SIGNAL LINE FAULT MONITORING SYSTEM

摘要

PURPOSE:To detect the fault of a signal line through which a system selection signal is transmitted. CONSTITUTION:The host devices 30 and 31 turn the ACT signals (system selection signals) of a level '0' or '1' into the pulses and output them to an ACT control circuit 32 via the control signal lines S0 and S1 respectively. The circuit 32 detects whether the pulses are contained or not in the ACT signals of 0 and 1 systems in order to monitor the presence or absence of the faults of both lies S0 and S1. Meanwhile the circuit 32 converts the ACT signals turned into the pulses into the ACT signals of a level '0' or '1' and outputs them to a system selection circuit 33. If a fault of the line S0 of the 0 system is detected in a 0 system ACT state, for example, the circuit 32 turns the ACT0 signal of the system 0 into '1' form '0' and outputs it to the circuit 33. Thus the system switching is possible with switching of the ACT signal of the device 31 of the 1 system.