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Published in October 2021, this article explains Near Field Communication (NFC), a wireless technology that enables secure data exchange between two devices in close proximity. NFC is an evolution of RFID technology, specifically classified as RFID HF (High Frequency) because it operates at 13.56 MHz.
How NFC Technology Works
NFC technology offers three primary functionalities. First, peer-to-peer (P2P) data exchange between two devices—for example, smartphones can transfer information securely by bringing them within 3–4 centimeters of each other. Second, host card emulation (HCE) allows devices to simulate smart cards and process secure payments via smartphone. Third, NFC enables reading and writing of NFC tags, which are RFID transponders capable of storing and exchanging information with NFC-equipped devices.
Understanding NFC Tags
NFC tags are small transponders consisting of a microchip (integrated circuit) connected to an antenna. Each tag has a unique code and rewritable memory. The antenna enables communication with an NFC reader, such as a smartphone. NFC tags are commonly manufactured as adhesive stickers but can be integrated into various formats including cards, bracelets, key chains, and promotional items. Because NFC tags are powered by the magnetic field of an NFC sensor, they require no direct power source and can function reliably for years once attached to an object.
Memory capacity varies by chip type but typically does not exceed one kilobyte in the most common tags. This limitation is offset by the NDEF (NFC Data Exchange Format) standard, developed by the NFC Forum, which allows tags to perform sophisticated functions. Marketing applications frequently program tags with URLs linking to web pages. Compared to QR codes, NFC tags offer greater data capacity and require no app for reading on Android devices. The tag’s memory is divided into blocks, enabling more complex applications such as inventory management and medical records.
Tag Properties and Programming
Every NFC tag contains a unique identifier (UID) stored in non-modifiable memory, allowing tags to be uniquely associated with objects or persons and enabling applications that identify and interact with them. Tags can be programmed with private commands—such as activating or deactivating Wi-Fi, Bluetooth, GPS, adjusting volume or brightness, or opening applications—using dedicated apps like Trigger. Standard commands defined by the NDEF format include opening web pages, accessing Facebook, sending emails or SMS messages, initiating calls, saving contacts as V-Cards, and launching applications (Android and Windows only). For these standard commands, most smartphones require no app installation, with the exception of iPhones. Reading NFC tags requires only that the NFC sensor be activated on the device; no separate application is necessary for most phones. NFC tags offer advantages over UHF RFID tags because they can be read by basic mobile phones and programmed independently using free Android, BlackBerry, or Windows Phone applications.
Frequently Asked Questions
What is the operating frequency of NFC technology?
NFC operates at 13.56 MHz and is classified as RFID HF (High Frequency). It represents an evolution of RFID technology.
How much memory do NFC tags typically have?
Standard NFC tags generally have memory capacity under one kilobyte, which is sufficient for many applications using the NDEF format, such as storing URLs, contact information, and commands.
Do NFC tags need a power source?
No; NFC tags are powered by the magnetic field of the NFC sensor in a reader device such as a smartphone, allowing them to function reliably for years without direct power.