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  2. Electromagnetic door holder - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_door_holder

    A simple electromagnetic door holder consists of a strong electromagnet, usually attached to a wall or mounted in a floor pedestal enclosure, next to the door it controls. The mechanism may be mounted near the floor, at the upper corner of the open door, or at any convenient height along the latch edge (away from the hinged edge).

  3. Reed switch - Wikipedia

    en.wikipedia.org/wiki/Reed_switch

    Commonly-used circuit symbol Operation of the reed switch The reed switch [ i ] is an electromechanical switch operated by an applied magnetic field . It was invented in 1922 by professor Valentin Kovalenkov at the Petrograd Electrotechnical University , [ 1 ] and later evolved at Bell Telephone Laboratories in 1936 by Walter B. Ellwood into ...

  4. Security alarm - Wikipedia

    en.wikipedia.org/wiki/Security_alarm

    Alarm control panel (ACP), or simply panel: The panel reads sensor inputs, tracks arm/disarm status, and signals intrusions. In a modern device, there are typically one or more computer circuit boards inside a metal enclosure. Many newer networks often use sealed plastic boxes.

  5. Electromagnetic lock - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_lock

    These door holders were traditionally used to hold doors open, but in this application Saphirstein believed that they could be packaged and adapted to work as a fail-safe lock. After a successful prototype and installation at the Forum, Saphirstein continued evolving and improving the design and established the Locknetics company to develop ...

  6. Fire alarm system - Wikipedia

    en.wikipedia.org/wiki/Fire_alarm_system

    A fire alarm control panel Fire alarm speaker and pull station. Fire alarm systems are composed of several distinct parts: Fire alarm control panel (FACP), or fire alarm control unit (FACU): This component, the hub of the system, monitors inputs and system integrity, controls outputs, and transmits information.

  7. Fire alarm control panel - Wikipedia

    en.wikipedia.org/wiki/Fire_alarm_control_panel

    Coded panels were the earliest type of central fire alarm control, and were made during the 1800s to the 1970s. A coded panel is similar in many ways to a modern conventional panel (described below), except each zone was connected to its own code wheel, which, depending on the way the panel was set up, would either do sets of four rounds of code until the initiating pull station was reset ...

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    mail.aol.com

    Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!

  9. Remote keyless system - Wikipedia

    en.wikipedia.org/wiki/Remote_keyless_system

    On some minivans, the power sliding doors can be opened/closed remotely. Some cars will also close any open windows and roof when remotely locking the car. Some remote keyless fobs also feature a red panic button which activates the car alarm as a standard feature. Further adding to the convenience, some cars' engines with remote keyless ...