Modern Xiaomi smartphones, working on the basis of shells MIUI HyperOS, or HyperOS, by default have a well-thought-out interface that visually highlights the active number during an incoming or outgoing call. However, users often experience a situation where the screen is locked, the notification has disappeared too quickly, or in the call history it is not clear from which number the call was made. SIM-maps where the separation of communication flows becomes critical to cost control and availability.
Understanding how the system tags calls not only saves money, but also enables smart communication, separating work and personal contacts. In this article, we’ll take a look at all the ways you can identify an active number, from standard interface settings to hidden engineering menus and third-party utilities. Visual display is just the tip of the iceberg, and knowing the deep settings will give you complete control of the device.
It’s worth noting that the multi-sim algorithms may vary slightly depending on the operating system version and regional firmware (Global, China, EEA).However, the basic principles remain the same across the Redmi, Poco and Xiaomi ecosystem. We’ll look at both the standard tools and specific codes that will help resolve any doubts about where your call is currently going.
Visual indication in the call interface
The most obvious and quick way to identify an active SIM card is to pay attention to the phone app interface during dialing or conversation. Xiaomi developers have implemented clear color coding and text tags to minimize user errors. When you dial a number, under the input field or next to the call button, a signature is always displayed indicating which one is the right one. SIM-The card will be used for connection.
In most cases, the system uses color differentiation: the first SIM card is often marked in blue or orange, and the second is marked in green or yellow, although these colors can vary depending on the theme of your choice. If you make an outgoing call, a pop-up notification or a static plaque with text like “SIM 1” or “SIM 2” will appear before the screen beeps, which can be switched before the connection begins. When the incoming call, the operator’s network name or the SIM-1/SIM-2 label is displayed at the top of the lock screen, right above the contact name.
For those who often forget to prioritize, there is a useful force selection feature: If the settings don't have a "always ask" rule, the phone will use the default SIM card for voice calls, and you can check this by opening your call history: next to each number on the list will be a small "1" or "2" icon, or a corresponding color indicator that shows which line the conversation took place, which allows you to retrospectively analyze whether you accidentally called from your work number to your personal.
⚠️ Note: In some custom design themes downloaded from the GetThemes store, SIM card visual indicators can be hidden or replaced with unreadable icons. If you don't see the tags, try temporarily switching to the standard Classic or Default theme in the screen settings.
Also, at the top of the screen, in the status bar, there are always signal level indicators on the screen, and during a conversation, one of them can change state (for example, display a conversation timer or an active microphone icon), which also indirectly indicates an active line. However, you should not rely only on the status bar, since in the standby mode, it simply displays the signal level of both networks simultaneously without reference to a specific action.
Setting priorities and labels in MIUI and HyperOS
Deeply adjusting the behavior of SIM cards is done through the system menu, where you can rigidly fix the rules for using numbers, which eliminates the need to look at the screen every time and guess which card is active. To get to the desired section, go to Settings, then select the item SIM-Maps and mobile networks. This is where you have the control center for all the communication flows of your device.
In this section, you'll find the default for calls. Here you can choose from three smartphone behavior strategies: the first is "Always Ask" when the phone will display the dialog box before each call; the second and third are the forced choice of "SIM 1" or "SIM 2." Choosing a specific default number ensures that you never accidentally call from the wrong card unless you manually switch the settings first.
To make navigation even easier, the system allows you to assign your own names to SIM cards. Instead of abstract "SIM 1" and "SIM 2", you can prescribe "Work", "Personal", "MTS" or "Beeline" and these names will be displayed in all interfaces, including the lock screen and call history, which makes it much easier to identify. The renaming process takes a few seconds: click on the card name in the settings menu and type in the desired text.
☑️ SIM card setting
It is also important to consider the function “use”. SIM-Although it does not directly affect voice calls, users often confuse the active SIM card for data and for calls. It is important to understand that these are independent settings: you can talk on the first SIM card while the Internet is running through the second. In the settings menu, this is clearly divided, and the current state is always highlighted.
Use of the USSD-codes and engineering menus
For more advanced users who want to get technical information about the status of SIM card registration on the network, there are special ones. USSD-query and engineering codes, which allow you not only to see which card is active, but also to check the status of registration on the network, which is useful for communication problems. Standard carrier codes (e.g. *100# or *102#) only work to check the balance and tariff of a particular SIM card if it is selected to be called.
However, Xiaomi smartphones have access to a hidden engineering menu that provides detailed statistics. To get there, you need to type in the phone book code ##4636##. Once you enter the last character, the hidden “Testing” menu will open, where you need to select “Phone Information.” If you have two SIM cards, at the top of the screen will be tabs “SIM 1” and “SIM 2”.
Switching between tabs, you can see the details of signal strength (dBm), network type (LTE, 5G, GSM), connection status, and most importantly, registration status. If the Mobile Network field says Connected or Connected, the SIM card is active and ready to call, and if the Disconnected or Network Search status is the default one, you won't be able to make calls from that card.
What to do if the engineering menu is not opened?
Changing the settings in fields you don’t understand (such as your preferred network type) can cause you to temporarily lose communication. Use it only to view information. For the average user, the SIM Status tab is enough, where you can clearly see which card is registered in the operator’s network.
Analysis of the history of calls and detailing
The MIUI call log stores detailed information about each connection. If you missed the call and forgot which card you were talking from, the story will be your main assistant. Open the Phone app and go to the Recent tab. In the call list, each contact or number is accompanied by a small icon in the form of a number (1 or 2) or a color dot corresponding to the SIM card used.
When you detail a specific call (clicking on an arrow next to a number or a long tap), an event card opens, which can specify the time, duration and type of call (incoming, outgoing, missed). Some versions of the shell also display the operator name or the SIM card name, if it was set by the user, which allows you to quickly filter the calls in your mind without taking new actions.
For a deep analysis of costs and activity, you should ask the operator for details, this can be done through the operator's application or personal account on the site, in detail will indicate the exact time and date of all calls. By comparing the time of the call from the detail with the time in the smartphone log, you can determine with 100% accuracy which SIM card the connection went through, since operators do not see calls made through another SIM card of your phone.
| Method of verification | precision | Difficulty | Conditions required |
|---|---|---|---|
| Screen during the call | Tall. | Low. | Active screen |
| Call magazine | Tall. | Low. | Preserved history |
| Engineering menu | Technical | Medium | Knowledge of codes |
| Details of the operator | Absolute. | Tall. | Access to operator's LC |
There's also a nuance about redirecting calls, and if you're configured to redirect from one SIM card to another, the receiver's phone log will show the number of the person who was called initially, not your second number, but the details of the receiver operator will show exactly the number that was physically called, which is important to consider when analyzing the incoming numbers.
Third-party applications for call management
Xiaomi’s regular functionality is usually enough, but if you need more flexible management, such as automatic SIM-linked conversation recording or a complex switching scenario, you can turn to third-party solutions. Google Play Market features a variety of caller apps like Truecaller, Simple Dialer or CallApp.
These applications often have their own call log interface, which can be more informative than the standard one: they can display large SIM icons, use sound notifications ("Call with Sim 1") and keep separate statistics on each card, installing such an application allows you to replace the standard "caller", taking over all control of incoming and outgoing.
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When installing a third-party call on Android 10 and higher, the system will require you to allow access to your phone and contacts, and you may also need to manually select a new app as the “Default App” for calls in your system settings.
However, be careful: some applications may request excessive permissions. When choosing a “caller” from the store, pay attention to the rating and reviews. For most users, it is enough to simply install the SIM card switch widget to the desktop, if this feature is supported by the launcher, to always see the current status without logging into the menu.
⚠️ Warning: Third-party calling apps may conflict with proprietary battery optimization MIUI. If call notifications stop coming after installing a new call, add the app to the power saving exception list (“No restrictions”) in the battery settings.
Solving the problem of number determination
There are times when the phone is not behaving properly: tags are missing, calls are coming from the wrong card, or the system does not see the second SIM card at all. The first step should always be to reboot the device. This trivial action resets the errors of the Radio Interface Layer communication module and makes the phone re-register on the network, often returning the correct indication.
If the problem persists, check physical contact. Remove the SIM card tray, wipe the card contacts with soft cloth and make sure they are properly installed in the tray (the cut corner should match). Sometimes oxidation of the contacts or a loose landing leads to the system seeing the card unstable, which can cause the indication to disappear or "jump".
In rare cases, network resets help. This won't delete your personal data, photos or contacts, but will return all connection settings (Wi-Fi passwords, Bluetooth and APN settings) to factory values. Path to reset: Settings → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth. After this procedure, the phone will redeem carrier settings.
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If the SIM card indicators disappeared after the system update, check the design theme settings or reset the network settings - this solves 90% of the software interface glitches.