NFC: how it works and what this chip in your smartphone is really used for

NFC, or Near Field Communication, is a technology allowing data to be exchanged between a reader and any compatible mobile terminal or between the terminals themselves. This is the technology used by your bank card for contactless payment, or your transport card. The advantage of this technology is that in principle no application is required. Simply bring the two supports together. Be careful, these must not be too far from each other: around ten centimeters maximum!

Small clarification of vocabulary: we are talking about NFC, but the standard is based on RFID technology. NFC is a very short-range variation (a few centimeters), designed for secure exchanges such as payment, whereas “classic” RFID is used more for the identification of objects at a greater distance.

Note that for this article, we will prefer the basic acronym to the French one, much less common — CCP for Near Field Communication.

Where is NFC used?

NFC works using a chip which allows the exchange of information between two equipped devices. This can be between 2 telephones, between a telephone and a payment terminal or a speaker. This technology is used by manufacturers of contactless bank cards. If your card is compatible, a small logo quite similar to that of Wi-Fi is present on it.

Before going any further: yes, Apple phones have been equipped with NFC technology since the iPhone 6, but Apple obliges, the uses are very limited. Even if iPhones are now compatible with the Navigo Pass.

Since this article, the situation has evolved a lot on Apple's side. Under pressure from European regulations (DMA), Apple ended up opening access to its NFC chip to third-party developers, which now allows banks and services to offer their own payment solution without necessarily using Apple Pay.

With Android, we can do many more things if this little chip is integrated into our smartphone.

Real-world applications can be divided into three broad categories:

- card emulation

- reader mode

- peer-to-peer data transfer (device to device)

In the first case, the phone becomes a sort of smart card. This is called “passive” mode. The phone sends information to the NFC receiver. The latter can be positioned in the doors of metro entrances or in a payment terminal. Thus, the uses are numerous: mobile payment, transport tickets, coupons, tickets, etc.

The second category concerns tags, these small electronic labels which are sometimes present on signs in cities or at bus stops. Clearly, by passing your phone in front of these tags, you will collect practical information which will be automatically displayed on your phone. This type of use resembles QR Codes.

How does NFC work? Video explanations

Contactless mobile payment

The best-known use of NFC is mobile payment. It's a small revolution: leave your bank cards in the dresser and pay with your phone. But then, how to proceed?

You're in luck, we wrote a file specifically on this subject. Please note that many services offer this type of functionality, but that the big players like Apple, Samsung and Google offer more complete and easier to use solutions.

To go further

Apple Pay, Google Wallet, Samsung Wallet… everything you need to know about the platforms to pay with your phone

The transport card (Navigo, Pastel, etc.)

Public transport users in large cities are used to regularly validating their transport cards. These cards also use NFC technology, and the smartphone can therefore easily replace them, when the city service provides for it.

Several transport networks have already started on this subject. We were able to test the Navigo service from Île-de-France Mobilités with a Samsung smartphone. Tisséo also offers to replace the Pastel des Toulousains card on any Android smartphone with Ticket Easy.

On Apple's side, the control exercised by the brand over the NFC function does not facilitate the adaptation of transport services. As is often the case, the firm plans to do things on its own and has already launched Apple Pay Transit in a handful of cities around the world (London, Chicago, Beijing, Shanghai, Moscow, etc.).

Connect an accessory

NFC can be used to transfer connection data between a smartphone and an accessory. It has become common for Bluetooth headsets to offer an NFC pairing mode, which allows you to avoid going through more tedious settings menus.

Generally, you just need to place the NFC area of ​​the accessory directly on the back of the phone, a notification then appears on the smartphone to confirm the association between the two devices. It's simpler than putting both devices into Bluetooth pairing mode and confirming the security codes.

Send data with NFC

Originally, NFC on mobile mainly allowed peer-to-peer transfer, that is to say exchanging data – files, photos, contacts – between two phones that have NFC. This function has long relied, since Android 4.0, on a native tool called Android Beam – which has now disappeared.

Back when Android Beam existed, all you had to do was activate NFC on both devices, open the file to share and tap the two phones back to back: a small noise and vibration confirmed the transfer. Today, this role is played by Google Nearby Share (formerly Nearby Share), which relies on Bluetooth and Wi-Fi rather than NFC.

For a time, Samsung also offered its own function with S Beam, an extension of Android Beam that appeared on the Galaxy S III. This technology used Wi-Fi Direct to exchange files, resulting in faster transfer speeds. S Beam has now disappeared, but it is still possible to exchange files via Wi-Fi Direct on Samsung devices.

Where Bluetooth is less practical than NFC for pairing two devices, it has the advantage of speed: NFC is not really suited to transferring large files.

How to activate NFC on your phone?

Today, the vast majority of Android phones have an NFC chip, but you still need to know how to activate it. To do this, nothing too complicated: go to the phone settings, then to the “Connected devices” or “Connections” section depending on the overlay. This is also where you activate contactless payment.

Also note that most phones offer a shortcut to activate and deactivate NFC directly from the notifications panel.

To go further

Apple Pay, Google Wallet, Samsung Wallet… everything you need to know about the platforms for paying with your phone