1) An access device such as a keypad, card reader, or fingerprint reader, or combination of these devices is located outside the entry point. The entry point can be a gate, interior, or exterior door.

2) A pushbutton or push-rail is located on or adjacent to the door for egress. All doors must have a positive fail-safe way of exiting.

3) A magnetic lock or electric strike is used to physically secure the door.

4) Power supply with battery backup is used to power the keypad, locking device, and the controllers. The battery backup is necessary to assure that access is available during power outages.

5) Local controller module is linked to main controller. Each local controller can have 1-16 doors connected to it. In most installations the local controller is configured with 2-4 doors. This is to save wiring costs of running all lines to a central point. Some systems can have controllers daisy chained together or all remote controllers on a home run to the main controller.

6) Main controller usually stores data about users and their activities, and granting or denying access to restricted areas. The main controller can act independently as a stand alone system. It is usually connected to a computer. Most controllers can be connected directly to a printer to view transactions. Main controllers can connect to other local controllers to expand the system.

7) Computer is used for overall control of system and viewing data. The computer can act to retrieve data stored in controller or send data to the controller. The computer can update user info and view user’s history or act in real time displaying current activities.