Patent attributes
An IP telephone system includes an IP telephone apparatus, a Web server and an ENUM server. The IP telephone apparatus is connected to an IP network. The Web server registers talk volume information corresponding to a telephone number assigned to the IP telephone apparatus. The ENUM server registers a NAPTR resource record in which a URI specifies link data related to the talk volume information registered in the Web server. In the IP telephone system, the IP telephone apparatus that has received a call transmits, to the ENUM server, a query for a NAPTR record corresponding to a targeted recipient phone number. The IP telephone apparatus then transmits, to the Web server, a request for the talk volume information corresponding to the targeted recipient phone number according to the returned NAPTR resource record, and adjusts the talk volume according to the returned talk volume information.