Xiaomi’s modern smartphones offer a wide range of features that allow you to stay connected even in unstable cellular coverage. One of the most useful but often hidden features is the ability to make voice calls over a wireless Internet connection, an option that is especially relevant for residents of country houses, thick-walled office buildings or basements where base station signal is almost nonexistent.
VoWiFi (Voice over Wi-Fi) technology transmits voice traffic in the form of batch data, which ensures high sound quality and connection stability. Redmi and Poco users often do not know that their devices support this feature at the hardware level, but it can be blocked by software or a carrier. In this article, we will discuss in detail all the nuances of activation and configuration of this feature.
Before you start technical manipulation, you need to make sure that your tariff plan and SIM card support voice transmission through the Internet. IP-Many operators are gradually implementing this service, so even with a compatible smartphone, the function may not work without first requesting from the provider.
Verification of device and operator compatibility
The first step is to verify that your carrier supports the technology, and not all mobile providers have deployed VoWiFi infrastructure, and the list of compatible companies is constantly updated, usually on the operator's official website or in the subscriber's personal account in the service section.
The second important aspect is the model of your smartphone: flagship Xiaomi Mi, Xiaomi 11/12/13/14 and many Redmi Note series models of recent years have the necessary modules, but in budget devices or regional versions of firmware (for example, the Chinese CN instead of the global Global), the software may not contain the necessary scripts.
Also worth paying attention to is the version of the firmware MIUI or HyperOS. Outdated software may not contain current operator profiles, which will result in the absence of an item on the menu. Updating the system to the latest available version often solves the problem of disappeared settings.
Standard activation through smartphone settings
If your carrier supports the service and your phone is in Wi-Fi coverage, activation usually takes a few seconds, and you need to go to the standard device settings menu. The path may vary slightly depending on the version of the shell, but the logic remains the same for all models of the brand.
Open the Settings app and find the Connections and Sharing section or SIM-In some versions of the interface, the desired item is placed in a separate Wi-Fi call menu located immediately below the wireless switch.
When you turn on the status bar next to the Wi-Fi indicator, you should see a phone handset icon that says Wi-Fi or similar, which indicates that the phone is registered with the operator via an Internet channel and ready to make calls. If the icon does not appear, try restarting the device.
☑️ Activation checklist
Hidden settings and engineering menu
In situations where the standard path does not lead to the desired result, you can use hidden system settings. This requires caution, since changing unfamiliar parameters can affect the operation of other functions. Access to advanced features is often through special code or an engineering menu.
In the Calling app, dial ##869434## or #4636##. In the Phone Information menu that opens, find VoWiFi Carrier Provisioning or Wi-Fi Calling preferences, and you can force support to be enabled here, even if it is hidden by the operator.
⚠️ Note: Making changes to the engineering menu may cause Work device instability. Write down the initial values of the parameters before changing them so that you can return everything back if necessary.
Another method involves using the Activity Launcher app, which allows you to run hidden system activities. Find activity associated with com.android.phone that contains the word WifiCalling. Running this component can open a hidden settings menu that is not available through the standard interface.
What to do if the engineering menu is empty?
Configure with the Mi SIM Toolkit application
Some operators require a special profile or service activation through a proprietary app. On Xiaomi smartphones, this is often the responsibility of the built-in MI SIM Toolkit or Services & feedback app. Check for such an application in the Tools folder.
Inside the app, select your carrier and find the section dedicated to additional services, and it can be "Configure VoWiFi" or "Activate calls over Wi-Fi." USSD-request SMS to the operator server to configure your SIM card.
If the automatic setting does not work, manual settings may be required. APN. Go to Settings. → SIM-maps and mobile networks → Access points (APN). Select an active access point and check if there is a Protocol field. APN. It must be established in the meaning IPv4/IPv6.
Comparison of VoLTE and VoWiFi technologies
Users often confuse two similar technologies, but they do not solve the same problems. Understanding the difference will help to properly configure the smartphone and avoid problems with communication quality. Both technologies use batch data for voice, but delivery channels are different.
VoLTE (Voice over LTE) is a fourth-generation (4G) voice transmission that provides fast connectivity and the ability to use the internet and phone simultaneously, but in 2G/3G coverage or no cell tower signal at all, VoLTE is useless.
VoWiFi uses any Internet access available, whether it’s a home router or a public hotspot, and is the perfect solution for dead-zone spaces. Below is a table comparing the key features of these technologies for Xiaomi devices.
| Characteristics | VoLTE | VoWiFi |
|---|---|---|
| Transmission channel | 4G/LTE cellular network | Internet (Wi-Fi) |
| Dependence on the tower | Tall. | Not available (only router needed) |
| Sound quality | HD Voice | HD Voice (depends on Internet speed) |
| Traffic consumption | Not charged (usually) | Not charged (minutes are on the tariff) |
| Roaming work | Depends on the operator's agreement | It works like a home network (savings) |
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Use the Wi-Fi Preference mode in your call settings if you are at home, which will save battery life, as your smartphone will not have to constantly search for cellular signal in blind areas.
Solving Connection Problems and Errors
Even when set up correctly, there may be failures, most often network conflicts or incorrect date/time settings, and make sure that the device has AutoTune Time, as VoWiFi security certificates are sensitive to desynchronization.
If the icon appears and disappears, try forgetting the Wi-Fi network and connecting again. Sometimes routers with IPv6 enabled may conflict with the operator's settings. Try temporarily disabling IPv6 in the router's settings or changing the DNS to 8.8.8.8 in the Wi-Fi settings on your phone.
In some cases, network resets help. Go to Settings → Connections and Sharing → Reset Wi-Fi, mobile networks and Bluetooth. This action will remove stored Wi-Fi passwords, but often eliminates software errors of the communication stack.
⚠️ Note: If you reset your network settings, you will lose all saved Wi-Fi passwords to other Bluetooth devices. Make sure you remember passwords from important networks before performing this operation.
The Impact of Function on Autonomy and Safety
Using Wi-Fi calls can affect battery consumption in different ways. In a weak cellular signal (1-2 division), VoWiFi activation significantly prolongs battery life, since the GSM module ceases to constantly amplify the signal to search for the tower.
However, if you are in the zone of excellent 4G/5G reception and the Wi-Fi signal is unstable, the phone will constantly switch between networks, which can increase charge consumption.
From a security perspective, the connection is protected by encryption protocols similar to banking ones. The operator does not hear your conversations through the Internet provider, since traffic goes through a secure tunnel directly to the operator's gateways. Using public Wi-Fi networks with authorization (via SMS or web page) can interfere with the function.
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Wi-Fi calls are not only a way to communicate in the wilderness, but also an effective tool to save battery power when a poor cellular signal is used.