Overview
Keycard systems operate by physically moving detainers in the locking mechanism with the insertion of the card, by shining LEDs through a pattern of holes in the card and detecting the result, by swiping or inserting a mag stripe card, or in the case of RFID cards, merely being brought into close proximity to a sensor. Keycards may also serve as ID cards.
Many electronic access control locks use a Wiegand interface to connect the card swipe mechanism to the rest of the electronic entry system.
Read more about this topic: Keycard Lock