How to set up calls via MTS WiFi: A complete guide

The modern pace of life dictates its own rules, and mobile access must be stable anywhere. However, smartphone owners often face situations where signal level The signal drops to a critical minimum or disappears completely, despite having a strong reception outside. This is especially true for residents of apartment buildings with thick walls, office buildings with shielding, or remote summer cottages.

Fortunately, telecom operators, including MTS, have implemented technology that allows voice calls to be made over an internet connection. This feature, known as VoWiFi (Voice over WiFi) transforms a regular wireless router into a cellular network access point. Enabling calls via MTS WiFi requires no additional apps—everything works through the standard dialing interface, ensuring high-quality audio and uninterrupted communication.

In this article, we'll cover in detail how to activate this feature on various devices, the operator's requirements, and how to resolve common service registration issues. You'll learn why this technology is often better than messaging calls and how it helps conserve smartphone battery life in conditions with poor cell tower coverage.

What is VoWiFi and why does an MTS subscriber need it?

Technology VoWiFi This is the transmission of voice traffic over IP network protocols. Unlike the popular VoIP found in messaging apps, it uses the telecom operator's own infrastructure. For the subscriber, this means the call is placed through a regular phone number, charged according to your minute plan, and appears in the standard call history. No separate accounts or registration with third-party services are required.

The main advantage is the ability to penetrate concrete barriers where radio signals fail. If you only get 2G at home, or the connection is constantly dropping, and your Wi-Fi router is showing a full load, then switching to Wi-Fi Calling will be the ideal solution. Furthermore, the sound quality of HD Voice using a wideband codec often surpasses that of standard cellular communications.

⚠️ Attention: For this service to work, your tariff plan must support voice calls. On some legacy tariffs or corporate lines, this feature may be blocked by the carrier, even if the phone technically supports it.

It's important to understand the difference between calling through apps (WhatsApp, Telegram, Viber) and the phone's native calling function. In the former, you call a contact listed in the app, and the other person must be online in the same app. In the latter, you simply dial a number, and the MTS network routes the call through the closest available access point—be it a base station or your home router.

Device and tariff plan requirements

Before setting up, make sure your hardware and SIM card meet the required criteria. Not all smartphone models, even modern ones, have software support for Wi-Fi Calling with specific carriers. MTS maintains a list of certified devices whose firmware contains the required profiles.

The second critical factor is the SIM card type. Older Mini-SIM cards or earlier versions of Micro-SIM may not support the necessary encryption and authentication protocols for IP networks. It's also essential that the number is linked to the subscriber's personal account and not blocked by the operator.

Below is a compatibility table of popular brands and models that are guaranteed to work with MTS VoWiFi, provided the software version is up-to-date:

It's worth noting that having the technical capabilities of a phone is only half the battle. The carrier must "see" your device on the network and allow registration through VoWiFi gateways. If you've changed your phone but the SIM card is very old, it's a good idea to replace it with a new one at a mobile phone store to avoid security profile issues.

Activation of the service on the operator's side

Even if your smartphone is fully operational, the service may not be activated in your subscriber profile. MTS, like many other operators, is gradually rolling out this feature, so it may be disabled by default. Checking the status and connecting is the first step, and it shouldn't be ignored.

There are several activation methods. The fastest is using a USSD command. However, commands may vary depending on the region and number type. The universal method is through your personal account or the "My MTS" app. In the services section, you can often find the "Wi-Fi Calling" or "Voice over WiFi" option and activate it with one click.

⚠️ Attention: Pricing conditions are subject to change. Calls to MTS numbers are generally free (if included in the plan), while calls to other networks are charged according to your base plan. International calls via Wi-Fi may be charged as international calls unless you have a corresponding roaming plan.

If automatic methods don't work and you see a message in the app about service unavailability, you'll need to contact customer support. The operator can remotely update your SIM card profile (HLR), which can take anywhere from 15 minutes to several hours. You'll then receive an SMS confirmation of service activation.

Setting up VoWiFi on Android smartphones

The process of enabling the feature on devices running Android The menu may vary depending on the manufacturer's operating system. Samsung, Xiaomi, Huawei, and other brands hide the necessary switches in different places. However, the logic remains the same: find the cellular section and activate your preferred calling method.

On Samsung devices you need to go to Settings → Connections → Wi-Fi CallingHere, you should move the slider to the "On" position. It's also recommended to select the operating mode: "Wi-Fi only" (if there's no cellular signal at all) or "Prefer mobile network" (for automatic switching). On Xiaomi phones, the path may look like this: Settings → SIM cards and mobile networks → Wi-Fi calling.

In some cases, especially on custom firmware or phones imported through parallel import, there may be no standard switch. In these cases, activation is required through the engineering menu. To do this, enter a code into the dialer (for example, ##4636##), then select the "Phone Information" option. There you need to find the setting VoWiFi and activate it. Be careful: changing other settings in the engineering menu may impair the phone's operation.

What if the switch is grayed out or unavailable?

If the slider is active but won't turn on (grayed out), try turning Airplane Mode off and on again. If that doesn't help, make sure you're not using VPN services, which can block access to your carrier's gateways. Also, check that your date and time settings aren't set to automatic; incorrect time settings can prevent you from logging in.

Instructions for iPhone (iOS) owners

In the ecosystem Apple The setup process is as simple and unified as possible. If your iPhone supports the technology (iPhone 6 and later) and has the latest version of iOS, setup will occur automatically after activating the service with MTS. There's no need to search for hidden menus or enter codes.

To check and manage the function, go to Settings → Cellular → Wi-Fi CallingHere, you need to enable the "Wi-Fi Calling on this iPhone" toggle switch. The system may ask you to confirm your address for emergency services (E911), which is a standard security procedure. Once enabled, "MTS Wi-Fi" will appear in the status bar next to the carrier's name.

A unique feature of iOS is the ability to continue calls on other Apple devices. If you have an iPad or Mac connected to the same iCloud, you can answer calls from your phone using your tablet or computer, as long as they're on the same Wi-Fi network. This is convenient when your phone is in another room and you're working on your laptop.

Troubleshooting and Common Mistakes

Despite the simplicity of the technology, users may encounter connection difficulties. The most common issue is the absence of the VoWiFi icon in the status bar, even when all the settings appear to be correct. This may be caused by a network settings conflict or a router issue.

The problem often lies with DNS servers. If your router uses third-party DNS (for example, Google 8.8.8.8 or Yandex 7.7.7.7), your service provider may not recognize the traffic as trusted and block VoWiFi registration. Try temporarily switching your DNS to automatic (provided by your provider) in your router or smartphone settings.

It is also worth paying attention to the following possible causes of failures:

• 📶 Weak Wi-Fi signal: A stable call requires a signal strength of at least -75 dBm. If you're far from the router, connection quality will be poor.
• 🔒 Port blocking: In corporate networks or public Wi-Fi (cafes, airports), ports required for VoWiFi may be closed by the administrator.
• 📱 Outdated software: Check if there is an update available for the underlying modems or system.

⚠️ Attention: When using two SIM cards, VoWiFi can only work on one at a time, usually the one selected for voice calls by default. Make sure the correct SIM card is prioritized in your settings.

Compare quality and save traffic

Many users mistakenly believe that Wi-Fi calls eat up all their internet data. In fact, voice data is very efficient. One minute of high-quality conversation uses only about 0.5–1 MB of data. Even with active calls, data consumption is minimal and practically unnoticeable compared to watching videos or using social media.

In terms of quality, VoWiFi outperforms traditional cellular service indoors due to the absence of signal loss in walls. However, if the internet connection is unstable (high ping or jitter), audio delays or robotic voices may be experienced. Unlike 3G/4G, which prioritize voice, in Wi-Fi networks, voice traffic competes for resources with other devices on the network.

In conclusion, MTS's WiFi calling technology is a powerful tool for improving connection quality. It requires no complicated setup, is free to use (as part of your plan), and significantly expands your coverage area. If you haven't yet used this feature, consider activating it now to eliminate the problem of "subscriber unreachability" inside buildings.

Does MTS charge extra for Wi-Fi calls?

No, there is no separate fee for the technology itself. Calls are charged according to your main plan, like regular voice calls. Only internet traffic, which is usually included in the plan, is consumed.

Does VoWiFi work if you are abroad?

Technically, yes, if there's Wi-Fi. However, roaming rates will depend on your country's roaming plan. Calls to numbers in your country of residence may be free (like local calls), while calls to Russia will be charged at roaming rates. Check these before your trip.

Is it possible to call 112 via Wi-Fi?

Yes, emergency calls are supported. However, to ensure accurate location determination by emergency services, it's important to have a current address entered in your phone's settings, as GPS over Wi-Fi may be less accurate.