Glossary

Block ID

Block identifier. The entire group of 10,000 numbers or a specific group of 1,000 numbers within the NPA NXX.

CIC

Carrier Identification Code.

CLEC

Competitive Local Exchange Carrier

FMNP

Full Mobile Number Portability.

LATA

Local Access and Transport Area. Represents an area within which a carrier is permitted to offer exchange telecommunications and exchange access services.

LEC

Local Exchange Carrier.

LNP

Local Number Portability

MSA 100

Top 100 Metropolitan Statistical Areas. A MSA is one or more adjacent counties or county equivalents that have at least one urban core area of at least 50,000 population.

NANP

North American Numbering Plan.

NPA

Numbering Plan Area (Area Code)

NXX

The format of a central office code (N=2-9, X=0-9), digits 4-6 of a 10 digit NANP phone number. Also known as an exchange or prefix.

OCN

Operating Company Number.

Pooling

A method of reallocating telephony numbering space in the North American Numbering Plan. Specifically, allowing the 10,000 numbers in a NXX exchange to be subdivided into smaller blocks 1000.

PSTN

Public Switched Telephone Network.

RC

Rate Center. Identifies a telephone local exchange (NPANXX) service area.

SP

Service Provider, i.e., the telco carrier.