Telecommunication control unit

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A telecommunication control unit (TCU), line control unit, or terminal control unit[1] (although terminal control unit may also refer to a terminal cluster controller) is a Front-end processor for mainframes and some minicomputers which supports attachment of one or more telecommunication lines.[2] TCUs free processors from handling the data coming in and out of RS-232 ports. The TCU can support multiple terminals, sometimes hundreds. Many of these TCUs can support RS-232 when it is required, although there are other serial interfaces as well.

The advent of ubiquitous TCP/IP has reduced the need for telecommunications control units.

See also[edit]


  1. ^ System analysis handbook. Fort Benjamin Harrison (Ind.). Computer Science School, United States Army Soldier Support Institute. 1986. p. 3-118. Retrieved July 30, 2016. 
  2. ^ Arick, Martin R. (1987). Data Communications: Concepts & Systems. Wellesley, MA: QED Information Sciences. p. 76. ISBN 9780894351501. Retrieved July 30, 2016.