Method for providing location/geographic portability in a system having different service providers within a common numbering plan area

A method for routing a call placed by a calling party to a called Subscriber, the called Subscriber having been assigned a directory number NXX-XXXX by one Local Service Provider and having changed to a different Local Service Provider, both Local Service Providers providing service within a common Local Access and Transport Area (LATA), and wherein the called Subscriber has moved to a different location served by a switch having a different exchange code, NYY, comprising the steps of:

• (a) providing a database storing:
• (i) a relationship between each NXX-XXXX directory number assigned to Subscribers within a Numbering Plan Area (NPA) who have changed to a different Local Service Provider, and a call routing identifier, SPA, associated with the directory number, NXX-XXXX;
• (ii) a relationship between the NXX-XXXX directory number assigned to the called Subscriber and the different exchange code NYY and a line code YYYY of the called Subscriber where:
• the call routing identifier, SPA, is a three digit Service Provider Area (SPA) code assigned to each one of the Local Service Providers, each one of the Local Service Providers being assigned a different Service Provider Area (SPA) code;
• and,
• NXX is a three digit designation code representative of an exchange area within a Numbering Plan Area (NPA);
• (b) converting, in the database, the called Subscriber's directory number, NXX-XXXX, into SPA-NYY-YYYY;
• and
• (c) routing the call placed by the calling party to the called Subscriber using the converted number, SPA-NYY-YYYY.

A method for routing a call placed by a calling party to a called Subscriber, the called Subscriber having been assigned a directory number NPA-NXX-XXXX, and having moved to a different location served by a terminating switch having a different exchange code, NYY, where NPA is a Numbering Plan Area, comprising the steps of:

• (a) providing a database storing a relationship between the directory number assigned to the called Subscriber, the different exchange code NYY and a line code YYYY of the called Subscriber, and a Service Provider Area (SPA) code identifying a Local Service Provider of the called Subscriber;
• (b) converting, in the database, the called Subscriber's directory number, NPA-NXX-XXXX, into SPA-NYY-YYYY;
• (c) routing the call placed by the calling party to the terminating switch serving the called Subscriber using SPA-NYY-YYYY;
• (d) reconverting, within the terminating switch serving the called Subscriber, the number SPA-NYY-YYYY to the number NXX-XXXX;
• and,
• (e) routing the call to the called Subscriber.

A method for routing a call placed by a calling party to a called Subscriber, the called Subscriber having been assigned a directory number NXX-XXXX by one Local Service Provider and having changed to a different Local Service Provider, both Local Service Providers providing service within a common Local Access and Transport Area (LATA), and wherein the called Subscriber has moved to a different location served by a terminating switch having a different exchange code, NYY, comprising the steps of:

• (a) providing a database storing:
• (i) a relationship between each NXX-XXXX directory number assigned to Subscribers within a Numbering Plan Area (NPA) who have changed to a different Local Service Provider and a call routing identifier, SPA, associated with the directory number, NXX-XXXX;
• (ii) a relationship between the NXX-XXXX directory number assigned to the called Subscriber and the different exchange code NYY and a line code YYYY of the called Subscriber where:
• the call routing identifier, SPA, is a three digit Service Provider Area (SPA) code assigned to each one of the Local Service Providers, each one of the Local Service Providers being assigned a different Service Provider Area (SPA) code;
• and,
• NXX is a three digit designation code representative of an exchange area within a Numbering Plan Area (NPA);
• (b) converting, in the database, the called Subscriber's directory number NXX-XXXX, into SPA-NYY-YYYY;
• and
• (c) routing the call placed by the calling party to the terminating switch serving the called Subscriber using the converted number, SPA-NYY-YYYY;
• (d) reconverting, within the terminating switch serving the called Subscriber, the number SPA-NYY-YYYY to the number NXX-XXXX;
• and,
• (e) routing the call to the called Subscriber.