Duplex (telecommunications)

With duplex (also: full duplex), half duplex or simplex is called in communication technology, the directionality of communication channels.

The German terms described in DIN 44302 are not in use:

  • One-way data transmission (one-way communication)
  • Interdepartmental data exchange ( half duplex transmission, two-way alternate communication)
  • Two-sided data transfer ( both- way communication, two-way simultaneous communication)
  • Alternating operation ( half duplex transmission)
  • Counter mode ( duplex transmission)

When radio (eg, bad radio, marine radio ) is the name intercom for duplex or simplex operation for half-duplex operation use.

If changes are information transfer in both directions on the same medium, the information must be merged and separated by duplex.

Some practical examples:

  • In the analog telephony, the hybrid circuit is responsible for merging and separation of speech signals in both directions.
  • Time division duplex (English time division duplex, TDD ), for example applied for DECT phones. Here use transmit and receive channel at the same frequency, but separated in time. The information is transmitted in time-delayed short sequences with the aid of a predetermined timer. By digitization of the speech signal, the speech signals can be transmitted together in blocks. Nevertheless, there is a continuous layer on the analog voice communication in both directions. Another example of the TDD is a ping-pong method used in telephone systems, which is also referred to as Up0.
  • Frequency division duplex (English frequency division duplex, FDD) means to transmit the information for each direction by using a different carrier frequency. It allows a device to send and receive simultaneously. It is typical for historical, analog method for radio telephony, for example, in the A- network, B- grid and C- grid in Germany.

In mobile communications, a combination of time and frequency division duplex is used today mostly. The mobile subscriber sends, for example, on the uplink frequency of 890 MHz in the time slot 1 and receive on the downlink frequency of 935 MHz, a time delay for time slot 5

Norms and Standards

  • DIN 44302, issued February, 1987, Information processing - Data transfer, data transfer - Vocabulary
  • Communications Engineering
  • Wireless technology
Radiotelephone Hybrid coil Digital Enhanced Cordless Telecommunications B-Netz C-Netz
249905
de