Abstract: An attenuator circuit having three cascaded attenuator stages which become active, one at a time, as an input signal strength increases. In the highest gain state, the three attenuator stages are active. As the input signal increases, the attenuator stages become inactive sequentially starting with the last stage.

Abstract: Remote control apparatus for a power line communications system in which control signals are transmitted, via the power line to, from the location of utilization equipment to a control unit located at a remote point and by which the utilization equipment is controlled.

Abstract: A power line communications system in which information signals are frequency multiplied in a transmitter unit, so that the critical information portions of the information signals are frequency shifted from a notch in the frequency response characteristic between an outlet in the power line communications system to which the transmitter unit is connected and an outlet in the power line communications system to which a receiver unit is connected, whereby the critical information portions of the information signals are not lost in the notch.

Abstract: A power line telephone communications system having an ON HOOK digital voiceband messaging feature by which selected information contained in an incoming call to a telephone is received prior tc the telephone being lifted off its hook. The incoming ring signals, ON HOOK digital voiceband messaging and information signals are conducted by a base unit to the power line for transmission to an extension unit to which a telephone is connected.

Abstract: A coupling circuit for a power line communications system for coupling information signals from a transmitter unit to a power line and for coupling information signals from the power line to a receiver unit. The coupling circuit includes: (a) a ferrite core coupler for isolating the transmitter unit or the receiver unit from a power line and for coupling information signals from the transmitter unit to the power line and from the power line to the receiver unit, (b) a bandpass filter for selectively passing information signals from the transmitter unit to thew power line and from the power line to the receiver unit, and (c) an impedance matching pad for matching the impedance of the transmitter unit to the impedance at an outlet connected to the power line and to which the transmitter unit is connected and the receiver unit to the impedance at an outlet connected to the power line and to which the receiver unit is connected.