Editing Local loop (section)

== 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.