| 摘要 |
PURPOSE:To prevent system down from occurring when a fault occurs by monitoring the operation of a transmission control means which controls the operation of a transmission/reception part, and disconnecting the transmission/ reception part from a transmission control means. CONSTITUTION:When abnormality is found out in either a main CPU 2 or a sub CPU 3 for transmission, the output of a refresh pulse is stopped. When the input of the refresh pulse is interrupted for one or more seconds, the output part of a watchdog timer 4 is turned off, which sets a switching element 7 in a cutoff state. Therefore, a transceiver 6 is disconnected from the transmis sion line 12. Consequently, no abnormal signal is outputted to the transmission line 12, and the transmission of another POS terminal 1 can be prevented disturbed. Thereby, the system down can be prevented from occurring. |
