Modern smartphones Xiaomi While they offer a wide range of communication features, connection quality often depends on the cellular network signal strength. In rooms with thick walls or in remote areas, the signal can drop out, making it impossible to make or receive calls. This is where technology comes in handy. Voice over Wi-Fi, which allows voice traffic to be transmitted over an Internet connection.
Activating this feature on devices Redmi And POCO can dramatically improve connection stability in areas with poor coverage. You'll no longer have to run out onto the balcony or hold your phone up to the window to hear your caller. However, the activation process isn't always straightforward and depends on the OS version. MIUI or HyperOS, as well as from the support of the service by your operator.
In this guide, we'll cover in detail how to check your device's compatibility, where to find hidden switches in the engineering menu, and what to do if standard methods fail to activate a feature. Understanding the operating principles VoWiFi will help you stay connected even in the most challenging conditions.
How VoWiFi technology works on Xiaomi smartphones
Technology Voice over Wi-Fi (often referred to as Wi-Fi Calling) allows voice calls to be transmitted over IP, using a wireless network instead of a cellular carrier's radio frequencies. To the user, it appears like a regular call, but the signal travels through the router. Smartphones Xiaomi support this function at the hardware level, but the software implementation depends on the regional firmware.
The key difference from apps like Viber or WhatsApp The process is transparent for the subscriber. You don't need the other person to have the same messenger installed or an internet connection. System Automatically routes the call over Wi-Fi if the cellular signal is weak, or if this is the priority communication method in the settings.
⚠️ Please note: Call quality directly depends on the speed and stability of your internet connection. If your home network is overloaded, your voice may be interrupted.
It's important to understand that this feature requires support from your carrier. Even if your Xiaomi Technically ready, the menu may remain unavailable without service activation on the provider's side. Operators use dedicated IMS servers to encrypt and transmit voice packets.
Modern shells HyperOS And MIUI 14 Access to these settings has been significantly simplified, but in some cases manual activation via the engineering menu is required. This is due to regional restrictions and equipment certification for operation in specific countries' networks.
Checking operator and tariff compatibility
Before messing with your phone's settings, make sure your plan supports voice over IP. Major carriers are gradually rolling out this service, but it may not be available on older plans or require separate activation. Without confirmation from your provider, any phone operations will be useless.
Most often, the service is free, and minutes are consumed according to your basic plan. However, when roaming, conditions may vary: calls through Wi-Fi In their home country, they are often charged at the same rate as local ones, even if you are abroad, which allows you to save significant money.
- 📱 Make sure your SIM card supports 4G/LTE, as VoWiFi is often tied to LTE infrastructure.
- 🌐 Check your balance and make sure your number isn't blocked; services may not activate if you're in debt.
- 📞 Call your carrier's support service to check the status of your Wi-Fi Calling service.
In some cases, the operator requires updating the network profile. This can be done by sending a special USSD code or through the operator's personal app. If the profile is out of date, the phone will not be able to register with the IMS network required for this feature to work.
It's also worth keeping in mind that support may depend on the region in which your smartphone was released. Global versions Xiaomi have a wider list of supported operators compared to Chinese versions, where some frequencies or protocols may be blocked by software.
Basic activation via the standard settings menu
On most modern models Xiaomi, Redmi And POCO With the latest software version, the switch is publicly available. First, make sure Wi-Fi is enabled and your phone is connected to a network. Then, go to the device's main settings to find the required option.
The path to the settings may vary slightly depending on the shell version. Typically, you need to open the section Settings, then select SIM cards and mobile networksHere you'll see a list of installed cards. Click the one you want to configure for internet calls.
Settings → SIM cards & mobile networks → Select SIM → Wi-Fi callingIf the item Wi-Fi calling If the network is present, simply move the toggle switch to the active position. The system may prompt you to select a network priority: prefer mobile data or Wi-Fi. To save data and improve indoor connectivity, it's best to prioritize Wi-Fi.
In some interfaces this item may be called Wi-Fi calls or VoWiFiIf you don't find this switch in the specified path, your firmware may be hiding it, and you'll need to use the engineering menu or third-party utilities to activate the hidden functions.
Using the engineering menu for hidden functions
If the switch is missing from the standard menu, you can try to activate the function through the engineering menu. AndroidThis method works on many devices. Xiaomi, but caution is required. Changing unknown parameters may result in unstable operation of the communication module.
To enter the menu, enter a special code in your phone book. On most devices, this is ##4636##After entering the last character, a hidden testing menu will open. You are interested in the section Phone Information (Phone information).
- 🔍 Find the option in the list Turn off VoLTE provisioned or IMS status.
- 📡 Try switching your preferred network type to
LTE onlytemporarily to check registration in IMS. - ⚙️ Search for the item
Supports VoWiFiand make sure it is active.
⚠️ Warning: Do not change settings in the "Radio Band" section without understanding the consequences. Doing so may result in complete loss of cellular signal.
Often, the problem is resolved by resetting the network settings or re-registering with IMS. There may be a button in the engineering menu. Run Ping Test or Refresh, which forces the modem to re-request the profile from the operator. If the icon doesn't appear after this procedure, the blocking is either at the firmware or operator level.
☑️ Pre-activation check
Comparison of VoLTE and VoWiFi technologies
Users often confuse these two technologies, thinking they are the same. Both methods allow for high-quality voice transmission (HD Voice) over digital channels, but they use different data transmission media. Understanding the differences will help you properly prioritize your smartphone.
VoLTE (Voice over LTE) uses the operator's 4G network. It doesn't require internet access in the traditional sense, but it does require LTE coverage. VoWiFi Uses any available Wi-Fi connection, which is critical in basements, offices with shielded walls, or in the countryside.
| Characteristic | VoLTE | VoWiFi |
|---|---|---|
| Transmission medium | 4G/LTE cellular network | Internet (Wi-Fi router) |
| Dependence on coverage | Operator tower required | A Wi-Fi hotspot is required |
| Sound quality | High Definition (HD) | Depends on the internet speed |
| Consumption of minutes | At the operator's rate | Usually according to the tariff (depending on the operator) |
Ideally, a smartphone should automatically switch between these technologies. For example, you might be talking at home over Wi-Fi, then go outside, and the call seamlessly switches to VoLTE without interrupting the connection. Xiaomi implement this mechanism well, but only if both functions are activated correctly.
It's worth noting that VoWiFi uses battery power differently than standard mode. Constantly searching for a network in poor signal conditions consumes more power than a stable connection via a router. Therefore, enabling Wi-Fi calling can improve battery life in "dead zones."
What should I do if the icon disappeared after an update?
Network settings are often reset after updating MIUI. Go to the SIM card menu and re-enable the switch. If that doesn't help, delete the Wi-Fi hotspot and reconnect.
Troubleshooting and missing status bar icon
The most common issue is that the feature is enabled in the settings, but the handset symbol with Wi-Fi waves doesn't appear in the status bar (near the battery icon). This means the phone hasn't registered with the IMS network. First, check that Airplane mode isn't activated.
Sometimes deleting and re-adding the Wi-Fi hotspot helps. The network may have been assigned "metered" status or have background data restrictions. Go to Wi-Fi settings, click the gear icon for your network, and make sure "Use as primary" or something similar is checked.
In rare cases, you may need to clear the cache of system communication apps. Go to Settings → Apps → All apps, find system processes related to the phone and SIM cards and click Clear cacheDo not confuse this with "Clear data" to avoid resetting your network settings.
⚠️ Please note: Carrier interfaces and phone settings may vary. If the instructions don't match your screen, check the manufacturer's or carrier's official website.
If all else fails, your router may be blocking required ports or protocols (e.g., SIP ALG). Try connecting to a different Wi-Fi network (e.g., sharing internet from another phone) to rule out a hardware issue.
Security and data usage during calls
Many users are wary of enabling Wi-Fi calling due to concerns about data security or rapid data consumption. Voice traffic in VoWiFi technology is encrypted by the operator, making it more difficult to intercept than in open messaging apps. The channel is protected by cellular security protocols.
As for traffic, one minute of high-quality talk time consumes approximately 0.5–1 MB of data. This isn't much, but if you have limited mobile data (roaming Wi-Fi), you should be careful. With unlimited home plans, this consumption is completely unnoticeable.
- 🔒 Data is encrypted between the phone and the operator's gateway.
- 📉 Traffic consumption is minimal compared to video calls.
- 🌍 When roaming, calls to local numbers via Wi-Fi may be free (check with your operator).
Although the voice stream itself is protected, it is best not to make calls that transmit confidential information (passwords, SMS codes) over open networks.
For maximum security when using public Wi-Fi, using a VPN is recommended, although this may increase latency and degrade connection quality. At home, additional security measures are generally not necessary.
Why is there no "Wi-Fi Calling" option on my Xiaomi?
This could be due to three reasons: your carrier doesn't support the service in your region, your phone's firmware isn't certified for your carrier, or the feature is hidden in the engineering menu. Try changing the region in your phone's settings to your carrier's country.
Do you charge for Wi-Fi calls when roaming?
Terms and conditions depend on your plan. Often, these calls are charged as incoming and outgoing calls within your home region, which is advantageous. However, some carriers may consider this as internet traffic. Always check the current terms and conditions with your provider before traveling.
Is it possible to make calls via Wi-Fi if the SIM card is not active (no signal)?
Yes, this is the main advantage of this technology. If your SIM card doesn't see the network (for example, in a basement), but your phone is connected to Wi-Fi, you'll be able to receive and make calls as usual. To the system, it will appear as a standard call.
Does VoWiFi affect internet speed?
Voice traffic has priority, but it takes up bandwidth. At very low internet speeds (less than 1 Mbps), call quality may degrade, or the internet may become slower. At modern speeds (from 10 Mbps), the impact is unnoticeable.