INC Documents

About INC: With the increasing demand for telephone numbers in a society driven by mobile communication, ATIS' Industry Numbering Committee (INC) is the source for ensuring all parties requesting numbers in the North American Numbering Plan (NANP) work from the same guidelines. INC provides an open forum to address and resolve industry-wide issues associated with planning, administration, allocation, assignment, and use of NANP numbering resources within the NANP area.

TBPAG and COCAG Zip Files: Since the Thousands-Block Number Pooling Administration Guidelines (TBPAG) and Central Office Code (CO/NXX) Assignment Guidelines possess a large number of attachments, you will find that the ATIS document number for these two documents is linked to a zip file, containing the document and all its attachments.

COCAG and TBPAG Part 2 Job Aid with Part 2 Forms: A COCAG and TBPAG Part 2 Job Aid can be located on theTelecom Routing Administration (TRA) web site, at the following link: This job aid contains information on the fields, data and processes involved in completing the COCAG Part 2 Forms, as well as the TBPAG Part 2A Form. The downloadable job aid zip file also includes the Part 2/2A forms themselves, for ease of reference. Any questions about the process should be directed to Telcordia at: 732-699-6700 or

For additional information, please contact ATIS staff using the "Contact Us" link on the left.


ATIS Document Number


Last Issue Date


555 NXX Assignment Guidelines

This document was superseded by ATIS-0300115, 555 NXX Line Number Reference Document on October 5, 2016.

June 17, 2015

Guidelines Revision Marked

800-855 Number Assignment Guidelines

This document specifies guidelines for the assignment of line numbers within the 800-855-XXXX resource which will only be used for the purpose of accessing public services on the Public Switched Telephone Network (PSTN) intended for the deaf, hard of hearing or speech impaired.

January 4, 2016

Guidelines Revision Marked

9YY NXX Code Assignment Guidelines

This document specifies guidelines for the assignment of NXX codes within the 9YY Service Access Code (SAC) to carriers. These guidelines are provided to accommodate a method which utilizes unique NXX codes within the 9YY SAC to identify individual carriers in order to allow multiple carrier 9YY access. This method requires a Local Exchange Carrier (LEC) to 6-digit translate the 9YY NXX portion of a 9YY-NXX-XXXX number in order to identify the carrier for call routing.

January 4, 2016

Guidelines Revision Marked

Carrier Identification Code (CIC) Assignment Guidelines

This document describes guidelines for the assignment of Carrier Identification Codes (CICs) in the North American Numbering Plan (NANP) area. The assignment practices detailed in these guidelines apply to the assignment of CICs made directly by North American Numbering Plan Administration (NANPA) to a specific entity. Therefore, the maximum number of CICs an entity may be assigned under these guidelines pertains to the number of CICs the administrator may directly assign to that entity. Accordingly, codes obtained via means other than direct assignment by the NANPA are outside the scope of these assignment guidelines. The requirements specified in these guidelines will apply to all CICs (e.g., the access and usage requirements for retaining CICs) regardless of the manner through which an entity obtained a code.

September 2, 2016


Guidelines Revision Marked

Central Office Code (NXX) Assignment Guidelines (COCAG)

This document specifies guidelines for the assignment of central office (CO) codes. Examples of uses for CO codes (NXX) for which these guidelines apply include plain old telephone service (POTS), Centrex, Direct Inward Dialing (DID), cellular mobile service, pagers, data lines, facsimile, coin phones, and customer owned pay phones. While these guidelines were developed at the direction of the FCC, they do not supersede controlling appropriate NANP Area governmental or regulatory principles, procedures and requirements.

January 10, 2017

TN Administration Guidelines Revision Marked

Guidelines for the Administration of Telephone Numbers

These guidelines identify Service Provider (SP) responsibilities with respect to individual telephone numbers in the 10-digit NANP number format (NPA-NXX-XXXX) within existing geographic central office (NXX) codes administered by the North American Numbering Plan Administrator (NANPA) and the Pooling Administrator (PA). It contains guidelines for the administration of Aging Numbers, Reserved Numbers, and Sequential Number Assignment.

January 4, 2016

Guidelines Revision Marked

International Inbound NPA (INT/NPA/NXX) Assignment Guidelines

This document specifies guidelines for the assignment of NXX codes used in conjunction with the 456 Numbering Plan Area (NPA) code for individual carriers. The purpose of NPA 456 and its associated NXX's is to enable the routing of inbound international calls for carrier specific services, particular to that service provider's network, to and between NANP Area countries. This is accomplished by providing carrier identification within the dialed digits of the E.164 number. The routing to the appropriate carrier will be accomplished at the originating end of the call, i.e., within the network of the foreign administration.

November 9, 2012

LRN Assignment Practices Revision Marked

Location Routing Number Assignment Practices

This guideline establishes industry criteria for the assignment and administration of Local Routing Numbers (LRN), a new numbering resource.

January 10, 2017



Guidelines Revision Marked

Non-Geographic 5XX-NXX Code Assignment Guidelines

(formerly Personal Communications Services (PCS) 5YY NXX Code Assignment Guidelines)

This document specifies guidelines for the assignment of NXX codes within a 5YY non-geographic Service Access Code (SAC) used for personal communications services. For the purpose of these assignment guidelines, personal communication service is a set of capabilities that allows some combination of personal mobility, terminal mobility, and service profile management. It enables each personal communication service user to participate in a user-defined set of subscribed services, and to initiate and/or receive calls on the basis of some combination of a personal number, terminal number, and a service profile across multiple networks at any terminal, fixed or mobile, irrespective of geographic location. Service is limited only by terminal and network capabilities and restrictions imposed by the personal communication service provider.

January 4, 2016


Guidelines Revision Marked

North American Numbering Plan Numbering Resource Utilization/Forecast Reporting (NRUF) Guidelines

This document specifies guidelines and procedures that address the North American Numbering Plan Numbering Resource Utilization/Forecast (NRUF) Report. Service Providers are required to submit an NRUF Report to provide both utilization and forecast data for numbering resources from geographic numbering plan area (NPA) codes, as well as data for including numbering resources in the PCS N00 NXX (e.g. NPA 500) and 900 Non-Geographic NPAs. The NRUF Report addresses the need to collect both utilization and forecast data in a single tool. Along with forecasting NPA and NANP exhaust, the NRUF Report also assists in assessing the utilization of numbering resources within an NPA code for the potential application of numbering resource optimization measures. This data provides valuable insight to the impact of various numbering resource optimization measures that may be implemented to extend the life of an NPA code. In addition, utilization data collected via the NRUF Report may also serve in the audit process of an individual service provider's usage of numbering resources.

January 4, 2016

Guidelines Revision Marked

NPA Allocation Plan & Assignment Guidelines

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.

January 4, 2016

Guidelines Revision Marked

NPA Code Relief Planning and Notification Guidelines

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.

January 4, 2016

Guidelines Revision Marked

P-ANI Administration Guidelines

This document specifies guidelines for the administration and assignment of non-dialable pseudo Automatic Number Identification (p-ANI) numbers to Eligible Users in areas where access to such numbering resources has been ordered or implemented. P-ANIs are typically used for call routing and location display of callers that subscribe to a service that is either mobile, nomadic, or that involves a user telephone number containing an NPA that is foreign to the serving E9-1-1 selective routing system.

January 4, 2016


Procedures for Change in E.164 Country Code Assignments

This ICCF document establishes a uniform U.S. procedure that coordinates the awareness and implementation functions for all Country Code assignment changes and ensures the participation of all appropriate carriers/networks.

September 5, 2014


Guidelines Revision Marked

Thousands-Block Number (NXX-X) Pooling Administration Guidelines (TBPAG)

This document specifies guidelines for the process of assigning thousand block (NXX-X) to service providers for use at a switching entity or point of interconnection which they own or control. In addition, these guidelines outline the processes used between the Pool Administrator and Code Holder, Local Exchange Routing Guide (LERG) Assignee, Block Holder, CO Code Administrator, and the Number Portability Administration Center (NPAC). Number Pooling, in the context of these guidelines, allows for sharing of central office codes among multiple service providers serving the same rate area.

, 2016


Guidelines Revision Marked

Vertical Service Code (VSC) Assignment Guidelines

This document provides guidelines for the assignment of Vertical Service Codes (VSC) for which standardization or consistency is desired across all industry sectors in the Public Switched Telephone Network (PSTN). For the purposes of these guidelines, VSCs are customer-dialed codes in the *XX dialing format for touch tone and NXX dialing format for rotary phones. They are used to provide customer access to features and services provided by network service providers such as local exchange carriers, interexchange carriers, Commercial Mobile Radio Service (CMRS) etc. VSCs are assigned to features or services to enable consistent accessibility throughout the PSTN. The purpose of common/standard VSCs is to minimize customer confusion and provide a standard service access approach for features and services within multiple individual networks (multi-network applications).

January 4, 2016


ATIS Document Number


Last Issue Date


500/900 Report on LEC Number Portability

This report is in response to the Federal Communications Commission's first report and order and further notice of proposed rulemaking, in the matter of telephone number portability. The document addresses the issue of the technical feasibility of modifying the existing toll free database to make only those 500 and 900 numbers that are assigned to local exchange carriers portable. The FCC also further asked that this examination consider whether the technical feasibility could be achieved through modifying the existing toll free database or through another system.

July 31, 1998


D Digit Report

An underlying assumption in INC's work on the expansion of the NANP has been the release of the D digit coincident with NANP expansion. This is necessary to effect a transition in which both the existing and the expanded numbers can be dialed by using the historic D digit as a trigger. Release of the D digit would permit any digit value from 0-9 to be used in that position. The objective of this report is to identify and investigate the technical impacts of D digit release.

January 24, 2003


Initial Report to the North American Numbering Council (NANC) on Number Pooling (Version 2)

This report defines, describes, and analyzes the number administration and assignment process known as number pooling. The report identifies the attributes or parameters associated with pooling, discusses the principles, assumptions, and constraints under which pooling can potentially be provided, develops specific alternatives for the implementation of pooling, and describes the impact of number pooling on network architecture, number assignment and administration processes. In addition, the report assesses the practicality of pooling with respect to certain criteria and identifies criteria for the characterization of the pooling alternatives, uses those criteria to assess the alternatives, explains how the transition from the current (central office based) number assignment process to pooling could potentially take place, and offers recommendations and conclusions relative to the use of pooling.

December 4, 1997


Interim NANP Expansion Report and Cover Letter

*Updated NANP information may be obtained from the NANPA website

This INC Interim NANP Expansion Report documents the status, as of year end 1999, of the North American industry's efforts to establish a NANP expansion plan. In this report the INC has identified five options for further analysis and evaluation. These five options are described in detail in this report. The INC's objective is to select a single option for recommendation to NANP area national regulatory authorities for final approval. Two major assumptions regarding use of the INC Uniform Dialing Plan and release of the D digit have been highlighted and national regulators have been urged to comment on these two assumptions.

December 10, 1999


Numbering for Internet-Based Relay Services Report

A North American Numbering Council (NANC) Action Item to the Alliance for Telecommunication Industry Solutions (ATIS) Industry Numbering Committee (INC) regarding Video Relay Service (VRS) numbering has led to the production of this report. To meet the understood goals, the INC proposes that VRS Users be assigned geographic North American Numbering Plan (NANP) numbers using currently available call routing methods and that a centralized mechanism administered by a neutral party be provided for obtaining a VRS User's current Internet Protocol (IP) address based on the assigned telephone number (TN).

December 19, 2007


Recommended Plan for Expanding the Capacity of the North American Numbering Plan

The Recommended NANP Expansion Plan report defines the changes in the format and numeric structure of the NANP being recommended by INC. It also identifies the transition strategies, trigger points and dependencies required to ensure the smooth and timely evolution of the NANP. This plan is intended to be a living document to be kept current by the industry through regularly scheduled updates or action trigger mechanisms which are identified and maintained in the document.

December 13, 2001


Report on Number Portability

This report touches upon some of the issues associated with other forms of number portability and also documents and summarizes number portability among and between service providers. In addition, some issues and concerns with portability among wireless providers and between wireline and wireless networks are addressed.

July 11, 1996


Report on Personal Communications Services (PCS) N00 Portability

(Commonly referred to as "PCS 5YY ")

The purpose of this INC report is to document the steps required for a potential implementation plan and guidelines for enabling the portability of the PCS N00 numbers among service providers. Included in this work is the development of a migration plan to this portable environment from an assumed N00 NXX service provider implementation. This report addresses a high level target PCS N00 portability architecture and describes how to migrate from an NXX implementation.

August 1999


Report on Unassigned Number Porting (UNP)

This report defines, describes, and provides an evaluation of the concept of Unassigned Number Porting (UNP) by the industry in response to FCC 00-104, paragraph 231 and resolves INC Issues 177 and 222.

January 8, 2001



ATIS Document Number


Last Issue Date


Automatic Number Identification (ANI) Information Digit Codes

This document provides a table which lists and defines ANI Information Digit Codes which are assigned by the North American Numbering Plan Administration (NANPA) at the request of the Industry Numbering Committee (INC).

September 18, 1998


North American Numbering Plan (NANP) Expansion Reference Document

*Updated NANP information may be obtained from the NANPA website.

The NANP Expansion Reference Document provides reference information on the procedures and criteria used to support the selection of an expanded NANP to meet the long-term needs of the telecommunications community for the geographic area served by the NANP. It includes all options that were considered by INC and the rationale for excluding those options no longer under consideration as well as the process by which they were eliminated.

August 16, 2002


Numbering and Dialing Plan within the United States

This technical document seeks to document the format and values of telephone numbers in the United States portion of the NANP, thereby coining a "United States Numbering Plan " and a "United States Dialing Plan. " It further defines the other telecommunications industry uses of numbers and describes these uses in the United States. The NANP exists under Country Code 1, shared among 19 countries, under the International Telecommunication Union (ITU) Recommendation E.164, "The international public telecommunication numbering plan " (Rec. E.164).

December 2008


Uniform Dialing Plan

The purpose of this document is to evaluate potential uniform dialing plans for the North American Numbering Plan (NANP) serving area and make appropriate recommendations. The document includes a brief history of dialing in the NANP area, provides comparisons of identified dialing plan alternatives considering specific impact areas (e.g., end user impacts), and recommends a transition to a uniform dialing plan described in Section 6.

Attachment A: Dialing Plan Options (ATIS-0300059.ata)

Attachment B (ATIS-0300059.atb)

*Current Attachment A and B data can be found on the NANPA website, , under NPA Reports.

July 31, 1998


555 NXX Line Number Reference Document 

The purpose of this document is to capture the history of the 555 NXX line numbers, including the uses prior to the creation of the 555 NXX Assignment Guidelines in 1994, to the sunset of the Guidelines in 2016. This document also addresses issues associated with implementation, a summary of assignment data, the Industry Numbering Committee’s (INC) 2016 agreement to sunset the 555 NXX Assignment Guidelines, and agreement that the future of 555 line numbers will be determined if a need for the resource is identified and agreed to by INC.

January 10, 2017

© Alliance for Telecommunications Industry Solutions. All rights reserved. | 1200 G Street, NW Suite 500 | Washington, DC 20005 | +1 202-628-6380

Review the ATIS privacy policy.