To provide an IP telephone system which can use effectively a limited global IP address by changing the IP address without producing a delay and to provide its method.
In the IP telephone system, a plurality of IP networks having an IP address system which has different local IP address and global IP address are connected to each other. A voice signal is transferred through the local IP network, and a voice speech is performed. The IP telephone system includes an IP address changing means connected to the local IP network to give or recover the local IP address and the global IP address to the IP telephone. The IP address changing means gives the local IP address to the IP telephone during a standby state that the IP telephone does not perform the speech, and gives the global IP address to the IP telephone when entering from the standby state to the speech state is detected. When the end of the speech of the IP telephone is detected, the global IP address is recovered from the IP telephone.
YAMAKADO HITOSHI
MIYAMOTO TORU
Masatake Shiga
Masakazu Aoyama
Masahiko Ueyanagi
Fujitsuna Hideyoshi
Osamu Suzawa