ATIS - Alliance for Telecommunications Industry Solutions
适用范围
PURPOSE AND SCOPE 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-XXXX1@ Section 14.0 provides details of the format). NPA codes have traditionally been used to identify distinct exclusive geographic areas@ commonly referred to as area codes. NPAs have also been assigned to services provided on a non-geographic basis (e.g.@ 800 NPA is assigned to a service for which the called party@ rather than the calling party@ is charged for the call). These guidelines apply only to the assignment of NPA codes. These guidelines were developed by the Industry Numbering Committee (INC) using the industry consensus process. These guidelines are expected to apply throughout the area served by the NANP unless the affected regulatory administrations direct otherwise. These guidelines do not supersede applicable governmental or regulatory principles@ procedures and requirements. The assignment of an entire NPA code to an entity for its exclusive use will not be permitted (excluding those situations referenced in Section 10).