Editing Local loop

{{Short description|In telephony, the last part of the connection to the customer}}
{{more citations needed|date=August 2022}}

[[File:Local Loop.jpg|thumb|Local Loop]]

In [[telephony]], the '''local loop''' (also referred to as the '''local tail''', '''subscriber line''', or in the aggregate as the [[Last mile (telecommunications)|last mile]]) is the physical link or circuit that connects from the [[demarcation point]] of the [[Customer-premises equipment|customer premises]] to the edge of the [[common carrier]] or [[telecommunications service provider]]'s network.<ref>{{Cite web |title=What is a local loop? |url=https://superioressexcommunications.com/faqs/what-is-a-local-loop/ |access-date=2022-08-12 |website=Superior Essex Communications |language=en-US}}</ref>

At the edge of the carrier [[access network]] in a traditional public telephone network,<ref>{{Cite web |title=The corDECT Wireless Local Loop: Capacity Predictions |url=https://www.researchgate.net/publication/2888455_The_corDECT_Wireless_Local_Loop_Capacity_Predictions}}</ref> the local loop terminates in a circuit switch housed in an incumbent [[local exchange carrier]] or [[telephone exchange]].

== Infrastructure ==
Traditionally, the local loop was an [[electrical circuit]] in the form of a single pair of conductors from the telephone on the customer's premises to the local [[telephone exchange]]. [[Single-wire earth return]] lines had been used in some countries until the introduction of electric tramways from the 1900s made them unusable.

Historically the first section was often an aerial open-wire line, with several conductors attached to porcelain insulators on cross-arms on "telegraph" poles. Hence [[party line (telephony)|party line]] service was often given to residential customers to minimise the number of local loops required. Usually all these circuits went into aerial or buried cables with a [[twisted pair]] for each local loop nearer the exchange, see [[outside plant]].

Modern implementations may include a [[digital loop carrier]] system segment or [[fiber optic]] transmission system. The local loop may terminate at a circuit switch owned by a [[competitive local exchange carrier]] and housed in a [[point of presence]] (POP), which typically is an incumbent local exchange carrier telephone exchange. A local loop supports voice and/or data communications applications in the following ways:

* analog voice and signaling used in traditional [[Plain old telephone service|POTS]]
* [[Integrated Services Digital Network]] (ISDN)
* variants of [[digital subscriber line]] (DSL).

The term "local loop" is sometimes used for any "[[Last mile (telecommunications)|last mile]]" connection to the customer, regardless of technology or intended purpose. Local loop interrelations in this sense include:

*Electric power lines. 
*Cable connections used with television, internet and telephone.
*Wireless signals or local loop (WLL): [[Local multipoint distribution service|LMDS]], [[WiMAX]], [[GPRS]], [[HSDPA]], [[DECT]]
*Satellite connections for beamed signal.
*Optical or fiber optics services.

==See also==
* [[Access network]]
* [[ISDN]] (Integrated Services Digital Network)
* [[Local-loop unbundling]]
* [[Metallic path facilities]]
* [[Outside plant]] (as an instance of a local loop)
* [[Serving area interface]]
* [[Telephone line]]

== References ==
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[[Category:Local loop| ]]
[[Category:Telecommunications infrastructure]]