Local Calling Areas Database

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Local Exchange Basic Service Areas

Produced: on or before 5th calendar day monthly
Current Release: June 4, 2024
Distribution Frequency: monthly or quarterly (issue date: January, April, July, October)
Distribution Format: Internet download

The Local Calling Area Database can be used to quickly identify the jurisdictional relationship between any originating NPA NXX and terminating NPA NXX call combination. These relationships include determining whether the call is local, intraLATA, interLATA, intraState, interState, and for wireless to wireless or wireless to landline whether the call is intraMTA or interMTA.

Compiled from current carrier sources, the Local Calling Area Database contains local calling area information to identify the basic and expanded local calling areas for telephone exchanges in the United States and Canada based on incumbent wireline carriers' calling area definitions. They can be used as an aid in calling plan design, traffic and least cost routing, or similar application that needs to distinguish between local and toll calls.

Download Sample Data

Local Calling Cross-reference
FieldData TypeField Description
ORC_EXCHANGECHAR (8)Unique originating exchange index within the Rate Center.
ORC_STATECHAR (2)Originating Rate Center state, province, or territory abbreviation.
ORC_ABBRCHAR (10)Originating Rate Center standardized 10 character LERG abbreviation.
ORC_LATACHAR (3)Originating Rate Center LATA number.
ORC_MTAINT (11)Originating Rate Center MTA number.
TRC_EXCHANGECHAR (8)Unique terminating exchange index within the Rate Center.
TRC_STATECHAR (2)Terminating Rate Center state, province, or territory abbreviation.
TRC_ABBRCHAR (10)Terminating Rate Center standardized 10 character LERG abbreviation.
TRC_LATACHAR (3)Terminating Rate Center LATA number.
TRC_MTAINT (11)Terminating Rate Center MTA number.
OCNCHAR (4)When populated identifies the competitive local carrier whose local calling area differs from the incumbent local exchange carrier.
CALL_TYPEVARCHAR (20)Local call type relationship between originating and terminating Rate Centers.This field identifies terminating exchanges as local or expanded local in relationship to the originating Rate Center.

NPA NXX to Exchange Cross-reference
FieldData TypeField Description
NPACHAR (3)Numbering Plan Area code, the first three digits of a 10 digit North American Numbering Plan (NANP) number, commonly called the Area Code.
NXXCHAR (3)Central Office Code, the first three digits following the Area Code in a 10 digit NANP number, commonly called the telephone exchange or prefix.
BLOCK_IDCHAR (1)Block identifier. Implies, represents, or identifies either the entire group of 10,000 numbers or a specific group of 1,000 numbers within the NPA NXX.
EXCHANGECHAR (8)Unique exchange index used to identify the NPA-NXX-BLOCK_ID combination.