IP telephone system, IP telephone apparatus and method for performing telephone conference

摘要

An IP telephone system includes a plurality of IP telephones and an ENUM server. The IP telephones are connected to an IP network and perform a mixing process on communication data output from other IP telephones. The ENUM server stores a NAPTR resource record specifying a number which identifies a telephone conference being conducted among these IP telephones and specifying identification information for another participating IP telephone, and transmits a corresponding NAPTR resource record in response to a query from the IP telephone. In the IP telephone system, one participating IP telephone transmits to the ENUM server a query for a NAPTR resource record by specifying the number which identifies the telephone conference, obtains identification information for another participating IP telephone according to the received NAPTR resource record, places a call based on the identification information and performs a mixing process on communication data output from other IP telephones.