Abstract: A feedback sensor which detects the reception of pulses and the response thereto by the remote receivers of a load management system associated with a power transmission system. The receivers are of the type which respond to pulsed messages injected onto the power lines and include electomechanical elements operative upon receipt of pulses for which the particular unit is coded. An optical switch is fixed to the receiver and a shutter to the actuating member such that the optical switch is caused to change state whenever the receiver responds to a transmitted pulse. The detected signal is returned to the injection station, such as by telephone lines, to verify proper response of the receivers in the system. A unit located at the injection station can be used to assure that the signal is being injected properly.