Modern Xiaomi smartphones offer a wide range of functionality to improve communication quality, and one of the most useful but often hidden features is Wi-Fi calls. This technology allows you to make and receive calls over a wireless network, which is especially true in areas of low coverage of cell towers. Many users face a situation where the indoor network is not catching well, but home Internet is stable, and this is where Voice over Wi-Fi (VoWiFi) comes to the rescue.
Activating this option not only improves audibility, but also helps save battery power, since the device does not have to constantly search for a cell tower signal. However, despite the popularity of the technology, finding a switch in the MIUI or HyperOS shell is difficult due to differences in firmware and regional settings, in this guide we will examine all the nuances of activation, operator configuration and solving typical problems.
It is worth noting that the success of the procedure depends not only on the model of your gadget, but also on the support of the service by your mobile operator. SIM-The operator card and the tariff plan support voice transmission via the Internet Protocol. Without this condition, the phone settings will remain inactive or hidden from the user.
What is VoWiFi and why does the user need it?
VoWiFi (Voice over Wi-Fi) is a standard for voice calls over Wi-Fi networks using the Internet. IP-Unlike regular calls via messengers like WhatsApp or Telegram, it uses your regular phone number and the connection is established directly through the carrier’s servers. This means that the interlocutor at the other end of the wire does not even know that you are not in the range of the cell tower, and use a home router.
The main advantage of this feature is the stability of communication inside buildings with thick walls, where cellular signal hardly penetrates. For owners of Redmi and POCO smartphones, this is often the only way to stay connected in basements, business center offices or country houses. In addition, switching between Wi-Fi and the cellular network is invisible to the user during the conversation if you leave the coverage area of the router.
⚠️ Attention: The sound quality of Wi-Fi calls depends on the speed and stability of your Internet connection. If the network is congested with other devices, delays or interruptions may occur.
It is important to understand the difference between VoWiFi and VoLTE. If VoLTE is broadcasting voice over fourth-generation (4G/LTE) networks, VoWiFi uses wireless LAN. Both standards are packet switching but use different data channels. On modern Xiaomi devices, these functions often work together to provide seamless coverage.
Checking the compatibility of the operator and the tariff
Before you start complex manipulations in the menu of the smartphone, you need to make sure that your mobile operator provides VoWiFi service. In Russia and CIS countries, this technology is supported by almost all major market players, but the connection conditions may vary. For example, some operators have the service automatically connected, others require activation through a personal application or USSD-team.
For owners of Xiaomi devices, it is important to consider that the list of supported operators in the firmware for the global market (Global) is wider than in the Chinese versions (CN). If you use SIM-map of the Russian operator, but the firmware of the phone is Chinese, the settings menu may be hidden, in which case it may be necessary to change the region or install appropriate profiles.
- 📱 Megaphone: service is usually active by default, check through the application "My Megaphone".
- 📶 MTS: activation is required in the personal account or application "My MTS", support depends on the phone model.
- 🌐 Beeline: connection is free through a team or website, support from the device is required.
- 🚀 Tele2: option available on tariffs with the Internet, activated in the application.
It's also worth checking if the feature is blocked at the plan level.Some archival rates may not support voice transmission through IP. If in doubt, it is easiest to call your carrier’s support team and check whether VoWiFi is working on your phone. SIM-map and whether your phone model is compatible with their network.
Basic activation via the standard menu
In most cases, if the operator supports the technology and SIM-The map is correctly defined, you can turn on the function through the standard Android settings menu. MIUI or HyperOS has a built-in switch that becomes active automatically after detecting a compatible network. First, make sure your smartphone is connected to a Wi-Fi network, and mobile internet and Bluetooth can be enabled to more accurately determine the location.
Go to the settings section associated with SIM-The path may vary slightly depending on the version of the operating system, but the logic remains the same. You need to find the point responsible for the use of networks. If the operator is correct, you will see an active switch. In some cases, the system may offer to download the operator’s settings profile – agree to this action.
If the switch is turned on in the status bar, the corresponding icon (often a phone handset with Wi-Fi symbols) appears, then the function works. Now you can make test calls. To save traffic and improve quality, it is recommended to use a 5 GHz network if your router supports dual-band mode.
☑️ Checking baseline activation
Sometimes, once the function is turned on, the device needs to be rebooted, so that the phone can re-register on the operator’s network using the new voice protocol, and if the icon doesn’t appear after the reboot, you may need to manually adjust or reset the network settings.
Hidden settings and engineering menu
If a standard switch is not available, Xiaomi owners can use a hidden engineering menu, which is effective for phones where the operator is formally supported, but the profile is not automatically tightened, and a special code is used to enter the test menu, which opens access to the deep settings of the radio module.
Open the Phone app and dial the combination ##869434##. This code activates the hidden VoWiFi debugging mode. Once you type in, you should see a pop-up notification "VoWiFi check Carrier was disabled" or a similar message confirming the entry into mode. If the code did not work, try an alternative method through the Engineering Mode app, which can be found in standard tools or downloaded separately.
Actions after entering the code:
1. Enter the code in the bell.
2. wait for the pop-up notice.
3. Go to Settings ->SIM- Maps and Mobile Networks.
4. Select the desired SIM- card.
5. Find the item "Wi-Fi Calls" that appears.Changing the settings that are not associated with VoWiFi can cause the communication module to malfunction. Once the hidden mode is activated, return to the normal settings. SIM-There should be a new option that allows you to turn on Wi-Fi Calling, select "Prefer Wi-Fi" or "Automatic" mode, so that the phone chooses the best channel for communication.
⚠️ Note: The engineering menu is not available on all versions MIUI. New security updates may block access to this code from developers.
Configure via the Mi Carrier app
Another effective method, especially for Chinese-based devices, is to use the Mi Carrier system application, which is responsible for loading carrier profiles and configuring them, and if you don't have the right operator on the list, it's possible that the operator's profile is not loaded into the system.
To start, find the Mi Carrier app in the list of all programs. If it is hidden, it can be found through a search in the settings or activated through hidden settings (access to the hidden settings is required). ADB or special rights. You need to find the "Carrier Provisioning" section inside the application, or"IMS Settings. Here is a list of available profiles for your SIM-map.
| Parameter | Description | Recommended value |
|---|---|---|
| IMS Registration | Registration status in IMS network | Registered |
| VoWiFi Switch | Enabled | |
| E911 Status | Status of emergency calls | Active |
| Carrier Name | Name of profile operator | Your operator. |
If your carrier is not listed, you can try changing the region of the phone -> Advanced settings -> Region and select a country where your carrier accurately supports VoWiFi (such as India or one of the countries in Europe). SIM-And often the profile is uploaded after this procedure.
What if you don’t want to change the region?
Solving and eliminating errors
Even with the right setup, there can be situations where Wi-Fi calls don't work. Often the problem is network conflict or an outdated carrier profile. If you see an icon but the calls fail, try forgetting the Wi-Fi network and reconnecting by entering a password. It's also worth checking if Traffic Saving mode for system services is on.
In some cases, network resets help, and this action will bring all Bluetooth, Wi-Fi and mobile Internet settings back to factory values, but it won't affect your personal data. The path to reset: Settings -> Connection and Sharing -> Reset Wi-Fi, mobile networks and Bluetooth. After this operation, the phone needs to be reconfigured as if it were first turned on.
- 🔄 Update: Make sure you have the latest version installed MIUI/HyperOS. Operators often add support for new networks in updates.
- 📡 Conflict IP: Try changing the type of address from static to dynamic in the router settings (DHCP) for your phone.
- 🔒 Antivirus: Third-party cleaning or protection applications can block VoIP system services. Try disabling them temporarily.
If nothing helps, your router may be using settings that are incompatible with the carrier’s protocols (e.g., specific settings). NAT or DNS). Try to prescribe in the Wi-Fi settings on your phone DNS-Google servers (8.8.8.8 and 8.8.4.4) often solve problems with voice traffic routing.
💡
Use 5GHz for calls. 2.4GHz is often overloaded with neighborhood routers and microwaves, causing interference in conversation.
The Impact of Function on Autonomy and Safety
Many users fear that the constant search for networks and the operation of additional communication modules will quickly land the battery. However, in the case of VoWiFi, the situation is reversed: When the phone is in a zone of poor cellular coverage, it spends a huge amount of energy constantly trying to catch the signal tower.
From a security perspective, VoWiFi calls are encrypted by the operator in the same way as regular voice calls on LTE networks. Data is transmitted over secure channels, and it is more difficult to intercept a conversation via a Wi-Fi router than through an open cellular network, thanks to the additional layer of IPSec encryption. However, when using public Wi-Fi networks in cafes or airports, it is recommended to be careful.
Owners of older Xiaomi models should consider that the simultaneous operation of Wi-Fi and 4G can create additional stress on the processor and radio module. If you notice a strong heating of the case, it makes sense to turn off the feature in home conditions where cellular communication is stable, and turn it on only if necessary.
💡
VoWiFi is not only an improvement in communication in blind areas, but also a way to extend the life of the battery in conditions of weak signal of the cellular network.