scope:

PURPOSE AND SCOPE

This document specifies guidelines for the assignment of NXX codes within the 9YY Service Access Code (SAC) and Numbering Plan Area (NPA) to carriers. 

For the purpose of these assignment guidelines, unique NXX codes will be utilized within the 9YY SAC to identify the individual carriers for routing purposes. A SAC is a non-geographic NPA or Easily Recognizable Code (ERC) used for the purpose of providing access to a specific type of service. ERCs are sometimes referred to as "NYY" codes to signify that N = digits 2-9 and YY = repeating digits 0-9.¹ 

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-XXXX² number in order to identify the carrier for call routing. Consequently, the assignment of individual NXX codes to specific carriers is required. The 9YY SAC may be accessed by dialing (1)+9YYNXX- XXXX.* As an option, use of 0+9YY-NXX-XXXX dialing may also be allowed for 9YY access. Use of the 101XXXX Carrier Access Code prefix is not consistent with NXX assignment and routing and is therefore not permitted. 

These guidelines were developed by the industry consensus process by the Industry Numbering Committee. 

These guidelines are expected to apply throughout the NANP serving area subject to the appropriate regulatory or governmental procedures and constraints.

¹ It should be noted that the INC has made the N11 NPAs (e.g. 211) not assignable, and has also reserved the N9X NPAs (where X = digits 0-9) for future NANP expansion purposes. See < www.nanpa.com > for further details. For practical purposes, YY is typically only repeating digits 0 and 2-8.

² N = digits 2-9 and X = digits 0-9