Telecommunication circuit

A telecommunication circuit is any line, conductor, or other conduit by which information is transmitted.

A dedicated circuit, private circuit, or leased line is a line that is dedicated to only one use. Originally, this was analog, and was often used by radio stations as a studio/transmitter link (STL) or remote pickup unit (RPU) for their audio, sometimes as a backup to other means. Later lines were digital, and used for private corporate data networks.

The opposite of a dedicated circuit is a switched circuit, which can be connected to different paths. A POTS or ISDN telephone line is a switched circuit, because it can connect to any other telephone number.

On digital lines, a virtual circuit can be created to serve either purpose, while sharing a single physical 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. See communications protocol.
  • An electronic path between two or more points, capable of providing a number of channels.
  • A number of conductors connected together for the purpose of carrying an electric current.
  • An electronic closed-loop path among two or more points used for signal transfer.
  • A number of electrical components, such as resistors, inductances, capacitors, transistors, and power sources connected together in one or more closed loops.


 This article incorporates public domain material from the General Services Administration document "Federal Standard 1037C" (in support of MIL-STD-188).