Abstract: A self-contained theft and vandalism deterrent system for equipment security includes sensors (12) for detecting conditions to which an alarm (24, 26, 28, 50) is responsive. The analog signals from the sensors (12) are serially delivered by a multiplexer circuit (16) when they are then directed to a network (20) for conversion to digital signals. The digital signals are delivered to a micro processor (22) where the signals are evaluated to determine if an alarm condition exists. The sensing means (12) include sound and vibration detectors for monitoring the ambient envelope. The micro processor (22) includes built in reprogramming and comparator circuits for varying the level at which a given condition will trigger an alarm response.