ELECTRICAL DEVICE

Provided is an electric apparatus for radio-transmitting a signal between devices by using an optical signal. The electric apparatus is able to continuously perform radio transmission by using an optical signal based on safety standards in a non-normal operating state such an adjustment work, even if safety measures for preventing adverse effects of the optical signal on the human body is suspended. The transmission rate setting unit sets the transmission rate of the signal transmission. The light-emitting unit emits an optical signal. The light-receiving unit receives the optical signal. The emission intensity control unit sets emission intensity of the optical signal emitted from the light-emitting unit. The notification means notifies a non-normal operating state. The transmission rate setting unit and the emission intensity setting unit, according to the notification means, decrease the transmission rate and the emission intensity of the optical signal while maintaining a bit error rate of the radio transmission set in the normal operating state. Therefore, in the non-normal operating state, it is possible to decrease the emission intensity of the optical signal to the emission intensity based on the safety standards while maintaining the communication quality of radio transmission equivalent to that in the normal operating state.