Patent ID: 7440743

Claim:
An IP telephone system comprising: a call control apparatus connected to an external network, an internal network and a wireless LAN access point; an information processing terminal connected to said call control apparatus over said internal network; and a mobile telephone adapted to connect to said wireless LAN access point, wherein said mobile telephone comprises a wireless LAN communication unit for communicating with said wireless LAN access point, and an RF ID tag unit, and said information processing terminal includes a contactless reading and writing device adapted to read and write data from or to said RF ID tag unit, and wherein when the presence of said RFID tag unit is detected by said contactless reading and writing device, said information processing terminal causes said contactless reading and writing device to set a state flag in said RF ID tag unit to a first state which indicates that said wireless LAN communication unit of said mobile telephone is in an inactive state, and sends presence information indicating the presence of said mobile telephone to said call control apparatus, when said state flag in said RF ID tag unit is set to said first state, said mobile telephone disables said wireless LAN communication unit, said call control apparatus receives said presence information and stores said received presence information in a database, when said call control apparatus receives a request for terminating an incoming IP telephone call on said mobile telephone, said call control apparatus searches said database and then sends, to said information processing terminal, incoming call information indicating said incoming call, and also transfers, to said wireless LAN access point, an IP packet signaling said incoming call, when said information processing terminal receives said incoming call information from said call control apparatus, said information processing terminal causes said contactless reading and writing device to set said state flag in said RF ID tag unit to a second state which indicates that said wireless LAN communication unit of said mobile telephone is in an active state, and when said state flag in said RF ID tag unit is set to said second state, said mobile telephone enables said wireless LAN communication unit to allow IP telephone communication.