ATIS 0300049

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.