The situation of indoors not catching the cellular network, but stable Internet is available, is familiar to many smartphone owners. In such conditions, ordinary voice calls become impossible, interrupted or do not pass. However, modern Xiaomi devices, including the popular lines of Redmi and POCO, are equipped with VoWiFi technology, which allows you to make calls over a wireless network.
Using this mode significantly improves the quality of communication in areas with poor coverage of cellular operators, such as basements, office centers with thick walls or country houses. VoWiFi does not require the installation of third-party applications and uses your current phone number, charging according to the terms of your operator. This makes the technology an ideal solution for those who value stability of communication.
In this article, we will discuss in detail how to activate this option, what nuances exist in different carriers and what to do if the menu item does not appear, you will learn about the technical features of the protocol and get answers to frequently asked questions, which will allow you to stay connected even where the usual network is powerless.
What is VoWiFi Technology and How Does It Work?
Voice over Wi-Fi (VoWiFi) is the standard for voice calls over the Internet protocol. Unlike instant messengers, which create a separate communication channel, VoWiFi integrates directly into your smartphone's standard "bell ringer." To the other person, your call looks like a regular call, not a call through an Internet application.
The principle is that the voice signal is digitized and transmitted through the Wi-Fi hotspot to the servers of the carrier, which then routes the call to the general telephone network, which provides higher sound quality compared to traditional audio. 2G/3G comparable to HD-And the traffic is minimal, and often not charged at all.
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Make sure your router supports 802.11ac or higher standards to ensure minimal audio delay during a call.
It is important to understand the difference between VoWiFi and VoLTE. If VoLTE is transmitting voice over 4G/LTE networks, VoWiFi uses a wireless LAN. On Xiaomi smartphones, switching between these modes is automatic and invisible to the user, ensuring continuity of conversation when moving.
Verification of device and operator compatibility
Before you start settings, you need to make sure that your hardware and SIM card support this feature. Not all phone models and not all data plans allow you to use calls over Wi-Fi. The list of supported devices is constantly expanding with each update of the MIUI or HyperOS firmware.
Operators should be technically able to provide VoWiFi services in your region, and major Russian carriers have already implemented this technology, but conditions may vary, such as some cases requiring 4G support, even if the call itself is via Wi-Fi.
To check compatibility, follow the following steps:
- 📱 Make sure your smartphone is Xiaomi, Redmi or POCO has an up-to-date version of the firmware.
- 📡 Check if your plan supports VoWiFi (often free).
- 💳 Make sure the SIM card is not too old (preferably support) 4G/LTE).
- 🌍 Locate in a region where the operator provides VoWiFi coverage.
If you use a dual-sim device, the feature can only work on one of the SIM cards at a time, usually the one chosen for voice calls by default, which is limited by the modem and network resource allocation.
Step-by-step: how to turn on VoWiFi on Xiaomi
Activation of the feature on devices with a shell MIUI or a new HyperOS usually takes a few seconds. the settings interface may vary slightly depending on the version of Android and the regional version of the firmware (Global, China, Russia).
The standard activation path is as follows:
- Open the Settings menu of your smartphone.
- Go to Connections and Sharing (or just Connections).
- Find Wi-Fi Calls or Voice over Wi-Fi.
- Move the switch to the active position.
☑️ Activation checklist
After turning on the status bar (in the curtain or next to the network indicator), a special icon should appear. It can look like a phone tube with a Wi-Fi symbol or have a W signature. If the icon appears, then the system is ready to make calls over the Internet.
In some cases, especially on older firmware versions, the path may be different: → SIM-maps and mobile networks → Select a SIM card. → Wi-Fi calls. If you can't find this item, it may be hidden or disabled by your carrier.
Hidden settings and engineering menu
Sometimes the operator and the phone support the technology, but the menu item is hidden, so you can try activating the function through the hidden engineering test menu, and be careful when changing the settings in this section, as incorrect actions can affect the operation of the communication module.
To enter the test menu, open the Phone app and enter the code ##869434##. In the VoWiFi Carrier Check window, you will see the status of the check. If the check box is "VoWiFi carrier check was passed", everything is set up correctly. If there is no tick or there is a ban, you can try to remove the restrictions by selecting Disable VoWiFi carrier check.
Alternative codes for different models
When you change the settings in the engineering menu, be sure to restart the device, which is necessary to apply the changes at the modem level. If after the reboot the VoWiFi icon does not appear, try turning off and on In-Flight mode or re-registering the SIM card on the network.
Set up services for telecom operators
Even with the right phone setup, the service may not work if it's not activated on the carrier side. Each provider has its own connectivity features. Below is a table of current activation methods for the main carriers.
| Operator. | Activation command | Conditions | Tariffing |
|---|---|---|---|
| MTS | *111*158# | 4G support | At the rate. |
| Megaphone | Automatically. | Compatible smartphone | At the rate. |
| Beeline | *110*750# | 4G availability | At the rate. |
| Tele2 | In the annex | Support for VoLTE | At the rate. |
Please note that some operators may have the service activated by default for all subscribers with compatible devices. Other times require a confirmation via personal account or call to support. Always check the relevance of commands on the operator's official website, as they may change.
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Without an active service on the operator side, setting up the phone will not give a result - the VoWiFi icon will not appear.
Typical problems and ways to solve them
Users often find that all settings are correct but the function is not working, and one common reason is that they use custom or global firmware on devices designed for the Chinese market, which may require a change of region in the phone settings.
Try changing the region of the device to your carrier’s country (e.g. Russia, Ukraine, Kazakhstan). You can do this from the Settings menu → Advanced Settings → Region. After changing the region, the phone may need to reboot, and the SIM card settings menu may have the necessary switch.
⚠️ Warning: Changes in region may affect some system applications and ad integrations specific to the selected country.
Some router models have security or traffic filtering settings that block the ports needed to pass voice packets. Try temporarily connecting to another Wi-Fi network (such as sharing the Internet from another phone) to rule out hardware problems.
If nothing works, reset your network settings. This won't delete your personal data, but will return your Wi-Fi, Bluetooth and mobile network settings to factory values. Path to reset: Settings → Connection and Sharing → Reset Wi-Fi, cellular and Bluetooth.
Advantages and Disadvantages of Calling via Wi-Fi
VoWiFi has some advantages, but it also has some drawbacks, and the main advantage is the ability to call from dead zones where there is no cellular network, especially for residents of wooden houses, cottages or buildings with metal frames.
In addition, Wi-Fi calls often provide cleaner sound (HD Voice) and faster connection, and for travelers, this is the ability to call home numbers at home network rates while abroad, if the operator supports roaming via Wi-Fi (Wi-Fi Roaming).
- ✅ Stable communication in rooms with poor signal.
- ✅ High quality sound without noise or interruption.
- ✅ Saving battery power (search network) 3G/4G spend more energy).
- ❌ Dependence on the quality and speed of the Internet connection.
- ❌ Possible problems when switching between Wi-Fi and mobile network during a conversation.
Impact on the battery
The downside is the reliance on internet quality: If your Wi-Fi is overloaded (someone downloads large files or watches 4K videos), voice quality can deteriorate dramatically, delays or echoes, so it’s important to prioritize voice traffic in router settings (QoS), if available.