Modern cellular communications often face the problem of poor coverage inside buildings, where concrete walls shield the signal from base stations. Technology WiFi Calling (or VoWiFi) from MTS solves this problem by transferring voice calls and SMS messages to a Wi-Fi network. It's not just an alternative to a cellular network, but a fully-fledged replacement that runs on the operating system, not as a separate app.
To activate this feature, the user doesn't need to install third-party software or register for additional services. Your smartphone uses your standard phone number, and calls are charged according to your primary plan, just like regular calls. This is especially useful for those living in areas with poor reception, such as basements, offices with thick walls, or country houses.
Before you begin setting up, it is important to make sure that your device is technically compatible with VoWiFiMost modern smartphones released in the last four to five years already have built-in support for this technology, but the software must be updated to the latest version. In some cases, updating the device's firmware or changing carrier profile settings is required.
Checking device compatibility and conditions
The first step to ensuring a high-quality connection is verifying your device's capabilities. Not all models, even popular brands, support specific carriers without additional support. MTS actively collaborates with manufacturers, but the list of supported devices is constantly being updated.
It's crucial that your smartphone has the original firmware or certified software version installed. If you purchased a device intended for other markets (for example, Chinese versions without global firmware), the feature may be blocked at the system level. In this case, standard activation methods will not work.
- 📱 The smartphone must support IMS (IP Multimedia Subsystem) technology.
- 📶 Make sure your device is unlocked and not locked to another carrier.
- 🔄 The operating system must be updated to the latest stable version.
It's also worth keeping in mind that for the service to work correctly, a tariff plan that supports voice calls must be activated. This feature may not be available on archived or specialized data-only plans. Check your current plan in your personal account before setting up.
⚠️ Note: If you have a dual-SIM phone, WiFi Calling settings are applied individually to each SIM card. Make sure you are configuring the MTS SIM card you plan to use for Wi-Fi calling.
Additional restrictions may apply in some regions or when using corporate plans. If you have a corporate number, please check with your system administrator to ensure the service isn't blocked at the network level for your subscriber group.
Activation of the service on the operator's side
Before changing settings in your phone's menu, you must ensure the service is activated in your MTS subscriber profile. In most cases, this process occurs automatically on modern smartphones when you first connect to the network, but sometimes manual confirmation is required.
The fastest way to check the service status is to use a USSD request. Enter the command *111*0181# and press the call button. The system will immediately respond with a message informing you of the current status of the Wi-Fi Calling service. If it's not active, follow the instructions in the reply SMS to connect.
An alternative and more informative method is to use the My MTS mobile app. The VoWiFi status is often displayed in the services and options section. If the feature is available for your number but not yet enabled, you can activate it with a single click directly in the app.
Please note that after activating the service, your carrier may require you to reboot your device. This is necessary for the phone to re-register with the network and receive the latest settings profile from the update server.
Setting up WiFi Calling on iPhone (iOS)
Apple device owners typically encounter the fewest connection issues. The company implements carrier support at the system level, making the process as simple and standardized as possible. However, there are some nuances depending on the iOS version.
First, make sure your iPhone is connected to a Wi-Fi network. Go to the device's main settings and find the "Cellular" section. If your SIM card supports this feature and it's activated with your carrier, you'll see a "Wi-Fi Calling" option.
Turn on the "Wi-Fi Calling on This iPhone" switch. The system may ask you to confirm your emergency services address (E911). This is a standard procedure required by law in many countries, even though your actual address doesn't affect the functionality of this feature in Russia. Enter the requested information or confirm your existing address.
Newer versions of iOS now offer network priority settings. You can configure your phone to prefer cellular data even when Wi-Fi is available, or vice versa. For reliable performance in poor coverage areas, it's best to select "Prefer Wi-Fi."
- 🍏 Path to setting: Settings → Cellular → Wi-Fi Calling.
- 📡 Make sure iMessage and FaceTime are also enabled for full integration.
- 🔒 This feature may require a screen lock password to be enabled.
It's important to note that on devices with two physical SIM cards or one physical and one eSIM, the settings must be checked for each number separately. The switch is located in the settings menu for the specific SIM card.
Instructions for Android smartphones
The Android world is more diverse, and the location of settings may vary depending on the manufacturer (Samsung, Xiaomi, Huawei, Honor) and the version of the operating system. However, the logic remains the same: look in the mobile networks section.
On most devices, the process is as follows: go to "Settings," select "Connections" or "Network & Internet," then "Mobile Network." This is where the "Wi-Fi Calling" or "Wi-Fi Calling" toggle is located. On some Samsung models, this option may be located directly in the notification shade (quick settings panel).
If you can't find the item in the menu, try searching through the settings. Enter "Wi-Fi" or "VoWiFi" in the search bar. The system will automatically tell you where the switch is. It's also worth checking if the "Carrier Settings" app in the Google Play Store is up to date.
☑️ Android Setup Checklist
Xiaomi and Huawei smartphones deserve special attention. Their MIUI and EMUI/HarmonyOS skins sometimes require additional VoLTE activation, as the technologies are closely related. Without VoLTE enabled, the WiFi Calling toggle may be hidden or inactive.
⚠️ Note: Android interfaces are constantly changing. If the described path doesn't match your screen, use the settings search or refer to the official instructions for your model on the manufacturer's website.
Some models, especially those imported through parallel imports, may require changing the region in the phone settings. For example, to ensure proper operation of MTS features on some Xiaomi devices, setting the region to "Russia" or "Germany" in the default device settings helps.
Feature Support Table by Brand
Different manufacturers implement network support differently. Below is a summary table to help you navigate the setup details for popular brands.
| Brand | Menu location | Nuances | VoLTE is required |
|---|---|---|---|
| Samsung | Settings → Connections → Wi-Fi Calling | There is often a menu in the curtain | Desirable |
| iPhone (Apple) | Settings → Cellular | Maximum automation | No |
| Xiaomi / Redmi | Settings → SIM cards → Select card → Wi-Fi calling | VoLTE activation is required with an engineering code on older firmware versions. | Yes |
| Huawei / Honor | Settings → Mobile Network → Wi-Fi Calling | Depends on the firmware region | Yes |
| Realme / OPPO | Settings → Mobile network → SIM card | The interface is close to stock Android. | Yes |
As the table shows, VoLTE support is often a secondary requirement. This is because both technologies use IP protocols to transmit voice, and the operator's infrastructure processes them similarly.
If your phone model isn't on the popular list or is a budget model, it doesn't mean it's not supported. Always check the device's specifications on the manufacturer's official website or in the technical description on the box, looking for the abbreviation VoWiFi.
Troubleshooting and troubleshooting
Even with proper configuration, situations may arise where the feature doesn't work properly. The most common issue is that the phone icon with the handset and the Wi-Fi label doesn't appear in the status bar, even though the settings are enabled.
Data roaming is often the cause. To register with the IMS network (which enables calls), your phone may need to transfer a small data packet. If you're abroad, make sure "Data Roaming" is enabled, even if you don't plan to use the internet. Without it, registering with the voice service network may fail.
What to do if calls are dropped?
If Wi-Fi calls are constantly dropping, try disabling the "Data Saver" or "Power Saving Mode" features. Aggressive power saving can block background network services needed to maintain a connection.
Another common issue is the inability to make a call when the mobile network is turned off. Some carriers and phone models require the primary cellular network to be available for initial authorization. Try turning on mobile data and make sure your phone can see the MTS network, even if you're not making a call through it.
- 🔌 Restart your router: problems may be with your home internet connection.
- 🛡️ Check your antivirus: your firewall may be blocking ports used for VoWiFi.
- 📶 Weak Wi-Fi signal: For a stable call, you need a strong signal; it's best to be closer to the router.
If all else fails, it might be worth deleting your carrier profile. In your SIM card settings, find "Reset network settings" or delete your MTS carrier profile, then reboot your phone. The system will redownload the latest configuration files.
Tariffs and important restrictions
Users are often concerned about the cost. Calls via WiFi Calling are charged the same as regular calls on your plan. If you have free minutes enabled, they will be used. If you are in your home region, calls will be free according to your plan's terms.
However, there's an important nuance with international calls. If you're abroad and connected to Wi-Fi, incoming calls to a Russian number are generally free (just as if you were in Russia). Outgoing calls to Russian numbers are also charged at your home rate, not as roaming charges. However, calls to local numbers in the country of your destination will be considered international calls.
⚠️ Please note: When calling emergency services (112, 102, etc.) via WiFi Calling, there may be difficulties determining your location. The operator sees the address you provided when registering for E911, not your actual location. In emergency situations, it is better to use a regular cellular connection.
It's also worth keeping in mind data usage. Although voice traffic is minimal (around 1-2 MB per minute), it still goes through your Wi-Fi connection. If you have limited home internet or a limited corporate network, this is worth considering.
Frequently Asked Questions (FAQ)
Does making calls over Wi-Fi use up internet traffic?
Yes, traffic is used, but it's through your Wi-Fi connection. If you have unlimited home internet, you won't notice. The data usage is minimal: approximately 60-100 MB per hour of continuous use. With mobile carrier plans, this data usage isn't used because the connection is through your Wi-Fi router.
Can I use WiFi Calling if my SIM card is blocked?
No, for the service to work, the SIM card must be active and registered with the operator's network. If the SIM card is blocked due to non-payment or loss, the service will not work, as authorization in the MTS network core is required.
Does the service work if there is no mobile network coverage at all (for example, in a bunker)?
Yes, this is the primary use case. If your phone is connected to Wi-Fi and the service is configured, you will be able to receive and make calls even in Wi-Fi Only mode (Airplane Mode with Wi-Fi enabled), provided the phone has previously been initially registered with the network.
Why does the screen say "MTS Wi-Fi" instead of "MTS"?
This is normal behavior. The network indicator changes to indicate that the Wi-Fi internet connection is currently being used for voice communications, not the cell tower's radio channel. Once you leave the Wi-Fi zone, the indicator will return to the default.