Telco nomenclature for the prefix of a North American telephone number. [i.e. 212 NXX-2133].
The first 3 digits of the 7-digit telephone number, also known as central office codes.
Exchanges (First 3 digits of a 7-digit phone number). (2-to-9, 0-to-9, 0-to-9) (Digits 4, 5 and 6 in a 10 digit NANP telephone number - NPA-NXX-XXXX).
Exchange. A code normally used as a central office code. It may also be used as an NPA code or special NPA code.
The format of an NPA code or a central office code (N=2-9, X=0-9)
In the North American numbering system, the second three digits in the 10-digit addressing scheme also known as the prefix or central office code.
Exchange Number The second 3 digits of your 10 digit North American phone number.
(Numeric Numbering Exchange) NXX is the current general configuration for exchange codes within each area code.
N is any digit 2 through 9, X is any digit 0 through 9 (800 possible combinations). Also known as CO codes, or DRD (destination code) once entered into the RDBS records.
In a seven-digit local telephone number, the first three digits identify the central office of the telephone company that serves that number. These digits are referred to as NXX, where "N" can be any number from 2 to 9, and "X" can be any number.
The first three(3) digits of a telephone number.
The second three (3) numbers in the 10 digit dialing pattern and the first three (3) numbers of the local seven digit telephone number required to identify which local service provider exchange switch the number is terminated at.
