NFC is the abbreviation of the English name for the wireless technology standard Near Field Communication. It is a technology for secure communication between two devices over a very short distance. NFC works on a frequency of 13.56 MHz and is specified by the ISO/IEC 18092 standards. It is a technology very similar to, and in some respects compatible with, RFID (Radio Frequency Identification).
Communication
Communication takes place via an electromagnetic field. The device (reader/phone) transmits energy into its surroundings, which creates a radio-frequency field. As soon as an element working on the same frequency appears in this magnetic field, it begins to communicate with the transmitting device by modulating this radio-frequency field.
Range
To initialise NFC communication between two devices, it is enough for the user to bring the device within range of the radio-frequency field. This range varies according to the antenna used and the other factors affecting the quality of the environment for the propagation of the radio-frequency signal. The stated theoretical communication distance is 10 cm, but in practice this distance is smaller, at most 3-5 cm.
Data transfer
Thanks to the absence of any need to pair devices, NFC is used for fast data transfer. Speed here is represented precisely by the immediate transfer, without the need for pairing by the user. The transfer speeds themselves are, in comparison with other communication technologies, very low – NFC uses, as standard, 3 communication speeds - 106 kbps, 212 kbps and 424 kbps (ISO/IEC, 2012).
The channel for transferring data via NFC is established very quickly, but the data transfer itself is unsuitable for large data volumes. NFC is used for transfers of small amounts of data, which serve for the subsequent identification or initialisation of some other communication channel (bluetooth, wifi, pointing to a website, etc.). NFC transfer can be divided into communication of an active device with a passive device, and communication of two active devices (peer-to-peer).
Active and passive NFC device
Communication of an active and a passive device takes place in such a way that the active device approaches or touches the passive circuit (tag), whose small capacitor is charged by means of electromagnetic induction, and the tag establishes communication with the mobile device, or sends content.
Two active NFC devices
Communication of two active devices is similar to the previous one, with the difference that the second device is also active, and therefore charging by means of electromagnetic induction need not take place. The devices communicate by means of electromagnetic waves on the peer-to-peer principle. Two mobile phones can communicate in this way, for example, or a phone with a payment terminal, and the like.