How to call from the second SIM card on Xiaomi: the complete guide

Owning a smartphone with two active SIM cards has long ceased to be a rarity and has become a standard for many users, especially in the CIS. Devices from Xiaomi, running the shell MIUI or the new HyperOS, offer flexible tools for managing calls, but the interface can sometimes confuse the beginner. The question of how quickly and convenient to make a call from the right number, remains relevant, especially when one SIM is used for work and the second for personal purposes or the Internet.

There are times when you need to contact a caller from a particular number, and fortunately, Xiaomi engineers have figured out several ways to do this: from manually selecting before each set to automating processes through default settings. Understanding the logic of the call system will allow you to avoid unnecessary costs on the tariff and not miss an important work call by mixing up the numbers.

In this article, we will take a look at all the available methods for switching between SIM cards, look at hidden settings and codes, and find out what to do if the second SIM suddenly stops communicating. You will learn how to set up automatic selection of SIM for different contacts and what nuances the modern Android shell hides on Redmi and POCO smartphones.

Basic methods of switching SIM cards when dialing

The most obvious, but not always obvious, way to do this is to choose a SIM card right at the time of dialing. In the standard Phone app, which is pre-installed on all Xiaomi devices, the dialer interface is designed to minimize unnecessary actions. However, if you're used to push-button phones or other brands, the location of controls may vary.

When you enter a number in the dial box, look at the bottom of the screen or the area next to the call button. It usually displays the current selected SIM card, often with the operator or number (such as "SIM 1" or the MTS logo). By clicking on this area, you will call a pop-up menu where you can instantly switch to a second SIM card before pressing the green handset, this action must be done every time there are no automatic rules.

• 📞 Click on the current SIM icon in the dialer to open the selection menu before the call.
• 📱 The contact list next to the subscriber name may also display the last used SIM, clicking on which changes the priority.
• 🔢 When dialing the last number again, the system often offers to select a SIM card if the previous call was made with a different default.

Importantly, some versions of MIUI have a Always Ask feature, which if activated, will force the phone to select a SIM card before every outgoing call, even if there is a call history for that contact, which can be annoying with high-intensity communication, but ensures that you don't accidentally call a personal contact from your work number.

SIM card setting by default for all calls

For those who prefer stability and don’t want to be distracted by the number selection before each call, the best solution is to install a priority SIM card, in which case all outgoing calls will be automatically initiated from the selected SIM, unless you manually change the setting at the time of dialing, which is especially convenient if 90% of your calls are made from one main number.

To set this up, you need to go to the system settings of the device. The path may vary slightly depending on the version of Android, but the logic remains the same: you need a section responsible for managing networks and connections. Here you will find the item "Sim cards and mobile networks", where you make a global setting of priorities.

In the Outgoing Calls menu, you will be given three options: always use SIM 1, always use SIM 2, or ask every time. When you choose a particular SIM, you will assign it to the main SIM card, but remember that this setting is global and does not take into account individual preferences for different contacts without additional settings.

⚠️ Warning: Make sure the default SIM card has a balance or a packet of minutes attached.If the main limit is exhausted, the phone will not switch automatically to the second SIM and the call will simply not pass or be interrupted.

Also available in this section is a mobile Internet setting, which, although it does not directly affect voice calls, it makes sense to set the same SIM card as a priority for data transfer if you have unlimited rates to avoid accidental traffic consumption from a paid SIM during background processes.

Individual settings for contacts and groups

A more advanced and convenient way to communicate is to link a particular SIM card to a specific contact, which allows you to automate the process: when you call your mom, the phone always uses a home SIM, and when you call the client, it uses a work one, which eliminates the need to look at the screen and select a number every time, reducing the risk of error.

You can do this directly from the Contacts or Phone app. When you open the caller card, you'll see the setting button or the SIM card icon next to the phone number, and when you click on it, you'll be asked to select which SIM to call that person by default, and once you save the settings, any call to that call will go through the selected link.

Unfortunately, stock versions of MIUI don't always allow you to assign a SIM card to a whole group of contacts (like Work or Family) in one action. You'll have to go through each number in the group individually, but there are third-party apps from Google Play that can manage call rules more flexibly, creating complex switching scenarios.

Use of the USSD-codes and hidden menus

For users who prefer to control through commands, there are special codes that allow you to quickly switch settings or check the status of SIM cards.-2» form USSD-There is no code (since this action initiates a call rather than configuring it), there are codes to manage the forwarding and status of the lines.

For example, you can use codes to quickly redirect all incoming calls from one SIM to another if you are in a bad reception zone, but this already applies to the operator’s network settings. To manage the device itself, Xiaomi provides an engineering menu that requires caution.

Entering the #4636## code opens the testing menu. Here, in Phone Information, you can see the detailed status of each SIM card, signal level and network type. Although you can't call from here, it's a great diagnostic tool if the second SIM is missing or not logging in, and you can try to switch your preferred network type or restart the radio module.

• 📡 Code ##4636## - Entering the engineering menu to diagnose the status of SIM cards.
• 📞 Code ##6484## — CIT Menu (engineering iron testing menu) where you can check the performance of the speakers and microphone of each SIM.
• 🔒 Redirect control codes (e.g. **21*) operate at the operator level and can redirect calls between SIMs.

Using third-party dialing apps like Truecaller or Google Phone (if it's not the default one) can add your own quick access codes or widgets to select a SIM card right on your desktop.This creates another layer of convenience, allowing you to call "one click" from the desired number via a shortcut.

⚠️ Warning: Be extremely careful in the engineering menu (4636) changing settings like "Set preferred network type" to the wrong value (e.g., "Set preferred network type, GSM Only in the zone 4G) This can cause communication loss. Write down the baseline values before making changes.

Problems with calls from the second SIM card and their solution

Often, users are faced with a situation where the first SIM works perfectly, and the second does not ring, although the network indicator is displayed, this can be caused by a conflict of VoLTE settings, standby features, or a software failure of the MIUI shell. Understanding the nature of the problem is the first step to fix it.

One common reason is the two SIM mode. If one SIM is busy talking in 2G/3G, the second may become unavailable (DSDS mode - Dual SIM Dual Standby). However, modern Xiaomi smartphones support technology that allows you to take calls to the second SIM during a conversation on the first, but only if VoLTE is enabled and this function is supported by the operator.

To check and enable this feature, go to Settings → SIM cards and mobile networks → Select SIM card → Use VoLTE. If the slider is active and the HD icon is on in the status bar, then the technology is working. If the icon does not appear, it is possible that your tariff plan or carrier coverage in this area does not support voice over 4G.

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If the second SIM is permanently losing the network, try changing its network type to forced 3G (WCDMA) in the settings, which in some regions with overloaded 4G will stabilize voice communication, although it will reduce the Internet speed on this SIM.

Also worth checking are the limitations in the Traffic Savings or Battery section, which can aggressively restrict the background activity of the second SIM to save energy, causing it to periodically fall off the grid, adding system processes responsible for telephone communication to the exclusion of energy saving can solve the problem.

Using widgets and third-party applications to manage calls

Xiaomi’s regular tools are good, but sometimes they don’t work well for complex use cases. There are many tools in the Google Play app store that extend the ability to manage two SIM cards, and allow you to create smart rules, widgets, and even automate scheduled calls.

One of the most useful tools is direct dial widgets, where you can put two separate icons on your desktop for one contact: one that only calls SIM 1, the other one calls SIM 2. This is perfect for people who often hesitate about which number is the most convenient to call from at the moment, and don't want to get in touch every time.

Autoresponders and secretaries have also learned to work with multisymnost. They can offer to send messages. SMS-A message of apology and an indication that you will call back from another SIM if the one you called is busy, which increases the level of communication and eliminates the need to dictate the number for feedback.

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Creating shortcuts-widgets for different SIM cards on the desktop is the fastest way to call from the right number without being distracted by the phone’s settings in the moment.

Frequently Asked Questions (FAQ)