PURPOSE: To reduce a down-load time without increasing a load on a host and maintenance man-hour by sending data to lots of terminal systems with broadcast communication and discriminating the terminal system whose transmission is failed so as to send data automatically.

CONSTITUTION: A host system 1 uses a broadcast transmission processing 9 to send data to lots of terminal systems 2 by broadcast communication. Then a version number reported by a point-to-point transmission reception processing 8 is compared with a version table 5 and when they are dissident from each other, it is judged that data transmission is failed. Then data are sent to the systems 2 of less failed number automatically without manual intervention by the processing 9. Thus, the down-load time is reduced without increasing a load on a host and maintenance man-hour.