There are many manufacturers of these systems, and a wide variety of ‘bolt on’ options. It’s critical to choose the right system or ‘platform’ as you will be stuck with it in the future. Once you have made the investment in the software, training, badge technology and hardware, it’s prohibitive, in terms of cost to switch to another manufacturer.
The principle of these systems is that from a central location, you can truly control who goes in or out of any particular door, anywhere on the system, during what hours. There are a variety of alerts that can be enabled, such as if a door has been held open, or forced open, or if the emergency break glass has been broken.
Typically, there is a reading device at each door, which accepts swipe cards, or more typically is a proximity reader. This device is able to ‘read’ the information on a badge or fob from 2 or 3 inches. There are other readers with a longer read range, that help people comply with the Disability Discrimination Act.