Hidden calls from unknown callers are not just an annoying factor, but also a potential threat to the security of your personal data. Smartphone owners Xiaomi Redmi 9 are often faced with the need to restrict access to those who hide their caller ID (CLI). Modern versions of the shell MIUI provide a wide range of tools for filtering incoming calls, however, the settings can be hidden deep in the menu or work incorrectly without additional configuration.
Blocking anonymous numbers on a device with a processor MediaTek Helio G80 can be done in several ways: through the system settings of the phone, using the USSD commands of your cell phone operator or by installing specialized software. Each method has its own characteristics, advantages and limitations, which directly depend on the firmware version and tariff plan. Understanding the mechanics of how it works Caller ID will allow you to choose the most effective way to protect against unwanted communication.
In this article we will analyze in detail all the available options for resolving the problem. You will learn how to activate the Black List function in the standard Phone application, what codes you need to dial to activate the service from your operator, and why you sometimes need to reset your network settings. We will also look at the nuances of the function Antispam in the ecosystem Xiaomi, which automatically updates the database of fraudulent numbers.
Using built-in MIUI functions for blocking
Shell MIUIinstalled on Redmi 9has a powerful built-in security module that includes blacklist management. To access these settings, you do not need to download third-party applications, which saves battery power and RAM on your device. The standard algorithm of actions involves logging into the application Security, which is a system one and cannot be deleted without obtaining root access.
Inside the application you need to find the section responsible for filtering calls. The interface may differ slightly depending on the regional firmware version (Global, EU or China), but the logic remains the same. You need to go to the menu Black list and activate the switch that prohibits calls from hidden numbers. The system will automatically redirect such calls to the blocked event log, and your phone will not emit beeps.
However, it is worth considering that in some versions Android 10 or Android 11on which Redmi 9is based, The direct "Block unknown" option can be hidden or renamed. In this case, you should look for the setting with the name "Block calls from unknown numbers" directly in the settings of the “Phone” application. This option often conflicts with the operator's settings, so its activation requires verification.
⚠️ Attention: Activating the complete blocking of unknown numbers may cause you to miss important calls from couriers, doctors or emergency services, which sometimes use secure communication lines.
Periodically check the blocked call log in the Security application to ensure that important contacts are not included there due to a glitch in Caller ID.
Setting through the Phone application and blacklist
An alternative configuration path is available directly through the dialer interface. Open the application Phone and click on the three dots in the upper right corner of the screen to open the context menu. Select item Settings, and then go to section Blocking numbers. Here you will see a list of all active rules for filtering incoming calls.
To block hidden numbers, find the option "Block unknown numbers" or similar wording, depending on the localization. Once this feature is enabled, all incoming calls where the Caller ID is not reported to the network will be automatically rejected. The smartphone Redmi 9 at this moment may not even vibrate, creating complete silence for the user.
If the standard menu does not contain the desired switch, try using the manual addition to the blacklist function. Although manually adding a “hidden number” is not technically possible, some users create a dummy contact with the name “Anonymous” and a special character in the number field, but this method is unstable and is not recommended by experts. It is safer to use the system filter MIUI.
- 📱 Open the “Phone” application and go to the settings through the menu.
- 🚫 Find the “Blocking numbers” or “Black list” section.
- ✅ Activate the “Block calls from unknowns” toggle switch.
- 🔍 Test the function by asking someone to hide the number and call you.
Services of cellular operators for protection from anonymous individuals
The most reliable method of blocking is to use services on the side of the cellular operator. In this case, filtering occurs on the network before the signal reaches your Redmi 9. This reduces the load on the smartphone's processor and ensures that the call will not disturb you even in airplane mode (provided that Wi-Fi Calling is enabled, if the operator supports filtering at this level). Large operators, such as MTS, Beeline, MegaFon and Tele2offer special tariff options or free services.
To activate protection is usually enough send a USSD request or activate the service through your personal account. For example, some operators have a service called “Antispam” or “Black List”, where you can select a mode for blocking all hidden numbers.
Using network settings has one critical advantage: you do not depend on the firmware version MIUI. Even if the phone settings are reset after a software update, the operator-side protection will continue to work. This is especially true for users who rarely change their smartphone settings and prefer the “set it and forget it” principle.
| Operator | Name of service | USSD command (example) | Cost |
|---|---|---|---|
| MTS | Black List | *111*442# |
Paid / Tariff |
| Beeline | Black List | *110*771# |
Paid / Tariff |
| MegaFon | Antispam | *130# |
Free / Option |
| Tele2 | Black list | *220*04# |
Paid |
⚠️ Attention: Commands and the terms of service may be changed by operators unilaterally. Always check the current USSD codes in your personal account or on the official website of your telecom operator.
What to do if the USSD code does not work?
If the command returns with an error, the service may already be activated or your tariff plan does not support this function. Try disconnecting and reconnecting the service through the operator's mobile application or contact the support service at 0500 (for example).
Third-party applications for filtering calls
If built-in tools Xiaomi and operator services do not give the desired result, you can contact third-party developers. The store Google Play presents many applications specializing in number identification and spam blocking. The leaders in this niche are Truecaller, NumBuster i Kaspersky Who Calls. These apps use huge databases, crowdsourced (created by users), which allows you to identify not only hidden, but also known numbers of scammers.
When installing such an application on Redmi 9 you must provide it with advanced permissions. In particular, you will need access to the call log, contacts and, most importantly, the right to manage calls. Without this, the application will not be able to physically reject the incoming call. After setting up, in the application menu you need to find the “Blocking” section and activate the item "Block hidden numbers".
However, using third-party software has its disadvantages. Such applications often run in the background, consuming additional battery power and RAM. In addition, for them to work correctly, they require a constant connection to the Internet to check the number against the database in real time. On a budget device such as Redmi 9, this can lead to a noticeable decrease in battery life.
- 📥 Download the popular call blocking application from Google Play.
- ⚙️ Grant all necessary permissions when you first launch.
- 🛡️ Turn on the anonymous call blocking function in the application settings.
- 🔋 Monitor battery consumption, as the application runs constantly.
Third-party applications are more effective than system tools in recognizing spam, but require more device resources and access to your personal data.
Compatibility issues and features of Android 10-11
Users Redmi 9 must take into account the specifics of the operating system Android versions 10 and 11. Starting with these versions, Google has tightened security policies, limiting application access to telephony functions. This means that some old blocking methods through codes like #31# or third-party utilities may work unstable or be completely blocked by the system.
In particular, the function Call Screening (Call Verification), available in "pure" Android, is implemented differently in the shell MIUI and may not be available in some regions. If you don't find the settings you need, your firmware may be cut down or modified. In such cases, the only option is to use the operator’s services or flash the device to a global or European version of the software.
It is also worth mentioning the conflict between SIM cards. If Redmi 9 two SIM cards are installed, the blocking settings must be applied for each of them separately. Often, users set up a filter only for the main SIM card, forgetting about the second one, through which unwanted calls are received. Check the settings for both slots in the menu Settings → SIM cards and mobile networks.
⚠️ Attention: When using two SIM cards, make sure that the blacklist rules are applied to both communication lines, otherwise the protection will be incomplete.
☑️ Diagnosing the problem blocking
Additional security measures and tips
Blocking hidden numbers is just one step in protecting your digital hygiene. To minimize the number of unwanted calls to Redmi 9, it is also recommended to register your number in the advertising call registry (if such a possibility is provided for by the legislation of your country) and not post your personal number publicly on forums or message boards.
Regularly update the spam database in the Security application from Xiaomi. This feature works automatically, but sometimes requires manual activation to download the latest scam signatures. Go to Settings → Passwords and security → Confidentiality → Special permissions → Access to contact list and make sure that system services have the necessary rights to identify callers.
If you are faced with a situation where the blocking does not work, try reset call settings. To do this, go to the application Phone, open the settings and find the item Reset call settings. This action will not delete your contacts or call history, but will return all routing and blocking settings to factory defaults, which often resolves software glitches.
Use Do Not Disturb mode at night by setting it to only allow calls from contacts from your address book. This is guaranteed to weed out all anonymous people during rest hours.
Frequently asked questions (FAQ)
Will the subscriber know that I have blocked his hidden number?
No, the subscriber will not receive any notification about the blocking. For him, the call will just take a long time and then drop or go to voicemail as if you didn't pick up. The system does not send a busy signal or a blocked message.
Is it possible to unblock a specific hidden number if you need it?
Unfortunately, it is technically impossible to add a “hidden number” to the whitelist, since it does not have an identifier. If you are waiting for an important call from someone hiding their number, you will have to temporarily disable anonymous call blocking or ask the caller to temporarily reveal their number.
Does blocking hidden numbers affect emergency services?
In most countries, emergency numbers (112, 911, 102, etc.) have priority and cannot be blocked user settings or operator services. However, in rare cases, private clinics or delivery services may use secure lines that will be blocked.
Why were the blocking settings reset after updating MIUI?
With major system updates (for example, the transition from MIUI 12 to MIUI 13), application access rights may be revoked for security purposes. You need to go back to the settings of the “Security” or “Phone” application and confirm the activation of the black list.
Does blocking work if the phone is turned off?
If blocking is configured on the operator’s side (via a USSD command), the call will be rejected by the network even when the phone is turned off. If only software blocking is used on itself Redmi 9, then when the device is turned off, the call simply will not go through to the phone, and you will see the missed call after turning it on.