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  2. Security alarm - Wikipedia

    en.wikipedia.org/wiki/Security_alarm

    The technology typically found in motion sensors to trigger an alarm includes infrared, ultrasonic, vibration and contact. Dual technology sensors combine two or more forms of detection in order to reduce false alarms as each method has its advantages and disadvantages. Traditionally motion sensors are an integral part of a home security system.

  3. Electromagnetic door holder - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_door_holder

    An electric current typically energizes the electromagnet to attract and hold the steel plate, keeping the door open. Unlike electromagnetic locks, the magnetic attraction of an electromagnetic door holder is usually weak enough that it can be manually overpowered at any time by anyone, allowing the door to close. [citation needed]

  4. Edwin Holmes (inventor) - Wikipedia

    en.wikipedia.org/wiki/Edwin_Holmes_(inventor)

    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]

  5. Home security - Wikipedia

    en.wikipedia.org/wiki/Home_security

    A control panel is implemented to arm and disarm a home security system. The control panel is the main connection to the alarm company monitoring a home. It typically features a touchpad or buttons to easily maneuver the system, and some newer systems also feature voice control or wireless remotes (key fobs).

  6. Electromagnetic lock - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_lock

    Magnetic locks are almost always part of a complete electronic security system. Such a system may simply consist of an attached keycard reader or may be more complex, involving connection to a central computer that monitors the building's security. Whatever the choice of locking system, fire safety is an important consideration. [2]

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