![]() One example is when you access data from the NFC tag using another NFC device (e.g., a smartphone). The second mode is the reader/writer mode. (Image: st.com, TN216) Mode: Reader/Writer Figure 1: Near Field Communication passive mode of operation exploits the inductive coupling of the devices to generate enough current in the passive device to operate. NFC uses a compact antenna pattern that fits onto a retail tag, sticker, or card. Passive NFC tags do not need a power supply because they take advantage of the slight current generated by the inductive coupling. This is how people can share information and files with each other through NFC versus Bluetooth, for instance. In the active P2P mode, both devices generate the radio wave alternately at a carrier frequency of 13.56 MHz. While one active NFC device sends signals, the other one listens. People can share information using two smartphones as active devices, with the smartphones alternately generating radio waves. (As a comparison, Wi-Fi commonly operates at 2.4 and 5 GHz).Īs an example of active P2P communication, a smartphone might have an antenna that’s on the battery or case. It operates at the 13.56 MHz frequency, which is a license-free section of HF on the RF spectrum. NFC works by exploiting the properties of electromagnetic fields, using the inductive coupling between NFC devices. The radio waves for NFC are generated using an antenna. ![]() The active NFC device has to be enabled (turned on) first. NFC devices communicate with each other via radio waves. NFC passive devices are used in many applications because the passive NFC device can be a simple tag. The active device, with an external power supply, can power the passive device with the electromagnetic field coming from the active device. In an active peer-to-peer (P2P) mode, two active devices create a wireless communication channel between them. NFC supports three modes of communication: peer-to-peer, read/write mode, and card emulation. Using NFC, two devices can be set up in less than one-tenth of a second. The other device can be either active or passive (unpowered). In many cases, this would be a smartphone, tablet, security pad, or a payment terminal. Of the two devices communicating using NFC, at least of them has to be an active device (powered). When two NFC enabled devices are very close to each other, about 4 cm or less, they can communicate with each other using the radio waves. NFC is a type of Radio-Frequency Identification (RFID) technology. The use of NFC tags is growing in several markets, including the medical, consumer, retail, industrial, automotive, and smart grid markets. Near Field Communication (NFC) is a wireless communication technology that acts over short distances for two-way communication.
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