What is NFC and how does it work. Let's brush up on the basics?

Hello users of Habr! I present to your attention the translation of the article "What is NFC and how does it workby Robert Triggs. It seems, it would seem, why would the author of the original write on this topic in 2019, and should I translate on the threshold of 2020? Today, NFC has taken on a life of its own and is no longer a geeky token technology. Now these are payments, and partly a smart home and smart production. And therefore - why not repeat the past, and for someone new?

NFC is a priority wireless technology, thanks to the development of online payment systems such as Samsung Pay and Google Pay. Especially when it comes to flagship devices and even mid-range (smartphones). You may have heard the term before, but what exactly is NFC? In this part, we will analyze what it is, how it works and what it is used for.

NFC stands for "Near Field Communication" and, as the name suggests, enables short distance communication between compatible devices. This requires at least one device to transmit and another to receive the signal. A number of devices use the NFC standard and will be considered passive or active.

Passive NFC devices include tags and other small transmitters that send information to other NFC devices without the need for their own power source. However, they do not process any information sent from other sources and do not connect to other passive devices. They are often used for interactive wall signs or advertisements, for example.

Active devices are able to send or receive data and exchange data with each other as well as with passive devices. Smartphones are currently the most common form of active NFC device. Public transport card readers and touch payment terminals are also good examples of this technology.

How does NFC work?

Now we know what NFC is, but how does it work? Like Bluetooth, Wi-Fi, and other wireless signals, NFC works by transmitting information over radio waves. Near field communication is one of the standards for wireless data transmission. This means that devices must meet certain specifications in order to communicate properly with each other. The technology used in NFC is based on the old ideas of RFID (Radio Frequency Identification), which used electromagnetic induction to transmit information.

This marks one major difference between NFC and Bluetooth/WiFi. The former can be used to induce electricity into passive components (passive NFC), as well as simply send data. This means that passive devices do not require their own power supply. Instead, they are powered by an electromagnetic field generated by active NFC when it enters the area of ​​effect. Unfortunately, NFC technology does not provide enough inductance to charge our smartphones, but QI wireless charging is based on much the same principle.

The NFC data rate is 13,56 megahertz. You can send data at 106, 212, or 424 kbps. It's fast enough for a range of data transfers, from contact details to image and music sharing.

To determine what type of information will be available for exchange between devices, the NFC standard currently has three different modes of operation. Perhaps the most common use of (NFC) in smartphones is peer-to-peer mode. This allows two NFC-enabled devices to exchange different information with each other. In this mode, both devices switch between active when sending data and passive when receiving.

The read/write mode is one-way data transfer. The active device, perhaps your smartphone, communicates with another device to read information from it. NFC advertising tags also use this mode.

The last mode of operation is card emulation. The NFC device functions as a smart or contactless credit card in order to make payments or connect to public transport payment systems.

Comparison with Bluetooth

So how is NFC different from other wireless technologies? You would think that NFC is not really needed, given that Bluetooth is more widespread and has held the lead for many years (and, by the way, prevails in the smart home and smart production systems mentioned above). However, there are a few important technical differences between the two that give NFC some significant advantages in certain circumstances. The main argument in favor of NFC is that it requires much less power than Bluetooth. This makes NFC ideal for passive devices such as the interactive tags mentioned earlier, as they operate without a main power supply.

However, this energy saving has a number of significant drawbacks. In particular, the transmission range is much shorter than that of Bluetooth. While NFC has a working range of 10 cm, just a few inches, Bluetooth transmits data at a distance of just over 10 meters from the source. Another downside is that NFC is a bit slower than Bluetooth. It transfers data at a maximum speed of only 424 kbps, compared to 2,1 Mbps for Bluetooth 2.1 or about 1 Mbps for Bluetooth Low Energy.

But NFC has one major advantage: faster connections. Due to the use of inductive coupling and the lack of manual pairing, the connection between two devices takes less than one tenth of a second. While modern Bluetooth connects fairly quickly, NFC is still very handy for certain scenarios. And while mobile payments are its undeniable scope.

Samsung Pay, Android Pay, and Apple Pay all use NFC technology—although Samsung Pay works differently from the others. As long as Bluetooth works better for connecting devices to transfer/share files, connect to speakers, etc., we hope that NFC will always have a place in this world thanks to rapidly developing mobile payment technologies.

By the way, a question for Habr - do you use NFC tokens in your projects? How?

Source: habr.com