The Xiaomi Mi 9T (also known as the Redmi K20 in China) is a powerful device that combines advanced communication technologies. One key but sometimes hidden feature is the NFC (Near Field Communication) module, which not only allows you to transfer files, but also turns the phone into a digital wallet, allowing you to pay for purchases in stores with a single touch of the terminal.
However, users often find that after buying or upgrading the system, the contactless function stops working or does not activate at all, this can be due to software failures or improper settings in the region. In this article, we will discuss in detail how to properly activate the module, configure payment systems and fix common errors.
Understanding the principles of contactless communication will help you to make the most of the capabilities of your gadget. We will consider not only standard methods of inclusion, but also specific settings for payment applications, which often require additional attention from the owner of the device.
Where is the antenna and how to check for the module
Before you start software setup, it is important to make sure that the physical health and location of the component. In the Xiaomi Mi 9T model, the NFC antenna module is traditionally located at the top of the rear cover, closer to the main camera unit.
To quickly check the system's health, you can use the built-in engineering menu or third-party utilities. If you plan to use your phone to read access cards or tags, knowing exactly where the read zone is will save you time.
⚠️ Warning: Having a protective cover with metal inserts or magnetic fastener may block the signal.If you can't read the card or pay for the purchase, try removing the case and try again.
For a detailed diagnosis, install an NFC Check app or similar from Google Play, which will show the status of the chip, its version and supported protocols, which is especially useful if you bought a used device and want to make sure that the previous owner did not make changes to the hardware.
Basic NFC activation via Android settings
The standard way to enable a feature in the MIUI or HyperOS shell is simple enough, but it has its own features depending on the firmware version. In most cases, management is concentrated in the connection settings section. To activate the module, follow the following steps:
- 📱 Open the Settings menu and find the Connection and Sharing section (or simply Connect and Sharing»).
- 📡 In the list of options, find a paragraph NFC and move the switch to the active position.
- 💳 Click on the menu item itself to enter the advanced settings and select the mode of operation.
- 🔒 Make sure that the Security menu does not have restrictions on the use of the module.
Some versions of the firmware may have different paths, such as those in older MIUI builds that might have setups in the "Advanced" or "System Applications" section, and if you don't find the switch in a standard location, search for settings by typing in "NFC." The system will redirect you to the desired section.
It is important to note that once the module is enabled, the system may request confirmation or offer to configure Android Beam (for file transfers). For modern tasks, such as payment, this protocol is no longer required, but its presence in the list of supported features indicates that the drivers work correctly.
Contactless Payment Settings: Google Pay and Mi Pay
Using a smartphone as a means of payment is one of the most popular features. For Xiaomi Mi 9T, two main ways are relevant: through Google services and through its own Mi Pay system (depending on the region and version of the software), each of which requires certain security conditions to be set up.
Google Pay (or its equivalents like Google Wallet) requires that the device not receive root rights and unlocked bootloader. If the bootloader is unlocked, the payment system may refuse to work for security reasons, considering the device to be compromised.
- 💳 Add a bank card to your bank’s app if there’s a separate tokenization module there.
- 🔐 In the settings NFC Select the Security Element, which is usually HCE Wallet.
- 📲 Download the Google Wallet app (or Mi Pay) and follow the instructions for linking the card.
- ✅ Pass verification via SMS or a call from the bank to confirm account ownership.
If you use Mi Pay, the process is similar, but the binding is through your Mi Account.This solution is popular in regions where Google services are limited, or for local bank cards that are better integrated with the Xiaomi ecosystem.
What to do if the card is not tied?
Emulation mode and label reading
In addition to payment, Xiaomi Mi 9T It can emulate access cards and read information from different tags, which is useful for opening intercoms (if the frequency and protocol match) or automating tasks through the use of a computer. NFC-Stickers: Mode of the module can be switched depending on your current needs.
The module settings often include "Aerial position" or "Air Mode." To read tags (such as smart alarms when you raise your phone), you need the screen to be unlocked or the constant scan mode is on, but this can increase battery consumption.
| Mode of work | Description | What is used for |
|---|---|---|
| Card Emulation (Card Emulation) | The phone is pretending to be a card | Payment, travel, keys |
| Reading (Reader) | Phone reads data | Smart tags, posters, tickets |
| P2P (Peer-to-Peer) | Data exchange between devices | Photos and Contacts (Android Beam) |
When using the access card emulation mode (for intercoms), it is important to understand that modern security systems (for example, Mifare DESFire) can be incompatible with a standard smartphone chip without additional software. Mifare Classic base cards are often emulated successfully through built-in tools or applications like MI Door Card.
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Use it. NFC-Labels for automation: stick a label on the desktop, so that when you bring the phone on silent mode and start the calendar.
Problem Solving: The module does not turn on or see the map
When the NFC switch on the Xiaomi Mi 9T turns gray (inactive) or spontaneously shuts down, it is rare but requires intervention, most often the problem lies in a software conflict or a failure of system services responsible for communication.
The first step should always be to restart the device. This trivial action often resets the dangling driver processes. If that doesn't work, check if the flight mode ("Air mode") is on, which forcibly disables all wireless interfaces.
⚠️ Note: If the module stopped working after updating the firmware, perhaps in a new version MIUI There is a bug. In this case, you should wait for the patch or temporarily roll back to the previous version of the software.
It’s also worth checking your energy saving settings. Aggressive MIUI algorithms can kill NFC background processes to save charge. Go to your battery settings, find an app that uses NFC (like Google Pay), and set No Limits mode.
☑️ Diagnostics of trouble NFC
Safety and use in public transport
Using the Xiaomi Mi 9T to pay on the subway or bus requires an understanding of security measures. When paying through NFC, your real card number is not transferred to the terminal. Instead, a unique token (one-time code) is generated, making it almost impossible for fraudsters to intercept data.
However, there are risks associated with physical access to an unlocked phone, so it is important to set up mandatory authorization for payments, and you can set the screen unlock requirement (PIN, fingerprint, or Face ID) in the NFC and payment application settings before each transaction.
Public transport often uses turnstiles with powerful readers, and to make a payment, you need to bring the phone smoothly, without removing it immediately after the beep, and the system must have time to conduct handshake protocol with the terminal.
- 🛡️ Enable fingerprint payment confirmation in Google Wallet settings.
- 🚫 Do not store scans of the back of the card on your phone. CVC-code.
- 👁️ Use the “Closed Review” feature in the lock screen settings to hide payment notifications from prying eyes.
Remember that with a battery running low (backup mode), some Xiaomi models allow you to make an emergency payment.This feature works several hours after the phone formally shuts down due to lack of power, but depends on battery capacity and ambient temperature.
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Security NFC-payments to Xiaomi Mi 9T It is provided by data tokenization and an isolated security element (Secure Element), which makes this method even safer than using a plastic card.