MRC

ELECTRIC RESISTORS AND INTRUSION DETECTION EQUIPMENT-NAMELY, SYSTEMS USING TRANSDUCERS IN A PROTECTED AREA TO EMIT AN AUDIBLE TONE AND DETECT VARIATIONS IN REFLECTED TONE DUE TO MOTION IN THE AREA, INCLUDING ELECTRONIC CONTROLS, SIGNAL PROCESSING DEVICES, TONE SIGNAL GENERATORS, ALARM-CONDITION RESPONSIVE DEVICES, ALARM TESTERS AND TELEPHONIC DEVICES FOR REMOTE AUDIO MONITORING OF PROTECTED AREAS