
• a frequency discriminating instrument for discriminating whether or not the measured frequency is a desired frequency;
• and
• wherein the CPU is changed from the standby mode to the operation mode and the first clock is turned ON depending on a discrimination result of the frequency discriminating instrument, and optical communication is executed by the transmission/reception circuit.