SIMPLEX OPERATION

1. Operation in which transmission occurs in one and only one preassigned direction. Synonym one-way operation. ( 188 ) Note: Duplex operation may be achieved by simplex operation of two or more simplex circuits or channels. 2. Operating method in which transmission is made possible alternately in each direction of a telecommunication channel , for example by means of manual control. Note: In general, duplex operation and semiduplex operation require two frequencies in radiocommunication ; simplex operation may use either one or two. [ NTIA ] [ RR ] Note 2: These two definitions are contradictory, however, both are in common use. The first one is used in telephony and the second one is used in radio . The user is cautioned to verify the nature of the service specified by this term.