Alarm for access closure - has push buttons operating coding bistables to switch off alarm during set period

摘要

The alarm is designed to signal the entry of an intruder into an enclosure having doors or access openings. In the electrical circuit are switches whose operation is controlled by opening of the doors or openings. The system has a timing circuit and an alarm suppression means which is controlled by operation of a code during the operating period of the timing circuit. The code determination and display means consists of several bistables mounted in parallel in the alarm circuit, each being controlled by a push button. Each push button returns to its initial position when released, independently of the position of the bistable.