A power line carrier controlled lighting system connected to an AC power line. The system has: at least one motion detector for detecting at least one predetermined parameter in a detection zone of the motion detector, the motion detector outputting at least one detect signal in response to the predetermined parameter; at least one transmitter for transmitting during a first predetermined time period a power line carrier signal on the AC power line indicative of the detect signal; at least one receiver receiving the power line carrier signal on the AC power line and outputting at least one control signal indicative of the power line carrier signal during a second predetermined time period, the receiver having an AGC circuit for providing substantial noise immunity so that the receiver reliably recognizes the power line carrier signal; and at least one light in a predetermined area and having at least two different light intensity levels, the light having a switching circuit for switching between the light intensity levels, the switching circuit being activated by the control signal. The power line carrier signal is a digital signal and the AGC circuit determines a logical one/zero reference level relative to noise on the power line.