Modern Xiaomi smartphones provide users with ample opportunities for voice communication, but the transition to fourth-generation networks is sometimes difficult. Many device owners face a situation when after turning on 4G calls do not pass or switch to 3G, interrupting high-speed Internet. Voice over LTE technology is designed to solve this problem, allowing you to conduct conversations with high sound quality without losing the packet connection.
In this article, we will discuss how to activate this feature on various models, from budget Redmi to flagship Mi. You will learn about hidden engineering menus, features of MIUI and HyperOS firmware, as well as ways to circumvent the restrictions imposed by carriers.
Before you start complex manipulations, make sure your device is physically capable of maintaining high communication standards, and compatibility testing is the first and most important step that is often ignored when trying to adjust incongruent parameters.
Checking the compatibility of equipment and SIM-card
The first thing to do is make sure your Xiaomi smartphone is technically LTE-enabled. Most current models released after 2016 have the modules they need, but regional versions may differ. For example, global versions (Global ROMs) often have a wider range of supported frequencies compared to Chinese counterparts.
The second critical moment is the SIM-If you use a card that was issued many years ago, it may not support the standards. 4G. In this case, no phone settings will help, and you will need to replace the plastic in the cabin operator, it is also important that the balance was connected to the appropriate tariff plan, as some operators require explicit activation of the service.
For quick diagnosis, you can use built-in system tools or third-party applications. Pay attention to the indicator at the top of the screen: if an incoming call is an icon 4G/LTE disappears and H appears+ or 3G, So the voice call is going through the old protocol.
- 📱 Make sure the slot is installed SIM-support-card 4G (These are usually Nano-SIM cards).
- 📡 Check coverage area: in some remote areas, network 4G It may be missing even if the phone supports it.
- 🔒 Make sure that the device is not installed custom firmware with stripped down radio modules.
- 💳 Contact the operator to clarify VoLTE support on your tariff.
It is worth noting that dual-sim modes also affect the availability of the feature. In some configurations, when the first SIM is actively spoken, the second one may temporarily lose network, which is a feature of the modem architecture, not a software bug.
Basic activation via the standard menu
In most cases, to enable the technology, it is enough to use the standard interface of the MIUI shell or HyperOS. Manufacturers try to simplify this process as much as possible, hiding complex technical settings from the average user.
To start, go to the basic settings of the device. Find the mobile networking section. The path may vary slightly depending on the Android version, but the logic remains the same: we need to get to the control. SIM-map.
In the menu that opens, select the active SIM card, and here you will see the switch that selects the network type you want, and that's where the key to solving the problem lies.
☑️ The basic configuration algorithm
If the use of VoLTE is missing or inactive, it may mean that the operator has not added your phone to the whitelist or the firmware does not contain the appropriate profiles.
⚠️ Note: If the switch is switched on HD Or VoLTE didn't appear in the status bar, so don't rush to reset. Sometimes it takes up to 5 minutes for a new type of network to log in.
It's important to understand the difference between just having 4G and having voice over it. A phone can show high Internet speeds, but calls can be made over 3G. Our goal is to bring those processes together.
Use of the Engineering Menu to Activate
When standard methods fail, the engineering menu comes to the rescue, which is a hidden part of the system that's designed to be used for testing by specialists, and you can force VoLTE support to be turned on even if the operator does not transmit the appropriate activation flag.
A special code is used to enter the diagnostic menu. Open the Phone app and dial the combination ##4636##. If the code is entered correctly, the Testing menu will open where you need to select Phone Information.
There's a lot of technical stuff inside this partition, and we're interested in VoLTE Provisioned, and if there's a tick next to it, it means the phone's ready to go. If it's not, activate it.
Path to the menu:
1.Type ##4636###
2. Select Phone Information
3. Find toggle "VoLTE Provisioned"
4. Activate the switchOnce you turn on the setting, restart the device, often enough to make the HD icon appear in the status bar, but newer versions of MIUI may not allow access to the menu.
- 🔍 The code may not work on some carriers or on newer versions of Android.
- 🔄 After changing the region in the phone settings, hidden items can appear automatically.
- 📵 Do not change other unknown options in the engineering menu to avoid loss of communication.
What if the code doesn't work?
Application of third-party applications and operator codes
In situations where embedded tools are blocked by the manufacturer, users resort to third-party solutions, and one of the most popular tools is the Activity Launcher app, which allows you to run hidden system activities.
The essence of the method is to find a specific system component responsible for setting the modem. SIM-maps and manually change configuration settings.
In addition, some operators allow the activation of the service through USSD-This is a less reliable way, as the settings can reset after rebooting, but it does not require the installation of additional software.
| Operator. | USSD-activation | Shutdown command | Status check |
|---|---|---|---|
| MTS | *111*370# | *111*371# | *111*370# |
| MegaFon | *150# | *150*0# | *150# |
| Beeline | *110*1881# | *110*1880# | *110*188# |
| Tele2 | Automatically. | - | Personal office |
Using third-party software requires caution, and applications with system settings can interfere with the radio module, which in rare cases leads to unstable communication.
⚠️ Note: When using Activity Launcher, be careful to change settings like "Preferred Network Type" to values not supported by your region (e.g., "Preferred Network Type, LTE Only, can lead to complete disappearance of the network and the ability to make emergency calls.
If you decide to use this method, be sure to write down the initial values of the parameters, in order to return everything as it was, if necessary.
💡
Before making changes to system configurations through Activity Launcher, take a screenshot of the current values of all switches, which will save time if you have to roll back the changes.
Setting up two SIM-maps and modes of operation
Xiaomi smartphone owners often use two SIM cards, which creates additional difficulties when configuring VoLTE. The logic of the modems is that in standby mode both cards can be on the 4G network, but during a conversation the second often goes to 2G/3G.
Technology DSDS (Dual SIM Dual Standby allows you to keep both cards online, but full VoLTE on both SIM cards at the same time (Dual VoLTE) is not supported by all models and not all operators. HD-The second line is waiting for the incoming.
To set priority, go to the settings SIM-You can choose which card will be used for mobile Internet by default and which for calls. 4G/LTE For both cards, if this option is available.
In some cases, temporary retrieval of the second SIM-After successfully activating VoLTE on the main card, you can insert a second card and check if the settings are still in place.
- 📶 Make sure both of you SIM-The cards are in slots with support 4G (These are usually both slots in modern Xiaomi).
- 🔄 Switch the mobile internet to that one. SIM-The card you want to activate VoLTE on, then back.
- 📞 Check if the “Call Through” function is working SIM 2" while we are talking about SIM 1.
- ⚙️ Enable the “Allow Data Switching” option for uninterrupted internet during a call.
It should be borne in mind that during an active conversation on VoLTE, the battery consumption may slightly increase, since the communication module operates in a more active data transfer mode.
💡
For stable performance of two SIM cards in 4G mode, make sure that your data plan allows the use of VoLTE, otherwise the second card will constantly switch to 3G during the conversation.
Solving common problems and errors
Even after setting up properly, users may find the VoLTE icon disappearing or communication becoming unstable, often because of a firmware update that resets the operator's configuration files.
One of the common problems is regional mismatches: If you bought a phone that was designed for the Chinese market and you use it in Europe or the CIS, the carrier profile may not load automatically, and that helps with changing the region in the phone settings.
Problems can also arise when using outdated versions of APN databases, cleaning the access point settings and creating a new configuration with current operator parameters often solves the problem of lack of Internet and VoLTE.
Instructions for APN resetting:
Settings ->SIM-Maps and mobile networks
2. Select SIM-map -> Access Points (APN)
3. Menu (three dots) -> Reset by defaultIf nothing helps, consider flashing the device to a global version of the software or installing specialized patches if you have sufficient technical knowledge.
⚠️ Warning: Flashing your phone or getting root permissions to make system changes will void the warranty.
Remember, the quality of communication depends not only on the phone settings, but also on the congestion of cell towers. During peak hours, the network can be congested, and the phone will automatically switch to a more stable, albeit slower, 3G.