In wired telephony

Telephony

In telecommunications, telephony encompasses the general use of equipment to provide communication over distances, specifically by connecting telephones to each other....

, a private line or tie line

Tie line

A tie line, also known as a tie trunk, is a communication connection between extensions of a private telephone system, typically two PBXes.-References:...

 is a service that involves dedicated circuits, private switching

Circuit switching

Circuit switching is a methodology of implementing a telecommunications network in which two network nodes establish a dedicated communications channel through the network before the nodes may communicate. The circuit guarantees the full bandwidth of the channel and remains connected for the...

 arrangements, and/or predefined transmission

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...

 paths, whether virtual or physical, which provide communications

Telecommunication

Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...

 between specific locations. Most private lines connect only two locations though they may be switched at either end or both. Some have multiple drop points.

Note: Among subscribers to the public switched telephone network

Public switched telephone network

The public switched telephone network is the network of the world's public circuit-switched telephone networks. It consists of telephone lines, fiber optic cables, microwave transmission links, cellular networks, communications satellites, and undersea telephone cables, all inter-connected by...

(s), the term "private line" is often used to mean a one-party switched telephone line

Telephone line

A telephone line or telephone circuit is a single-user circuit on a telephone communication system...

, as opposed to a party line

Party line (telephony)

In twentieth-century telephone systems, a party line is an arrangement in which two or more customers are connected directly to the same local loop. Prior to World War II in the United States, party lines were the primary way residential subscribers acquired local telephone service...

.

CTCSS

In radio or wireless telephony, Private Line is a term trademarked by Motorola to describe their implementation of a Continuous Tone Coded Squelch System (CTCSS

CTCSS

In telecommunications, Continuous Tone-Coded Squelch System or CTCSS is a circuit that is used to reduce the annoyance of listening to other users on a shared two-way radio communications channel. It is sometimes called tone squelch...

), a method of using low frequency subaudible tones to share a single radio channel among multiple users. Each user group would use a different low frequency tone. Motorola's trade name (especially the abbreviation PL) has become a genericized trademark

Genericized trademark

A genericized trademark is a trademark or brand name that has become the colloquial or generic description for, or synonymous with, a general class of product or service, rather than as an indicator of source or affiliation as intended by the trademark's holder...

 for the method. General Electric used the term 'Channel Guard' to describe the same system and other manufacturers used other terms. A later digital version of Private Line is called Digital Private Line, or DPL.

See also

• 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...
  
  
• Dedicated line
  Dedicated line
  In computer networks and telecommunications, a dedicated line is a communications cable or other facility dedicated to a specific application, in contrast with a shared resource such as the telephone network or the Internet....
  
  
• Party line
  Party line (telephony)
  In twentieth-century telephone systems, a party line is an arrangement in which two or more customers are connected directly to the same local loop. Prior to World War II in the United States, party lines were the primary way residential subscribers acquired local telephone service...
  
  
• Lec billing
  Lec billing
  LEC billing is a form of billing for internet-based or other usually electronic services where the user is charged through his account with the local telephone company , rather than directly from the provider of the service....
  
  
• IXC