Spam calls and annoying offers from banks or collectors have become a real problem for smartphone owners. This is especially true for budget models, such as Redmi 9C, which are often used as a second work phone or for elderly relatives. Constant calls are not only distracting, but can also lead to accidental charges or infection of the device with malware.
Fortunately, the shell MIUIinstalled on your device provides powerful built-in tools for filtering incoming calls. You don't have to download third-party applications that can overload your RAM. In this article we will analyze in detail all the available methods of isolating from unwanted communication, from simple settings to advanced blocking scenarios.
We will consider both standard blacklist functions and less obvious methods available through the engineering menu or special codes. The correct configuration of these parameters will allow you to forever forget about calls from unknown numbers, while maintaining the ability to communicate with important contacts.
Using the built-in Security application
The most reliable and easiest way to manage calls on Xiaomi is to use a pre-installed system application. It is deeply integrated into the operating system and works more stable than any third-party analogues. To get started, open the application menu and find the icon with the name Security, which usually has a green shield as a logo.
Inside the antispam settings section you will find flexible tools for sorting incoming traffic. Here you can not only add a specific number to the black list, but also set up automatic screening of calls based on certain criteria. This is especially convenient when calls come from different numbers of the same spammer.
Pay attention to the section Black list, which is the central element of protection. This is where all filtering rules are stored. The system allows you to create complex rules, for example, block everyone who is not in your phone book, or hide calls from hidden numbers.
⚠️ Attention: When you enable the blocking mode for all unknown numbers, make sure that you do not expect important calls from couriers, doctors or delivery services that may call from strangers SIM cards.
Periodically check the blocked call log in the Security application to make sure that important contacts do not end up there due to errors in the number.
Manual blocking through the call log
If you need to quickly block a specific annoying number, there is no need to go into deep settings. The most efficient method is to use call history. Open the standard application Phone and go to the tab with a clock image, which displays the chronology of all incoming and outgoing connections.
Find the number you want to block in the list. Click on it or the information icon (i) next to it to open the contact card. In the menu that opens, you will see several options, among which there will be an item Block or an icon of a crossed out circle. After clicking, the system will confirm the action, and this number will no longer be able to reach you.
This method is ideal for targeted combat against specific scammers or annoying friends. However, it requires manual processing of each new number, which can become tedious during a massive spam attack. In such cases, it is better to combine manual blocking with automatic filters.
- 📞 Open the call history and find the desired number.
- 🛑 Click on the block button in the contact menu.
- ✅ Confirm the action in the pop-up window.
- 🔍 Check the blocked list in the settings.
Setting up automatic screening of unknown numbers
For those who want to radically solve the problem of spam, MIUI there is a function to block all calls from subscribers who are not in the contact list. This is a “nuclear” protection option that provides absolute silence, but requires caution in use. You can activate this option through the app Security.
Go to the section Antispam and select the blacklist settings. Here you'll see a switch labeled "Block calls from unknown numbers" or similar wording. When this mode is activated, the phone will automatically drop any call if the caller's number is not saved in your address book.
It is important to understand the difference between an “unknown number” (which is simply not recorded with you) and a “hidden number” (which is technically not transmitted by the network). The settings allow you to flexibly configure the behavior of the device in both cases. You can allow calls from unknown people, but block only hidden ones, or vice versa.
☑️ Setting up total protection
⚠️ Attention: The settings interface may vary slightly depending on the MIUI firmware version (Global, Russia, China). If you do not find the item in the specified location, use the search in the settings.
Blocking hidden and private numbers
A separate category of problems consists of calls where the subscriber deliberately hides his identifier. Such calls are often used by scammers, since they cannot be added to the blacklist in the usual way - the system simply does not have the digits of the number to block. On Redmi 9C, this problem is solved through special call settings.
Open the application Phone, click on the three dots in the upper right corner and select Settings. Next, go to section Blocking numbers. There should be a separate toggle switch here that says “Block hidden numbers.” Enabling this feature will cause the phone to automatically reject calls where the Caller ID field is empty.
It is worth noting that the effectiveness of this feature may depend on your mobile operator. Some telecom providers transmit hidden numbers in a special way, which the system may interpret as "unknown" rather than "hidden". Therefore, it is recommended to enable both blocking options for maximum protection.
| Number Type | Description | Blocking Method |
|---|---|---|
| Specific Number | Known Digital Identifier | Add to Black list |
| Unknown number | Number not saved in contacts | Contacts only mode |
| Hidden number | The subscriber has hidden his ID | Check "Block hidden" |
| International spam | Calls from other countries | Blocking by country code |
Why are hidden numbers dangerous?
Fraudsters often use hidden numbers to avoid reverse tracking and blocking by the victim. Such calls often precede attempts at social engineering.
Use of codes and engineering menu
For advanced users for whom standard settings are not enough, there are special USSD codes and engineering menu commands. These tools allow you to manage forwarding and blocking at the network level or deeper Android system settings. However, they should be used with extreme caution.
One of the common methods is to activate the “Barring all incoming calls” service, except those coming from the home network or from certain groups. This is done through code **43# or similar combinations, depending on the operator. Also in the engineering menu MIUI (called by code ##6484##) you can check the status of the radio module, although direct blocking is rare there.
A safer option is to use codes to check the forwarding status. If your number is redirected to some fraudulent service, you can track it. Enter the code *#61#to find out where calls go if you don't answer the phone. This will help identify hidden settings that may have been changed by malware.
*#06# - Checking device IMEI*#61# - Checking forwarding when busy
*#62# - Checking forwarding when unavailable
⚠️ Attention: Entering unknown codes into the engineering menu may lead to resetting network settings or changing radio module parameters. Use only proven commands.
Engineering codes are a powerful tool, but for regular spam blocking the capabilities of the Security application are sufficient.
Third-party applications and spam databases
If the built-in tools are not enough, the market offers many applications for identifying and blocking spam. The leaders in this area are GetContact, NumBuster i Kaspersky Who Calls. These services use huge databases collected by users to mark callers as “Collectors”, “Taxi” or “Fraudsters”.
Installing such an application on Redmi 9C will add a new level of protection. The app will analyze the incoming call in real time and check the number against the online database. If the number is marked as spam by other users, the call will be automatically rejected before the phone starts ringing.
However, this method has a downside: such applications require access to your phone book and call history. This poses certain risks to the confidentiality of your data. In addition, the background operation of such apps can quickly drain the battery of a budget smartphone.
- 📥 Download a proven application from Google Play.
- 🔐 Provide the necessary permissions for operation.
- ⚙️ Adjust the level of blocking aggressiveness.
- 🗑️ Regularly update spam databases.
Alternative to third-party applications
Instead of installing heavy apps, you can use the Caller ID function from your mobile operator, which is often available in your personal account.
What to do if the number is blocked erroneously
Sometimes it happens that an important contact accidentally gets blacklisted, or you yourself activate the blocking mode for all unknowns and then forget about it. As a result, you may miss a call from your employer or emergency services. Restoring access for a specific number is very simple.
Return to the application Security and open Black list. Here you will see a complete history of all blocked calls and a list of numbers that are banned. Find the desired number in the list, click on it and select the option Unblock or the trash can icon to remove from the list.
If you enabled the “Block all unknowns” mode, simply disable this toggle switch in the antispam settings. After this, the phone will again begin to receive calls from any numbers, but the spam will also return. Therefore, it is better to use targeted unlocking by adding important numbers to the white list or simply saving them to contacts.
Is it possible to block a number if it is not displayed in the log?
If the number is not displayed in the log (for example, there was one beep), you can manually add it to the black list through the Security application menu by clicking the "Add" button and entering the numbers independently.
Will the caller know that he is blocked?
The subscriber will not receive direct notification. For him, the phone will simply buzz for a long time or drop the call, simulating a situation when you do not pick up the phone or are busy.
Are SMS from blocked numbers blocked?
By default, adding to the blacklist blocks both calls and SMS. However, in the black list settings, you can separately manage these functions, leaving the ability to receive messages.
Are blocking settings reset when updating the software?
Usually the list of blocked numbers is saved in the device memory and is not reset when updating the MIUI system, but it is recommended to take a screenshot of the important list before major updates.
How to block an entire city or country code?
There is no such function in the standard MIUI firmware. To block by mask (for example, all numbers +7 495...) you will need to install third-party applications with advanced functionality.