Card Access Control 101

Card Access Systems are the simplest and most effective way to secure entrances to rooms and buildings.

In this article we will cover all the basics of card access systems including: 

  • What they are & why they are necessary over more traditional methods of securing doors
  • How a card access system works, including different components and how they interact as a complete system

It is important to note that card access encompasses a variety of related technologies including: key cards, proximity cards, swipe cards, badges and even fobs.  At Square, we offer all of these choices based on what best fits your individual needs.  For now though, all of these technologies are similar enough to fall under the larger umbrella term of card access.

What Is Building Access Control?

Card access is a modern form of “access control”.  Simply speaking, access control refers to what the name implies: a way to control who has access to a physical space, whether this be a specific room or an entire building.

The most basic & universally known method of access control is of course a basic key and lock containing a cylinder.

However, for most commercial & multi-tenant residential operations, a simple key and lock system is no longer a viable option.

Problems with traditional key and lock systems include: 

  • Having to replace all of the locks and keys if one key is compromised (stolen or lost)
  • No way to act immediately.  Even if you know security has been compromised, you will have to wait for an actual locksmith to show up and change all of the locks
  • Whoever has the key has access to that room at all times.  In some cases you may only want that person to have access to a sensitive area during business hours
  • No way to track and audit who has entered which room and when

What Card Access Is?

Card access systems, on the other hand, rely on a computer chip in each card that allows card readers to identify who is at the door. Each access card contains a unique code that is evaluated by the control panel to see if it meets the requirements that you have set for that user at that time. Since each card contains a unique number, the system can be customized to give certain privileges to certain people (cardholders).

Because these requirements are electronically stored, they are accessible and able to be changed by the operator of the system 24/7.  This can be done remotely, even if the owner is not in the office, via their phone or computer.

Advantages of a Card Access System: 

  • Control over which specific cardholder has access to which specific rooms at which specific times.  (For example:  Bob can only access this room between 9 AM – 5 PM, but Mary has 24/7 access).
  • If a key goes missing or an employee is no longer trusted, the system operator can simply change the settings (remotely from a phone or computer) so that the specific card in question will no longer work. The rest of the system remains intact and secured.
  • Since the information is relayed back to a Control Panel and stored, it can be viewed so that you can track and see who used what door and when.
  • As many doors as are necessary can have custom settings for just one card.
  • The system can detect when a door has been left open

Components of a Commercial Card Access System

Card Reader:  

Located at the door a person is trying to enter, this is where the person will tap of swipe their card.  The information on the specific card is then read and passed to the control panel where the information is evaluated to see if it meets requirements (time of day, cardholder eligibility etc.) for that door’s reader.


The information that is transmitted from the card reader to the control panel passes through cables that run between the two devices.  These cables also transmit information to the control panel related to the door status and electric strikes (see later).

It is important to keep these cables secure and protected. When cables would otherwise be exposed to vandalism or weather, Square installs them in a protective metallic conduit.

Control Panels:  

Control panels are the intelligence of the card access system.  The control panels hold the database of the cardholders and decides based on the requirements given to it by the operator, if a card meets the requirements (for example if that person is allowed access, if they are allowed within this specific time etc).  It is important that the control panel is well-protected and installed in a secure space, such as a server room that has restricted access.

Electric Strikes:

If the card presented meets the requirements, the control panel sends power to the electric strike and unlocks it.  These Strikes are located on the physical door.

Door Position Switches: 

Let the system know when the door is open or left open. Located on the door frame.

System Management:

A good card access system will include a system management interface that allows the user to set and customize the requirements of each card to each door.  The systems Square installs are accessible through a web browser allowing you to easily access and manage the system from a computer in your office or remotely from any internet connected device.  As our systems are browser based, no complicated software needs to be installed on your computer and our system is fully compatible with any Windows, Macintosh or Linux computers that have a web browser like Chrome, Edge, Safari or Firefox. Through our browser interface, you are able to add or delete users, change access schedules and review event history.


Now that you know how a card access system works and what it consists of, you are in a better position to assess whether or not your location needs one.

If you are in the Ontario Canada, Square Security offers the high-quality security installations.  All new systems include full-training for staff and an industry leading, unmatched 3-year warranty.

Schedule a free consultation to get started!

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