Mobile communications have become an integral part of life, but cell tower coverage isn't always ideal, especially within buildings with thick walls or in remote areas. Many users are familiar with the situation where their phone shows a single bar or no service at all. VoWiFi technology offers a solution to this problem, allowing you to make and receive voice calls over the internet using a standard phone number.
This feature is available free of charge for MTS subscribers and doesn't require installing any additional apps if your smartphone and data plan support it. This means you can continue using your regular number even in areas with poor cellular coverage, as long as you have a stable Wi-Fi connection.
In this article, we'll cover in detail how to activate the service, which devices support the technology, and how to avoid unnecessary charges. You'll learn the intricacies of setting it up on different operating systems and understand the differences between Wi-Fi calling and popular messaging apps. VoWiFi technology (Voice over Wi-Fi) is not just a SIM card replacement, but a complete expansion of your operator’s coverage area.
What is VoWiFi and how does it work with MTS?
Technology Voice over Wi-Fi (VoWiFi) allows voice traffic to be transmitted over the internet, bypassing standard GSM, 3G, or LTE cellular frequencies. For the subscriber, the process is completely transparent: you dial a number from your phone book and make a call as usual. MTS, the mobile operator, uses secure tunnels to transmit your voice, ensuring high sound quality and a secure connection.
The main advantage is that calls are charged according to your basic minute package. If you have unlimited calls to Russian numbers enabled, they are also free over Wi-Fi. This is especially important when roaming abroad: while roaming, you can connect to local Wi-Fi and call Russian numbers at the rates of your home region, saving you significant money.
It is important to note, that the technology requires hardware support. The smartphone must have the appropriate module and software, and the operator must have the implemented infrastructure. MTS is actively developing this network, allowing the use of VoWiFi in thousands of populated areas.
⚠️ Attention: Make sure your plan doesn't limit the use of additional features. While the service itself is free, some archived plans may require a basic package to activate advanced features.
This feature doesn't require you to remember complex codes or navigate special dialing menus. All the magic happens in the device's network settings and firmware. The carrier automatically detects that you're in an area with strong Wi-Fi but poor cell tower coverage and switches the call routing.
Checking device and SIM card compatibility
Before setting up, you need to ensure your equipment is ready to work with modern communication standards. Not all smartphones, even relatively new ones, have software support for VoWiFi for specific carriers. This often depends on the region of purchase and the firmware version of the device.
First of all, check if yours supports it smartphone This feature. The list of compatible models is constantly expanding and includes devices from Apple, Samsung, Xiaomi, Huawei, and other manufacturers. If the phone was officially purchased in Russia, the likelihood of support is highest.
The condition of the SIM card is also critical. Old Mini-SIM cards or cards issued many years ago may not work correctly with new authentication protocols. If your SIM card is more than 5-7 years old, is a non-standard size, or has been manually cut, it is recommended to replace it.
Card replacement at MTS stores is usually free and takes just a few minutes. The new card will have updated security profiles required for VoWiFiAfter replacing the device, make sure that 4G/LTE mode is enabled in your mobile network settings, as the technology is often tied to IMS data packets.
| Parameter | Requirement | Where to check |
|---|---|---|
| Phone model | VoWiFi support | Settings -> Mobile network |
| SIM card | USIM (4G/4G+) | Visual inspection, age of the card |
| operating system | Current version | Settings -> About phone |
| Service status | Active | Personal account or USSD |
Activation of the service on the operator's side
Even if the phone is fully ready, the service must be enabled on the network. MTS offers several ways to activate Wi-Fi Calling. The fastest way is using a USSD command, which works on any phone without internet access.
Type the command on your phone keypad *111*878# and press the call button. You will receive a confirmation message confirming activation. Alternatively, you can use a short code. *151#, where in the menu you need to select the appropriate item to manage services.
What to do if the command doesn't work?
If the USSD code returns an error, this may mean the service is already activated by default on your plan, or your plan doesn't support this option. Try logging into your personal account to check the status.
A more convenient and informative way is to use the "My MTS" mobile app or your personal account on the website. In the "Services" section, find the "Communications" or "Internet" category. There you'll find a "Wi-Fi Calling" toggle.
Use the service search in the app by entering "Wi-Fi." If the service is available for your number, you'll see a "Connect" button. Once activated, the status will change to "Active." Please note that changes may take a few minutes to take effect.
Setting up iPhone (iOS) for Wi-Fi Calling
Apple smartphone owners are fortunate to have the simplest setup process. The iOS ecosystem integrates communication technologies deeply, and features are managed through the standard settings menu. Make sure your iPhone is updated to the latest version of iOS.
To activate, go to Settings, then select the section Cellular communications. Find the item Wi-Fi callingMove the slider to the active position. The system may request address verification for emergency services—this is a standard procedure required by law.
☑️ iPhone Setup Checklist
Once enabled, you'll see "MTS Wi-Fi" or "MTS Wi-Fi" in the status bar next to your carrier's name. This indicates that your phone is ready to route calls over the wireless network. If you're within range of a cellular network, your phone will prioritize it, switching to Wi-Fi only when the signal degrades.
In some cases, especially when using two SIM cards, you need to configure each line separately. Select the desired number in the "Cellular" menu and repeat the process. iOS Allows flexible control over which SIM card uses the Internet tunnel for voice communications.
Instructions for Android smartphones
On Android devices, the setup path may vary slightly depending on the manufacturer and OS version. The general principles remain the same, but menu names may vary.
Go to Settings, select Connections or Network and Internet. Find the section Mobile network or SIM cards. Search for the item Wi-Fi calling or Wi-Fi Calling. Activate the switch.
If you don't see this option in the menu, it may be hidden in the engineering menu or not supported by the firmware. For Samsung devices, the following path often works: Settings -> Connections -> Wi-Fi callingMake sure you have the latest version installed in the About phone -> Software details menu.
On some models, for example, from Xiaomi or HuaweiAdditional activation via the engineering menu may be required, but this is risky for inexperienced users. It's best to wait for an official firmware update from the manufacturer that will add support for MTS.
Tariffs and features of use in roaming
One of the most frequently asked questions concerns the cost. MTS lists Wi-Fi calls as part of its basic package. This means your minutes are charged the same as if you were calling through a base station. If you have the "Unlimited" package, calls are free.
Particular attention should be paid when traveling abroad. While roaming, you can connect to Wi-Fi at a hotel or cafe and call Russian numbers. In this case, the rates for your home region will apply, rather than roaming rates. This allows you to save significantly by avoiding roaming charges for incoming and outgoing calls in other countries.
⚠️ Attention: Special rates may apply when making calls from roaming via Wi-Fi to numbers in your host country or third countries. Always check the per-minute rate for a specific destination in your operator's app before making a long call.
It's important to remember about data usage. Voice data is consumed from your Wi-Fi plan. Call quality directly depends on the speed and stability of your wireless connection. For a comfortable conversation, a speed of at least 1 Mbps is recommended.
Diagnosing problems and troubleshooting
Despite the simplicity of the technology, glitches can sometimes occur. If the "Wi-Fi" icon next to the operator's name doesn't appear and calls aren't connecting, try a few checks. First, make sure you're connected to a Wi-Fi network and not using mobile data.
Try restarting your smartphone. This refreshes the IMS network registration and often resolves issues with "sticky" status. Also, check that Airplane Mode isn't enabled. While modern smartphones can enable Wi-Fi while Airplane Mode is active, VoWiFi sometimes requires full radio functionality.
If the issue persists, check your date and time settings. Incorrect time can disrupt encryption and authentication on your carrier's network. Set automatic time synchronization via the network.
In rare cases, the problem may be with your Wi-Fi provider. Some corporate or public networks block the ports needed for VoWiFi. Try connecting to a different network or sharing Wi-Fi from another phone to check.
Why do calls drop when I leave a Wi-Fi zone?
Handover technology (transferring a call from Wi-Fi to a mobile network) is not supported by all phone models or in all regions. If your smartphone doesn't support seamless handover, the call will simply be disconnected if the Wi-Fi signal is lost.
Do people I'm talking to hear me worse over Wi-Fi?
HD Voice over Wi-Fi is often even better than over a regular network, thanks to the high-quality codec used. However, if the internet connection is congested (due to someone downloading files), artifacts or delays may occur.
Is it possible to make calls over Wi-Fi if there are 0 rubles on my account?
If you have a postpaid plan or a minute bundle, calls will work. If you have a prepaid plan and your balance is zero and your minute bundle is exhausted, the call will fail, as authorization in the IMS network also requires a positive balance or bundled resources.