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3 Differences Between Proximity Cards and Key Fobs (Simple Guide)

James McKellar April 8, 2021 7 min read

The popularity of contactless, and tap technology has been growing across the last decade, despite its inception many years prior. 

There are a wide variety of factors as to why this has happened, from improving technology to changing mindsets, to the evolution of crime.

You may have used these two technologies and not even realised or thought about their implications, benefits, and usages. 

In this quick guide, we are going to look at two popular areas of access control, Proximity Cards, and Key Fobs. We will be looking at what they are, how they work, their benefits, and how they differ from each other.

  • Proximity Cards Background
  • Key Fobs Background
  • Benefits of Proximity Cards
  • Benefits of Key Fobs
  • Key Fobs vs Proximity Cards - 3 Differences
  • Summary

What Are Proximity Cards?

Proximity Cards have become more and more popular in recent years, and you probably have used them without even realising.

‘Prox’ Cards are a type of contactless smart card that, as the name suggests, do not require being inserted into the reader to be identified. 

The read range of these low-frequency cards is typically only up to a few centimeters or inches. These cards are commonly used as payment cards.

The rise of contactless became even more prevalent due to many factors, from ease of use, to slowing the spread of germs or viruses. Proximity cards are also very popular in access control.

How do Proximity Cards Work?

As you can probably guess by their name, Proximity Cards work when they are close to their reader, the radius is normally very small and is often referred to as tap technology. 

The Proximity Cards have an antenna embedded in them which is where they transfer the data to the reader, this data can be anything from identification to payment, to authorisation for opening a door or lock.

In security, Proximity Cards are used for access control, which allows you to control who has access to your buildings, locks, gates, and doors. As a rule of thumb, Prox Cards are read-only and have a fairly limited amount of data within them.

The transfer of data from the card to the reader happens in a matter of microseconds and can almost instantly determine a user’s eligibility to access an area.


What Are Key Fobs?

Key Fob technology first rose in popularity in the 1980s where the systems were used for unlocking cars and had infrared technology, which was typically a short-range line of sight form of access control.

The Key Fobs we see in circulation today utilise a few different technologies, from radio, to NFC, to Bluetooth, but they all do the same thing, grant short-range access to a door, lock, or gate.

As the industry shifted away from the traditional lock and key methods, access control and Key Fobs became much more popular and commonplace in all industries and businesses.

How Do Key Fobs Work?

Basically, your Key Fob is a close radius electronic key that will communicate with the reader via a small transmitter within the fob when you get within range (which is normally arm’s length at maximum).

Models differ, but a lot of Key Fobs use Radio Frequency Identification (RFID), which is a type of barcoding that uses electromagnetic fields to send data from the fob to the reader via radio waves.

So, in short, Key Fobs mostly use radio waves to transfer information over a short distance that will either grant or deny access to a lock, gate, or door. It is a simple as yes or no, black or white, which eliminates any chance of duplication or fake IDs.

What Are The Pros of Proximity Cards?

There are countless benefits of utilising Proximity Cards and each business will have its own reasons for picking this technology. With this in mind, we will be looking at the general pros of this contactless access control type.


You will not have to worry about explaining this technology to your staff and users. There is no learning curve for a contactless or tap access control method such as Proximity Cards, the answer is literally in the name.

Be in close range with your card and you will be granted access. If you do not have the right credentials or you are too far from the reader then you will be denied access, as simple as that.

Less Wear & Tear

A major pro of having a Proximity Card is the fact there are no moving parts to get damaged, so they are much less likely to be broken. On top of this, you are not actually touching the reader or inserting the card, which reduces the possibility of wear and tear.

This not only will reduce your costs but also the potential for users being locked out or unable to access a door due to their defunct card. The fact they are cheap to make means that when you do need to replace them, it is easy and cost-effective.


Finding ways to improve your efficiency and reduce wasted time is the core to running more successful operations, this is just one reason why Proximity Cards have become so popular.

Having a card that fits in your pocket, a wallet or an ID lanyard means you can quickly access it much faster than a traditional key, for example. 

Using the high-frequency technology you can get through a door in seconds, rather than reaching for your keyring and fumbling through metal.


What Are The Pros of Key Fobs?

Let us look at a few of the benefits of Key Fobs and implementing them in an access control system or within your business.


Key Fobs give you the ability to manage and oversee exactly who is coming in and out of your controlled areas. You will have a full digital record of where people accessed and door and when.

This can create a much safer and secure working environment. From tracking your staff in an emergency to keeping tabs on unusual entry times, to monitoring performance. 

Easier to Remember

Whether it is because it is on your staff member’s keychain or that they do not have to remember a complex code or password, Key Fobs are easier to use.

This has helped the rise of token-based authentication systems which normally use a physical ‘token’ or item as a way to access a door or lock, as opposed to knowledge-based such as passwords or keycodes.

Plays Well With Others

Key Fobs are very easy to link to other systems and are often paired with CCTV systems to further increase security and develop two-layer authentication. 

Having an access control solution that works well with your current security can be a massive weight off of your shoulders, and allow much simpler integration and implementation.


What Are The Main Differences Between Key Fobs and Proximity Cards?

Key Fobs and Proximity Cards despite their different names, actually share a lot of features and do primarily the same jobs in the same way. 

They are both small token-based systems that grant access to a building. With this being said there are a handful of differences that set them apart.

Shape & Size  

As the names tell us, these two forms of access control look different, one is a card, and the other is a fob. A card is fairly universal sized and will be in line with credit card sizing generally speaking.

A Key Fob,  on the other hand, can come in a wide variety of shapes and sizes, some can be the size of a coin, and some can be the shape of a small die. 

Normally Key Fobs are pretty small, but they do not have to be. The original premise is to fit on a keychain, but they have strayed away from this connotation. 


As we alluded to Key Fobs and Proximity Cards can use different technology. Proximity Cards will typically use high-frequency radio waves, whereas Key Fobs can use passive radio waves, Bluetooth, or even Near-Field Communication (NFC).

There are some basic nuances between these types of technology, but they all use close-range signals to transfer data from the card/fob to the reader. Each has its own benefits and usages, but all have been proven to be effective for access control.


One of the points of differentiation is the industries that these two technologies are implemented in. Gym Access Control has become incredibly popular in the 2010s and beyond, with most gyms opting for a form of Key Fob system. 

Proximity Cards are often used in the fitness industry but are more prevalent as a form of ID cards so are typically utilised more in professional industries and working environments. 


Key Fobs vs Proximity Cards Summary

As you probably have guessed by this point, these two access control types share a lot more common ground than differences. They are both effective methods of increasing your security, improving your operations, and reducing risks.

Both of these access control solutions have come a long way from their inception and continue to evolve and shape the way we approach security.

If you are interested in learning more about the security industry, access control, and small business security then take a look at some of our other articles and guides.

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It seems that people and vehicle access control is an incredibly complex world using hard to understand technology, yet it impacts so many of the environments we interact with on a daily basis.

We are here to fill in the disconnect. We'll break down access control, the benefits, and drawbacks as well, including expert insight based on over 30 years experience in the industry operating as an independent British company. Our goal is to give you ALL the information so you know what's right for you.

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James McKellar

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