Mobile communication terminal, mobile switching center, message storage device, and message storing method

A mobile switching center capable of controlling communication between a calling-side terminal and a receiving-side terminal and storing in a storage device a message transmitted from the calling-side terminal to the receiving-side terminal, the mobile switching center comprising:

• means for discriminating whether or not the receiving-side terminal is capable of answering a call made by the calling-side terminal via a communication line of a circuit-switched network;
• means for switching the communication line with the calling-side terminal from the circuit-switched network to a packet-switched network, when the means for discriminating discriminates that the receiving-side terminal is not capable of answering the call;
• means for connecting the communication line of the packet-switched network with the storage device;
• and
• means for transmitting the message that has been transmitted from the calling-side terminal via the communication line of the packet-switched network that has been switched by the means for switching, to the storage device via the communication line of the packet switched network that has been connected by the means for connecting.

A method for storing a message from a calling-side terminal to a receiving-side terminal, the method comprising:

• making a call from the calling-side terminal to the receiving-side terminal via a communication line of a circuit-switched network;
• switching the communication line from the circuit-switched network to a packet-switched network, when a network system discriminates that the receiving-side terminal is not capable of answering the call;
• transmitting the message from the calling-side terminal for the receiving-side terminal to be stored, to the network system via the communication line of the packet-switched network that has been switched by the switching;
• and
• storing the message that has been transmitted by the transmitting in a storage device without performing a Codec conversion.

The method according to claim 8, further comprising:

• notifying the receiving-side terminal that the message for the receiving-side terminal is stored;
• transmitting a message acquiring request to the network system from the receiving-side terminal;
• discriminating an optimal Codec to deliver the message to the receiving-side terminal, when the message acquiring request from the receiving-side terminal is received;
• converting a Codec of the message based upon a result of the discriminating;
• and
• delivering to the receiving-side terminal the message that has been converted by the converting.