What are key card and key fob systems?

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What are key card and key fob systems?

When securing your gated community, one popular option is installing a key card or key fob system. Not only does it offer increased security, but also convenience and peace of mind. To put it simply, a residential key fob and key cards are types of credentials that authenticates access to a secured area. 

While doing a quick search on Google is sure to pull up countless system options out there, not every fob system is perfect for every community. So how do you decide what’s best for you?

In this article, you’ll get a brief overview of (1) what key card and key fob systems are and how they work, (2) the different types and their respective pros and cons, (3) and a potential alternative.  

What are key cards and key fob systems?

Over the years, key cards have been given many different names. You probably know them as fobs, swipe cards, proximity cards, magnetic cards, smart cards, and RFID cards. No matter the name, they all work pretty much the same, allowing a resident to access the community, building, or restricted area by swiping or walking through an entry gate. When you break down these systems, you’ll usually find they have the following components:

  • Access credentials – usually a credit-card-sized piece of plastic or metal with a sensor or a chip to store credential information 
    • Cards/Badges: Thin, flexible plastic cards are a highly common credential. They can easily be placed inside wallets and purses. 
    • Clamshells: SImilar to cards however clamshells are thicker and more durable. 
    • Key Fobs: Probably the most common they can easily be placed on keychains. 
    • Stickers/Tokens: Adhesive devices that can be placed on surfaces for example car windshields. 
  • Entry readers – units located at community gate entrances that read the keys/credentials 
  • Lock – to secure or unlock the gate when required; these may be manually operated (magnetic) or automatic (electric)

Generally, when a resident swipes or inserts their card, the system receives information about who is trying to access the community. The system then decides whether to allow access or not. 

What are the types of key cards and fobs?

Proximity cards

Proximity cards or “prox cards” connect with proximity readers via radio waves. However, users must be within range of a proximity card reader to use it. Most property managers choose prox cards for gates that need to remain locked, such as side/pedestrian gates into the community or a building entrance. Depending on the card, the proximity card reader can use an active or passive reader.


  • Low cost compared to other access control technologies
  • Easy to set up and maintain


  • Have a limited range; users must be close to the card reader
  • May be vulnerable to electromagnetic interference (EMI) caused by power lines and other sources
  • Can be easily copied or written
  • Can be easily shared with unauthorized individuals 

Wiegand magnetic cards

Wiegand cards encode authentication and identification data onto a magnetic strip, which a Wiegand card reader reads. To verify user credentials, the reader evaluates changes in the wiring. Named after their inventor John R. Weigand, these cards are the basis for nearly all key card technologies. 


  • Can’t be erased or reprogrammed using magnetic fields
  • More resistant to breakage because there is no microchip


  • More expensive than proximity cards
  • Can easily be duplicated (26-bit)
  • Limited cable distance between controller and reader (90m)

Swipe cards

Unlike the Weigand card, which can only store a limited amount of information, swipe cards can keep an ID number and handwritten signature. Swipe cards work much like a credit card, with an encoder on one side, where the user places their card, and a reader on the other to interpret the encoded data.


  • Low cost compared to Wiegand cards
  • Easy to set up and maintain


  • Has a limited reading range; users must be close to the card reader
  • May be vulnerable to EMI
  • Can be easily duplicated

RFID key fobs and cards

RFID technology can be used for proximity cards and key fobs. Like swipe cards, RFID cards have an encoder on one side and a reader on the other. Unlike swipe cards, RFID cards don’t need to be swiped. They can be read from a few inches away. Like magnetic stripe cards, RFID cards can store identification numbers and handwritten signatures.


  • Easily change credentials and print out new key cards for residents
  • Allows for convenient contact-free entry with the right RFID reader
  • Can have a single RFID key card for multiple locations within the community


  • May be compromised or hacked by tech-savvy individuals
  • Expensive to set up the RFID system
  • Potential issues with electric RFID keycards due to power outages
  • Difficulty in managing visitor entry because RFID doesn’t allow you to verify visitor identity or grant remote access

Smart cards

Unlike the conventional proxy card, the smart card offers better security because it is harder to hack or clone. Smart cards have access control information encrypted using 64-bit diversified security keys with one-of-a-kind serial numbers. Even better, the smart card and its reader use a symmetrical algorithm, meaning they can only speak to each other.


  • Higher security levels with a lower risk of duplicated cards
  • Larger memory capacity compared to the typical proximity card
  • Can be used for multi-application credentials (e.g., biometrics, time and attendance, transit pass, information access)


  • Expensive compared to proximity, conventional RFID, and swipe cards
  • Lightweight and small, which means residents can lose it
  • Vulnerable to man-in-the-middle attacks

Mobile credentials: An alternative to key card and key fob systems

While there are many advantages to key card and key fob systems, many potential security issues can’t be adequately addressed. Consider mobile credentials, which allow residents to unlock gates and other doorways within the community using their smartphones via NFC or Bluetooth.

Using mobile credentials allows gated communities to stop managing an inventory of key cards and fobs since mobile credentials are digital and can be issued via email. Furthermore mobile credentials help to reduce what we call lost, loan, and clone.

Lost: Credential holders notoriously misplace key fobs and cards requiring them to have to reach out to management to issue them a new one. Management then has to go through the hassle of deactivating the old one so that someone doesnt get a hold of it and gain access into the building or community. 

Loan: One of the biggest gripes property managers have about physical credentials is resident and tenants allowing unauthorized persons to borrow their fob or card to use community amenities that are reserved to residents. A resident or tenants is a lot less likely to let someone borrow their iPhone then they are a fob. 

Clone: One of the most glaring vulnerabilities with older physical credentials such as fobs and proxy cards is they can be cloned. It used to be that someone could literally take a fob down to their local Home Depot or grocery store and make a copy of that fob. Well that’s impossible with mobile credentials. They are unique to that device, they cannot be cloned, and if someone loses their phone, the person that finds their phone either needs to have the same face as the owner or know the password or else they are not getting in! 

Get in touch with Proptia

Proptia offers a seamless single sign-on cloud-based software that integrates multiple standalone applications from mobile credentials, license plate recognition, visitor management, and telephone entry– allowing communities to not stress over managing various systems. If you are considering a key card or key fob system for your gated community, get in touch with Proptia to find the proper solution for your needs.