Modern smartphones Xiaomi, working on the shell MIUI or new HyperOS, have a wide range of functionality that is often hidden from the average user. One of these useful, but not always obvious, features is technology Voice over WiFi (VoWiFi). It allows you to make voice calls and send SMS messages over a Wi-Fi network, bypassing standard cell towers. This solution is ideal for areas with poor GSM signal strength but stable internet access.
Many device owners wonder how to enable Wi-Fi calling on Xiaomi devices, as the corresponding switch may not be available in the standard settings menu. This depends not so much on the smartphone itself, but rather on whether your mobile operator supports the technology and whether the firmware is properly configured. In this article, we'll cover the steps, potential issues, and solutions in detail.
Activating this option can significantly improve connection quality in office buildings, basements, or country houses where the cellular signal is unstable. However, successful implementation requires several conditions to be met by the telecom operator and proper device configuration. Let's look at the technical details of this process.
What is VoWiFi technology and how does it work?
Technology Voice over WiFi Voice over IP (VOIP) is the transmission of voice traffic over IP protocols, similar to how instant messaging apps work, but integrated into the standard phone book and dialer. For the user, the process is transparent: you simply dial a number, and the smartphone decides whether to route the call over the cellular network or Wi-Fi. A special icon may appear on the screen during the call, such as Wi-Fi Call or a handset icon with a wireless network symbol.
The main advantage of this technology is its independence from mobile operator coverage. If your apartment only has one 3G or 2G network connection, but your internet connection through your router is blazing fast, VoWiFi will provide crystal-clear sound. Xiaomi actively implements support for this function in its devices, however, the implementation may differ depending on the firmware region (Global, EU, China).
It's important to understand the difference between VoWiFi and regular messaging calls. With the native phone feature, you use your regular phone number, and the other person sees the incoming call as if you were calling over a cellular network. Calls are typically charged at your regular plan unless your carrier has set special conditions.
⚠️ Attention: Connection quality directly depends on the stability and speed of your internet connection. If the router is overloaded or the channel is weak, voice quality may be interrupted or delayed.
The function is supported by protocols IMS (IP Multimedia Subsystem). Smartphone Xiaomi Constantly monitors the cellular signal quality and the availability of available Wi-Fi networks. With certain settings, priority can be given to the wireless network, which helps conserve battery life, as the cellular module operates in enhanced search mode in poor signal conditions, which drains the battery faster.
Checking carrier and device support
Before searching for the coveted toggle switch in the settings, make sure your mobile operator supports VoWiFi technology in your region. Major national carriers have already implemented this feature, but it may not be available for corporate plans or in certain regions.
It's also important to check your smartphone model. Flagship lines Xiaomi, Redmi Note And Poco Recent models typically have full hardware support. However, the software may hide this option if the carrier isn't whitelisted in the firmware.
To check, follow these steps:
- 📱 Make sure that the SIM card is installed in a slot that supports 4G/LTE (usually any slot in modern models).
- 📡 Check if VoLTE is activated, as VoWiFi often works in conjunction with it.
- 📝 Visit your carrier's official website and find a list of supported devices for Wi-Fi Calling.
- 🔄 Update your smartphone software to the latest available version via
Settings → About phone → MIUI version.
If your carrier confirms support but the option isn't available in the settings menu, manual activation may be required via the engineering menu or by changing the region. Some users report that a simple toggle appears after rebooting the device with a SIM card from a specific carrier installed.
Standard activation via the settings menu
In most cases, if the carrier and firmware are compatible, you can enable this feature using the built-in tools. The path to the settings may vary slightly depending on the version. MIUI or HyperOSThe standard algorithm is as follows:
Open the app Telephone or go to general Settings smartphone. Find the section responsible for SIM cards and mobile networks. In newer versions of the shell, this item is often called SIM cards and mobile networks.
Select the desired SIM card if you have two. Scroll down the list of options. Look for the option called Wi-Fi calling or Wi-Fi CallingMove the switch to the active position. If the item is found and activated, the system is fully operational.
In some cases, after enabling, you'll need to select a preferred network for outgoing calls. The following options are available:
- 📶 Wi-Fi preferred: The phone will always try to use the wireless network if one is available.
- 📡 Mobile network preferred: Wi-Fi will only be used when the cellular signal is very weak.
- ⚖️ Don't ask: Automatic selection based on signal quality.
⚠️ Attention: If you're roaming abroad, enabling this feature can help you avoid incoming calls, but be sure to check your carrier's Wi-Fi Calling pricing terms before you travel.
☑️ Activation checklist
Hidden settings and engineering menu
If the standard method doesn't work, you can try accessing hidden settings. On smartphones Xiaomi There's an engineering menu that allows you to control many hidden parameters of the radio module. Be careful: changing unknown parameters may lead to unstable communication.
To enter the engineering menu, open the application Telephone and dial the combination ##4636##If the menu does not open automatically, you may need to install a special code dealer app from the store. Google PlayIn the menu that opens, select Phone Information (Phone information).
Inside this section, find the item Set Preferred Network TypeMake sure you're in a mode that supports LTE. Also look for a switch. VoWiFi Provisioned or similar. Activating it forcibly notifies the system that the device is ready to use VoWiFi.
Another way is to use the hidden operators menu. Dial ##869434## (The code may differ for different models). This menu is often called Carrier VoWiFi & VoLTE ProvisioningHere you can manually enable the checkbox. VoWiFi Carrier check, removing the operator check.
##4636## — Android engineering menu
##869434## — VoWiFi/VoLTE testing menuAfter making changes in the engineering menu, be sure to reboot your device. If the VoWiFi icon doesn't appear after rebooting, try turning Airplane Mode on and off (Airplane mode) so that the communication module can re-register with the network.
Risks of using the engineering menu
Changing settings in the engineering menu may cause your phone to stop detecting the network or to constantly lose signal. If you're unsure of what you're doing, it's best not to change any settings other than the obvious VoWiFi switches.
Changing the region and additional methods
One of the most effective "tricks" for owners Xiaomi Changing the device's region is crucial. Firmware for different countries has different lists of supported carriers. For example, firmware for India or Indonesia may have a wider list of supported VoWiFi carriers than the Russian or European version.
To change your region, go to Settings → Advanced Settings → RegionSelect a country where your carrier officially supports the technology (CIS countries or Turkey often help). After changing the region, your phone may require a reboot, after which the necessary switch may appear in the SIM card settings.
Another method is manually adding the carrier configuration. This is a more complex method, requiring root access or using ADB (Android Debug Bridge). You can use a computer to send a command to modify the configuration file. carrier_config.xml, adding there the IMSI code of your operator with the VoWiFi support flag.
The table below shows sample region codes and how they affect feature availability:
| Region | Probability of VoWiFi availability | Peculiarities |
|---|---|---|
| Russia (RU) | Average | Depends on the specific operator in the firmware |
| India (IN) | High | Often all network functions are unlocked |
| China (CN) | Low | There are many Chinese services, so there may be problems with notifications. |
| Global | Average | Basic set of functions without country binding |
Keep in mind that changing the region may affect the operation of other system apps, such as the preinstalled apps or themes. You can return to your original region at any time through the same settings.
Diagnostics and troubleshooting
Even after successful activation, connection quality or stability issues may persist. A common issue is that the phone doesn't switch to Wi-Fi during an incoming call, remaining on the 3G network. This may be due to power saving settings.
IN MIUI An aggressive power-saving system can "kill" background processes responsible for registering with IMS. Go to battery settings and find the app. Telephone And Settings, and set the power saving mode to No restrictionsThis will allow the system to maintain a constant connection with the operator's servers.
Also, check your router settings. For VoWiFi to work properly, your router must handle SIP traffic correctly. Sometimes disabling this feature helps. SIP ALG in your router settings, as it may conflict with your operator's data packets. Also, make sure your router doesn't have MAC address filtering enabled, which could block your phone.
If the problem persists, reset your network settings. Go to Settings → Connection and sharing → Reset Wi-Fi, mobile networks, and BluetoothPlease note that this action will delete saved passwords for Wi-Fi networks and Bluetooth device pairings, but will not affect personal files.
⚠️ Attention: After resetting your network settings, you'll need to re-enter the passwords for all previously connected Wi-Fi networks. Make sure you remember them or have access to them.
In rare cases, the problem lies with the SIM card itself. If your SIM card is very old (issued more than 5-7 years ago), it may not support modern IMS authentication protocols. In this case, the best solution is to replace the SIM card with a new one at a carrier store while keeping your phone number.
Why does the Wi-Fi Call icon disappear?
The icon may disappear if the phone loses connection to the carrier's IMS server, even if the internet is working. Try temporarily turning Wi-Fi off and then back on, or putting the phone in airplane mode for 10 seconds.
Frequently Asked Questions (FAQ)
Does using VoWiFi affect traffic consumption?
Voice calls over Wi-Fi typically don't use up your mobile data plan, as the traffic is routed through your carrier's network. However, technically, the data is transmitted over your Wi-Fi network. If you have limited home internet, keep in mind that a minute of call consumes approximately 0.5–1 MB of data.
Will VoWiFi work if the router is distributing the Internet from the phone (modem mode)?
Generally, no. Carriers block VoWiFi calls if they detect that you're connected via a hotspot from another mobile device. The carrier's security system identifies this as an attempt to circumvent billing or an incorrect connection.
Is it possible to use VoWiFi abroad without roaming?
Yes, this is one of the best ways to save money. When traveling abroad, connect to Wi-Fi at your hotel. If your carrier supports VoWiFi while roaming, you'll be able to receive and make calls to your number at your home network rates (or your carrier's roaming rates), without paying international calling fees. Just remember to turn off your mobile data so your phone doesn't access the local network.
Why does VoWiFi only work on one SIM card on my dual-SIM Xiaomi phone?
This limitation may be related to network priority settings. In the section SIM cards and mobile networks Check which SIM card is selected for data transfer. VoWiFi is often only active on the SIM card that provides internet access, or on the one installed in the default 4G slot. Try swapping the SIM cards.