Patent ID: 7519049

Claim:
A mobile phone system which performs communication between a mobile phone terminal and an opposite party terminal via a network, wherein the mobile phone terminal comprises means for transmitting a connection request of a packet switching line to the side of the network in addition to a calling connection request of a circuit switching line to the opposite party terminal or a calling connection response of a circuit switching line to the opposite party terminal in response to key operation of a user, and means for transmitting data corresponding to a desired voice message via a packet switching line connected with the network on the basis of the connection request, the network comprises data/voice message converting means for converting data transmitted from the mobile phone terminal via the packet switching line to corresponding voice message, and means for merging the converted voice message to the circuit switching line to transmit the same to the opposite party terminal, and a voice from the opposite party terminal is transmitted to the mobile phone terminal via the circuit switching line, while data from the mobile phone terminal is converted to a voice message by the data/voice message converting means to be transmitted to the opposite party terminal via the circuit switching line.