An access control system consists of a number of "access points" which either grant access or deny access to your staff or visitors. An access point is usually a door with an electro-mechanical door lock, but can be a turnstile or a car park barrier and is controlled via an electronic keypad or card.

Electronic keypads can be programmed to allow entry on the input of a valid code and are usually the most simple of access systems. The next level of security is the card based system where each person is issued with a unique coded card which must be presented to a card reader to allow access through the door.