JPS6437698A - Alarm device - Google Patents

Abstract

PURPOSE:To improve the crime preventing functions of an equipment such as an automatic transaction device by deciding the disconnection of a cable at the time of detecting the overcurrent of current flowing into a connection cable. CONSTITUTION:When a somebody short-circuits a cable 5 by trying to cut off the cable with scissors or the like or the conductors of the cable 5 is short- circuited after cutting off the cable 5, overcurrent flows from a power supply circuit 40 into the earth through an overcurrent detecting fuse 39 and then short-circuited signal line 5c. Thereby, the fuse 39 is melted and current supply to a light emitting diode 37d in a photocoupler 37 is interrupted, so that a flip-flop (FF) 33 is set through a phototransistor 37t. Thereby, a non-inverted output Q of the FF 33 is supplied to an alarm buzzer 10 through an OR circuit 30, an inverter 56, and a FF 57 as a driving signal. Simultaneously, a cable disconnection displaying LED 23 is also turned on by the inverted output, the inverse of Q, of the FF 33.