Most storage devices that do not require vision and a brain to read data fall into this category. Electromagnetic data may be stored in either an analog data or digital data format on a variety of media.
Direct Tripwire Alarm - The wire placed across the path is directly connected with the cord, wire or string placed across the particular path. Laser Tripwire Alarm - An invisible laser, typically an infra-red, is used instead of a cord or string.
This may be a rigid steel or aluminum pipe, called a conduit, or in one of several varieties of metal or non-metallic tubing. Wires run underground, for example, may be run in steel or plastic tubing encased in concrete, but metal elbows may be used in severe pulls. Wiring in exposed areas, for example factory floors, may be run in raceways or cable trays. For protection from flame spread, fire stopping material of silicone may be used.