Patent ID: 8588212
Filing Date: 2013-11-19
Classification: H04L

Abstract:
1. An IP (Internet Protocol) telephone system comprising an IP telephone terminal communicating with an opposite party using SIP (Session Initiation Protocol), and a network device transferring a packet from the IP telephone terminal, wherein the IP telephone terminal comprises a CPU (Central Processing Unit) transmitting an SIP packet indicating an e-mail address related to a telephone number of the opposite party when the terminal resides in a non-disaster area and calls the opposite party in a disaster area with a disaster mode being set, and the network device comprises an SIP packet processing part terminating an SIP packet whose destination is an e-mail address, an e-mail creation part converting a voice packet of RTP (Real Time Protocol) from the IP telephone terminal into text data and creating an e-mail, and a packet transmitting part transmitting the e-mail to the opposite party, wherein the network device is a media gateway, wherein the IP telephone system further comprises a first network gateway and a second network gateway, wherein the first network gateway transmits the SIP packet whose destination is an e-mail address to the second network gateway through the media gateway and an e-mail server, in a non-disaster situation, wherein the first network gateway transmits the SIP packet directly to the second network gateway without using the media gateway and the e-mail server, in a disaster situation.