Telecommunication circuit

A telecommunication circuit may be defined as follows:

• The complete path between two terminals over which one-way or two-way communications may be provided.
• An electronic path between two or more points, capable of providing a single or multiple communication channels.
• An electronic closed-loop path among two or more points used for signal transfer.

In operational terms, a telecommunication circuit may be capable of transmitting information in only one direction (simplex circuit), or it may be bi-directional (duplex circuit). Bi-directional circuits may support half-duplex operation, when only one end of the channel transmits at any one time, or they may support full-duplex operation, when independent simultaneous transmission occurs in both directions.[1]

Originally, telecommunication circuits transmitted analog signals. Radio stations used them as studio transmitter links (STLs) or as remote pickup unit (RPU) for sound reproduction, sometimes as a backup to other means. Later lines were digital, used in pair-gain applications, such as carrier systems, or in enterprise data networks.

A leased line, private circuit, or dedicated circuit, is a circuit that is dedicated to only one use and is typically not switched at a central office. The opposite is a switched circuit, which can be connected to different paths in a switching center or telephone exchange. Plain old telephone service (POTS) and ISDN telephone lines are switched circuits.

On certain packet switching telecommunication circuits, a virtual circuit may be created, while sharing the physical circuit.

 This article incorporates public domain material from Federal Standard 1037C. General Services Administration. Archived from the original on 2022-01-22. (in support of MIL-STD-188).

• Patrick D. van der Puije (2002). Telecommunication Circuit Design. New York: John Wiley & Sons.