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Exterior alarm bell box. If a potential intruder tries to enter into a house, they test whether it is closed and locked, uses tools on openings, or/and applies pressure, creating low-frequency sound vibrations. Before the intruder breaks in, the infrasound detector automatically detects the intruder's actions.
A voice-activated radio-dispatched alarm, or VARDA-alarm, is a type of burglar alarm that, when activated or "tripped", broadcasts the type of the alarm and the transmitter location over the local police radio frequency using a pre-recorded audio message. [1] In 1968, the voice-activated radio dispatched alarm (VARDA), was invented.
The Underwriters Laboratories' UL 365 is a safety standard that governs the construction, performance, and maintenance of police station-connected burglar alarm units and systems. These systems are designed primarily for use in mercantile premises, including mercantile safes and vaults, as well as bank safes and vaults.
The word alarm comes from the Old French a l'arme meaning "to the arms", or "to the weapons", telling armed men to pick up their weapons and get ready for action because an enemy may have suddenly appeared. [1] The word alarum is an archaic form of alarm. It was sometimes used as a call to arms in the stage directions of Elizabethan dramas. [2]
The housing of the bell box may be manufactured from wood, metal, or plastic. The basic core component of a conventional bell box is an electromagnet and a bell or other metal piece, some of which create a repetitive sound. [1] The bell sound is normally created inside the box, although the unit may have bells mounted on the outside of the box.
A fence-mounted perimeter intrusion detection system installed on a chain link fence. A perimeter intrusion detection system (PIDS) is a device or sensor that detects the presence of an intruder attempting to breach the physical perimeter of a property, building, or other secured area.