Learn how Near Field Communication (NFC) works at a technical level.
February 25, 2020
Near Field Communication (NFC) is a technology that allows two-way communication between a phone and an NFC tag; this communication is established when a phone is brought within 10 cm of the NFC tag.
NFC technology establishes a short-range network to exchange data using electromagnetic radio fields. NFC tags can be both read and written; they contain between 96 and 4,096 bytes of storage depending on type of tag. This requires at least one transmitting device and another to receive the signal — a phone is often used as the signal receiver.
Two major specifications exist for NFC technology: ISO/IEC 14443 and ISO/IEC 18000-3. The first defines the ID cards used to store information, such as those found in NFC tags; the second specifies the RFID communication used by NFC devices.
A type of RFID (radio frequency identification), NFC is limited to communication within the aforementioned 10 cm range; however, some forms of RFID can be read at a much larger distance. NFC specifically refers to a branch of high-frequency (HF) wavelengths within the family of RFID technology. For more on the differences in these technologies, see our article on RFID vs. NFC.
Active NFC devices, like phones, can collect and read information from NFC tags, exchange information with other compatible devices, and alter information on the NFC tag (if authorized). Android devices, as well as newer Apple devices, use active NFC.
One of the main functions of active NFC is payment, such as Google Wallet and Apple Pay.
Passive NFC, on the other hand, can only send data — it contains information that other devices can read, but does not read any information itself. Passive NFC can run without power; therefore, passive NFC inlays can be installed in all sorts of devices that need to communicate with other devices.
For instance, Smartrac CIRCUS DURA is a popular passive NFC inlay used in a variety of applications, including retail, brand protection, consumer experiences and product authentication. The innovative CIRCUS DURA paves the way to new consumer engagement and loyalty opportunities for brands and retailers. It is a small, robust and cost-effective tag that can withstand high environmental stresses. For example, when embedded into garments, CIRCUS DURA can survive multiple washing and drying cycles, making it ideal for wash-and-wear applications in clothing and footwear industries.
The Smartrac BULLSEYE inlay is another passive and highly reliable NFC tag. Its unique ID (UID) makes the inlay perfectly suited for high-volume product authentication and other marketing applications. The UID enables the chip’s serial number to be mirrored as part of its encoded URL address; this enables every tag to be read as unique from the application perspective, without requiring users to encode tags with carriable numbers.
In most cases, an NFC tag consists of an antenna + IC (chip), PET substrate, adhesive package and release liner. However, manufacturers like Blue Bite’s partner Smartrac sometimes customize their manufacturing process to fulfill custom needs.
There are four types of NFC tags defined by the NFC Forum. An additional fifth type, with related NFC-V technology, is now included in the NFC Forum specifications. The basic unit of information used in memory management is called a block. Each block has a fixed size of 16 bytes. The number of memory blocks available depends on the chip hardware. Memory blocks are not addressed directly, but relative to the service they belong to.
Containing data collision protection, NFC type 1 tags can be set to be either rewritable or read-only. Their memory size ranges from 93 bytes to 2 KB — enough for a URL or other small amount of data — with a communication speed, or data rate, of 106 kbit/s. Type 1 tags come with a lower market price and do not support the anti-collision mechanism.
Like Type 1 tags, Type 2 NFC tags also are compliant with ISO/IEC 14443A, can be rewritable or read-only, and have a communication speed of 106 kbit/s. However, the memory size for these tags range from 48 bytes to 2 KB, and the they do support the anti-collision mechanism.
Type 3 NFC tags have more memory and faster speeds than type 1 and 2 tags. They are compliant with ISO/IEC 18092 and JIS X 6319-4 standards, except that encryption and authentication that are not supported. Type 3 tags can be set to either read-only or rewritable mode, support the anti-collision mechanism, and contain 2 KB of memory. The data rate is 212 kbit/s or 424 kbit/s.
Type 4 NFC tags comply with the ISO/IEC 14443 standard. They are factory-set to read-only mode, and require specific service equipment to update their data. They hold up to 32 KB of memory and support 106 kbit/s, 212 kbit/s and 424 kbit/s data rates, as well as the anti-collision mechanism.
Type 5 NFC tags have recently been adopted by NFC Forum specifications; they comply with the ISO/IEC 15693 standard, contain more than 64 KB of memory, support a 26.48 kbit/s data rate and the anti-collision mechanism.
Beginning with iPhone XR and XS, phones from Apple now support native NFC. Users read the NFC tags by tapping their iPhone to it. For iPhone 7 through 10, the process is much the same, except an app, like Decode, is required to read NFC.
Most Android phones read NFC natively; experiences are activated by touching the back of an Android device to the NFC tag.
NFC-enabled mobile phones can activate a wide variety of applications, including mobile marketing (like coupons and loyalty programs), identity and access control, ticketing, gaming, and much more.
The standard functionality of NFC in many mobile phones also allows consumers to perform safe, contactless transactions, access digital content, and connect electronic devices simply. An NFC chip in a mobile device can act as a card, a reader or both, enabling consumer devices to share information and to make secure payments quickly.
Blue Bite developed this article with partner Smartrac, a producer of NFC tags and inlays. A leading developer and manufacturer in RFID industry, Smartrac provides NFC tags for retail, financial services, access control and more.