The 6 Easy Basics of Access Control Systems

What is an Access Control system?
If you’re trying to figure it out on your own it can be complicated and confusing. The good news is that if you understand a few basics everything just falls into place and makes sense.

When I first started working with electronic security I was overwhelmed by all of the different systems and technologies. Even now, after more than twelve years in the business, I still learn something new every day. It took me a long time to figure out what a request-to-exit motion detector does. Maybe that’s why I give such a longwinded explanation later in this¬†post.


Here’s a quick list of the 6 main components that make up an access control system:

1.) Server & Software:
Every access control system has both a server and software. Obviously, the software is where you as the user interface with the system to set schedules, run reports and so on. The server is where the software is installed. It can be on a PC, laptop, or industrial grade mainframe-like NASA uses.

2.) Control Panel:
The control panel is definitely the unsung hero in our story. He does all the work and no one even knows he exists. These panels are typically mounted in an unlabeled metal box on the wall of an electrical room somewhere and forgotten about. All of the equipment that follows in this list wires up to the control panel. The panel processes every transaction, door open and exit, and sends out commands to grant or deny requests.

3.) Card Reader:
The card reader is the part that mounts to the wall next to the door. Fifteen or twenty years ago you’d insert your card and swipe it like a credit card. Now proximity technology is most common. Users just hold their card near the reader and the information is transmitted wirelessly.

4.) Request-to-Exit:
The request-to-exit or REX is a motion detector that is placed on the secure side (the inside) of the door that is protected by the lock. Have you ever been to WalMart or Target and the door magically opens as you walk up? Same thing.

Except at the store when you step in front of the motion detector it tells the door to open. With access control, the REX doesn’t tell the door to open. It tells the software that the door is about to open. Yes weird, I know. But, there is a good reason for it.

It’s because every door that has a card reader on it is also monitored for “forced entry”. If the door is opened without a valid card swipe then the software logs a forced entry alarm. When you exit the door the REX sees that you are about to leave and tells the system “Hey, someone is going to exit this door. I checked them out, it’s okay. Don’t sound the alarm.”

5.) Door Contact:
This one is easy. Otherwise known as door position indicator, door contacts provide a simple way to monitor door position. The door contact is a little two-part magnet that gets installed in the frame of the door. When the door is open the and the magnet is separated the system will recognize that as “door open”.

6.) Electrified Door Hardware:
This is the lock on the door that makes a sound like “CLANG!” when it unlocks. Users swipe their card and the electrified hardware pops open.

What kind of access control system do you have?