Modern Xiaomi smartphone users often face intrusive calls where the number detector does not display subscriber data, which creates a serious security and comfort problem, since fraudsters or unscrupulous marketers often hide behind the “No ID” or “Hidden Number”. Owners of devices with a MIUI shell and the new HyperOS have several built-in tools to combat this phenomenon without requiring the installation of third-party software.
However, standard settings don’t always work as expected, especially if the carrier doesn’t pass the hidden number tag correctly.In this guide, we’ll take a look at all the available methods, including system functions, specialized applications from the developer, and radical methods through USSD codes.
It's worth noting that blocking anonymous calls is not just a matter of silence, but also protection from social engineering. Xiaomi's Android system allows you to redirect such calls to voicemail or reset them instantly without giving the caller even a beep. Let's look at step-by-step instructions for different versions of firmware.
Use of built-in functions of the Phone application
The first and most obvious step is to check the settings of a standard caller. Redmi and Poco smartphones often pre-installed Google's Phone app or Xiaomi's own design. The interface may be different, but the logic remains the same. You need to find the partition responsible for filtering inboxes.
In most cases, the path is this: open the app, click three dots in the corner, and select Settings. Next, look for Locked Numbers or Antispam, and that's where the key option is hidden, which is often overlooked by users.
Activate the Block Unknown Numbers or similar switch, and note that in some versions of MIUI, this feature may be called Block Hidden Numbers. Once activated, all calls without an ID will be automatically rejected by the system.
It is important to understand the difference between “unknown” (who are not in contacts) and “hidden” (the number is not technically transmitted). Standard settings often confuse these concepts. If your phone resets calls from couriers or doctors whose numbers are not in the notebook, it is better to use a more subtle setting through the security menu.
Setup of Mi Security antivirus and database
MIUI is famous for its deep integration of system utilities. The Mi Security app has a powerful anti-spam module that works at the system level, not just the call application, and it's a more reliable way, because it intercepts a call before the phone starts ringing.
To activate the protection, open the Security app (green lightning icon) and go to Antispam or Lock, where you will be prompted to update the spammer database, a critical step, as the current databases contain millions of fraud numbers.
In the lock settings, look for the "Blocking Rules" section, where you can prioritize actions. Select the "Block Calls from Hidden Numbers" option. The system will offer several options for response: call reset, send busy or silent reset.
☑️ Set up Mi Security settings
Also available in this section is Blacklist, where you can manually add specific codes or prefixes to it, if you know which bands you're most likely to be called anonymously, which makes filtering much more efficient.
Radical Method: USSD Codes and Operator Services
If smartphone-level software methods don’t deliver 100% results, you need to use the capabilities of the cellular network. Telecom operators (the “big three” and virtual operators) have their own spam-fighting services that work independently of your device.
The most effective method is to activate the service "Anti-Determinator" in reverse mode or "Banning anonymous calls." USSD-However, each operator has its own codes, and they need to be known exactly.
Below is a table with the current codes for the main operators of Russia and CIS. Enter the command in the call app and press the call button.
| Operator. | USSD-activation | USSD-deactivation | Status of service |
|---|---|---|---|
| MTS | *111*442# | *111*442*0# | Paid/Free |
| MegaFon | *111*144# | *111*144*0# | Paid |
| Beeline | *110*771# | *110*770# | Paid |
| Tele2 | *155*001# | *155*000# | Free of charge. |
Once you activate the service on the operator side, all calls where the number is hidden will simply not arrive on your phone. You won't even see a missed call. This is the most reliable method, but it can be paid depending on the tariff.
⚠️ Note: Before activating paid services through USSD-codes be sure to specify the connection cost and subscription fee in your operator’s application to avoid unexpected costs.
Use of third-party applications for filtering
Xiaomi’s built-in tools are good, but specialized applications often have smarter algorithms, with leaders in this field being Truecaller, Yandex with a determinant, and Kaspersky Who Calls. They use cloud-based databases that are updated in real time.
Installing such an application requires broad permissions to access calls and contacts, which is necessary for the number detector to work, and then go to the application settings and find the "Block" section.
Turn on the option “Block hidden/private numbers.” The uniqueness of these applications is that they can analyze the behavior of the caller. If the number is hidden, but he often complains about spam filters of other users, the call will be blocked with a high probability.
Impact on the battery
Some users prefer to use Google Assistant with Call Filter, which is more suitable for the Western market, but in some regions it also works in Russian, automatically answering hidden numbers and recording conversations.
Specifics of working with HyperOS and new versions of MIUI
With the release of HyperOS, Xiaomi has redesigned many system processes, including call management, permission architecture and background services, and hidden number blocking is now more closely integrated with Mi Account and cloud services.
In newer versions of firmware, the path to settings may shift, and now there is a more common security management center, where the settings of both antivirus and cleaner and blocker flock, and the interface has become more minimalistic, but functional.
Pay special attention to the "Do Not Disturb" settings, which you can configure in HyperOS to allow only favorite contacts to be missed, and everyone else, including hidden numbers, to be blocked, creating a digital silence effect.
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If the lock settings are missing after the HyperOS update, try clearing the Phone and Security app cache through the Application menu -> All Apps -> Memory Management.
Also worth noting is the improved work with VoLTE and Wi-Fi calls, and hidden numbers coming through Internet protocols are now also successfully filtered by new algorithms, which was previously problematic.
Frequent problems and ways to solve them
Despite the many methods, users sometimes face situations where the lock is not working, the most common reason is a conflict of settings, for example, if the phone application has permission for everything, and Mi Security has a ban, the system can behave unpredictable.
Another problem is that there's no database updates, and antispam only works when it knows who to block, and if you haven't updated the database in months, the security effectiveness drops to zero. Always keep the databases up to date.
- 📞 Check if you have a record in your contacts with the name “Hidden Number” or an empty name that conflicts with the rules.
- 📶 Make sure the Security app has all the necessary permissions in the phone’s settings menu.
- 🔄 Restart your smartphone after changing the lock system settings to apply the new rules.
⚠️ Attention: By blocking all hidden numbers, you risk missing an important call from the bank, police or emergency services, who sometimes hide the number when you call back.
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A comprehensive approach combining operator settings, MIUI system anti-spam and up-to-date databases provides maximum protection against anonymous spam.
Differences Between Blocking and Ignoring
It's important to distinguish between "lock" and "ignore." When you block a number (or type of numbers), the caller hears the signals busy or reset. When you ignore the call, the phone just doesn't ring, but the call can show up in the log as missed.
For hidden numbers, it is better to use a hard lock. In Xiaomi settings, this is often called “Blacklist”. Ignoring (Do Not Disturb) can skip repeated calls if they come within 3 minutes, which is not an obstacle for spammers.
Set up a lock log. Security has a history of blocked calls. Check it regularly. If you see a lot of hidden numbers there, it means the protection is working. If you see missed calls from Unknown, it means the setting is not active.
Final safety recommendations
Protecting against hidden numbers is just one element of digital hygiene: you don't have to rely on technical means alone, and common sense and caution in dealing with strangers remain the main security tools.
Check your Google and Mi Account privacy settings regularly. Limit your data to apps. The less information you have online, the less likely your number is to be accessed by phone.
Use the second number to register on questionable sites, virtual number services or the second number. SIM-The card will help keep the main contact clean and allow you to easily sift out spam, simply turning off the second SIM in moments of silence.