Access Control – When a credential is presented to a reader, the reader sends the credential’s information, usually a number, to a control panel, a highly reliable processor. The control panel compares the credential’s number to an access control list, grants or denies the presented request, and sends a transaction log to a database. When access is denied based on the access control list, the door remains locked. If there is a match between the credential and the access control list, the control panel operates a relay that in turn unlocks the door. The control panel also ignores a door open signal to prevent an alarm. Often the reader provides feedback, such as a flashing red LED for an access denied and a flashing green LED for an access granted. There are different products that can be connected to provide control of access including swipe cards, pin code readers, card readers and key operated isolators.
There are three types (factors) of authenticating information:
- something the user knows, e.g. a password, pass-phrase or PIN
- something the user has, such as smart card or a key fob.
- something the user is, such as fingerprint, verified by biometric measurement