DISASTER PREVENTIVE DETECTOR, GAS LEAK DETECTOR, AND GAS LEAK MONITOR SYSTEM

摘要

PROBLEM TO BE SOLVED: To prevent the disaster preventive detector and a information transfer receiver from generating speech alarms at the same time by deciding whether or not a information transfer output terminal and the information transfer receiver are connected by a signal line and controlling the operation of a speech output circuit. ;SOLUTION: A connection decision circuit CD makes a decision by detecting a current flowing to the information transfer output terminal TMo at normal times. For this purpose, a proper threshold value is previously set and the value of the current flowing to the information transfer output terminal TMo is compared with the threshold value, to decide whether or not a housing information board is connected. According to the decision result, a current flowing to a relay driving coil Ryc is controlled to control the opening and closure of a relay contact Rys. The relay driving coil Ryc has one end connected to a DC power source and the other end connected to the connection decision circuit CD and is driven and controlled by the connection decision circuit CD. Further, the relay contact Rys is provided to the power supply line to a speech output circuit BG and turns on and off the power supply to the speech output circuit BG.;COPYRIGHT: (C)1997,JPO