The Telcordia LERG Routing Guide is a trademarked term of Telcordia Technologies

Telcordia Technologies

Telcordia Technologies, formerly Bell Communications Research, Inc. or Bellcore, is a telecommunications research and development company based in the United States created as part of the 1982 Modification of Final Judgment that broke up American Telephone & Telegraph...

, Inc., and is a comprehensive data product produced monthly by the Telcordia Routing Administration(TRA) and primarily used by telecommunications service provider

Telecommunications Service Provider

A telecommunications service provider or TSP is a type of communications service provider that has traditionally provided telephone and similar services...

s operating within the North American Numbering Plan

North American Numbering Plan

The North American Numbering Plan is an integrated telephone numbering plan administered by Neustar which encompasses 24 countries and territories, including the United States and its territories, Canada, Bermuda, and 16 nations of the Caribbean...

 (NANP) (i.e. World Zone 1). Its data supports the current local exchange network within the NANP and identifies reported planned changes in the network. The acronym "LERG" originally stood for "Local Exchange Routing Guide".

The LERG Routing Guide provides data to support:

• Routing of calls by service providers over 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...
  
   (PSTN) and interconnection points of the PSTN with the Internet Protocol
  Internet Protocol
  The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
  
   (IP) world
• A wide range of business needs of companies that require information about the network, numbering, and other data in the product

The LERG Routing Guide includes:

• Operating Company Numbers, Company Names, Routing Contacts
• Country Code
  Country code
  Country codes are short alphabetic or numeric geographical codes developed to represent countries and dependent areas, for use in data processing and communications. Several different systems have been developed to do this. The best known of these is ISO 3166-1...
  
   Assignments
• Numbering Plan Area (NPA) Assignments (also known as Area Codes)
• Local access and transport area
  Local access and transport area
  Local access and transport area is a term used in U.S. telecommunications regulation. It represents a geographical area of the United States under the terms of the that precipitated the breakup of the original AT&T into the "Baby Bells" or created since that time for wireline...
  
   (LATA) Codes By Region
• Destination Code assignments (NPA NXX Thousands-Blocks)
• Access Tandem Codes
• Oddball NXXs (e.g. 911, 976)
• Switching Entity Record detail (e.g. Equipment Type, V&H Coordinates), including PSTN and IP network elements
• Rate Center details (e.g. V&H Coordinates) and Localities (includes County and Postal Codes (US) of Localities)
• Switch Homing Arrangements (tandem and other switch-to-switch interconnections)
• Operator Access Tandem Codes (ATCs)
• Location Routing Numbers (LRNs)

See also

• Routing in the PSTN
  Routing in the PSTN
  Routing in the PSTN is the process used to route telephone calls across the public switched telephone network. This process is the same whether the call is made between two phones in the same locality, or across two different continents....
  
  
• Telcordia LERG Routing Guide Overview

• Category:Telephone numbers