An access control reader ‘reads’ a security card or fob when presented to a special pad. Access control keypads work in a similar way, but use a simple numerical code to allow entry into secure spaces.

Both check the data stored on the card, or the numerical code, against a secure database. If the data is identified, and the access level is correct. the door will open, if not, the door remains locked.

Additional levels of security can be added to an existing system, including multi-factor authentication. These include biometric readers such as fingerprint, palm, iris and face scanners, used in conjunction with a card or code.