Purpose and Scope 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 NXXs 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. As an example@ the 456 NPA will be used for calls destined for the public telecommunications network in NANP Area. NANP area gateway switch would be considered the public switched destination point for the inbound international call. The gateway operator then determines the subsequent routing of the call. It is not intended that the implementations of these codes change or revise the uniform settlements or pro rata return traffic practices between NANP Area carriers and international telecommunications organizations (ITOs) or violate any legal egulatory requirements incumbent upon network operators. Further@ these codes are not to be used for the routing of calls between different locations within the same NANP area country. The codes will be identified as INT/NPA/NXX codes throughout this document.1 These guidelines were developed by the industry consensus process under the auspices of the Industry Carriers Compatibility Forum (ICCF)/Industry Numbering Committee (INC) and are expected to apply throughout the NANP Area unless the affected administrations direct otherwise.2 These guidelines do not supersede appropriate controlling the NANP Area governmental or regulatory principles@ procedures and requirements. 1Teleglobe Canada Inc. currently has the exclusive mandate to carry all inbound and/or outbound Canadian international telecommunication traffic@ excluding traffic originating from or terminating in the United States. Therefore@ for the purpose of routing traffic for which Teleglobe Canada Inc. has an exclusive mandate@ no INT/NPA/NXX codes shall be assigned to Canadian entities other than Teleglobe@ without concurrence by the Canadian Government. 2 The Canadian Radio-television and Telecommunications Commission (CRTC) has approved the Canadian Adjunct to the INC International Inbound NPA (INT/NPA/NXX) Assignment Guidelines for the administration of INT/NPA/NXXs in Canada by the Canadian Numbering Administrator (CNA). The latest version is available at www.cnac.ca.