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

Information

Information in its most restricted technical sense is a message or collection of messages that consists of an ordered sequence of symbols, or it is the meaning that can be interpreted from such a message or collection of messages. Information can be recorded or transmitted. It can be recorded as...

 is transmitted

Transmission (telecommunications)

Transmission, in telecommunications, is the process of sending, propagating and receiving an analogue or digital information signal over a physical point-to-point or point-to-multipoint transmission medium, either wired, optical fiber or wireless...

.

A dedicated circuit, private circuit, or leased line

Leased line

A leased line is a service contract between a provider and a customer, whereby the provider agrees to deliver a symmetric telecommunications line connecting two or more locations in exchange for a monthly rent . It is sometimes known as a 'Private Circuit' or 'Data Line' in the UK or as CDN in Italy...

is a line that is dedicated to only one use. Originally, this was analog, and was often used by radio station

Radio station

Radio broadcasting is a one-way wireless transmission over radio waves intended to reach a wide audience. Stations can be linked in radio networks to broadcast a common radio format, either in broadcast syndication or simulcast or both...

s as a studio/transmitter link

Studio/transmitter link

A studio-transmitter link sends a radio station's or television station's audio and video from the broadcast studio to a radio transmitter or television transmitter in another location....

 (STL) or remote pickup unit

Remote pickup unit

A remote pickup unit or RPU is a radio system using special radio frequencies set aside for electronic news gathering and remote broadcasting. It can also be used for other types of point-to-point radio links....

 (RPU) for their audio, sometimes as a backup

Backup

In information technology, a backup or the process of backing up is making copies of data which may be used to restore the original after a data loss event. The verb form is back up in two words, whereas the noun is backup....

 to other means. Later lines were digital

Digital

A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...

, and used for private corporate

Corporation

A corporation is created under the laws of a state as a separate legal entity that has privileges and liabilities that are distinct from those of its members. There are many different forms of corporations, most of which are used to conduct business. Early corporations were established by charter...

 data networks.

The opposite of a dedicated circuit is a switched circuit, which can be connected to different paths. A POTS

Plain old telephone service

Plain old telephone service is the voice-grade telephone service that remains the basic form of residential and small business service connection to the telephone network in many parts of the world....

 or ISDN telephone

Telephone

The telephone , colloquially referred to as a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other...

 line is a switched circuit, because it can connect to any other telephone number

Telephone number

A telephone number or phone number is a sequence of digits used to call from one telephone line to another in a public switched telephone network. When telephone numbers were invented, they were short — as few as one, two or three digits — and were given orally to a switchboard operator...

.

On digital lines, a virtual circuit

Virtual circuit

In telecommunications and computer networks, a virtual circuit , synonymous with virtual connection and virtual channel, is a connection oriented communication service that is delivered by means of packet mode communication...

 can be created to serve either purpose, while sharing

Sharing

Sharing the joint use of a resource or space. In its narrow sense, it refers to joint or alternating use of an inherently finite good, such as a common pasture or a shared residence. It is also the process of dividing and distributing. Apart from obvious instances, which we can observe in human...

 a single physical circuit.

Definitions

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
  Communications protocol
  A communications protocol is a system of digital message formats and rules for exchanging those messages in or between computing systems and in telecommunications...
  
  .
• An electronic path between two or more points, capable of providing a number of channels
  Channel (communications)
  In telecommunications and computer networking, a communication channel, or channel, refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel...
  
  .
• 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
  Transfer
  Transfer may refer to:* Transfer * Transfer * Transfer DNA, the transferred DNA of the tumor-inducing plasmid of some species of bacteria such as Agrobacterium tumefaciens* Transfer...
  
  .
• A number of electrical components, such as resistors, inductances, capacitors, transistors, and power
  Electric power
  Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt.-Circuits:Electric power, like mechanical power, is represented by the letter P in electrical equations...
  
  sources connected together in one or more closed loops.