A method which is simplex operation at one end of the circuit and duplex operation at the other. RR Footnote: In general, duplex operation and semiduplex operation require two frequencies in radiocommunication; simplex operation may use either one or two. 2. Operation of a communications network in which a base station operates in a duplex mode with a group of remote stations operating in a half-duplex mode. Note: The terms "half-duplex" and "simplex" are used differently in wire and radio communications.