Abstract: An electronic security system has a plurality of remote sending units which transmit coded intrusion and other emergency signals to a central alarm station. The alarm station decodes the received signals and produces an appropriate warning from an alarm generator. Electronic alarm controls at the central station discriminate the intrusion signals from other emergency signals and may block or delay the intrusion signals to allow entry or exit from the protected area. Testing circuits are also included in the alarm controls to establish a test mode of operation in which sending units transmit intrusion signals, and receipt is indicated without actuating the alarm generator. During the test mode of operation, the alarm control still accepts priority alarm signals from other sending units and generates alarm warnings from the alarm generator.

Abstract: A triggering device for fire and smoke alarms in which a biased pin member is held in armed position by a latch element which is releasable when a bimetallic disc senses and responds to a selected temperature condition. The response of the disc is transmitted through a ball or antifriction element to which is imparted a lateral force for moving the latch element out of engagement with the pin member. The pin member is spring biased to urge the pin member against a member serving to cause actuation of the alarm.