| 摘要 |
PURPOSE:To prevent a system from being shut down by providing a master and a submaster station for one file. CONSTITUTION:A signal from a polling signal generation part 5 provided in the master 1 is transmitted to terminal equipments 3 and 3' through a transmission control part 6 and the submaster 2. Answer data from the terminal equipments 3 and 3' are written in a file 9 by a file access switching part 10 through a master 1 in the opposite route. The submaster 2 outputs a detection signal (d) by a circuit monitoring part 13 unless the polling signal from the master 1 is absent for a specific period to open a circuit switching part 7, and the file access switching part 10 is switched to allow the submaster 2 to generates a polling signal and write answer signals to it in the file 9 as a substitute for the master 1. |
