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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.
A security alarm is a system designed to detect intrusions, such as unauthorized entry, into a building or other areas, such as a home or school. Security alarms protect against burglary or property damage, as well as against intruders. Examples include personal systems, neighborhood security alerts, car alarms, and prison alarms.
A false alarm is one of the most significant issues with conventional alarm systems. They can be triggered for several reasons, such as the movement of pets, [6] typing in the wrong security codes, or loud sounds from windows or doors. In the case of fire alarms, aerosol sprays, smoking, or burning food can all lead to a false alarm.
Holdup alarms are alarms that require a person under duress [1]: ”someone in the room causing distress” to covertly trigger the alarm to summon the proper authorities. These types of alarms are most commonly found in retail establishments and financial institutions, but are sometimes an integrated feature of home burglar alarms .
There are 8,200 alarm sirens for civil protection throughout Switzerland. They are tested once a year, on the first Wednesday in February. [1] Sound sample ⓘ An 1860s-era siren. [2] A siren is a loud noise-making device. There are two general types: mechanical and electronic.
The Mosquito or Mosquito alarm is a machine used to deter loitering by emitting sound at high frequency. In some versions, it is intentionally tuned to be heard primarily by younger people. Nicknamed "Mosquito" for the buzzing sound it plays, the device is marketed as a safety and security tool for preventing youths from congregating in ...
The term "false alarm" may actually be semantically incorrect in some uses. For example, a residential burglar alarm could easily be triggered by the residents of a home accidentally. The alarm is not necessarily false – it was triggered by the expected event – but it is "false" in the sense that the police should not be alerted.
There is one account in 1992 of a thief in New York City rocking a car to deliberately trigger its alarm in order to help conceal the sound of a breaking window. [7] Because of the large number of false alarms with car alarms, many vehicle manufacturers no longer factory-fit simple noise-making alarms, instead offering silent immobilizers. [8]