The VoIP gateway in accordance with the present invention serves to send a
connection request to either the IP network or the PSTN on the basis of
the information stored in the VOIP gateway and the destination telephone
number contained in the connection request as sent from the telephone
terminal. Also, even if a connection request is decided to be sent to the
IP network, the VOIP gateway sends the connection request to the PSTN
when the IP network state judgment unit judges that the communication
through the IP network is impossible. Furthermore, if a destination
telephone number includes predetermined identification information, the
VOIP gateway can forcibly send the connection request to the PSTN.