To guarantee the securing of existing communication data even when data are not written normally by a cause such as electric power source interruption during update of information data.

Communication data required for communication with a external host are stored in a writable memory 3, the host is accessed from a terminal using the communication data, general data are sent from the host to the terminal together with musical data, and the general data are displayed on a screen 11 or sound-generated by an acoustic equipment 12 before or after performance of the musical data. The memory 3 is divided into plural storage areas, the communication data are stored independently into the plural storage areas, back-ups for the data written in the respective storage areas are prepared when the memory 3 is updated as to the date, and normal communication data are secured thereby all the time.