2012-05-26

Just like Bluetooth and WiFi, and all manner of other wireless signals, NFC works on the principle of sending information over radio waves.  Near Field Communication is another standard for wireless data transitions, meaning that there are specifications which devices have to adhere to in order to communicate with each other properly. The technology used in NFC is based on older RFID (Radio-frequency identification) ideas, which uses electromagnetic induction in order to transmit information.

This marks the one major difference between NFC and Bluetooth/WiFi, as it can be used to induce electric currents within passive components as well as just send data. This means that passive devices don’t require their own power supply, and can instead be powered by the electromagnetic field produced by an active NFC component when it comes into range.

The transmission frequency for data across NFC is 13.56 megahertz, and data can be sent at either 106, 212 or 424 kilobits per second, which is quick enough for a range of data transfers – from contact details to swapping pictures and music.

In order to determine what sort of information is to be exchanged between devices, the NFC standard currently has three distinct modes of operation for compliant devices. Perhaps the most common use in smartphones is the peer-to-peer mode, which allows two NFC-enabled devices to exchange various pieces of information between each other. In this mode both devices switch between active, when sending data, and passive states when receiving.

Read/write mode, on the other hand, is a one way data transmission, where the active device, possibly your smartphone, links up with another device in order to read information from it. This is the mode used when you interact with an NFC advert tag.

The final mode of operation is card emulation, whereby the NFC device can be used like a smart or contactless credit card in order to make payments or tap into public transport systems.

2012-05-26

NFC stands for “Near Field Communication” and, as the name implies, it enables short range communication between compatible devices. This requires at least one transmitting device, and another to receive the signal. A range of devices can use the NFC standard and can be considered either passive or active, depending on how the device works.

Passive NFC devices include tags, and other small transmitters, that can send information to other NFC devices without the need for a power source of their own. However, they don’t really process any information sent from other sources, and can’t connect to other passive components.  These often take the form of interactive signs on walls or advertisements.

Active devices are able to both send and receive data, and can communicate with each other as well as with passive devices. Smartphones are by far the most common implementation of active NFC devices, but public transport card readers and touch payment terminals are also good examples of the technology.