Revealed: What is NFC?

I believe everyone knows NFC. Nowadays, almost all flagship mobile phones support this function. With it, we can use our mobile phones to take buses and subways, open doors, and pay with our mobile phones. So do you know what NFC is?

NFC stands for "Near Field Communication", which, as the name suggests, supports short-range communication between compatible devices. It requires at least one transmitting device, and one receiving signal. A range of devices can use the NFC standard and will be considered passive or active.

There are two main types of NFC devices - passive NFC devices and active NFC devices. Passive NFC devices include NFC tags and other small transmitters that can send information to other NFC devices without the need for power. However, they cannot process information from other sources and cannot connect to other passive devices.

Active NFC devices are able to send and receive data and can communicate with each other and with passive devices. Currently, smartphones are the most common active NFC devices, but other common examples include public transportation card readers and payment terminals.

How NFC works

Now that we know what NFC is, how does it work? Just like Bluetooth, Wi-Fi, and various other wireless communication technologies, NFC works by sending information over radio waves and is a standard for wireless data transmission. This means that devices must adhere to specific specifications in order to communicate with each other correctly. The technology used in NFC is an evolution of the older contactless radio frequency identification (RFID), which uses electromagnetic induction to transmit information and is backward compatible with RFID.

This is also a major difference between NFC and Bluetooth/WiFi. NFC uses the principle of electromagnetic induction. Active NFC components can induce current and send data in passive components. This means that passive devices do not need their own power supply. When NFC components enter the communication range, they can be powered by the electromagnetic field generated by active NFC components. However, NFC technology does not have enough induction force to charge our smartphones, but QI wireless charging is also based on the same principle.

The operating frequency of NFC is 13.56MHz. Within a distance of 10cm, its transmission speed is 106Kbit/s, 212Kbit/s or 424Kbit/s. This transmission speed is sufficient for transferring files such as pictures and music.

Application scenarios of NFC

To determine what type of information will be exchanged between devices, the NFC standard currently has three different operating modes: peer-to-peer, reader/writer, and card emulation.

Smartphones are most commonly used in peer-to-peer mode, which allows two NFC-enabled devices to exchange various information with each other. In this mode, the two devices switch between active and passive when sending and receiving data.

Reader/writer mode is a one-way data transmission. In this mode, an NFC phone with reading function collects data from the TAG and then processes it according to the application requirements. NFC advertising tags and access control cards use this mode.

The last working mode is the card emulation mode. In this application mode, the NFC reader collects data from the NFC mobile phone with TAG capability, and then sends the data to the application processing system for processing through the wireless transmission function. Typical applications based on this mode include mobile payment, taking buses and subways, etc.

Other interesting applications of NFC include storing data information in NFC and changing the settings of the mobile phone through NFC tags.

Comparison between NFC and Bluetooth

So, how does NFC compare to other wireless technologies? Considering that Bluetooth has been around for so long, some people might think that NFC is unnecessary. However, there are several important technical differences between the two, which give NFC some significant advantages in certain situations. One big advantage NFC has over Bluetooth is that it consumes less power, which makes NFC very suitable for passive devices, such as the advertising tags mentioned earlier, because they can operate without a power source.

However, there are two sides to every coin, and NFC's low energy consumption also brings some disadvantages. The most obvious one is that NFC has a much shorter transmission distance than Bluetooth. As mentioned above, the maximum transmission range of NFC is about 10 cm, while the transmission distance of Bluetooth connections can be up to 10 meters or even further. Another disadvantage of NFC is that its transmission speed is much slower than Bluetooth. The maximum speed of NFC data transmission is only 424 kbit/s, while the transmission speed of Bluetooth 2.1 is 2.1 Mbit/s, and the transmission speed of Bluetooth LE (low energy) has also reached 1 Mbit/s.

But NFC has another major advantage: faster connection speed. Because NFC uses inductive coupling technology, there is no need for manual pairing, and it takes less than one tenth of a second to establish a connection between two devices. Although modern Bluetooth connection speeds are already very fast, they are still far behind NFC connection speeds, and fast connections are crucial for some scenarios, such as mobile payments.

Summarize:

Although Bluetooth works better in connecting devices together for file transfer, sharing connections with speakers, etc., IT Home believes that NFC technology will always have a place due to the rapid popularization of mobile payments, the Internet of Things, etc.