Modern smartphones Xiaomi, Redmi And POCO are equipped with powerful communication modules, but in some regions or specific models the wireless calling function may be hidden by default. Technology VoWiFi Voice over WiFi (Voice over WiFi) allows you to make voice calls in areas with poor or no cellular coverage, using your internet connection. For users who frequently find themselves in "dead zones" like basements or thick-walled offices, enabling this feature is critical to maintaining communication.
Enabling this service does not require root access or complex reflashing of the device, however, the standard settings menu does not always contain the necessary switch. Xiaomi devices for Russian operators often require activation via the engineering menu or special codes, as global firmware may not have local profiles. In this article, we'll cover all known activation methods, from simple settings in the MIUI interface to using hidden diagnostic tools.
Before you begin any technical manipulations, you need to ensure that your tariff plan and mobile operator support this technology. Without support from your service provider, any actions on your phone will be useless. Below, we'll cover a list of the main operators, connection requirements, and step-by-step instructions for various shell versions.
Checking operator support for technology
The first and most important step is to verify the service's availability with your telecom provider. The Big Four carriers have already implemented support. VoWiFi, but conditions may vary depending on the region and type of SIM card. For example, MTS, Beeline, Megaphone And Tele2 require that the 4G/LTE service be activated on the SIM card, even if the call itself goes through a Wi-Fi router.
Subscribers often forget that for this feature to work, the phone must be registered with the carrier's home network before switching to a wireless hotspot. If you're roaming, the rules may be different, and incoming calls over Wi-Fi may incur roaming charges in some cases, even though the traffic is technically going over the internet.
⚠️ Attention: Operators' personal account interfaces and pricing terms are subject to change. Before activating, be sure to check the current terms in your operator's official app or website, as some plans may require a fee or a separate subscription.
To activate the service on the network side, it's usually enough to send a USSD request or use the operator's mobile app. Below is a table with the main codes and methods for popular companies, but please note that these may not work with corporate plans.
| Operator | USSD code / Method | Condition | Status |
|---|---|---|---|
| MTS | *111*868# | Availability of a 4G SIM card | Works |
| Beeline | Personal account | Internet service | Works |
| Megaphone | *111*171# | VoLTE support | Works |
| Tele2 | Personal account | Compatible tariff | Works |
Basic settings in the MIUI menu
If the service is connected to your carrier, the next step is to find the switch in the standard smartphone interface. In current versions of the shell MIUI 12, 13, and 14 The setup path is usually standardized, but may have slight differences depending on the regional firmware version (Global, Russia, Europe).
You need to open the standard Phone app or go to the general system settings. Look for the section related to SIM cards and mobile networks. This is where you'll find the toggle switch that controls wireless connection priority for voice calls. If you don't see this option, your phone model or firmware may not be certified for your region.
The step-by-step algorithm of actions is as follows:
- 📱 Go to
Settings→SIM cards and mobile networks. - 📶 Select the active SIM card for which you want to enable the function.
- 🔌 Find the item Wi-Fi Calling and activate the slider.
- 📞 In the Phone app, tap the three dots (menu) →
Settings→ Calling accounts and select the priority.
In some cases, even after turning on the toggle switch, the handset icon with the Wi-Fi symbol doesn't appear in the status bar. This may mean the phone can't register with the operator's server via the current network. Try switching the network mode in Preferred network type on 4G/LTE, since the technology is often tied to the LTE core.
Activation via the engineering menu and codes
When default settings fail, Android's hidden features come to the rescue. The engineering menu is a diagnostic interface designed for testing the device's hardware and software components. On smartphones Xiaomi Access to it is often closed, but there are codes that can open the options we need.
The most common method is to use a code to verify phone information. Enter the following combination into your dialer: ##4636##If the menu opens, select the item Phone Information. Scroll down to the item Set Preferred Network TypeIt's important not to reset the network settings here, but you can try switching the mode to the one that contains the mark IMS or WiFi, if such an option is available in the list.
⚠️ Attention: Changing parameters in the engineering menu (
4636) may result in signal loss or incorrect modem operation. Write down the original settings before making any changes so you can roll back later.
There is also a specific code for activating the Carrier menu, which sometimes helps to “awaken” hidden operator settings:
##869434##Entering this code should trigger the "VoWiFi Carrier check allowed" notification. After this, the coveted toggle may appear in the standard SIM card settings menu. However, this method doesn't work on all models and depends on the underlying firmware version.
What to do if the code doesn't work?
If you enter the code ##4636## If the error message doesn't work or returns an error, access to the engineering menu is blocked by the manufacturer at the system level. In this case, the only solution is to install third-party apps from Google Play, such as "Force LTE Only," which uses the Android API to change network settings without root access.
Using apps to activate VoWiFi
Because Xiaomi Since it often hides native settings, developers have created special utilities that allow you to enable the feature through system APIs. The most popular and time-tested solution is the app Force LTE Only (4G/5G)It does not require root access and is safe for the device, as it does not make changes to system files, but only changes configuration flags.
The activation process via the app is as follows:
- 📲 Download the app Force LTE Only from Google Play Store.
- ⚙️ Launch the program and select the operating method «Method 2: Android 11+» (or Method 1 for older versions).
- 🔍 In the system window that opens, find the item
IMS Statusor VoWiFi. - ✅ Set the value to Enabled or 1.
After applying the settings, your phone may lose network connectivity for a few seconds. This is normal, as the modem is rebooting to apply the new settings. If the icon appears in the status bar after rebooting, Wi-Fi Call or a handset with a Wi-Fi symbol, which means the procedure was successful.
☑️ Activation checklist via the app
Configuration via the Mi Carrier Config app
Another effective, but more complex method is to manually install the operator configuration files. System MIUI uses files with the extension .xml To determine network settings. If your firmware doesn't have a profile for your carrier, your phone simply won't display the call option.
You'll need to find the latest configuration file (Carrier Config) for your carrier and phone model. These files are typically distributed on specialized forums (such as 4PDA or XDA). After downloading the file, place it in the root of your internal storage or in a dedicated folder. /data/misc/carrier_config/ (access may require root).
An easier way for non-rooted users is to use an app Mi Carrier Config (if available for your model) or installing a global firmware that already includes these files. You can also try clearing the data in the Settings and Phone apps to force the system to reread the configuration when the internet is available.
It's important to understand that installing the wrong configuration file can cause your phone to stop detecting the network altogether. Therefore, use only files specifically designed for your model and region.
Troubleshooting and error resolution
Even after all these steps, users may encounter a situation where the icon remains lit, but calls don't connect, or, conversely, the feature spontaneously disables. One common cause is an aggressive power-saving system. MIUIIt can "kill" Wi-Fi calling to save battery life.
To eliminate this factor, you need to go to the battery settings, find the “Phone” and “Settings” application, and set the power saving mode to the position "No Limits"Also, make sure the "Wi-Fi Assistant" feature is disabled in your Wi-Fi settings. This feature can switch your phone to the mobile network at the slightest deterioration in the router's signal, terminating the VoWiFi session.
- 📶 Problem: The icon is there, but the call is made via 3G/4G. Solution: In the Phone app → Settings → Calling accounts, select "Prefer Wi-Fi".
- 📵 Problem: When there is an incoming call, Wi-Fi is disabled. Solution: Check your router settings; client isolation mode may be enabled or QoS may be blocking voice traffic.
- 🔄 Problem: The function disappears after reboot. Solution: Your carrier is likely requiring re-authorization. Try turning airplane mode on and off.
⚠️ Attention: Call quality directly depends on the stability of your internet connection. If the ping to your operator's gateway is high, you'll experience delays or disconnects. In such cases, it's best to switch to a regular cellular network.
Does activating VoWiFi affect traffic consumption?
Voice traffic over Wi-Fi is typically not billed as internet traffic by your carrier if you're in your home region. However, technically, data is transmitted over the internet. If you use paid Wi-Fi at a hotel or cafe, the traffic will be deducted from your internet provider's balance.
Is it possible to make calls via Wi-Fi if the SIM card is blocked?
No. To register for a VoWiFi network, your SIM card must be active and have at least a minimum signal strength for initial authentication with the operator's server. A completely blocked or unreadable SIM card will not allow you to use the service.
Does this feature work on custom ROMs (LineageOS, PixelExperience)?
On custom ROMs, VoWiFi support is often absent or unstable, as it requires proprietary blobs and configurations from Xiaomi to function correctly. On stock MIUI, the likelihood of successful activation is significantly higher.