Subset of RF identification (RFID) : : NFC

NFC is a different kind of wireless. A proximity technology, it only works when two devices are brought close together so eavesdropping is almost impossible. What's more, NFC is unique in the way it uses energy. Only one of the two devices needs to be powered for an interaction to take place. The first can power the second, so the second can save its battery for other things - or not have a battery at all.

NFC is a specialized subset of RF identification (RFID). It operates at 13.56 MHz and performs many of the same functions as RFID tags and contactless smartcards. NFC operates in one of three communication modes: Read/Write, Peer-to-Peer, and Card Emulation.

Read/Write mode

In Read/Write mode, an NFC reader/writer reads data from NFC smart objects and acts upon that information. With an NFC-enabled phone, for example, users can automatically connect to websites via a retrieved URL, send short message service (SMS) texts without typing, obtain coupons, etc., all with only a touch of their device to the object.

Peer-to-Peer

In Peer-to-Peer mode, any NFC-enabled reader/writer can communicate to another NFC reader/writer to exchange data with the same advantages of safety, security, intuitiveness, and simplicity inherent in Read/Write mode. In this mode, one of the reader/writers behaves as a tag, creating a communication link. For example, two devices (such as smartphones) with readers/writers can communicate with each other.

Card emulation mode

An NFC device in card emulation mode can replace a contactless smartcard, enabling NFC devices to be used within the existing contactless card infrastructure for operations such as ticketing, access control, transit, tollgates, and contactless payments.