How to block unknown numbers on Xiaomi Redmi: Security Guide

Spam calls and intrusive advertising have become a real scourge of modern smartphones. Owners of Xiaomi and Redmi devices often face a situation when the phone is torn from calls from unknown numbers, interfering with work or rest. Fortunately, the Android operating system, in conjunction with the proprietary shell MIUI or HyperOS, offers powerful built-in tools to filter incoming calls without the need to install additional software.

In this article, we will discuss how to set up a lock on numbers that are not in your phone book.We will look at the regular system tools, hidden features of a standard call and effective third-party solutions.You will learn to create a quiet hour for unwanted contacts, while maintaining accessibility for loved ones and colleagues.

Many users are unaware that their smartphone is capable of analyzing incoming calls and cutting off potentially dangerous or advertising numbers. The “unknown numbers” lock feature at Xiaomi works at the system level, which ensures that no missed notifications are available even when the screen is turned off. Let’s move from theory to practice and secure your personal space.

Use of the built-in filter in the Phone application

The easiest and most effective way to weed out unwanted calls is to use the standard Phone app, which is pre-installed on all Xiaomi and Redmi smartphones, and the developers have implemented a special algorithm that can detect spam and block hidden numbers. To activate this function, you do not need to be an expert in the field. IT.

Open the Phone app and look at the top right-hand corner for a three-dot icon or a gear setting. The menu that opens you're looking for an antispam or lock. That's where the inbound traffic control center is located. By clicking on this section, you'll be taken to a menu where you can flexibly configure filtering rules.

Inside the lock menu, find the "Block Unknown Numbers" switch, activating this option will cause any call from the number that is not in your contacts to automatically be rejected, the caller will hear the "busy" signal, and you will not receive any notification that will save your nerves.

⚠️ Warning: By including a complete lock on unknown numbers, you risk missing an important call from a courier, doctor or employer who calls from an unfamiliar phone.

In addition, in the same menu, you can configure blocking by keywords in SMS or hiding notifications from certain categories of spam. The system regularly updates the number databases, which increases the effectiveness of protection.

Configure through the Security app

The second layer of protection is hidden in the system application "Security" is the "command center" of your Xiaomi, where you combine antivirus, memory cleanup and, of course, the call blocker. The interface here may differ depending on the version of MIUI, but the logic remains the same.

Run the Security app (a zipper or shield icon). On the home screen, look for the Antispam or Lock icon. If you don't see it on the first screen, click three dots in the corner and select Settings -> Antispam, which is often more functional than a simple call.

In the lock settings section, you'll see a list of categories, you're interested in the option "Block calls from unknown numbers," you can also turn on "Smart lock" here, which analyzes the behavior of the caller, and if the number is marked as spam by other users, the call will be blocked automatically.

• 📞 List Blocking: The ability to manually add a specific number to a blacklist.
• 🔇 Quiet mode: Set up a schedule when the lock is active (e.g. at night).
• 📂 Block Log: View all rejected calls and messages.

It's important to check the lock log periodically, and sometimes legitimate calls can come in, like from delivery services that use new numbers, and you can always quickly unlock the number directly from the log, adding it to your contacts.

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If you are waiting for an important call from an unfamiliar number, temporarily disable the lock or add the number of the expected subscriber to the contacts in advance, even without a name, just so that the system “recognizes” it.

Do Not Disturb as an Alternative

If you want temporary silence rather than permanent lockdown, Do Not Disturb mode is ideal. Unlike the blacklist, this mode does not reject calls aggressively, but simply drowns out sound and vibration, allowing the phone to lie quiet.

To set up, go to Settings -> Sound and vibration -> Do not disturb. You can create a schedule or turn on the mode manually. The main thing is to set exceptions. You can allow repeated calls (if a person calls a second time in 15 minutes, the call will pass) and, most importantly, calls from selected contacts.

The good thing about this method is that it doesn't cut off the connection, the caller doesn't hear the "busy" beep, but just can't get through to you in the call log, and the missed call will still show up, so you won't lose anything.

Use Do Not Disturb mode during meetings, movies, or nighttime sleep, when complete isolation is not necessary, but you should not be disturbed either, a softer tool than a hard lock.

Third-party applications for extended protection

Staff funds are sometimes not enough, especially if spam attacks are massive, in which case specialized applications from Google Play come to the rescue, with Truecaller, Kaspersky Who Calls and Yandex.Number Definition being considered the market leaders.

These apps use huge cloud databases. When you get a call, the number is checked in the database in a fraction of a second. If it's an advertising company or a scammer, the app will either drop the call or alert you with a pop-up marked "Spam" or "Real Estate Sale."

But installing these programs has its nuances: They require broad permissions to work effectively, like access to contacts, a call log, even a microphone, which raises questions about the privacy of your personal data, and they can consume more battery power than their system counterparts.

⚠️ Warning: When installing number identifiers from unknown sources, be careful. Some applications may transfer your phone book to their servers without your knowledge.

If you choose to use third-party software, set it up so that it works in conjunction with the system blocker, rather than replacing it completely. Often you can configure the application only to determine the number, and leave the reset to the Xiaomi system.

Working with USSD codes and the operator

Remember that your mobile operator also provides spam protection services. Every major operator (MTS, Beeline, MegaFon, Tele2) has its own services that block unwanted calls before they reach your smartphone.

Often these services are paid or require connection through the operator’s personal application, but basic functions such as Anti-Detector (hiding your number) or simple locks can be accessed through the operator’s personal application. USSD-For example, code *111*00101# (A conditional example, codes change, can activate the protection.

The advantage of carrier-side locking is that your phone doesn't even receive an incoming call signal, which saves battery power and traffic, and it works even if the phone is off or out of range (the call just won't go through).

Frequently Asked Questions (FAQ)

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Comprehensive protection is a combination of Xiaomi system settings, competent use of the Do Not Disturb mode and, if necessary, cloud databases of operators or application-definitions.