ATIS 0300055

Reissued with the resolution of issue 701 and 713.

This document specifies guidelines for the assignment of Numbering Plan Area (NPA) codes. NPA codes are the first three digits of the 10-digit North American Numbering Plan (NANP) format (the format is made up of 10 digits in the form of NXX-NXX-XXXX). NPA codes have traditionally been used to identify distinct exclusive geographic areas, commonly referred to as area codes.