| 摘要 |
PURPOSE:To save the time required for the system expansion and to prevent a pseudo fault due to mis-operation (input interruption alarm interruption mistake) by stopping the input interruption alarm in a channel not in use automatically in the input circuit check of a transmitter in a communication system used in a field on emergency or the like. CONSTITUTION:An input terminal connection detection circuit 12 detecting the presence of mechanical connection of a terminal connection cable 2 connected to an input terminal for each system of a transmitter 3 having the signal input terminal 4 for plural systems in terms of a binarizing signal and an input signal detection circuit 8 detecting the presence of the input signal at each input terminal 4 in terms of a binarizing signal are provided to the system. Then an input alarm circuit 9 is driven by an output of an AND circuit 14 between an output of an exclusive OR 13 of an output of both the circuits corresponding to each input terminal 4 and an output of the input terminal connection detection circuit 12. That is, if no input signal is detected regardless of the normal connection of the terminal connection cable 2, an alarm is outputted and becomes an object of a fault retrieval. If no connection of the terminal connection cable 2 is made and the input signal detection output is naturally absent, because it is not a fault, no alarm is outputted. |
