Owners of Xiaomi, Redmi and POCO smartphones often face intrusive calls from advertising agencies, scammers or simply from “jammers” that do not display the subscriber’s name. The problem is relevant for all versions of the MIUI shell and the new HyperOS, since standard settings may not be obvious to the average user.
There are several effective ways to limit unwanted contacts from accessing your device, such as using built-in system capabilities, third-party applications, or special operator codes, and it is important to understand that the methods differ in their effectiveness and severity: some simply drown out the call, others completely break the connection to the tone.
In this article, we’ll look at all the options available, from simple menu settings to advanced Blacklist features, and we’ll also look at how to distinguish system lock from SIM-level lock so you can choose the most appropriate action algorithm for your situation.
Use of built-in lock in the "Security" application
The most reliable and easy way to use any Xiaomi device is to use the system application Security, which is already integrated into the core of the system and does not require the installation of additional software, which has a positive effect on autonomy.
To get started, you need to open the Security app (the shield and lightning icon) and in the menu, find the Blocker or Blacklist section. This is where all the filtering settings for incoming connections are located. SMS-message.
☑️ Blocker setup
Inside the locker menu, you'll find several key control options, which can be set to automatically lock hidden numbers or manually add specific combinations of numbers, and allows you to flexibly control the behavior of the phone when a prohibited call arrives.
⚠️ Warning: When you turn on Block All Unknowns, be careful.You may miss an important call from a courier or doctor if their number is not stored in your phone book.
Once the rules are set up, all calls that fall under the criteria will be automatically reset, and in the lock log you will see the history of attempts to communicate, which sometimes helps to identify the source of persistent spam.
Filtering Unknown and Hidden Numbers
Special attention should be paid to the function of filtering numbers that are not defined by the system or hidden by the subscriber, which in modern versions of MIUI has become more intuitive, but requires the right approach to configuration.
Go to the locker settings and find Settings (usually the gear in the corner) and there will be a section that will govern the lock rules, and you will be asked to choose a level of severity, from soft filtering to hard cut off everyone who is not in contacts.
- 📞 Block hidden numbers: disables calls where the subscriber has hidden his or her phone ID (It is defined as “Unknown Number»).
- 📵 Blocking all foreign robots: useful if you do not receive calls from abroad, but are actively annoyed by international robots.
- 📖 Blocking from non-contacts: a radical method that only misses the stored phone book records.
When choosing a mode of work, consider your lifestyle. For business or active sales, the Contacts Only mode can be disastrous, as you lose potential customers, in which case it is better to leave the standard spam protection and manually blacklist nuisance numbers.
Why are the calls still going through?
Manual addition of numbers to the blacklist
If automatic filters fail and you are pestered by a particular subscriber, the method is to manually add to Blacklist, which ensures that a particular number can never reach you again through a standard channel.
The procedure is done through a call log. Find an unnecessary number in the history, click on it (or the "i" icon next to it) and select the option Add to the blacklist. The number will instantly move to the blocked database.
| Action. | Where to find out. | The result |
|---|---|---|
| Addition from the journal | Call history → (push-on) → Lock down | Number is locked permanently |
| Addition from contacts | Contacts → Select contact → Menu → Blacklist | Contact will not be able to call and write |
| Manual input | Security → Blocker → Settings → Blacklist → Add | Blocking by mask or exact number |
There's also a mask add-on feature on the blacklist menu, so for example, you can block an entire group of numbers that start with a specific code if spam comes from a single pool of addresses, a powerful tool to combat mass mailings.
Blocking through settings SIM-operator's cards and codes
Keep in mind that filtering can be done not only at the smartphone level, but also on the carrier side, which is especially true if you need to lock the number while the phone is off, or if you use a button phone in parallel.
Mobile operators (MTS, Beeline, MegaFon, Tele2) There are services such as “Anti-Determinator” or “Black List” that are managed through the USSD-Activation of such a service often allows you to block up to 1000 numbers in the operator's database.
*111*442# — Example of USSD-code for list management (depending on operator)In addition, there is a universal inbound lock activation code that works at the network level (requires operator support for the service):
**03* Phone number # – activation of a specific number lockNetwork settings have their advantages: they are independent of your Xiaomi battery and work even when you change your device. However, such services are often paid, unlike free system features MIUI.
⚠️ Note: Operator codes may vary depending on your region and tariff plan.
Third-party applications for spam protection
If built-in funds are not enough, specialized applications from Google Play come to the rescue, with market leaders such as GetContact, NumBuster and Truecaller using crowdsourcing databases collected from millions of users.
The main advantage of these applications is the ability to identify the caller before the answer. If the number is marked by other users as “Advertising” or “Crackers”, the phone will alert you or automatically reset the call.
- 🛡️ Truecaller: has one of the largest number databases in the world, but requires careful privacy settings.
- 📞 GetContact: popular in the CIS, great shows tags that other people gave you, and has a powerful spam filter.
- 🚫 Blacklist: lightweight app, lock-only, without unnecessary social features and cloud synchronization.
When installing third-party software, remember access rights, and you need permission to read your phone book and manage your calls to work, which is inevitable, because that's how they analyze incoming traffic.
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Tip: When installing number identifiers, read the license agreement carefully. Some applications may upload your phone book to the cloud. If contact privacy is critical to you, only use local blockers without cloud sync.
Frequent problems and their solution
Even after setting up, users may encounter nuances of the system, such as calls may not be blocked if the MIUI settings enable Do Not Disturb mode with exceptions, or if the Security app has been forcibly closed by the power saving system.
A common problem is that the caller hears the beeps, although he should hear "busy"; this depends on the lock mode chosen; in some cases, the system simulates a normal reset so as not to give the fact that the blocker is installed (although this rarely matters to spammers).
If the blacklist stops working, try clearing the Security app cache and restarting the device. Also make sure the locker settings don't tick "Stop Lock" (Temporary Shutdown Mode).
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Xiaomi’s system blocker runs at a low level and consumes minimal power, unlike heavy third-party applications that can drain the battery faster.