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    Security 2 min read

    Security key fob in use, opening a door.

    Reviewed by Web Webster

    What is a key fob?

    key fob is a small hardware device  that can be programmed to control access to a physical space. Cars, privately owned buildings and restricted spaces are frequently secured in this way.

    Fobs are just one subset of the growing category of security tokens. Other examples include programmable key cards (common in hotels) and increasingly, mobile based security applications.

    Devices using a fob don’t need to be unlocked manually. Instead, they have a mechanism that enables them to open automatically when a signal is received.

    How a key fob works

    A key fob contains a short range radio transmitter and receiver. It uses radio frequency identification (RFID) to communicate with its paired device, which also has its own RFID hardware.

    Within its given read range, you can use the fob to send a signal to the device, using radio waves. The secured device will only respond to the unique information transmitted by its counterpart fob. Thus, key fobs act as a physical authentication device, ensuring access to spaces and data is limited to verified parties.

    Recommended Reading: Interested in learning more about Security? Visit the TechRepublic Academy.

    History of the Key Fob

    Key fob is also a word used to describe a key chain and several other similar items and devices. The word fob is believed to have originated from watch fobs, which existed as early as 1888. The fob refers to an ornament attached to a pocket-watch chain. Key chains, remote car starters, garage door openers, and keyless entry devices on hotel room doors are also called fobs, or key fobs.

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