Patent ID: 8213899

Claim:
In a telephony system having a plurality of carriers providing telecommunications services, a method of identifying the carrier to which a user of a phone subscribes, comprising the steps of: (a) a signal control point of a first wireless carrier identifying a directory number of the phone; (b) consulting a table to determine which carrier in the plurality of carriers was assigned a block of telephone numbers which includes the directory number, wherein the table comprises a local exchange routing guide (LERG) table; (c) determining that the directory number is portable; (d) obtaining a location routing number for the phone; (e) comparing the location routing number to a list of location routing numbers associated with the first wireless carrier and identifying the carrier from such comparison, wherein if the location routing number is not in the list of location routing numbers associated with the first wireless carrier, identifying the carrier includes directly querying a number portability database maintained by a second wireless carrier using the location routing number, and (f) consulting a further database to determine the identity of a virtual operator the phone subscribes to, wherein the method is performed by the signal control point of the first wireless carrier in an advanced intelligent network.