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What are the Different Types of Key Card Systems?

Patrick Roland
Patrick Roland

Metal keys with a jagged row of teeth are becoming increasingly rare as technology improves. In locations as diverse as hotels and office buildings, people are using key cards instead of traditional keys. There are four types of key card systems: holecards, bar code cards, magnetic strip key cards and radio frequency identification (RFID) cards. Each type offers simple use, with some providing more security than others.

Key card systems operate on the relationship between a plastic card and electronic access control locks. Each card is programmed to respond to a particular key card reader, a lock or a set of locks. An individual key card is programmed by a computer with a unique electronic signature. If stolen, magnetic strip cards and RFID cards can have the signatures changed, adding security protection from theft.

Some key cards have magnetic strips.
Some key cards have magnetic strips.

Holecards are the earliest type of key card systems. In 1975, inventor Tor Sornes devised a system that would punch a series of 32 holes into a plastic card. The card would correspond to a lock and would open a door when it was inserted into a slot in the door. As technology increased, this key card security system fell out of favor because of its coding limitations, the labor involved in production and its fragility.

Bar code cards were the next innovation in key card technology. In this type of key card system, an individual bar code is created to correspond with a particular lock and is printed on a card. The code is exactly like the bar code found on many products sold in stores. When the bar code is held under an electronic scanner, it unlocks the corresponding door. This key card type lost popularity when magnetic strips became more readily available, because bar codes could be forged and the electronic reader easily fooled.

Magnetic strip key card systems are widely used in the hotel industry and in workplace security. This card looks like a credit card with a thin metallic strip on the back. This card is swiped through a scanner like a credit card, and it opens a corresponding door because of the electronic signature on the card. This type of card is much more difficult to forge than holecards and bar codes, providing an added layer of security.

RFID key card systems are a more recent form of technology than holecards, bar code cards or magnetic strip cards. RFID cards have a radio sensor chip embedded inside the card. When brought into close proximity of a correspondingly programmed reader, the door unlocks. The technology used by this type of card includes microchips and radio technology, so it is considered the most difficult to forge and provides the highest level of security.

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Discussion Comments


Is there a lock system that would charge a credit card a certain amount to open a door lock?

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    • Some key cards have magnetic strips.
      By: Claudio Divizia
      Some key cards have magnetic strips.