Keycard lock
From Wikipedia, the free encyclopedia
A keycard lock is a lock operated by a keycard with identical dimensions to that of a credit card or drivers license. Keycard systems operate operate either by physically moving detainers in the locking mechanism with the insertion of the card or by reading digital data encoded on the card's magnetic strip.
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[edit] History
In the 1970s, the lodging industry had an increasing problem with hotel crime. It was common that hotel room keys, even master keys, were sold on the street with tags identifying hotel and room number. Furthermore, these locks had few key variations and were easy to copy. The result was increasing problems with hotel room thefts and even assaults on hotel guests. As a consequence, the industry was looking for a new type of lock, where the key could be changed for every new guest. The first mechanical keycard lock was installed for testing in a hotel in 1977, the first US installation was at Peachtree Plaza Hotel, Atlanta, Georgia in 1979. In the early 1980s the key card lock was electrified with LEDs that detected the holes.
[edit] Types of Keycards
[edit] Mechanical Based
Mechanical keycard locks employ detainers which must be arranged in pre-selected positions by the key before the bolt will move. This principle was the base for the first known card operated lock, the VingCard, invented by Tor Sørnes. This was a mechanical type of lock operated by a plastic key card with a pattern of holes. There were 32 positions for possible hole locations, giving up to 2 raised to the power of 32 = 4.2 billion different keys. The key could easily be changed for each new guest by inserting a new key template in the lock that matched the new key (See US patent 4,149,394).
[edit] Magnetic Strip Based
Magnetic strip (sometimes "stripe") based keycard locks function by running the magnetic strip over a sensor that reads the contents of the strip. The strip's contents are compared to those either stored locally in the lock or those of a central system. Some centralized systems operate using hardwired connections to central controllers while others use various frequencies of radio waves to communicate with the central controllers. Some have the feature of a mechanical (traditional key) bypass in case of loss of power.
