IP TELEPHONE SYSTEM, IP TELEPHONE APPARATUS AND CALLING METHOD

摘要

An IP telephone system includes an IP telephone apparatus that performs voice communication via an IP network or a PSTN, a carrier that manages the voice communication performed by the IP telephone apparatus via the IP network and a server that returns a NAPTR resource record in response to a request from the IP telephone apparatus. In the IP telephone system, when the IP telephone apparatus performs the voice communication, the IP telephone apparatus transmits, to the server, a request for a NAPTR resource record corresponding to a destination IP telephone apparatus, chooses either the IP network or the PSTN as a communication path according to the received NAPTR resource record and performs the voice communication.