Patent ID: 8325639

Claim:
An IP telephone system, comprising: (i) a plurality of communication devices allowed to mutually communicate through a network; (ii) a server for executing a connection starting process of communication between the communication devices, as well as for controlling sound data transmitted and received between the server and the communication devices during the communication between the communication devices; and (iii) a data transmission and reception controller for mutually switching, upon input of a predetermined command, communication mode between a standard communication mode and a power-saving communication mode in a condition that communication connection is established between the communication devices upon execution of the connection starting process, wherein: the sound data is transmitted and received between the communication devices and the server in the standard communication mode; and transmission and reception between the communication devices and the server is stopped with respect to the sound data below a predetermined level while being continued with respect to the sound data beyond the predetermined level in the power saving communication mode.