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Contactless Explained

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Contactless Technology Explained


 Contactless technology is everywhere and has incorporated itself seamlessly into everyday life, from paying with a contactless bank card at a shop, using your phone to earn loyalty points in your favourite restaurant, or tapping a card or wristband to gain access to the gym.  We are going to break down the different types of contactless technology and the different uses.


 The umbrella term for all the different types of contactless technology is RFID, which stands for Radio Frequency Identification. RFID can be broken up into Low Frequency or LF, NFC, and UHF.


 Before we go into the different types of RFID, it is important to take a minute to learn how RFID works. 

 RFID works by having an antenna and a reader that powers the antenna and then reads the signal it emits. As an example of this, if you have an Oyster card or another travel card, it has an antenna inside it that, when held near the reader, powers the antenna inside the Oyster card and allows the payment for your journey to be accepted and you allowed to continue on your journey.

 Another fundamental, in understanding RFID, is learning about the signal that is emitted once the antenna has power. So, what the signal contains is the Card or devices UID which stands for the Unique Identifier. This is usually a series of numbers.

So now you understand the mechanics behind RFID, lets look at some of the different types and their functions.


 Low Frequency runs at a frequency of 125 kHz and is very basic in what it can provide. It can’t hold data; it can just return the UID. These can be used in lots of different variations, though, such as door entry systems, running clubs, and anything where you just need to record a basic transaction like start times, or who entered or left a building. You may think that LF just returning the UID isn’t helpful. However, most people use a Database to assign UID to employees or customers, which then helps you track their movements.

  One of the benefits of Low Frequency is that you can get rewritable versions of cards, fobs, tags, or wristbands. A great application of this would be if you owned a SPA where you need to give your customers a wristband or fob for a while and then rewrite the same fob after they have left to give to a new customer. Or if you need to restrict or allow access to parts of your building to an employee but don’t want to issue a new access card every time. You can give them a rewritable fob and change the access as you need it.

NFC and Mifare


NFC, also known as Near Field Communications, runs on a frequency of 13.56 Mhz, which has a sizeable increase in the amount and type of information that is stored within the chip. NFC’s predominant use is on Phones; the most common applications for NFC on the phone is through contactless payments and Loyalty schemes. Mifare also runs on the same Frequency and is usually used as a physical card, fob, or tag.

Now the annoying part is that you can technically use NFC with a physical card, fob, or tag and use Mifare on your phone. However, these are not the most common applications for this, and so for the sake of all our sanities. I am going to park this here and just talk about the most common uses of NFC and Mifare.

A factor of both NFC and Mifare is that they can hold sensitive data such as bank details or personal data tied to a loyalty scheme. To be able to hold secure data, it is made up of Blocks and sectors; the data can be locked down securely in the blocks and sectors. Which, once locked, can’t be changed or accessed by anyone. Think of the Hunger monster from the shreddies adverts, rather than layers of shredded wheat keeping hunger imprisoned it’s your sensitive data, locked in a series of Blocks and sectors keeping everything secure.



 UHF stands for Ultra High Frequency, and its two big selling points are that it can be read incredibly quickly by a reader, and it can read from a long distance. A UHF reader can read hundreds of UHF tags in seconds, allowing for a large area to be scanned very quickly. There are many practical purposes for this type of technology. It is used in the London Marathon at the Start and Finish Lines. So when everyone starts the race, it records everyone passing through the barrier, and when they finish, it records their stop time. Another excellent application for UHF is in warehousing. If there is a lot of product, you will be able to scan a rack of clothing just by walking next to it, and it tells you how many in each size you currently have. However, with all RFID the only thing that is read is the UID and so to make sure you understand what has been scanned, you will need to put in quite a bit of work to build a database which will link the UID to the specific product.


 RFID comes in a lot of different forms. It can be used as Wristbands, Cards, Fobs, Tags, Stickers and Applications. They can be put into very small stickers and tags if space is an issue. However, it is essential to note that the smaller the tag or sticker, the smaller the antenna is inside, so it will be harder to pick up by a reader.


 RFID does have its flaws and one of the big ones is that its Kryptonite is Metal. If you put any type of RFID directly onto metal, it will become useless and won’t be able to be read by your readers. However, this can be worked around by backing your RFID tag onto a Ferrite background, which then allows it to be placed onto a metal surface and still be read by the readers.

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