Modern smartphones Xiaomi And Redmi They are equipped with powerful communication modules, but in some situations, standard cellular network coverage is insufficient. This is especially true for device owners living in areas with unstable signal or working in buildings with thick walls, where mobile service often drops out. VoWiFi (Voice over Wi-Fi) allows you to make voice calls and send SMS via an internet connection, providing a stable connection where a regular network is powerless.
Many users encounter a situation where their carrier already supports a feature and their tariff plan allows it, but the desired switch is missing or inactivated in the phone's menu. This is a common issue related to firmware features. MIUI And HyperOS, as well as the specifics of device certification for different regions. In this article, we'll take a detailed look at how to bypass system restrictions and configure wireless network connectivity.
Enabling this option not only improves call quality but also helps conserve battery power in areas with poor reception, as the phone doesn't have to constantly search for a lost cell tower. Below are proven methods for enabling this feature, which work on most current models, including the following series: Mi, Redmi Note And Poco.
What is VoWiFi and why do Xiaomi owners need it?
Technology Wi-Fi Calling Voice over IP (Voice over IP) is a method of transmitting voice traffic over IP, similar to how instant messaging apps work, but integrated directly into the standard phone book and dialer. For the subscriber, this means incoming and outgoing calls are handled through a standard interface, without the need to launch separate applications. The sound quality often surpasses that of standard voice calls, especially when using the HD Voice codec.
The main advantage for smartphone users Xiaomi The advantage of this feature is the ability to stay connected in basements, country houses, or office buildings, where GSM/LTE/4G signal is virtually nonexistent. The system automatically switches calls from the mobile network to Wi-Fi and back without interrupting the connection if you leave the router's coverage area. This is critical for business people and those waiting for important calls.
It's worth noting that this feature only works if supported by your mobile operator. In Russia and the CIS, most major providers have already implemented this technology, but activating it on the subscriber's end may require additional steps. Without operator permission, even if the setting is enabled on the phone, internet calls will not work.
- 📶 Stability: Guaranteed connection in places where only Wi-Fi works.
- 💰 Saving: Calls are charged at the same rate as your package's regular minutes; roaming is often either absent or cheaper.
- 🔋 Energy efficiency: Reducing the power consumption of the communication module in weak signal conditions.
- 📞 Integration: There is no need to teach your loved ones how to use new apps; the number remains the same.
⚠️ Please note: Using VoWiFi consumes your internet data. While the data volume for a voice call is minimal, make sure your Wi-Fi plan doesn't have any restrictions or limits that could be exhausted during long calls.
Checking if the function is supported by your operator and SIM card
Before delving into deep system settings or using the engineering menu, you need to ensure basic compatibility. The first step is to check whether your mobile operator supports the technology. IMS (IP Multimedia Subsystem), which is the foundation for VoWiFi. The list of supported operators is updated regularly, so it's best to check the provider's official website for information.
The SIM card type also plays a significant role. Older SIM cards, issued many years ago, may not have the necessary profiles to work with modern voice protocols. In this case, a free SIM card replacement at a mobile phone store with a new one that supports 4G/5G often solves the problem of a missing switch in the menu.
Another important aspect is the SIM card's registration region. Some operators provide VoWiFi service only to subscribers in certain regions or only when they're in their home region. If you're roaming, the service may not activate even if Wi-Fi is available.
To check the service status, you can use USSD commands or your operator's personal account. Often, you'll need to manually check the "Wi-Fi Calling" service. Without this permission, your phone's network settings will be useless.
Standard activation via the MIUI and HyperOS settings menu
In most modern versions of the shells MIUI and new HyperOS The switch is located in the standard menu, but its location may vary depending on the Android version and firmware region (Global, EU, Russia, China). The steps are generally standardized, but the item names may differ slightly.
To find the setting, open the Phone app (green phone) and go to the settings menu by tapping the three dots or gear icon. In the list of options, look for Wi-Fi calling or Wi-Fi callsIf it's empty, try the path through the general system settings: Settings → SIM cards & mobile networks → Select SIM card → Wi-Fi calling.
In some cases, the switch may be grayed out (inactive). This means the phone has detected the SIM card but hasn't received a signal from it or the network to activate it. Try restarting the device after turning the switch on in your operator account.
☑️ Standard Activation Checklist
If there is no item in the SIM card settings menu, go to Settings → Connections and Sharing → Wi-Fi CallingOn dual-SIM devices, the setting is configured separately for each slot. Make sure you're trying to enable the feature on the SIM card that supports the service.
Activation via engineering menu and encoder
If standard methods fail to enable the function, you can use the hidden engineering menu. This method requires caution, as changing unfamiliar parameters may affect the radio module's operation. We'll use a code to access the testing.
Open the Phone app and enter the code ##869434##This code is for activating VoWiFi test mode. The window that opens will show the function's status. If it says "VoWiFi Carrier check was disabled," click the button. Enable VoWiFi Carrier Checkto change the status to enabled.
##869434##After enabling carrier verification in the engineering menu, return to the phone's regular settings. Often, after this manipulation, a previously hidden switch appears in the SIM card menu. VoWiFiIf the code doesn't work or returns an error, your firmware version may be blocking access to that specific test.
There is an alternative code to enter the full engineering menu: ##4636##In it, select "Phone Information." Scroll down to "Voice/Data Switching Settings" or something similar. However, code 869434 is more specific to unlocking carrier verification.
⚠️ Caution: Do not change other settings in the engineering menu unless you are sure of their purpose. Resetting the radio module may result in temporary loss of network connectivity or the inability to register with the operator's network.
Configuration via the Mi Carrier Config app
One of the most effective techniques for devices Xiaomi is the use of a system application Mi Carrier ConfigThis is a service application that is hidden from the user by default but is responsible for loading carrier settings profiles. This is where the configurations that enable or disable VoWiFi for specific SIM cards are stored.
To access this tool, you'll need a third-party app, such as Activity Launcher or QuickShortcutMaker, both available on Google Play. Once installed, launch Activity Launcher, search for "Carrier," and select Mi Carrier ConfigSelect your SIM card from the list that opens.
Within your operator profile, you need to find the setting responsible for enabling the feature. Look for lines with the words config_enable_volte, config_enable_vowifi or carrier_volte_available_boolChange the value from false on trueAfter changing the settings, be sure to restart your smartphone.
What to do if Mi Carrier Config won't open?
If the app doesn't launch or crashes, try clearing its data via Settings → Apps → All apps → Show system data → Mi Carrier Config → Clear. Also, make sure you have the Activity Launcher permissions set to always be on top.
This method is especially relevant for Chinese smartphones with global firmware installed, or for devices locked to a specific carrier. Manipulating profiles allows you to "trick" the system into thinking the carrier officially supports the feature.
| Parameter | Default value | Required value | Description |
|---|---|---|---|
| carrier_volte_available_bool | false | true | Enables VoLTE for the operator |
| carrier_vowifi_available_bool | false | true | Enables VoWiFi for the operator |
| config_enable_volte | false | true | Global VoLTE Enablement |
| config_enable_vowifi | false | true | Global VoWiFi Enablement |
Troubleshooting: Icon not appearing or calls not making progress
Even after successful activation in the settings, the icon Wi-Fi Calling The icon may not appear in the status bar. First, make sure your mobile data is turned off (for testing purposes) and Wi-Fi is turned on. On some models, the icon only appears during an incoming or outgoing call.
If the icon is lit but calls aren't connecting, check your firewall or antivirus settings. Sometimes they can block ports required for the SIP protocol. Also, try resetting your network settings: Settings → Connection and sharing → Reset Wi-Fi, mobile networks, and Bluetooth.
A common issue is a conflict between the "4G/LTE Only" mode and VoWiFi. Try changing the mobile network settings (##4636## → Phone information → Set preferred network type) set the mode LTE/TD-SCDMA/CDMA EvDo/GSM/WCDMARemove "LTE Only" modes if they are set.
In rare cases, the problem lies with the router itself. Some home internet providers block ports or use NAT, which interferes with the connection. Try connecting to a different Wi-Fi network (for example, by sharing internet from another phone) to rule out a router issue.
Impact of firmware region on feature availability
Company policy Xiaomi The functionality of devices may vary depending on the firmware region. Global versions typically have a full feature set but may not include profiles for local operators in the CIS countries. European (EU) and Russian (RU) firmware versions are most often optimized for local operators.
If you are using a Chinese (CN) version of your smartphone with a reflashed global firmware, you may not have the app. Mi Carrier Config or corresponding profiles. In this case, activation via the engineering menu is the only viable option. Chinese firmware is often tightly bound to Chinese carriers.
When changing the region in the settings (Settings → Advanced Settings → Region) Your phone may prompt you to reboot and update the list of available carriers. Setting the region to "Russia," "Ukraine," or "Kazakhstan" often unlocks hidden menu options for local SIM cards.
Please note that updating the firmware may reset all settings you've made through the engineering menu or Mi Carrier Config. After each major system update (for example, upgrading from MIUI 13 to 14), it's recommended to double-check the feature's activation status.
Why does the VoWiFi icon disappear after leaving home?
This is normal behavior. The icon only appears when the phone is registered to a Wi-Fi network and is ready to make calls over it. As soon as you disconnect from Wi-Fi, the phone switches to the cellular network, and the icon disappears, giving way to the 4G/LTE icons.
Is there an extra charge for Wi-Fi calls?
Operators typically charge these minutes according to your basic plan, just like regular calls. However, if you're abroad (roaming), the rules may differ: calls to numbers in your home country may be free or cheaper, but it's best to check with your specific operator.
Is it possible to use VoWiFi without mobile internet?
Yes, VoWiFi technology does not require an active mobile internet connection (3G/4G/5G). A Wi-Fi connection is sufficient. A mobile network is only required for initial SIM card registration and the exchange of IMS service signals.
How to check if a call went through via Wi-Fi?
During a call, look at the top of the screen (the status bar). A special handset icon with a Wi-Fi symbol should be lit there. A "Wi-Fi" label may also appear next to the call duration in the call log after the call ends.