An SMS related table memory portion of a memory device has a storing region for each SMSC apparatus, and the telephone number of the SMSC apparatus, the program of the communication protocol, the parameter and the like are stored in each storing region. When sending a short message, a controlling device selects an SMSC apparatus based on whether a short message is inputted from an input device or sent from a slave unit, refers to the storing region for the selected SMSC apparatus of the SMS related table memory portion, and performs dial calling from a network control device based on the telephone number and the communication protocol of the SMSC apparatus that are stored. After a line is established, short message data that has been prepared in advance are sent to the SMSC apparatus.