Flexible dial plan for a data network telephony system

Abstract

A dial plan for a data network telephony system is provided. A variable-length-code scheme is used to assign communication numeral strings to user identifiers and/or device identifiers, such as SIP URIs (Universal Resource Identifier). The dial plan enables a user to enter a user identifier (or device identifier) into a conventional keypad of a data network telephone, such as an Internet telephony phone. Additionally, embodiments of the disclosed dial plan include techniques for dialing from one data network telephone to another data network telephone utilizing the same service provider, dialing from one data network telephone utilizing a first service provider to a second data network telephone utilizing a second service provider, and dialing from a data network telephone to a PSTN phone and vice versa. The flexible dial plan preferably includes formulating a communication number into a domain portion and a subscriber portion, where the domain portion and the subscriber portion each include a quantity indicator to specify a number of digits making up the remainder of the domain portion, the subscriber portion, or the entire communication portion. Upon accepting an entered communication number from a user, the data network telephone parses the entered communication number into the domain portion and the subscriber portion and accesses database to determine a user identifier or device identifier corresponding to the entered communication number. The data network telephone may then set up a call using the determined user identifier.