These systems control one or many doors in a building. Access is gained by using a numeric code, PIN with a keypad, by presenting a proximity or magstripe token, or by 'possesion' with hands free tokens depending on which type of reader fitted. PC based access control offers central control, via a network.

Instructions given at the PC are sent to each of the doors. A token can be barred from all of the doors instantly. Flexible control allows you to set up different access permissions for individuals or groups of users.

Reports may also be generated to track movement, who went where and when. Many systems allow control of additional buildings via existing LAN/WAN. PC based systems are increasingly being used to control other services within buildings, for example intruder alarms, fire doors, lifts and lighting.
Typical applications:

1. Small/medium premises
2. Large corporate premises
3. Multiple-site premises
4. Government buildings
5. Universities
6. Sports clubs
7. Car parks

PC based systems are ideal for medium to large sites providing simple management control of users and large numbers of doors. The system can be extended very easily, and advanced features such as event reporting and integration with CCTV and other systems make such a system much more than just a replacement for a bunch of keys.

Networked (or PC based) access control means that the door is controlled from a computer rather than being stand alone. Usually the PC is not required to be switched on all of the time as the controller will make decisions once it has been configured ny the software on the PC.

Organizations of all sizes are realizing the benefits of replacing their old key- based systems for controlling access to buildings with electronic access control systems. Besides for lower operating costs, a PC-based system benefits you with ease of administration. A good example is when keys are lost, locks would need to be replaced to maintain security. On the other hand, a card-based access control system allows lost cards simply to be cancelled. Cards are also interchangeable between access control and swipecard timeclocks.

Card access control systems also increase security levels, by controlling which parts of a building can be accessed, and by whom. A PC-based, networked access control system, will maintain control from a central location and provide reports on the movements of employees and visitors throughout the building.

Access control is a system which enables an authority to control access to areas and resources in a given physical facility or computer-based information system. An access control system, within the field of physical security, is generally seen as the second layer in the security of a physical structure.

Access control is, in reality, an everyday phenomenon. A lock on a car door is essentially a form of access control. A PIN on an ATM system at a bank is another means of access control. Bouncers standing in front of a night club is perhaps a more primitive mode of access control (given the evident lack of information technology involved). The possession of access control is of prime importance when persons seek to secure important, confidential, or sensitive information and equipment.