An index of all the common telecoms terms, jargon and acronyms.

Telecommunications Glossary > L


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LAN – Local Area Network

A geographically localised network located on an individual organisation’s premises. LAN-enabled computer devices can communicate with each other as well as share and have access to peripherals such as printers, fax services, modem services and centralised databases.

LATA – Local Access Transport Area

A geographical area within which a divested RBOC is permitted to offer regional toll and access services.

Local Exchange

Geographic area determined by the appropriate state regulatory authority, in which calls generally are transmitted without toll charges to the calling or called party. Several local exchanges may exist within a LATA.

LCR – Least Cost Routing

A telephone system feature that automatically chooses the lowest cost phone line to the destination. The ‘lowest cost’ is determined by algorithms, equations and decision trees programmed into a PBX.

LIDB – Line Identification Database

Database deployed by RBOCs and all local telephone companies that contain all the valid telephone and calling card numbers in their regions, and have the necessary information to perform billing validation.

Line Served by Switch

Any Directory Number that’s connected to the switch. The DN may be physical subscriber port of virtual DN.

LNP – Local Number Portability

The ability of telephone subscribers to maintain their phone numbers when they change local telephone companies.

LEC – Local Exchange Carrier

Any company authorised to sell local telephone services.

LERG – Local Exchange Routing Guide

Often used by carriers for network design.

Local Loop

The Local Loop is the telephone line that runs from the local telephone company’s end office switch to the user’s premises.

LLU – Local Loop Unbundled

The routing of alternative suppliers when lines hit the exchange, generally utilising Openreach copper to terminate to an NTE. The exchange then has space for the appropriate carrier to install their own equipment.

LRN – Local Routing Number

A 10 digit number used to uniquely identify a switch that has ported numbers.

LES – Loop Emulation Services

An ATM forum specification designed to emulate a customer’s local loop using ATM by extending class 5 service capabilities, along with high-speed data services, to customers.


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