Patent ID: 6128377
Filing Date: 2000-10-03
Classification: H04M,H04Q

Abstract:
A method for routing a call to a called Subscriber using a dialed number, such dialed number being either NXX-XXXX or NPA-NXX-XXXX, comprising the steps of:(a) determining, at a local switch, whether an incoming call to the local switch is an intra-LATA call, or a call to an exchange code served by the local switch; and,(i) if the call is a call to an exchange code served by the local switch, determining whether the dialed number is served by the local switch; and(1) if the dialed number is not served by the local switch, determining whether a Service Provider Area (Scode, an exchange code NYY and a line code YYYY, assigned to the dialed number are populated in the local switch, where NYY-YYYY is different from NXX-XXXX and SPA code is a three digit designation code assigned to each one of a plurality of Local Service Providers within a common Numbering Plan Area (NPA), each one of the plurality of Local Service Providers being assigned a different Service Provider Area (Scode in the common Numbering Plan Area (NPA);(A) if the SPA code, the exchange code NYY, and the line code YYYY are not populated in the local switch, accessing an External Local Number Portability Database using the dialed number to retrieve the SPA code, the exchange code NYY and the line code YYYY, the External Local Number Portability Database storing a relationship between each dialed number, NPA-NXX-XXXX or NXX-XXXX, that is assigned an exchange code NYY and a line code YYYY and such exchange code and line code and the SPA code assigned to the dialed number, where NYY-YYYY is different from NXX-XXXX; and,(B) if the SPA code, the exchange code NYY, and the line code YYYY are populated in the local switch using such SPA code, exchange code NYY, and line code YYYY to provide a call routing number SPA-NYY-YYYY and routing the call using the call routing number SPA-NYY-YYYY; and,(2) if the dialed number is served by the local switch, routing the call to the called subscriber using the dialed number;(ii) if the call is an intra-LATA call, accessing an External Local Number Portability Database using the dialed number to retrieve the SPA code, the exchange code NYY and the line code YYYY; and,(b) if accessing the External Local Number Portability Database in step (a)(i)(1) (A) or (a)(ii) and,(i) if an NPA code is absent from the dialed number, adding to the dialed number an NPA code assigned to the dialed number to provide a modified dialed number;(ii) retrieving from the External Local Number Portability Database, based on the dialed number or the modified dialed number, a corresponding SPA code, exchange code NYY, and line code YYYY; and(iii) if the call is a call to an exchange code served by the local switch, populating the local switch with the corresponding SPA code, exchange code NYY, and line code YYYY; and(iv) using the corresponding SPA code, exchange code NYY, and line code YYYY to provide the call routing number SPA-NYY-YYYY; and(v) routing the call using the call routing number SPA-NYY-YYYY.