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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.
In this way, he quickly assembled a 700-alarm network, which his father then copied in New York. [8] In 1878, Holmes became the president of the newly established Bell Phone Company. While he sold his interests two years later for US$100,000, [9] he kept his rights to use the company phone lines for his alarm system. [8]
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.
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]
An alarm-industry lobbying group estimates that 1.5 million customers still need to upgrade their fire or burglar alarms, while about half a million have medical alert devices that run on 3G; it ...