Modern Xiaomi smartphones are full of various indicators at the top of the screen that signal the state of the device. One of these icons is VoWiFi, which can appear unexpectedly after a firmware update or change. SIM-For many users, this symbol remains a mystery, raising questions about whether the phone has connected to paid roaming or whether there was a bug in the network.
In fact, the acronym is a sign of the activation of advanced voice technology: Voice over Wi-Fi allows you to make and receive calls using an Internet connection instead of a standard cell tower radio signal, and this is especially true for residents of thick-walled homes, country houses or office buildings where the signal level of the operator leaves much to be desired, but stable Wi-Fi is available.
In this article, we will take a look at how this feature works on Redmi and Poco devices, how to set it up correctly and what to do if the icon is on, but calls do not pass. Understanding the principles of VoWiFi will help you save battery power and stay connected even in dead signal zones.
VoWiFi technology: the principle of work on Xiaomi devices
VoWiFi (Voice over Wi-Fi) is a standard IP-It's a telephony system that's integrated directly into the dialer of a smartphone, and unlike popular messaging apps like Viber or Telegram, you don't have to install additional apps or ask someone to be online. The call is made to a regular phone number, and for the subscriber at the other end of the wire, it does not matter how you connect.
When you see a VoWiFi icon on your Xiaomi screen, it means that the phone has automatically switched the voice traffic route.If the cellular network is unavailable or its signal is too weak, the device uses a secure connection through the Wi-Fi hotspot to transmit voice to the operator's network. This provides a high quality sound comparable to HD-voice, and almost instantaneous connection.
It is important to understand that this feature only works with support from your mobile operator. Even if your Mi or Redmi phone is technically capable of running in this mode, without the appropriate service, the icon will not appear on the tariff plan.
⚠️ Note: When using VoWiFi on trips abroad, make sure you have data roaming turned off if you don't want to pay for the internet.Although calls themselves may be charged as local (depending on the operator), Wi-Fi traffic must be free or included in your home fare.
The quality of the connection depends on the stability of your home or public Wi-Fi. If the network is congested or the router signal is weak, there may be delays or interruptions similar to those that occur with poor Internet during a video call.
What is the difference between VoWiFi and VoLTE?
Users often confuse two similar icons: VoLTE and VoWiFi. Both refer to voice over data packets (4G/LTE and Wi-Fi respectively), but operate in different environments. VoLTE uses a fourth-generation network for calls without switching to 2G or 3G, which speeds up the connection and improves sound.
The main difference is the signal source. VoLTE relies on a cell phone tower, so it needs a confident 4G reception. In turn, VoWiFi ignores the power of the tower signal using the Internet channel, which makes it indispensable in basements, elevators or deep rooms where radio waves simply do not penetrate.
Below is a comparison table that will help you better understand the differences between these technologies on Xiaomi smartphones:
| Parameter | VoLTE | VoWiFi |
|---|---|---|
| Signal source | Cellular tower (4G/LTE) | Wi-Fi hotspot |
| Dependence on coverage | We need a 4G signal. | We need Wi-Fi. |
| Tariffing | Operator's rates (minutes) | Operator's rates (minutes) |
| Traffic consumption | Not spent (usually) | Wi-Fi traffic is being consumed |
Xiaomi's current flagships can automatically switch between these modes, so if you leave your home, your phone will move from Wi-Fi to VoLTE without interrupting your conversation, ensuring continuity in all environments.
How to Enable and Configure VoWiFi on Xiaomi
Activation of the call function via Wi-Fi on devices MIUI HyperOS usually occurs automatically if the carrier supports the service and it is activated on your computer. SIM-However, in some cases, manual adjustment is required, and the first step should always be to check the conditions with your mobile provider, because without them, the phone settings will be useless.
To enable the feature, go to your smartphone's settings menu. The path may vary slightly depending on the shell version, but most often it looks like this:
Settings → SIM-maps and mobile networks → Select SIM-maps → Enable VoWiFiIf you don't find one, try searching by settings by typing "Wi-Fi calls." On some Redmi Note or Poco models, the switch can be directly in the notification curtain. To do this, unlock the screen, pull the curtain down, and find an icon that says "Wi-Fi calls" or "VoWiFi."
☑️ Checklist for VoWiFi activation
Once you turn on the option, the network indicator should show an icon next to it. If that doesn't happen, try restarting the device. Sometimes the system takes time to register with a new type of network.
Why VoWiFi icon is on, but calls are not coming
It is not uncommon for VoWiFi on Xiaomi’s screen to burn, but outgoing calls to break or not connect, most often the problem lies in router settings or firewalls that block specific ports needed to pass voice traffic.
Another common cause is conflict between work regimes. SIM-If the network priority is set strictly on 2G/3G, The phone may not be handling the Wi-Fi switching for voice.It is recommended to set the network mode to the value Preferably 4G (LTE) or 5G/4G/3G/2G (motor-car).
⚠️ Note: If you use a dual-sim phone, make sure that VoWiFi is enabled for the same phone. SIM-The card you're trying to make a call with, the settings for each card are independent.
It’s also worth checking if your phone has a third-party antivirus or memory cleaner app that can aggressively save energy by turning off the phone’s background processes. Try adding the Phone and Settings system apps to power saving exceptions.
In some cases, resetting network settings helps, which will remove stored Wi-Fi passwords and Bluetooth settings, but return network settings to factory values, often eliminating software conflicts.
Compatibility of operators and regions
The availability of VoWiFi is highly dependent on the geographic region and the specific carrier. In Russia, the main operators (the “big four”) have already implemented this technology, but the conditions for its provision may vary, for example, one operator may have a free service and connect automatically, and another may require a written application or a certain tariff.
When using a Xiaomi phone purchased in China (CN Version), it can be difficult to display the icon or function in European or Russian networks. Global ROMs usually do not have these problems, as they contain the necessary certificates and profiles of telecom operators.
Hidden codes for status verification
If you're traveling, remember that VoWiFi can roam, which allows you to call "at home" while abroad, provided your home carrier supports this option, but always check your rates to avoid unexpected bills.
The Impact of VoWiFi on Autonomy and Security
Voice over Wi-Fi technology has its own power consumption features: on the one hand, the phone doesn't need to waste energy searching for a weak cell tower signal, which, in poor coverage, can significantly extend battery life; on the other hand, the constant active operation of the Wi-Fi module also consumes charge.
With excellent 4G reception, the difference in autonomy will be minimal. However, if the phone constantly “jumps” between Wi-Fi and the cellular network due to unstable signal, battery consumption can increase, in which case Xiaomi recommends using the “Flight Mode” feature with Wi-Fi enabled for maximum energy saving when making calls.
From a security perspective, VoWiFi is encrypted, operators use banking-like security standards to protect voice traffic from eavesdropping, and yet there is always a risk of “Man-in-the-Middle” attacks when connected to public Wi-Fi networks (cafes, airports).
💡
For maximum security when calling via public Wi-Fi, use VPN-connection if your operator allows VoWiFi to run over VPN. This will create an additional secure tunnel for your data.
Poco and Redmi smartphone owners should keep an eye out for security updates, as they often contain patches for network modules that improve connection stability.
💡
VoWiFi is not a separate application, but a system function that depends on the bundle: Operator + Tariff + Phone Settings + Router.