Modern smartphones of the Xiaomi brand offer users not only powerful hardware, but also advanced tools to filter incoming calls. The problem of intrusive advertising, fraudulent calls and communication with unpleasant people is acute, so the lock function is one of the most popular. Built-in algorithms of the MIUI system (or HyperOS) allow you to effectively manage the list of unwanted subscribers without installing additional software.
The lock procedure can vary depending on the operating system version and regional firmware. Contact locking in Xiaomi is done at the telephony level, which ensures that no sound signals and vibrations are present when calling. It is important to understand that the blocked subscriber will not receive a notification that his number is blacklisted, he will just hear the beeps or reset.
In this guide, we will take a look at all the ways you can isolate unwanted numbers, learn how to quickly blacklist a number through a call log, set up automatic spam filtering, and what hidden Android capabilities are for tighter control of incoming traffic.
Blocking through call log and contacts
The fastest and most obvious way to stop a person’s calls is to use the standard Phone interface, which works equally consistently on older models like the Redmi Note 9 and the flagships of the Xiaomi 14 series. To start, open the Phone app and go to the Journal or Contacts tab.
Find the number you want in your recent call list. Click on it to expand the context menu or go to the subscriber card. Here you should look for the crossed-out icon or the "Block" item. In some versions of the MIUI shell, this item is hidden under the top right of the screen.
Once confirmed, the number is immediately placed on the ignored list, and the system will stop missing calls and SMS-If you accidentally block an important person, you can easily cancel the procedure by going back to the lock settings.
Use of the built-in "Security" application
The unique feature of Xiaomi smartphones is the availability of the system application “Security” (Security), which is not just an antivirus, but a powerful combine for controlling access to the device, and this is where the most delicate anti-spam filter settings are located, which allows you to block entire categories of numbers, not just specific contacts.
To access the advanced settings, open the Security app and look for the Lock section, where you will see a list of all locked numbers and call statistics. By clicking on the Settings gear, you can activate Do Not Disturb mode or enable hidden number locking, which is especially true for those who are often called by anonymous scammers.
The same section also includes a Blacklist feature, where you can manually add numbers or import them from contacts, and the clever MIUI algorithm is able to analyze the database and tag suspicious numbers with “Advertising” or “Telemarketing” labels, suggesting that they be blocked preventively.
☑️ Setting up a smart lock
It is important to note that the functionality of the application may vary depending on the region. In global versions (Global ROM) some functions can be reduced compared to Chinese firmware (CN ROM), but the basic functionality of the blacklist is everywhere.
Hidden Android settings and USSD-code
The Android operating system that HyperOS runs on has its own lock mechanisms that sometimes conflict or supplement the manufacturer's settings. There is a universal way to forward calls that works at the carrier level, but is managed via the phone, called conditional forwarding.
You can use it. USSD-For example, code ##4636## opens a test menu where you can see information about the phone, although direct locking is rare there. **21* and the subsequent number to which the calls will go (usually to voicemail or a non-existent number).
The danger of using third-party codes
Also worth mentioning is the possibility of blocking through Google Contacts. If you sync a phone book with a Google account, you can lock the number directly in the web interface or Google Contacts app. This lock is “linked” to the account and will work even after changing the device or resetting the phone.
Automation of blocking scenarios
For advanced users, Xiaomi offers a Script tool (formerly known as Macros) that allows you to create complex logical chains, for example, if you get a number calling that is not in the contact book, the phone can automatically reset the call and send it to the user. SMS-reply.
Creating a script requires care. Go to your system settings, find the "Special Features" or "Scenarios" section. Create a new script with the "Incoming Call" condition and the "Not in Contacts" option.
This approach allows you to create a whitelist of contacts, where the phone only rings for a select few and everyone else is automatically ignored, which is ideal for a vacation period or when you need to focus on work without too much noise.
| Locking method | Difficulty | Efficiency | Notes |
|---|---|---|---|
| Through the call log | Low. | Tall. | Blocks only a specific number |
| Security Annex | Medium | Very high. | There are spam number databases. |
| Google Contacts | Low. | Medium | It works through the cloud. |
| Scripts (Macros) | Tall. | Maximum | It requires fine tuning. |
Third-party filtering applications
If built-in funds are not enough, Google Play offers a variety of specialized number detectors, with market leaders including Truecaller, GetContact, and Yandex (with Alice) using huge crowdsourcing databases to tag fraudsters and ad agencies.
Installing this software gives you access to automatic category locking, and you can set the filter to keep your phone silent when you call from Advertising, Food Delivery, or Courier Services, but privacy is important: these apps often require access to your entire phone book.
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When installing a number detector, read permissions carefully. They often require access to SMS and contacts. For maximum privacy, use the built-in MIUI tools.
It is important to set priorities correctly. On Android, the default primary calling app is the system phone. Third-party apps must be assigned assistants or have permission to “Master over other windows” to reset the call before you hear the beep.
Frequent problems and their solution
Users sometimes encounter a situation where locked numbers still pass, which may be due to the caller using Internet telephony (VoIP) or changing the number of the determinant (spoofing), in which case the standard lock on the number is powerless.
Another common problem is application conflict: if you have multiple number detectors or antiviruses with blocker function installed, they can interfere with each other, in which case it is recommended to leave only one active protection module, preferably built into MIUI.
⚠️ Warning: If you continue to hear short beeps after blocking or see missed calls from a locked number, check if you have an enabled service called Anti-Determinator from the operator or if a redirect at the SIM card level is activated.
It’s also worth checking for system updates. In older versions of Android (below version 9), the lock mechanism worked differently and could have vulnerabilities. Upgrading to the current version of HyperOS or MIUI 14/15 often solves spam skip issues.
How to unlock the number back
Life situations change, and sometimes you need to unblock it. To do this, go back to the Security app -> Lock. Click on the list icon or gear to see the Blacklist.
In the list that opens, find the contact you want. Usually, there's a switch or deletion button (basket/cross) to the right of the number. Once deleted, the number can call you again. Changes take effect instantly, no reboot is required.
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Timely cleaning of the blacklist is important to avoid accidentally missing an important call from a doctor, courier or employer whose number may have been mistakenly included in the spam database.
If you used third-party applications, you need to unlock them, since the system list may not synchronize with the databases of Truecaller or analogues in the opposite direction.