Access Control describes any mechanism that controls passage (pedestrian or vehicular) into or out of an area. Access Control devices range from a single lock and key to sophisticated electronic systems that network multiple doors and users to a host computer.

Typically, Access Control systems are comprised of a host computer, modems, terminals, softwares, SensorPanels and card (or badge) readers. Each individual is issued an access badge, card or other credential that may also serve as a form of identification.