Speco Technologies of Amityville, New York, has developed the Digital Deterrent System to help deter crime—not just record it. A surveillance camera that is networked to a DVR detects motion, an alarm annunciates and a custom audio-visual warning is automatically broadcast. For crime prevention, a custom sound file can be recorded, transported, and saved to the DVR’s hard drive. The motion sensor for a specific camera can trigger the audible message and a strobe light to convince the intruder that someone is watching. The device can also be used as a marketing tool—for example, delivering an advertising message to shoppers as they pass by a camera.