Near Field Communication Technology to Send Data

NFC technology is one of the latest technological advances where it’s mainly used for payments. Data can be transmitted and received by two devices which are placed near each other, usually not more than a few centimeters away. Many major companies in the world like Sony, Samsung, Apple, Google, and Nokia are tapping into the potential of near field communications. Let’s take a look at this fascinating technology in more detail.

Near field communications can be operated in three different types of modes: 

  1. In the reader/writer mode, the reader/writer collects data and writes the information in the form of a smart tag.
  2. In the peer-to-peer mode, the two NFC devices exchange data.
  3. In the mode for card emulation, NFC device works like a contactless transportation card or payment card to the reader device.

Basically, the NFC Technology was created through RFID tags and most of the NFC devices include ISO/IEC 14443 protocols which provide data transmission in the two types, namely, Type A and Type B. It has a frequency band of more than 13.56 MHz.

Type A communication is based on Miller-bit coding and it provides 100 percent modulation. The signal varies in the range of 0 to full amplitude, which provides low and high values. Miller is based on “delay encoding” and it works by changing the time between signal transition, which depends on sequence of bits which is similar to clock signals, and it transmits data at the rate of 106 kbps.

Type B communication uses the variations of Manchester encoding which provide 10 percent modulation and in this case, 90 percent of signal is low and 100 percent is high. Manchester encoding looks at the signal transition and the transition varies from low to high. The change from low to high is considered to be 0 while the change from high to low is equal to 1.

In near field communication technology, when the two devices are in short range (such as 4 cm), the reader device sends RF signals which allows the current to flow to the antenna. As the signal builds on the smart card or the RFID Tags, it activates the circuit. The antennas serve as a coil of transformer and the distance serves as air core. As you get changes in signal transmission, power flow in the tag changes and it is accomplished through load modulation which results in detection of signal by the reader. The data is transmitted many times between the two devices through the code scheme, and once the current flows, the reader gets the “tag”.

Once the communication method is established, a link is formed, and the reader informs the user about the application it supports, and also requests data, while the tag sends the data corresponding to the request. Later, the connection can be terminated between the two devices.

The NFC Forum was established by Sony, Nokia and NXP semiconductors and its members defined standards on ISO / IEC 18092 for near field communication implementation. The forum is committed to the promotion of NFC technology as well as the expansion of its uses.