Modern smartphones, especially popular models from Xiaomi, have become the primary communication tool, but even flagship devices are sometimes helpless against cellular network "dead zones." If you're in a thick-walled building, a basement, or a remote country house where the network indicator shows one bar or disappears entirely, technology comes to the rescue. Voice over Wi-FiThis feature allows voice calls to be transmitted over an internet connection, providing crystal clear sound in areas where regular cellular service is ineffective.
Activation Wi-Fi Calling on devices Redmi And POCO It doesn't require installing third-party apps like Skype or Viber, as it uses a standard phone number and the built-in dialer interface. The operator treats these calls as regular calls, charging them according to your minute plan, making the technology cost-effective and convenient. In this article, we'll take a detailed look at how to enable Wi-Fi calling on Xiaomi and the nuances of different versions. MIUI And HyperOS, and what to do if the desired button does not appear in the menu.
Before you begin setting things up, you need to make sure your device and SIM card are technically ready to work with packet voice. Most modern smartphones Xiaomi support this feature out of the box, but the software shell may hide the switch depending on the firmware region. The key requirement is that your mobile operator supports VoWiFi technology., because without this, calls through the router will not work, even if the phone is fully functional.
Technological principles and equipment requirements
Technology VoWiFi (Voice over Wi-Fi) is the transmission of voice traffic via IP protocols, similar to how instant messaging apps work, but at a deeper system level. Unlike app-based calls, it doesn't require a separate account or the other party's consent to use specific software. Smartphone Xiaomi Automatically routes calls through an available wireless network if the cell tower signal is too weak to establish a connection. This is especially useful in dense urban areas or industrial zones.
To successfully implement Wi-Fi calling, your device must meet a number of technical requirements. First and foremost, this means support for standards. IMS (IP Multimedia Subsystem), which are built into modern processors and modems. Smartphones XiaomiDevices released in the last four to five years are generally fully compatible with this protocol. However, it's important to understand that the software implementation depends on the operating system version and the device's regional configuration.
⚠️ Note: If you're using a custom ROM or a global version flashed from a Chinese version, this feature may be blocked by software. In such cases, you'll need to edit system files or change your region.
Additionally, the quality of your home or office router is critical. An unstable connection, high ping, or packet loss will result in interrupted calls or no sound at all. It is recommended to use a network with a frequency 5 GHz, which is less congested and provides more stable data transmission in real time, which is critical for voice communications.
Checking operator and tariff compatibility
Even the most powerful flagship Xiaomi You won't be able to make calls over Wi-Fi if your mobile operator doesn't offer this service or it's not activated on your SIM card. In Russia and the CIS, major operators are gradually rolling out support. Voice over Wi-Fi, but conditions may vary. Some tariff plans require a separate activation of the service, while others have it enabled by default.
Users often encounter a situation where the phone detects the network, but the toggle switch is missing in the settings. This is a sure sign that the carrier hasn't transferred the configuration profile to the phone or hasn't authorized the technology for this subscriber. You should contact your personal account or the provider's support team to check the service status. It's also worth checking whether the feature is blocked at the tariff level, especially if you're using archived plans.
Below is a table showing the approximate status of technology support among major operators (data may change, so check official resources for up-to-date information):
| Operator | VoWiFi support | Need for connection | Peculiarities |
|---|---|---|---|
| MTS | Yes | Automatically / Personal account | Network profile update required |
| Megaphone | Yes | Personal account / USSD | Works in roaming |
| Beeline | Yes | Personal account | 4G support required |
| Tele2 | Yes | Automatically | Available on most plans |
It's important to note that having carrier support is only half the battle. Your plan must include voice calls, as Wi-Fi calls use up your package's minutes, not your data plan (although signaling uses a minimal amount of data). If you run out of minutes, Wi-Fi calls won't work or will be charged at an additional rate.
Basic setup via smartphone menu
If your operator has confirmed support for the service, the next step is to activate the function directly on the device. XiaomiThe settings interface may differ slightly depending on the shell version. MIUI or HyperOS, but the logic remains the same. You'll need access to the SIM card and mobile network menus.
To get started, open the default Phone app or go to the general system settings. Find the section responsible for SIM card management. Both SIM cards are usually displayed here if your device has dual SIM. Select the card for which you want to enable Wi-Fi calling. In the menu that opens, look for "Wi-Fi Calling" or "Wi-Fi Calling."
☑️ VoWiFi Enablement Algorithm
After turning on the switch, the system may ask for confirmation or a device reboot. In some cases, the smartphone will prompt you to select a network priority: "Prefer Wi-Fi" or "Prefer Mobile Network." Selecting the former will force the phone to always attempt to make a call over a wireless network when available, saving battery power in areas with weak cellular coverage.
Sometimes the desired option is hidden deep within a menu. Try searching through the settings by searching for "Wi-Fi." If the search doesn't yield any results, your phone's region settings may not match your SIM card's region. Changing the region to "Russia" or your country of residence often unlocks hidden features.
Activation via the engineering menu and codes
In situations where the standard switch is missing, hidden diagnostic menus come to the rescue. On smartphones Xiaomi Advanced settings can often be accessed through special USSD codes or the engineering menu. This method is riskier, but it allows you to force support. IMS And VoWiFi.
One of the most effective ways is to use a code to enter the testing menu. Enter the command in the dialer ##86583##If the code is entered correctly, you should see the message "IMS Feature Switcher Disabled" (or "Enabled" if it's already enabled). Entering the command again will change the status. Afterwards, restart your phone and check if the switch appears in Settings.
⚠️ Caution: Do not change other parameters in the engineering menu unless you are sure of their purpose. This may result in incorrect operation of the communication module or complete loss of network connectivity.
Another useful code is - ##4636##This opens the testing menu, where you can select "Phone Information." Here, scroll down to "Set preferred network type." Make sure you select a mode that supports LTE and IMS, for example, LTE/TD-SCDMA/CDMA EvDo/GSM/WCDMAThe presence of IMS support is often indicated by a separate line or checkbox in the same menu.
What to do if the codes don't work?
Some carriers or firmware versions block access to engineering codes. In this case, install the Activity Launcher app from Google Play, navigate to "Settings" -> "SIM cards," and try accessing the hidden activity menu. However, this requires caution.
It's worth remembering that after updating the firmware, the settings may be reset, and the procedure will have to be repeated. If the codes stop working after an Android update, this may mean the manufacturer has patched a vulnerability or changed the menu structure. In this case, you'll have to wait for an update from your carrier or change your region.
Setting up a router for stable calls
The quality of Wi-Fi calls directly depends on your router's configuration. Default settings are often designed for maximum compatibility, which doesn't always translate into the best performance for voice traffic. To ensure connection stability, Xiaomi It is recommended to carry out a number of optimizations.
First of all, make sure that the router is in the enabled mode. WMM (Wi-Fi Multimedia). This protocol prioritizes multimedia traffic, including voice packets, over regular web surfing or file downloads. Without WMM enabled, a phone may take a long time to establish a connection or interrupt a call while downloading updates in the background.
It's also important to choose the right wireless network channel. In apartment buildings, the airwaves are clogged with signals from neighboring routers, which creates interference. Use Wi-Fi analyzer apps on your Xiaomito find a free channel and fix it in the router settings. For the range 2.4 GHz It is better to choose channels 1, 6 or 11, and for 5 GHz - those that do not intersect with radar ones.
- 📡 QoS (Quality of Service): If your router supports QoS, set the priority for your smartphone's IP address or for the ports used by your operator.
- 🔒 Safety: Use an encryption protocol WPA2-AES or WPA3Outdated protocols (TKIP, WEP) can slow down the connection and cause lags.
- 🔄 Roaming: If you have a mesh system, make sure that the transition between access points is configured correctly so that the call does not drop out as you move around your home.
Solutions to common problems and errors
Despite proper configuration, users may encounter issues. One common error is that the handset icon with the Wi-Fi symbol appears, but calls fail or are immediately dropped. This often indicates a problem registering with the operator's IMS network. Try turning Airplane Mode on and off to restart the communication module and re-register with the network.
Another common situation: calls are made, but the other person can't hear you, or they hear you with a significant delay. This is a classic symptom of problems with NAT or the router's firewall. Try temporarily disabling the router's firewall or enabling UPnP. Also, check if your router has a bandwidth limit for your device.
In some cases, resetting network settings helps. Go to Settings → Connection and sharing → Reset Wi-Fi, mobile networks, and BluetoothPlease note that this action will delete saved passwords from Wi-Fi networks, but it often resolves software conflicts that interfere with operation. VoWiFi.
Impact of MIUI version and region on functionality
Company policy Xiaomi The software's functionality is highly dependent on the region selected during initial launch or in the settings. Global firmware versions (Global ROMs) typically have a full feature set but may lag behind in implementing new features for specific regions. Chinese versions (CN ROMs) often lack preinstalled profiles for European or Russian operators.
If you purchased a phone intended for the Chinese market and flashed it to a global firmware, you may encounter a missing Wi-Fi Calling switch. This is due to the system files not having configurations for local carriers. A solution may be to change the region in your phone settings to your country or install a local firmware version (e.g., Russia Global).
Owners of devices with an unlocked bootloader and custom firmware (LineageOS, Pixel Experience) should be aware that VoWiFi functionality depends on the presence of proprietary blobs (binary files) from the manufacturer. Without the original modem and vendor files, Wi-Fi calling will not work, as it requires carrier certification, which is baked into the original firmware.
Why did the VoWiFi icon disappear after the update?
System updates often reset user settings or change carrier configuration files. After a major MIUI/HyperOS update, it's recommended to recheck your SIM card settings and, if necessary, re-enter the engineering code to activate IMS.
Does Wi-Fi Calling use up internet traffic?
Technically, data usage is used, but operators typically don't charge per megabyte if the call is to numbers within their region. However, if you're abroad, the rules may differ, and a Wi-Fi call may be considered a roaming call. Check with your operator before traveling.
Is it possible to make calls via Wi-Fi if the SIM card is not found?
No. VoWiFi requires an active SIM card for authentication with the operator's network. Without a SIM card, the phone will not be able to register with the IMS subnet, and the call will fail.
Does Wi-Fi Calling work on two SIM cards at the same time?
Yes, modern smartphones Xiaomi Allows you to activate VoWiFi for both SIM cards simultaneously, if both cards and carriers support this feature. The switch will be available for each SIM card separately in the settings menu.