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Tech class

[Discussion] [Device Team] [Tech Class] Chapter 43 : All About NFC

2017-11-29 14:43:10
11653 132
Hi, Mi Fans
Welcome to Tech Class session. NFC is something you may often hear mentioned with regard to new smartphones, but it's something which few people know about, or even use. Yes, it’s an acronym, but not all acronyms have to be scary. NFC is both easy to understand and can be incredibly useful. Here’s all you need to know what NFC is and why you should use it.

What is NFC?
NFC stands for Near Field Communication. Essentially, it's a way for your phone to interact with something in close proximity. It operates within a radius of about 4-10 cm and provides a wireless connection between your device and another. This allows for two-way communication, with both devices involved being able to send and receive information. This NFC connection does not rely on Wi-Fi, 3G, LTE or otherwise, and it doesn't cost anything to use.
NFC devices are used in contactless payment systems, similar to those used in credit cards and electronic ticket smartcards and allow mobile payment to replace/supplement these systems. This is sometimes referred to as NFC/CTLS (Contactless) or CTLS NFC. NFC is used for social networking, for sharing contacts, photos, videos or files. NFC-enabled devices can act as electronic identity documents and keycards. NFC offers a low-speed connection with a simple setup that can be used to bootstrap more capable wireless connections.

How does NFC work on Android?
NFC transmits or receives data via radio waves. It's an established standard for wireless communication, so if devices stick to the NFC protocols they'll be able to communicate with each other. It differs from Bluetooth in that it functions through electromagnetic induction. This means there can be a passive device, such as a poster or sticker, requiring no power source of its own that can transmit data when an active device, like your smartphone, comes into contact with it.
As an active NFC device, a smartphone can send and receive data over NFC. It encompasses the full range - three modes - of NFC:
- Reader/writer (e.g. for reading tags in NFC posters)
- Card emulation (e.g. for making payments)
- Peer-to-peer (e.g. for file transfers)

NFC Tags
NFC tags are passive devices, which means that they operate without a power supply of their own and are reliant on an active device to come into range before they are activated. The trade-off here is that these devices can’t really do any processing of their own, instead, they are simply used to transfer information to an active device, such as a smartphone. In order to power these NFC tags, electromagnetic induction is used to create a current in the passive device. We won’t get too technical on this, but the basic principle is that coils of wire can be used to produce electromagnetic waves, which can then be picked up and turned back into a current by another coil of wire. This is very similar to the techniques used for wireless charging technologies, albeit much less powerful.

Here you can see the induction coil and the tiny microchip on the back of an NFC sticker tag.
Xiaomi has NFC tags manufactured which are basically stickers that you can program to do something when your phone reads the NFC. These tags contain data and are typically read-only, but may be rewriteable. They can be custom-encoded by their manufacturers or use the specifications provided by the NFC Forum, an industry association charged with promoting the technology and setting key standards. The tags can securely store personal data such as debit and credit card information, loyalty program data, PINs and networking contacts, among other information. The NFC Forum defines four types of tags that provide different communication speeds and capabilities in terms of configuration, memory, security, data retention and write endurance. Tags currently offer between 96 and 4,096 bytes of memory.

NFC sticker tags manufactured by Xiaomi.
  • At its core, all NFC is doing is identifying us, and our bank account, to a computer. The technology is simple. It's a short-range, low power wireless link evolved from the radio-frequency identification (RFID) tech that can transfer small amounts of data between two devices held a few centimeters from each other.
  • Unlike Bluetooth, no pairing code is needed, and because it's very low power, no battery in the device being read. By tapping your phone on a contactless payment terminal in a shop, train station or coffee shop is able to identify your account (and even your personal preferences, shopping habits and even your most frequently traveled routes) and takes payment through an app on your phone.

Uses Of NFC
- Make a payment: NFC can also be used to make mobile payments. Download Android Pay or Mi-Pay, add your credit or debit card details, then use it in any store that has a contactless payment terminal.

  • As with proximity card technology, near-field communication uses magnetic induction between two loop antennas located within each other's near field, effectively forming an air-core transformer. It operates within the globally available and unlicensed radio frequency ISM band of 13.56 MHz. Most of the RF energy is concentrated in the allowed ±7 kHz bandwidth range, but the full spectral envelope may be as wide as 1.8 MHz when using ASK modulation.
  • Theoretical working distance with compact standard antennas: up to 20 cm (the practical working distance of about 4 cm).

- Send a phone number: NFC is the simplest way to give a person your digits because you don’t actually have to type any digits. Just navigate to a contact in your address book (it can be yours or somebody else's), then press your phone to the recipients. When your phone says “touch to beam”, just tap the display.

- Send a picture: Open the picture you wish to send in your preferred image viewer, then bring the phones together.

- Send a document: Navigate to the file you want to share and bring the devices closer.

- Direct someone to your new favorite app: With NFC you can direct fellow Android fans straight to the Play Store to pick up your favorite apps or games. As long as you are using the app or game at the time, NFC will direct the recipient to the app's Google Play page.

- Send directions: There are many occasions when you are required to explain directions to somebody, but with NFC you don't have to. Use Google Maps to create some directions, then bring the phones together. Beautiful.

- Launch an app on someone else's phone: If you are using an app or playing a game that is already installed on someone else device, you can launch it for them. Say you are using Google Photos and your friend wants to check their photos too, but can't find that app: tap the phones together and beam.

There are two modes of pairing using NFC:-
  • Passive communication mode: The initiator device provides a carrier field and the target device answers by modulating the existing field. In this mode, the target device may draw its operating power from the initiator-provided electromagnetic field, thus making the target device a transponder.

  • Active communication mode: Both initiator and target device communicate by alternately generating their own fields. A device deactivates its RF field while it is waiting for data. In this mode, both devices typically have power supplies.

- NFC employs two different codings to transfer data. If an active device transfers data at 106 kbit/s, a modified Miller coding with 100% modulation is used. In all other cases, Manchester coding is used with a modulation ratio of 10%.

- NFC devices are able to receive and transmit data at the same time. Thus, they can check for potential collisions if the received signal frequency does not match with the transmitted signal's frequency.

- A standard Ultralight NFC tag can store a URL of around 41 characters, whereas the newer NTAG203 NFC tag can store a URL of around 132 characters.


Bluetooth Low Energy
Tag requires power
Cost of Tag
$0.10 USD
$5.00 USD
$5.00 USD
RFID compatible
ISO 18000-3
Standardisation body
Bluetooth SIG
Bluetooth SIG
Network Standard
ISO 13157 etc.
IEEE 802.15.1
IEEE 802.15.1
Network Type
not with RFID
20 cm
~100 m (class 1)
~50 m
13.56 MHz
2.4–2.5 GHz
2.4–2.5 GHz
Bit rate
424 kbit/s
2.1 Mbit/s
1 Mbit/s
Set-up time
0.1 s
6 s
0.006 s
Current consumption
15mA (read)
varies with class
15 mA (read and transmit)

Xiaomi devices that support NFC
Mi 5
Mi 5 Pro
Mi Note 2
Mi Mix
Mi 2A

There you have it. NFC provides the quickest way to set up connections between electronic devices and provides the fastest solution for file transfer between handsets in close proximity. NFC is great for when you’re out of credit, out of 3G or LTE data, have no Wi-Fi or carrier signal, or don’t have a cable to do a PC transfer. It’s quick, easy, and bumping two phones together is fun.

In Case You have missed any tech class thread!

Do you use NFC on your smartphone? What uses have you found for it?

Credits: Wikipedia, AndroidPIT, Google Images.

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2017-11-29 14:43:10
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Master Bunny

Vizard | from Redmi Note 5 Pro


Great info , thanks for sharing , but i think more Mi devices also supports Nfc , kindly check and post.
2018-03-13 00:54:26

Master Bunny

Saurabh Rai | from app


Great info. Thank you Sourav for sharing this.
2018-03-13 01:20:46

Wizard Bunny

Sampath madurai | from Redmi Note 4


Nice Thanks for your information
2018-03-13 01:52:35

Master Bunny

Vicnfsmw | from Redmi Note 5 Pro


nice info...
2018-03-14 00:10:37

Advanced Bunny

arunsdharsan | from Redmi Note 4


good information
2018-03-14 00:17:57

Advanced Bunny

Rk Bavasiya | from app


2018-03-14 00:21:44

Pro Bunny

P_R_A_D_E_E_P | from Redmi Note 4


nice information
2018-03-14 00:25:56

Pro Bunny

MiFanSVR | from Redmi 4


Good information
2018-03-14 00:28:11

Master Bunny

Sk Sam | from Redmi 4A


great nice information thanks for sharing
2018-03-14 00:32:28

Semi Pro Bunny

Rishikesh@98 | from Mi A1


nice and good
2018-03-14 00:32:59
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