Abstract: In a board work system, the CPU of a board work device transmits error related information which relates to an error in a case where the error has occurred in the own device. Then, the CPU receives the error related information which relates to the error of the other board work device, and stores the received error related information in the HDD. Then, the display operation section is controlled such that information (other device error notification screen) based on the stored error related information is notified to the operator in a case where the power source of the board work device (other board work device), in which the error has occurred, is detected to be switched off.

Abstract: 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 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.