Modern smartphones Xiaomi, Redmi and POCO They are equipped with advanced communication modules that allow you to simultaneously use two SIM-This is incredibly convenient for separating work and personal calls, as well as saving on tariffs from different operators, but in some situations it is necessary to temporarily or completely disconnect the second line to avoid unnecessary roaming costs or reduce the power consumption of the device.
The deactivation process can vary depending on the version of the MIUI shell or the new HyperOS. Users often find that standard settings are hidden or moved by developers. In this article, we will discuss in detail all available ways to manage SIM cards, including hidden engineering menus and call settings.
Understanding the Dual SIM module will help you manage communications flexibly, not only disable an unnecessary number, but also set priorities for mobile Internet and voice, which will significantly improve the experience of using the gadget.
Standard methods of SIM-card management in MIUI
The most obvious and safe way to disable the second line is to use the operating system's standard interface, and to do that, you need to go to the Settings section, which is usually represented by a gear on the home screen or in the notification curtain, and here is the control center for all components of the smartphone.
In the menu you should find the item SIM-Maps and mobile networks. In some versions of firmware, this section may be called simply Two SIM-You'll see a list of all the cards that have been installed with switches in front of each one, and moving the slider to an inactive state instantly blocks the card from being registered on the operator's network.
Note that when one card is disabled, the system will automatically redirect all traffic and voice calls to the remaining active line, unless otherwise prioritized, allowing communication to be maintained using only one number, without the need to physically remove plastic from the tray.
All data will remain intact and will be available immediately after reactivation, which distinguishes software disabling from a complete reset of network settings.
Setting Challenge Priorities and the Internet
Often users want to not completely disable the second line, but only limit its functionality, for example, to prohibit the use of mobile Internet through it. MIUI It has a flexible traffic distribution system, and you can choose which one. SIM-The card will be responsible for data transmission in networks 4G/5G.
To change the settings, go to the menu Use SIM-You can set the default card for voice calls and you can set the default card for mobile Internet, and if you set "Always Ask" for calls, the smartphone will tell you which number to dial from, which is convenient when you have tariffs with free minutes on different networks.
- 📱 Main card: used for all default operations unless otherwise selected.
- 🌐 Internet: You can easily get one SIM, So that the second one doesn’t waste traffic.
- 📞 Calls: Setup allows you to divide outgoing calls by contacts or groups.
Also available in this section is the "Use mobile data for calls when Wi-Fi." If activated, if the signal is poor Wi-Fi smartphone can use the second line to ensure the quality of communication (VoWiFi or just switch to LTE).
💡
To the second SIM-card does not consume battery power in the area of poor reception, disable the 5G network search settings for it, leaving only 2G/3G.
Using an engineering menu to turn off the line
For advanced users who don’t have the standard options, there is an Android engineering menu that allows you to control the radio module at a deeper level, so to log in, open the Phone app and type in the combination ##4636##.
If the code is working correctly, the Testing menu will open, where you need to select Phone information. This displays technical information about the network status. In some Xiaomi firmware, this entry can be blocked by the operator or manufacturer, then you will need to install a special application dealer from the Play Market store.
Inside the phone information section, you can find a Turn off radio switch, and activating that switch completely disables the radio module for the slot you select. SIM-maps, but are executed programmatically.
⚠️ Warning: Be extremely careful in the engineering menu. Changing unknown parameters can lead to unstable operation of the communication module or complete disappearance of the network.
After making changes to the engineering menu, it is recommended to restart the device so that the new settings are applied correctly and there are no conflicts between the active processes of the radio module.
Controlling the second line through call settings
Special attention should be paid to adjusting the behavior of the second line directly during making calls. The phone app has its own settings that can overlap the system. Press three dots or a gear in the dialing interface.
In the Call Settings -> In addition (or SIM Accounts), you can set the rules for each SIM, for example, you can turn off the second line in quick access if you rarely use it, leaving it active only for incoming.
Some users confuse disconnection of the line with switching standby mode. It is important to distinguish these concepts: in standby mode, the second SIM is simply not used for outgoing, but accepts calls.
☑️ Check before disconnecting the line
Also, call settings often hide the "Disallow Calls" function, which allows you to limit outgoing calls from a particular location. SIM-It's a useful compromise for those who only want to take calls to number two.
Comparison of disconnection methods: table of possibilities
To make it easier for you to choose the right way to control the second line, we have prepared a comparison table that shows the differences between software shutdown, flight mode for one card, and priority settings.
| Method | Impact on the battery | Availability for calls | Traffic consumption |
|---|---|---|---|
| Complete shutdown in settings | Minimum | Unavailable. | No. |
| Disable only data | Average. | Available. | No (wi-fi only) |
| 2G mode only | High (network search) | Available. | Minimum |
| Engineering menu (Radio Off) | Minimum | Unavailable. | No. |
As you can see from the table, completely disconnecting through settings is the most energy-efficient way if you don't need a second line right now. 2G mode can, on the contrary, discharge the phone faster in areas of uncertain 4G/5G reception, as the module will constantly try to find the best signal.
Problems with displaying the second SIM-map
Sometimes users are faced with a situation where the second line disappears from the active list or becomes gray (inactive) without the ability to turn on, this can be caused by a software failure of the MIUI shell or physical contact.
First of all, try rebooting your smartphone. It's a standard procedure that eliminates up to 80 percent of the time-sensitive software errors. If that doesn't work, check if the card is properly installed in the tray. Even a microscopic shift can lead to loss of contact.
In rare cases, the problem lies in the SIM-Older Mini-SIM cards, trimmed with Nano-SIM, may not work smoothly, and the operator may block the card if there is a long absence of activity or when trying to install in someone else's device (IMEI-lockdown).
⚠️ Attention: If the second SIM-The card is no longer defined after the system update, do not rush to reset to factory settings. Try first to move the cards to neighboring slots (if there are two physical) or wipe the contacts with a pin.
For diagnosis, you can try to establish a problem SIM-If it doesn't work there, it should be done in the operator's cabin, not in the phone's settings.
What to do if the 4G/LTE badge is missing?
Optimizing energy consumption with two SIMs
The use of two active lines inevitably leads to increased battery consumption, and the communication module is forced to maintain registration in the network for two numbers at once, which creates an additional burden on the processor and the radio part.
To minimize power loss, it is recommended to turn off the second line at night or in areas where no operator has network coverage. Constant search of the network in the “dead zones” (basements, rural areas) can discharge the phone in a few hours.
Also worth paying attention to is the Adaptive Connection feature (if available in your firmware version) which allows the phone to automatically switch between the two. SIM-cards to provide better communication quality, but can consume more resources.
- 🔋 Energy saving mode: limits background activity of the second SIM.
- 📡 Network Search: Turn off automatic network selection in roaming by manually selecting a carrier.
- 🔕 Notifications: Turn off audible notifications for new messages for the second line if they are not important.
Proper configuration allows you to extend the battery life of the Xiaomi smartphone by 15-20%, which is especially important for long trips.
💡
The most effective way to save charge with two SIMs is to completely programmatically disable an unused card during periods of low activity.