The modern rhythm of life dictates its rules, and quality communication becomes critical not only in the center of the metropolis, but also in remote areas or buildings with thick walls, a situation where the signal level of the cellular network drops to a minimum and the Internet over Wi-Fi is stable, is familiar to every smartphone owner, and it is at these moments that Voice over Wi-Fi technology comes to the rescue, allowing voice calls over wireless networks, bypassing the weak coverage of base stations.
Owners of Xiaomi, Redmi and Poco devices often wonder how to activate this feature, as it may be hidden in some regions or firmware. This technology, known as VoWiFi, provides high sound quality and allows you to stay connected even in basements or in the country, where the usual GSM-In this article we will discuss in detail all the nuances of the setting, possible errors and how to fix them for stable communication.
Before getting into the technical details, it’s important to understand that successful activation depends on three factors: your carrier’s support of the function, smartphone model compatibility, and system configuration. Integrating these components requires careful attention, especially if you’re using Global ROM or custom firmware. Let’s figure out how to turn your gadget into a reliable communication tool in any environment.
What is VoWiFi and how does it work on Xiaomi?
Voice over Wi-Fi is a voice-over-internet-based technology, similar to the way instant messengers work, but with integration into a standard phone book and dialer. The process is transparent to the user: you dial the number as usual, but the connection is established not through a cellular radio module, but through a Wi-Fi hotspot. This is especially true for Xiaomi devices, which often have powerful Wi-Fi antenna modules, but may have difficulty receiving a signal in certain LTE frequency bands.
The main advantage is that Wi-Fi calls are not charged as international roaming if you are abroad, but are connected to the local network of a hotel or apartment. MIUI and its successor HyperOS have built-in support for the IMS standard (IP Multimedia Subsystem), which is necessary for this function. However, activation often requires manual intervention or hidden settings, since telecom operators prefer not to advertise this feature, so as not to reduce the load on their base stations.
It is important to note that the quality of communication depends on the stability of the Internet connection. If your router is overloaded or the Wi-Fi signal is unstable, there may be delays or breaks. Critical condition is the support of IMS technology by your carrier on the server side, without which any settings on the smartphone will be useless.
Verification of support function operator and tariff
The first step towards stable communication is to verify the support of the service by your mobile operator. In Russia and CIS countries, major market players such as MTS, Beeline, Megafon and Tele2 have already implemented this technology, but the terms of its provision may vary.
For activation on the operator side, it is usually enough to send USSD-For example, in the application My MTS or My Beeline, you need to find a section with communication services and activate the item "Calls over Wi-Fi." Without this step, the Xiaomi smartphone will not physically be able to register on the network. IMS, This is a common mistake when users try to set up the phone, ignoring the need for activation on the provider side.
It is also important to note that some of the older SIM-The cards may not support the modern security protocols required for VoWiFi. SIM-The new card will be a must-have in the salon. Operators often change the cards for free or for a nominal fee, referring to upgrades to the new card. 4G/5G Standards that automatically include support for required profiles.
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Before setting up your phone, make sure to go to the operator's personal account and make sure that the Wi-Fi Calls or VoWiFi service is activated. Without this step, further action is meaningless.
Basic setting VoWiFi in the smartphone menu
If the operator has met all the conditions, we move on to the configuration of the Xiaomi device. SIM-For the cards and firmware, the system will automatically prompt the function to be activated when a weak signal is detected on the cellular network.
The standard activation path is as follows:
- 📱 Open the Settings app and go to the section SIM-maps and mobile networks.
- 📡 Choose. SIM-The card you want to include a function for (if there are two of them).
- 📞 Find the Wi-Fi Calling (or Wi-Fi Calling) switch and activate it.
- 🌐 In the preferences menu that appears, select Prefer Wi-Fi or Always use Wi-Fi.
Once turned on in the status bar, a corresponding icon should appear next to the network indicator, often denoted as VoWiFi or a phone icon with a Wi-Fi symbol. If the switch is missing, this may mean that your current firmware does not contain configuration files for your region or operator, in which case a deeper intervention in the system will be required.
Remember that when switching between Wi-Fi and the mobile network during a conversation, modern Xiaomi smartphones support handover technology, which allows you to not interrupt the connection. However, for stable operation of this feature, it is recommended to choose a mode in the priority settings that firmly fixes the call to the current type of connection before it is completed.
☑️ Checklist of basic settings
Activation of hidden functions through the engineering menu
In situations where a standard switch is not in the MIUI interface, you can use a hidden engineering menu, which requires caution, since changing the wrong parameters can lead to unstable operation of the communication module. To enter the test menu, you need to open the Phone application and enter a special code.
Get a team on it.
##86583##This command activates a hidden switch to check for carrier provisioning. After you enter the code, you should see a pop-up notification that the feature is on (or off if it was already active). If the code does not work, try an alternative option for some versions of HyperOS:
##869434##Entering this code should remove the words "VoWiFi carrier check was disabled", which means activation of the check and the ability to use the function.
After successfully entering the code, return to the settings SIM-Often, after this procedure, there is a missing menu item to enable calls over Wi-Fi. If the item does not appear immediately, try to restart the device or turn on and off flight mode. This will force the modem to re-register on the network with updated settings.
⚠️ Warning: Do not change other options in the engineering menu unless you are sure of their purpose.Resetting the radio module settings can lead to temporary loss of communication or inability to determine the function of the radio module. SIM-map.
There's also an activation method available through the Activity Launcher app in the Play Market, which can help you find hidden activity that controls your IMS settings. Find an activity called imssettings or ImsService and run it, and it opens up an extended menu where you can force VoWiFi to be enabled and adjust the behavioral factors of the module.
Solving the problems with the disappearance of the VoWiFi icon
Even after setting up properly, users may find that the VoWiFi icon is missing or not appearing at all. One common reason is the conflict between network modes. If the mobile network settings are set to 4G Only or 5G Only, the Wi-Fi calling function can be blocked, as it is closely related to VoLTE. Network mode is recommended to set LTE or 5G/LTE/3G/2G (auto).
Another common problem is the use of two SIM-On many Xiaomi devices, VoWiFi only works on one SIM card at a time, usually the one chosen for data transfer. If you have two SIM cards from different carriers, try temporarily disabling one of them and checking for an icon. SIM-mobile-internet maps.
The table below shows the main symptoms and ways to eliminate them:
| Problem. | Possible cause | Decision |
|---|---|---|
| The badge doesn't show up. | Not activated by the operator | Check your personal account and tariff |
| The sound is intermittent | Weak Wi-Fi signal | Get closer to the router or change the frequency to 5 GHz |
| Challenge is dropped | Conflict with VoLTE | Try to disable VoLTE in SIM settings |
| No item on the menu. | Firmware locking | Use engineering code or Activity Launcher |
The impact of roaming on VoWiFi
Specifics of operation in flight mode and roaming
Using VoWiFi in travel is a powerful saving tool, and the way it works is you turn on flight mode, disabling all radios, and then manually switching on only Wi-Fi. In an ideal scenario, the phone registers with the operator's network via an Internet gateway. However, in practice, Xiaomi may require a minimum cellular signal for initial IMS authentication.
If you're in an area where a foreign carrier has a cellular network, but it's expensive and Wi-Fi is free, it gets interesting. You can leave the mobile network on, but in the Settings settings -> SIM-maps and mobile networks -> Data roaming is mandatory to disable data transmission. With active VoWiFi, calls will go over the Internet without spending minutes of the main package and without activating paid roaming, if the operator supports this logic of operation.
It is important to monitor the behavior of the smartphone when switching networks. If you are leaving Wi-Fi coverage, the phone may try to switch the call to the roaming operator's cellular network, which will lead to significant costs. To avoid this, some users recommend that you complete current conversations before leaving the Wi-Fi zone.
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In international roaming, Flight + Wi-Fi Calling is the safest way to stay connected, but always check your fare terms for paid incoming/outgoing communications, even over Wi-Fi.