What is NFC?

NFC stands for Near Field Communication and is a wireless communication standard that allows smaller amounts of data to be exchanged between NFC devices. Similar to Bluetooth, or WLAN connections, this exchange takes place wireless via radio transmission. 'Near Field' at this point means that this data exchange can only take place over a short distance of 1-10 cm. This is the main difference to a Bluetooth or WLAN connection.

Another major difference is that the data transfer is configuration-free. This means that no pairing via PIN (Bluetooth) or login via password (WLAN) is necessary to transfer data.

Although the technology has been around since 2008, it has only been gaining more and more relevance in a wide range of everyday applications for a few years now. Every current smartphone now has an NFC chip. Payment terminals and credit cards in particular had NFC chips to enable cashless and contactless payments.

In this article, we explain what NFC technology is used for. The focus here is on the smartphone for NFC use in everyday life. But NFC is also used in other application areas. We will use specific examples to illustrate the wide range of applications for NFC technology. Finally, we will go into technical details and functionalities of NFC technology.

What NFC is for

NFC can be used to exchange smaller amounts of data over short distances. Basically, two NFC chips are needed for this: A transmitter and a receiver. The sending or receiving process between such NFC chips does not require any configuration (pairing of the devices) or other login processes (e.g. password entries). It is sufficient to hold the desired NFC interfaces against each other.

NFC chips are usually not visible from the outside and are marked only by certain symbols. The transmission can take place through plastics, textiles and other non-metallic materials. NFC chips can, for example, be built into stickers, tags or even technical devices such as NFC-enabled smartphones.

Data transmission can only take place if at least one NFC chip is supplied with energy (for example, in a smartphone). Two loose NFC stickers cannot communicate with each other.

How NFC is used

With NFC, data can be exchanged easily over short distances, without password entry and pairing processes. The fields of application for NFC are diverse, suitable for everyday use and are continuously expanding.

For payment processes, PIN entry is generally no longer necessary for smaller amounts of money, as most payment terminals have an NFC chip. Such terminals communicate with NFC chips in credit/cash cards, or smartphones or smartwatches (Apple Pay & Google Pay), so that a transaction can be executed when the card, or smartphone/smartwatch, is held directly in front of the POS system.

In addition to contactless payment transactions, NFC chips can also be implemented in stickers, tags, wristbands or other everyday objects. Such NFC chips usually do not have their own power source. Nevertheless, smaller amounts of data can be stored on them - a mini memory in paper form. This enables a variety of use cases: On the one hand, certain settings and commands of a smartphone can be stored on an NFC chip. So-called short commands make it easier and faster to use the smartphone. A simple example of this is triggering the "set timer" command via NFC tag.

On the other hand, smaller data sets, such as access codes, contacts and especially URLs, can be stored on an NFC tag. The memory size depends on the type of NFC chip. An NFC chip on locking systems, in business cards, or even in clothing can therefore be used to create digital keys and business cards. In garments, an NFC tag can show the origin of the garment and integrate a digital interface.

Last but not least, pairing processes are greatly facilitated by NFC. NFC-enabled headphones, or speakers can be connected to the desired smartphone with a short contact, without the hassle of picking out the device from a list of Bluetooth devices.

The possible use cases of NFC technology are growing more and more and have long since extended not only to everyday applications, but also to use cases in the corporate context.

NFC: Technical Basics

At least one NFC chip must be supplied with power (active) so that data can be successfully transferred between two NFC chips. The energy of a smartphone that supplies the integrated NFC chip is perfectly sufficient. In this case, the NFC chip in the smartphone is the active transmitter.

The difference between an active and a passive transmitter is explained in the following paragraph.

Active and passive NFC transmitters

NFC transmitters can be divided into active and passive ones:

• Active NFC transmitters have the ability to initiate a connection to other NFC transmitters on their own (e.g. smartphones and tablets).
• Passive NFC transmitters don’t have the ability to initiate a connection on their own (e.g. NFC tags).

Active NFC transmitters are able to initiate connections because they contain an own energy source, which is needed to start a connection to another NFC transmitter. Passive transmitters like NFC tags don’t have such an energy source, so they are dependent on an active counterpart to transfer data. Once an active transmitter comes near a NFC tag, it provides the NFC tag with enough energy to transfer data via short distances (1-4 cm).

Types of NFC connections

There are two types of NFC connections:

• Active mode: between two active NFC transmitters (also known as peer-to-peer connection)
• Passive mode: between an active and a passive NFC transmitter

A NFC connection between two passive NFC transmitters isn’t possible, as both transmitters don’t have an own energy source, which is needed to initiate a connection.

In active mode both NFC devices (e.g. smartphones) generate an electromagnetic field, which enables them to exchange data in both directions. However, in passive mode only the active NFC transmitter generates such an electromagnetic field. Therefore, data can only be transferred from the passive NFC tag to the active NFC device.

Further information

• Wikipedia entry on Near Field Communication