What is NFC?

 Near-Field Communication (NFC) is a set of communication protocols for communication between two electronic devices over a distance of 4 cm (1​1⁄2 in) or less. NFC offers a low-speed connection with a simple setup that can be used to bootstrap more capable wireless connections.

NFC devices can act as electronic identity documents and keycards. They are used in contactless payment systems and allow mobile payment replacing or supplementing systems such as credit cards and electronic ticket smart cards. 

This is sometimes called NFC/CTLS or CTLS NFC, with contactless abbreviated CTLS. NFC can be used for sharing small files such as contacts, and bootstrapping fast connections to share larger media such as photos, videos, and other files.

NFC describes a technology that can be used for the contactless exchange of data over short distances. Two NFC-capable devices are connected via a point-to-point contact over a distance of 0 to 2 cm. This connection can be used to exchange data between the devices. 

                 NFC-enabled portable devices can be provided with application software, for example, to read electronic tags or make payments when connected to an NFC-compliant apparatus. Earlier close-range communication used technology that was proprietary to the manufacturer for applications such as stock tickets, access control and payment readers.

                NFC is based on inductive coupling between two so-called antennas present on NFC-enabled devices, Like other "proximity card" technology uses.

Every active NFC device can work in one or more of three modes:

NFC card emulation

Enables NFC-enabled devices such as smartphones to act like smart cards, allowing users to perform transactions such as payment or ticketing.

NFC reader/writer

Enables NFC-enabled devices to read information stored on inexpensive NFC tags embedded in labels or smart posters.

NFC peer-to-peer

Enables two NFC-enabled devices to communicate with each other to exchange information in an ad hoc fashion.

Comparison with Bluetooth

Aspect	NFC	Bluetooth	Bluetooth Low Energy
Tag requires power	No	Yes	Yes
Cost of tag	US$0.10	US$5.00
RFID compatible	ISO 18000-3	Active
Standardisation body	ISO/IEC	Bluetooth SIG
Network standard	ISO 13157 etc.	was IEEE 802.15.1; now by SIG specs
Network type	Point-to-point	WPAN
Cryptography	Not with RFID	Available
Range	< 20 cm	≈100 m (class 1)	≈50 m
Frequency	13.56 MHz	2.4–2.5 GHz
Bit rate	424 kbit/s	2.1 Mbit/s	1 Mbit/s
Set-up time	< 0.1 s	< 6 s	< 0.006 s
Current consumption	< 15 mA (read)	Varies with class	< 15 mA (read and transmit)

Note: This Table is taken from wikipedia