Modern communications are no longer tied to metal cell phone towers, especially when indoor signal strength is poor. MTS's VoWiFi (Voice over Wi-Fi) technology allows voice calls to be made through a wireless internet access point, providing crystal-clear sound in areas where traditional networks can only reach one network. This solution is ideal for residents of thick-walled apartment buildings or office buildings where base stations are overloaded.
The technology utilizes IP-based voice traffic, bypassing traditional cellular channels. For the subscriber, the process remains completely transparent: simply dial the number, and the phone automatically selects the best connection channel. The main advantage The problem is that the quality of the call depends not on the distance to the tower, but on the stability of your home router.
Many users still don't know that their smartphones support this feature out of the box, and MTS plans don't require an additional fee for its use. In this article, we'll cover in detail how to activate this feature, which devices support the technology, and how to avoid issues with switching between networks during a call.
How does VoWiFi technology work and why is it needed?
Voice over Wi-Fi technology turns your smartphone into an IP phone, using your broadband connection for voice transmission. Unlike messaging apps, where calls are routed through the app's server, MTS Wi-Fi calls are integrated into your phone's default dialer. This means you don't need to open a separate app, wait for a connection, or explain to your caller that you're on WhatsApp or Telegram—they'll see your regular number.
This service is especially useful in areas with strong Wi-Fi coverage but weak cellular signal, such as basements, lower floors of buildings, or remote country houses. MTS Routes traffic through its security gateways, guaranteeing conversation privacy. Furthermore, when moving from Wi-Fi to cellular coverage (if supported by the device and operator) or vice versa, the connection can be maintained without interruption.
It's worth noting that this feature doesn't require a separate SIM card for internet if you already have a plan with a minute bundle. Voice traffic is typically charged according to your main plan, just like regular minutes. However, if you're abroad, the terms may differ, so In international roaming, calls made via Wi-Fi are often charged as if they were coming from your home region., which is significantly cheaper than standard roaming.
Requirements for the subscriber's device and tariff
Not all smartphones and data plans support VoWiFi, although the list of compatible devices is constantly growing. First and foremost, your device must have the appropriate module and software. MTS regularly updates its database of supported models, which includes flagship and mid-range devices from leading manufacturers.
For proper operation, the device must have the latest version of the operating system installed. Manufacturers often add support for this technology through firmware updates, even if the model originally didn't have this feature. It's also important to upgrade the SIM card to a USIM format (usually all cards issued within the last 5-7 years), as older cards may not support the required encryption protocols.
Regarding tariffs, MTS offers the service free of charge for most modern archives and current offers. However, if you have a very old tariff plan, it may need to be updated. You can check compatibility in your personal account or via USSD request. Below is a table of the basic requirements for different platforms.
| Parameter | iOS (iPhone) | Android | MTS requirements |
|---|---|---|---|
| OS version | iOS 13 and later | Android 9.0 and later | Current firmware |
| Models | iPhone 5s and newer | Samsung, Xiaomi, Huawei, etc. | Certified devices |
| SIM card | USIM (4G/5G) | USIM (4G/5G) | Replacement in the salon if necessary |
| Settings | In the cellular communications menu | In the connections menu | Activation on the operator side |
Step-by-step instructions: how to enable it on iPhone
Apple device owners are especially fortunate, as setting up this feature on iOS is incredibly simple and often doesn't require complex navigation through your carrier's menu. First, make sure your iPhone is updated to the latest available version of iOS. Go to Settings, select "Cellular," and find "Wi-Fi Calling."
If you don't see this switch, the service may not yet be activated by your operator. In this case, you can try sending a USSD command or using the "My MTS" app. After turning on the switch, the system may request your emergency services address (E911), which is a standard procedure for location registration.
☑️ Pre-Power Check on iPhone
Once activated, a "Wi-Fi" icon or the text "MTS Wi-Fi" will appear in the status bar next to the operator's name. This indicates that the phone is ready to make and receive calls over the wireless network. If the icon disappears, check your internet connection—the router may be rebooting or there may be a problem with your provider.
Setting up the feature on Android smartphones
In the Android world, the situation is a bit more varied due to the presence of numerous skins from different manufacturers. The path to setting up the app may vary, but the logic remains the same. Typically, the function is located in the menu. Settings → Connections → Wi-Fi CallingOn Samsung devices the path may look like this Settings → Connections → Mobile network → Wi-Fi calling.
On Xiaomi, Realme, and other smartphones running MIUI or ColorOS, the menu may be hidden deeper. Sometimes you need to enable developer mode or use the engineering menu, but most often, finding the toggle in the main network settings is enough. If the menu is empty, try resetting the network settings to factory defaults, but keep in mind that this will delete saved Wi-Fi passwords.
⚠️ Attention: On some Android models (for example, older versions of Huawei or Honor), this feature may be software-locked by the manufacturer for a specific region. In this case, updating the firmware or changing the region may not help.
It's also important to check your network priority. In the settings, you can select "Prefer Wi-Fi" or "Always use Wi-Fi." The former will allow your phone to switch to the mobile network if the Wi-Fi signal becomes too weak for voice communication, ensuring uninterrupted conversations.
What should I do if the Wi-Fi Calling option is grayed out or inactive?
If the switch is grayed out, try removing and reinserting the SIM card. Also, make sure your date and time settings are set to automatic. Sometimes, temporarily disabling VPN services that may be blocking your carrier's ports can help.
Roaming pricing and features
One of the most frequently asked questions concerns the cost of such calls. Domestically (in your home region), the rates are the same as your main plan. Minutes spent on Wi-Fi calls are deducted from your plan's volume or charged at the base rate, like regular calls.
The situation changes dramatically when you're abroad. This is where the main "secret" to saving money lies. If you're roaming internationally and connecting to Wi-Fi at a hotel or café, incoming and outgoing calls may be charged as domestically (depending on the terms of your specific MTS plan). This allows you to avoid huge communication bills.
However, it's important to pay attention to details. If you leave the Wi-Fi coverage area during a call and your phone switches to a local mobile operator, your roaming charges will immediately change to standard roaming rates, which can be very expensive. Therefore, when traveling, it's recommended to temporarily disable mobile data and voice calls, leaving only Wi-Fi Calling enabled.
Possible problems and solutions
Despite the simplicity of the technology, users may encounter a number of difficulties. The most common is an inability to activate the service. Often, the problem lies in the carrier profile not being updated. Try turning Flight Mode on and off or simply restarting your smartphone.
Another common issue is intermittent audio or a "robotic" voice. This indicates an unstable internet connection or high latency (ping) on your Wi-Fi network. If your router is old or overloaded with devices, connection quality will suffer. In this case, rebooting the router or switching to a different frequency band (5 GHz instead of 2.4 GHz) may help.
| Problem | Possible cause | Solution |
|---|---|---|
| No Wi-Fi icon | The service is not activated by the operator. | Call 0899 or check in the app |
| Communication breakdowns | Weak router signal | Move closer to the access point |
| Doesn't work in roaming | Roaming option not enabled | Activate roaming in your phone settings |
| Outgoing only | E911 registration error | Check the address in iOS/Android settings |
It's also worth considering that some corporate Wi-Fi networks (in offices and airports) may block ports required for VoWiFi. In such cases, the only solution is to use mobile data or find an alternative network.
Frequently Asked Questions (FAQ)
Does making calls over Wi-Fi use up internet traffic?
Technically, data usage is used, but operators, including MTS, typically don't charge this data separately if you're in your home region. When roaming, Wi-Fi traffic is also typically not charged as data roaming, but it's best to check your plan's terms.
Is it possible to make calls via Wi-Fi if the SIM card is blocked or there is no signal?
Yes, this is the primary purpose of this technology. If your SIM card is locked with a PIN or in an unreachable area, but Wi-Fi is connected, you'll still be able to make emergency calls and phone calls if your device supports offline calling (depending on the model and settings).
Does Wi-Fi Calling affect internet speed?
A voice call takes up minimal bandwidth (around 64-128 kbps). At modern speeds, this is practically unnoticeable. However, if you're downloading large files or watching 4K video, call quality may degrade due to limited router resources.
⚠️ Attention: Pricing terms and supported devices are subject to change. The operator reserves the right to update its technical policy. Always check the operator's official app or website for up-to-date information.