Modern smartphones of the Redmi i Xiaomi line have long become the standard for users who need support for two active numbers. The ability to have personal and work phones at hand in one case is not just a convenience, but a necessity for many. However, the interface of the shell MIUI or the new one HyperOS can confuse a beginner, especially when it comes to fine-tuning communication priorities.
The process of switching SIM cards on Android in Redmi devices is not limited to just choosing a card for a call. The user has to deal with the separation of data streams, setting up roaming and managing notifications from different operators. An incorrect configuration can lead to the fact that the Internet will be consumed from a tariff where there is no unlimited package, or important calls will be missed due to a weak signal on a currently inactive line.
In this article we will analyze in detail the configuration algorithms, hidden menu options and ways to resolve typical conflicts between operators. You will learn to instantly change priorities right while dialing a number and optimize the operation of the device for maximum autonomy.
Basic setup of cards in the smartphone menu
Primary configuration occurs immediately after installing the modules in the tray. The system automatically recognizes inserted Nano-SIM and will offer to assign names to them, for example, “Work” and “Personal”. This is a critically important stage, since these are the labels that will be displayed in the notification shade and when selecting an operator for a call.
To access the main settings, you need to go to the section Settings and select the item SIM cards and mobile networks. Here is a summary dashboard where you can see the status of each card, signal level and current tariff plan. The interface allows you to flexibly manage settings without the need to reboot the device.
Particular attention should be paid to the “Default card” field. In modern firmware versions, this parameter is divided into two independent categories: “Calls” and “mobile data”. You can set a constant priority for one card or leave the Always Ask mode, which will force the phone to ask for a choice with every action.
⚠️ Attention: If you are using a card with 5G support, make sure that the high power consumption mode is disabled in the settings of the second card, otherwise overheating and rapid battery drain may occur when two radio modules are used simultaneously.
☑️ Check basic settings
Prompt switching during a call and in the curtain
A common situation: you have configured the main card for the Internet, but you need to call on the second line. Smartphones Redmi implement a convenient quick access system. Right in the dialing interface, next to the call button, the icon of the currently selected SIM card is displayed. Clicking on it instantly changes the priority for a specific call.
A similar mechanism is available through the quick settings panel, which can be called up by swiping down from the top edge of the screen. The network management widget allows you to switch mobile data from SIM 1 to SIM 2 with one tap. This is especially useful if one of the operators has temporarily lost the signal in your location.
It is important to understand the difference between temporary and permanent switching. If you change the card in the dialer menu, the next call will again go through the card that is set as the main one in the global settings. The system does not remember one-time changes for future operations unless a special mode is activated in the developer options.
- 📞 The handset icon with a number shows which line the current call will go through.
- 🌐 The antenna icon in the curtain indicates the active card for data transfer.
- ⚙️ Long Clicking on the network widget opens the full operator settings menu.
Setting Internet priorities and saving traffic
The most critical parameter for most users is the choice of card for data transfer. A mistake here can cost money if you activate the Internet on a card with an hourly rate or without package traffic. In the menu mobile data the system allows you to firmly assign one card or leave the choice to the user.
The “Mobile data switching” function deserves special mention. If you activate this option, then if there is no Internet on the main card (for example, in an area of poor coverage), the phone will automatically use the second SIM card. This ensures continuity of the connection, but requires caution.
To control costs, it is recommended to set traffic limits. In section Traffic You can set the limit value in gigabytes for each SIM card separately. When the threshold is reached, the system will automatically turn off data transfer or warn the user with a notification.
Settings → SIM cards and mobile networks → mobile data → Select card⚠️ Attention: The function of automatically switching the Internet to the second card may activate data roaming if you are in a border area. Always check the tariff conditions before enabling this option.
Set different wallpapers or themes for SIM card profiles in the settings to visually distinguish which line is currently active if the icons in the status bar are too small.
Manage notifications and contacts for different lines
Chaos in messages - a common problem for owners of two rooms. When SMS from the bank and spam from the operator arrive in the same pile, it’s easy to miss important things. The shell MIUI allows you to sort messages, visually linking them to a specific SIM card.
In the Messages application, each incoming message is marked with a color or signature corresponding to the name of the SIM card. In addition, you can customize notifications so that the sounds differ for different cards. This allows you to identify the sender without even taking the phone out of your pocket.
For calls, there is a function of assigning contacts to a specific SIM card. When creating or editing a contact in your address book, you can select Preferred SIM. Now, when you click on the subscriber's name, the call will always be initiated through the desired number, ignoring general settings.
| Setting type | Where is located | Impact on operation |
|---|---|---|
| SIM card name | Settings SIM | Display in the contact list and journal |
| Notification sound | Message settings | Audio identification of incoming SMS |
| Preferred SIM | Contact card | Automatic line selection for calls |
| Traffic limitation | Traffic menu | Blocking the Internet when the limit is exceeded |
How to hide the number of the second SIM card?
In the call settings, you can activate the "Hide number" function for each SIM card separately. This is useful if you call clients from a business line, but do not want to advertise your corporate number.
Solving problems with detection and switching
Sometimes users are faced with a situation where the phone sees only one card, or switching occurs with a delay. Most often, the reason lies in physical contact or outdated software. The first step should always be to reboot the device, which clears the radio module errors.
If the problem persists, check the SIM card tray. On models Redmi with a hybrid slot, the second card may not be installed correctly if an adapter is used. Make sure that the contacts on the card itself are not oxidized and that the chip has no visible damage.
In rare cases, resetting the network settings is required. This action will delete saved access points APN and Bluetooth pairs, but often resolves software conflicts between operators. Path to function: Settings → Connection and sharing → Reset Wi-Fi, mobile networks and Bluetooth.
- 🔧 Clean the contacts on the SIM card chip with a soft eraser or alcohol wipe.
- 🔄 Swap the SIM cards. in the tray to eliminate a malfunction of a specific slot.
- 📡 Make sure that your operator (frequencies) are supported by this phone model.
⚠️ Attention: Resetting network settings does not delete your personal files, photos or applications. However, you will have to re-enter passwords for Wi-Fi networks.
In 90% of cases, the problem with the invisibility of the second SIM card is solved by simply rebooting or reinstalling the card in the off state.
Specifics of working in Dual 4G and VoLTE mode
Technology Dual 4G allows both SIM cards to simultaneously be on the fourth generation network. Previously, one card worked in 4G, and the second rolled back to 2G/3G, which led to problems with dialing. On modern Redmi this function is enabled by default, but it is worth checking.
The protocol VoLTE (Voice over LTE) is critical for high-quality voice communications. It allows you to have a conversation over a 4G network without a drop in Internet speed. Make sure that the “Allow VoLTE” checkbox is active for both numbers in the mobile networks menu.
It is worth noting that support for these functions depends not only on the phone, but also on the telecom operator. Even if everything is turned on in the phone menu, without the VoLTE service on the provider’s side, switching between modes may occur incorrectly, causing connection interruptions.
Why does 4G disappear on the second card?
If during a conversation on the first SIM card the second one loses 4G, it means that your phone does not fully support the Dual VoLTE mode, or the operator has not configured this function for your region.
Frequently asked questions (FAQ)
Is it possible to make the Internet work from two SIM cards simultaneously to increase speed?
No, standard Android and MIUI tools do not allow you to aggregate channels from two different operators to increase download speed. The phone uses only one active access point to transmit data at a particular time.
Why doesn’t the second SIM card ring when the first one is in conversation?
It depends on the network technology. If VoLTE is not enabled, then when the channel is occupied by the first SIM card, the second one may temporarily become unavailable (go offline). Enable VoLTE for both cards to solve this problem.
How to disable the second SIM card at night to save battery?
In the menu Settings → SIM cards and mobile networks there is a switch opposite each card. You can temporarily disable any of them programmatically without physically removing them from the device.
Does the use of two SIM cards affect the speed of the smartphone?
There is a minimal effect, since the processor and radio module process signals from two networks. However, on modern processors Snapdragon or MediaTek in Redmi, this influence is not noticeable in everyday tasks.
What to do if, after updating the firmware, the SIM settings have been lost?
Go to the SIM cards menu and re-select priorities for calls and the Internet. Sometimes after major updates, the system resets these parameters to default values for security purposes.