How does NFC technology work?

Near Field Communication allows two devices to communicate — both can send and receive information — in contactless mode up to a theoretical distance of 10–20 cm, but which in practice reaches 4 cm.
It operates at high frequency (13.56 MHz), transferring data at a speed of up to 424 kilobits per second, with an average speed of 106 kbps. 

NFC technology dates back to 2004, when Nokia, Philips and Sony — later joined by other multinationals including LG, Samsung and Microsoft — founded the NFC Forum, an international non-profit organisation for the creation and dissemination of the NFC standard. 

Near Field Communication can be considered a subcategory of RFID technology, but unlike the latter, it only uses the 13.56 MHz frequency. While RFID tags can be both active and passive, NFC tags are only passive, drawing their energy from the reading system, which is located a short distance away.

Near Field Communication: features

NFC technology is based on two international standards: ISO/IEC 18092:2004, ‘Telecommunications and information exchange between systems Near Field Communication Interface and Protocol (NFCIP-1)’, later replaced by standards ISO/IEC 18092:2013, and ISO/IEC 21481:2012, ‘Telecommunications and information exchange between systems Near Field Communication Interface and Protocol -2 (NFCIP-2)’.

Standard ISO 18092 is compatible with ISO 14443 (Identification cards – Contactless integrated circuit cards – Proximity cards), which defines the standard for contactless cards, while ISO 21481 is compatible with both ISO 14443 and ISO 15693 (Cards and security devices for personal identification – Contactless vicinity), which concerns vicinity cards, which can be detected at a greater distance than contactless cards.

Three ways of communication

Near Field Communication involves three modes of communication: card emulation, reader/writer, peer-to-peer.

• Card emulation

In card emulation mode, the NFC device emulates the behaviour of a contactless card according to standards ISO/ICE 14443 and ISO/ICE 15693. The NFC device is a smartphone, which can be used to make purchases — as with a credit card — or to access public transportation — as with subscriptions in smart card format — by bringing the device close to a fixed reader. For banking transactions, data are stored in a chip called Secure Element, which is either removable or integrated into the smartphone.

• Reader/writer

In reader/writer mode, the NFC device can both read and write data inside a passive NFC tag or sticker with embedded tag, which can be applied to any object.   

• Peer-to-peer

The peer-to-peer mode, defined by standard ISO/ICE 18092, allows for communication and bidirectional data exchange between two NFC devices.