Patent ID: 7373158

Claim:
A communication terminal that is connected to a public line network, to communicate with a center apparatus connected to the public line network to send and receive short message data to/from another connnunieation terminal via the center apparatus, the communication terminal conmrising: a master unit; and a slave unit operatively connected to said master unit performing mutual wireless communications with the master unit, the slave unit including: a slave input device inputting short message data, wherein the slave unit sending the short message data inputted with the slave input device and receiving short message data from the master unit over wireless communications, the master unit including: a master input device inputting short message data, and a master communicating device that is connected to a public line network, sending and receiving short message data to/from the center apparatus, wherein the master communicating device unit sending short message data received by the master communicating device to the slave unit and receiving short message data from the slave unit, a storing device storing a plurality types of communication protocol information, each of which corresponds to a center apparatus, to be used to communicate with the master communication device, a selecting device selecting a center apparatus to be communicated with among the center apparatuses whose communication protocol information is stored, based on a predetermined condition, and a controlling device controlling the master communicating device so as to send short message data inputted with the master unit input device or short message data received by the master communicating device to the center apparatus when sending the short message data, and to receive short message data from the center apparatus when receiving the short message data, based on the communication protocol information of the center apparatus selected by the selecting device, and determining whether or not the short message data received from the center apparatus is addressed to the slave unit, and when the short message data is determined as being addressed to the slave unit, controlling the master communicating device so as to send the received short message data to the slave unit.