Modern mobile communications have long ceased to be limited only by the coverage of cell towers, especially in dense urban areas or rural areas with a weak signal. Technology Voice over Wi-Fi (VoWiFi) has become a real lifesaver for subscribers, allowing them to make and receive voice calls in areas where regular GSM or LTE coverage is poor or nonexistent. For MTS users, this feature is available under the name WiFi Calling and does not require the installation of additional applications, working at the level of the native phone book.
The main advantage of this technology is that the call is made over the internet but is charged at your primary plan, just like a regular outgoing call, which is especially important when roaming. To use this feature, your smartphone must support the VoWiFi standard, and the corresponding option must be enabled in the device settings and on the carrier's end. In this article, we'll detail the service setup process, check the compatibility of popular models, and address common setup errors.
Before getting started, make sure your SIM card is registered to the 4G/LTE network, as this is a basic requirement for modern voice services. If you have an older SIM card, issued many years ago, you may need to replace it at a mobile phone store, but in most cases, the update occurs automatically when you reboot your device. The WiFi Calling feature on MTS devices only works when there's an active Wi-Fi connection and doesn't switch to mobile internet if there's no cellular signal at all.
What is WiFi Calling and how does it work?
Technology Voice over Wi-Fi It's a method for transmitting voice calls over IP, using a wireless local area network instead of a cellular operator's radio channel. Unlike popular instant messaging apps, which require a separate app and an account with the other person, VoWiFi Integrated directly into the smartphone's system software, this means you dial the number as usual, and the call is automatically routed through the Wi-Fi router to MTS's gateways.
The principle of operation is to create a secure tunnel between your device and the operator's server, guaranteeing high-quality communication and privacy. The signal is immune to interference typical of radio waves in basements or buildings with thick walls, as long as the Wi-Fi channel itself is stable. Switching between Wi-Fi and cellular networks can occur automatically, but in the current implementation, on most devices, when leaving the router's coverage area, the call may be dropped or switched to a regular network if the Handover feature is supported.
The use of this service is especially relevant for the following categories of users:
- 📶 Residents of buildings with poor indoor cellular coverage (monolithic walls, basements).
- ✈️ Travelers abroad who want to avoid roaming charges for incoming calls.
- 🏢 Office workers in buildings with shielded signal, where mobile communications are unstable.
It's important to understand that sound quality directly depends on the speed and stability of your internet connection. When using technology HD Voice Wi-Fi provides crystal-clear sound, superior to traditional telephony. However, if the channel is congested with other devices or the provider limits the speed, delays or artifacts may occur during calls.
⚠️ Please note: When using WiFi Calling while roaming internationally, incoming calls may be charged as local calls, but outgoing calls may be charged at your home region's rates or special roaming terms. Always check the current pricing terms in your personal account before traveling.
Checking device and tariff compatibility
Before attempting to activate the service, you must ensure that your equipment is technically capable of supporting the standard. VoWiFiNot all smartphones, even those released in recent years, have native support for this feature for Russian carriers, as software certification is required. The list of supported devices is constantly expanding, including models from Apple, Samsung, Xiaomi, and other manufacturers.
For the technology to work correctly, it's also important that the device has the latest version of the operating system installed. MTS regularly updates settings profiles, and older versions of iOS or Android may not contain the necessary parameters for authorization on the VoWiFi network. Furthermore, the SIM card must be a USIM standard with 4G support, which is a prerequisite for modern voice services.
Below is a table of popular smartphone models and their current technology support status:
| Device model | operating system | Support status | Note |
|---|---|---|---|
| iPhone 6 and newer | iOS 13+ | Full | Operator profile update required |
| Samsung Galaxy S10+ | Android 10+ | Full | Reflashing may be required |
| Xiaomi Mi 11 | MIUI 12+ | Partial | Depends on the firmware region |
| Huawei P40 Pro | EMUI 10+ | Full | It works stably. |
If your model isn't listed or the status is marked as "Partial," this doesn't mean the feature won't work, but it may require additional configuration via the engineering menu or a software update from the manufacturer. For device owners Samsung And Xiaomi Often you have to manually enable the option in hidden menus if it does not appear automatically after an update.
How to find out the firmware version?
To check your software version, go to Settings → About phone (or About device). Look for the line "Software version" or "Build number." For stable VoWiFi operation, it is recommended to use global firmware versions (Global ROM) rather than Chinese or Indian ones, as they may lack the necessary operator certifications.
Activating the service in your MTS personal account
The first step in the setup process is activating the service with your carrier. Even if your phone supports the technology, Wi-Fi calls won't work without this option enabled in your subscriber profile. This can be done in several ways, but the most reliable and quickest is through your personal account or mobile app.
Log in to the "My MTS" app or the operator's web portal using the code sent via SMS. In the services or plan settings section, find the "Wi-Fi Calling" option (sometimes called "Wi-Fi Calling"). Toggle the slider to the on position. The system may request confirmation via SMS, after which the service will be activated immediately or within a few minutes.
Alternative activation methods include:
- 📞 Entering a short code
*111*197#(code may vary, current at the time of writing). - 💬 Send an SMS with the text "ON" to the service's short number (specified on the website).
- 👤 Contact the support chat or MTS mobile phone store.
After activating the service with your operator, we recommend rebooting your smartphone. This is necessary for the device to re-register with the network and receive an updated profile with the new settings. If the service icon doesn't appear after rebooting, check your account balance—the service is free, but requires a positive balance to be available.
☑️ Checklist before activation
Setting up WiFi Calling on iPhone (iOS)
Apple smartphone owners are the luckiest of all, as the setup Voice over Wi-Fi on iOS is extremely simple and often automatic. After you've activated the service in your MTS account and connected to a Wi-Fi network, an "MTS Wi-Fi" icon or similar should appear on the lock screen or in the notification shade.
If automatic activation does not occur, you will need to check the settings manually. Go to Settings → Cellular → Wi-Fi CallingMake sure the "Wi-Fi Calling on This iPhone" switch is turned on. You can also enable the "On Other Devices" option if you use an Apple device (iPad, Mac) and want to receive calls on them.
In some cases, especially after updating iOS, you may need to update your carrier settings. To do this, go to Settings → General → AboutIf an update is available, the system will prompt you to install it. Apple iPhone uses eSIM technology and physical SIM cards equally effectively for this function, so the type of SIM card does not matter.
⚠️ Please note: The emergency services address (E911) may not be accurately determined when calling via Wi-Fi, as it is based on the location of the router, not the cell tower. When calling emergency services, always provide your exact address to the dispatcher.
Frequent travelers should be aware that when leaving a Wi-Fi zone, your iPhone can automatically switch calls to cellular data if supported by your carrier and enabled in settings. However, when roaming, it's best to keep this option under control to avoid unintended charges.
Instructions for Android smartphones
On devices running Android The setup process may vary slightly depending on the manufacturer and shell version. The general principles remain the same, but the menu paths may have different names. Make sure you're using the original Phone app or a supported alternative, as third-party dialers may not have access to system VoWiFi features.
The standard activation process is as follows: open the "Phone" app, tap the three dots (menu), and select "Settings." Find the "Wi-Fi Calling" or "Wi-Fi Calling" section and enable it. On some models (e.g., Samsung), the process may be as follows: Settings → Connections → Wi-Fi Calling.
If you can't find this option in the standard menu, try the following:
- 🔍 Enter the phrase "Wi-Fi Calling" in the phone settings search.
- 📱 Make sure that "4G/LTE" or "5G" mode is selected in your mobile network settings.
- 🔄 Update the Phone app and Google Play services through the app store.
For smartphone owners Samsung And Xiaomi Sometimes you need to enter a special code in the engineering menu to force the feature to be enabled if it's hidden by your provider. However, this is rarely necessary for MTS, as the carrier actively certifies popular models. If your phone doesn't detect the VoWiFi network, try deleting the Wi-Fi network profile and reconnecting using the password.
Troubleshooting connection issues and errors
Despite the simplicity of the technology, users may encounter a number of difficulties when connecting. Most often, the problem lies in device incompatibility or outdated software. If you've followed all the steps and the feature still isn't working, check the list of supported devices again and make sure your phone model actually supports it. VoWiFi in the MTS network.
Another common cause is port blocking by your home internet provider. Some providers may block SIP traffic or ports required to establish a secure connection to the provider's servers. In this case, changing the DNS servers in your router settings or using an alternative Wi-Fi network for testing may help.
Common mistakes and their solutions:
- ❌ Registration error: Restart your phone and router. Check if the SIM card is active.
- ❌ Calls are disconnected: Check your internet speed. HD audio requires a stable connection of at least 1 Mbps.
- ❌ No icon in status bar: The icon may not appear on some models, but the feature will still work. Check in the settings.
It's also worth keeping in mind that corporate Wi-Fi networks in offices or public places (cafes, airports) often have restrictions on voice traffic. In such cases, you can connect to the network, but you won't be able to make calls. Use the MTS mobile app or your personal account to check the service status if standard methods don't help.
⚠️ Note: Menu interfaces and option availability may change after operating system updates. If you don't find the item you're looking for, search for a similar one or refer to the manual for your specific phone model.
What to do if nothing helps?
If none of the above helps, perform a full network settings reset (not data reset!). This will return all network settings to factory defaults. Go to Settings → System → Reset → Reset network settings. Then, re-enter your Wi-Fi password and test the reset function.
Frequently Asked Questions (FAQ)
Does MTS charge extra for using WiFi Calling?
No, using technology Voice over Wi-Fi Free. Call minutes are deducted from your main plan, just like cellular calls. You only pay for the data traffic unless you're connected to your home or free Wi-Fi.
Does WiFi Calling work if there is no mobile connection at all?
Yes, this is the primary purpose of this technology. If your SIM card can't see the network (for example, in a basement or out of town), but is connected to Wi-Fi, you'll still be able to make and receive calls. In this case, the screen will usually display the "MTS Wi-Fi" or "R" (Roaming) icon, even if you're at home.
Can I use WiFi Calling while roaming abroad?
Yes, this is a great way to save money. While abroad, you connect to local Wi-Fi and make calls as if you were in Russia (at your home region's rates). Incoming calls are often free, but the exact terms depend on your plan.
Why does the WiFi Calling icon appear and disappear?
This could be due to an unstable Wi-Fi signal or the phone switching between networks. The phone may also try to prioritize the cellular network if the LTE signal is strong enough. Check the network priority settings in the call menu.