NFC uses passive targets (with no batteries!) and random devices that are not powered (so called tags or stickers, sometimes aka transponders or labels) . NFC Tags are essentially “targets” that “want” to be touched by NFC devices like mobile phones. The communication is also possible between an NFC device and an unpowered NFC chip (“tag”).
Tags can contain information per se or point (i.e. direct) you to information, applications or services. NFC standards cover communications protocols and data exchange formats, and are based on existing radio-frequency identification (RFID) standards including ISO/IEC 14443 and FeliCa. The standards include ISO/IEC 18092 and those defined by the NFC Forum, which was founded in 2004 by Nokia, Philips Semiconductors (has became NXP Semiconductors since 2006) and Sony, and now has more than 160 members. The Forum also promotes NFC and certifies device compliance. It fits the criteria for being considered a personal area network.
NFC builds upon RFID systems by allowing two-way communication between endpoints, where earlier systems such as contact-less smart cards were one-way only. It has been used in devices such as Google Nexus, powered with Android Icecream Sandwich, named with a feature called “Android Beam” which was first introduced in Google Nexus. Android Beam uses NFC to enable Bluetooth on both devices, instantly pair them, and disable Bluetooth once complete automatically on both devices. This only works between Android devices version Jelly Bean and above. It has also been used in Samsung Galaxy S III, with feature named as S-Beam. It is an extension of Android Beam, it uses the power of NFC (to share MAC Address and IP addresses) and then uses WiFi Direct to share files and docs. The advantage of using WiFi Direct over Bluetooth is that it is much faster than Bluetooth, having a speed of 300Mbit/s for sharing large files. Since unpowered NFC “tags” can also be read by NFC devices, it is also capable of replacing earlier one-way applications.
NFC is a set of short-range wireless technologies, typically requiring a distance of 10 cm or less. NFC operates at 13.56 MHz on ISO/IEC 18000-3 air interface and at rates ranging from 106 kbit/s to 424 kbit/s. NFC always involves an initiator and a target; the initiator actively generates an RF field that can power a passive target. This enables NFC targets to take very simple form factors such as tags, stickers, key fobs, or cards that do not require batteries. NFC peer-to-peer communication is possible, provided both devices are powered. A patent licensing program for NFC is currently under development by Via Licensing Corporation, an independent subsidiary of Dolby Laboratories. A public, platform-independent NFC library is released under the free GNU Lesser General Public License by the name libnfc.
tags contain data and are typically read-only, but may be rewriteable. They can be custom-encoded by their manufacturers or use the specifications provided by the NFC Forum, an industry association charged with promoting the technology and setting key standards. The tags can securely store personal data such as debit and credit card information, loyalty program data, PINs and networking contacts, among other information. The NFC Forum defines four types of tags that provide different communication speeds and capabilities in terms of configurability, memory, security, data retention and write endurance. Tags currently offer between 96 and 4,096 bytes of memory.