Patent ID: 7561562

Claim:
A communication terminal connected to a public line network, for communicating with a center apparatus connected to the public line network to send and receive short message data to/from another communication terminal via the center apparatus, comprising: input means for inputting short message data, communicating means that is connected to the public line network, for communicating with the center apparatus, storing means for storing information identifying a plurality of center apparatuses and types of communication protocol information for each of the plurality of center apparatus to be used for communications of the communicating means, selecting means for selecting a center apparatus to be communicated with among the center apparatuses whose communication protocol information is stored, based on a predetermined condition, and controlling means for controlling the communicating means so as to send short message data to the center apparatus when sending the inputted 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 means, wherein the storing means includes an individual storing region assigned to each of the plurality of center apparatuses and a common storing region assigned commonly to the plurality of center apparatuses, in which individual storing region, at least identification information to identify the center apparatus, communication protocol information to be used for communications with the center apparatus, and short message data received from the center apparatus are stored, and the controlling means refers to the individual storing region assigned to the center apparatus selected by the selecting means, and controls the communicating means based on the identification information and the communication protocol information that are stored.