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Duplex, Semi-Duplex, Half-Duplex

To meet the various requirements of different types of productions, Radio-Rental.com offers three different radio-communication technologies. These are:

  • Half-Duplex Operation
    Half-duplex is still the standard in radio communications: One speaks, everyone listens.
    A participant may answer only when the first speaker is finished and has cleared the channel (e.g. by releasing the PTT button). In professional radiotelephony, this is signified by speaking the codewords "over" or "over and out." When the listener receives a question or instruction, the response should be "Roger," or simply "okay."
    For more information, see "Radio Language" and "Radio Discipline" in our wiki.
    So, half-duplex operation is also known as "two-way communication."
    All of the Motorola two-way radios we stock are capable of half-duplex operation.
  • Semi-Duplex
    Semi-duplex operation is a rather theoretical construct; it's of no importance to the user (although it may well be for the technician). In semi-duplex operation, reception occurs on one frequency while a different frequency is used for transmission. Technically, however, simultaneous receiving and transmitting are not possible for most radios, because (as with the Motorola CP040, for example) the PTT button is used to switch between the transmission (speaking) and receiving (listening) functions. A classic application for semi-duplex is the use of a repeater for range enhancement. The repeater receives on one frequency and re-transmits the signal on a different frequency. Semi-duplex is also known as "crossband operation."
    All of the Motorola two-way radios we stock are capable of semi-duplex operation too.
    To implement semi-duplex communications, we'd recommend using our digital two-way radios, like the Motorola DP3400 and Motorola SL4000. Add a digital Motorola repeater (which must also be semi-duplex-capable) like the Motorola SLR5500, and your duplex radio system is ready.
  • Full duplex
    In a duplex radio system, a two-way radio transmits on one frequency (the "upper band") and receives on a different frequency (the "lower band"), enabling simultaneous speaking and listening. In our experience, a relay station (-> repeater) is an absolute must for this type of operation. The repeater "transposes" the frequencies, which enables duplex communication.

An additional informative source on the subjects of duplex, half-duplex, etc. is the Wikipedia article at this URL: http://en.wikipedia.org/wiki/Radiotelephone

Or simply give us a call +49 30 2938197-0 , send us an mail mail@Radio-Rental.com.With more than a decade of practical experience, we'll gladly offer advice and work with you to quickly discover the best solutions for your project.

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