How to call on Wi-Fi on Xiaomi: the complete guide

Today’s Xiaomi and Redmi smartphones have powerful communication modules, but even they can have difficulty catching signals in dense buildings or away from the base station, and it is in these situations that VoWiFi technology, which allows voice calls to be made through the wireless network of an ISP, comes to the rescue. It is not just a replacement for cellular communication, but a full-fledged tool for those who value the stability of connection in dead zones.

Enabling this feature on devices with a MIUI shell or HyperOS often raises questions among users, since the setting depends not only on the phone’s settings, but also on the operator’s support for the service. We will analyze all the nuances of activation, hidden menus and possible errors that can be encountered during the configuration process.

Before you start setting up, make sure your plan allows voice calls over the Internet. Most major carriers have already implemented this option for free, but it requires the correct activation on the subscriber side. In this article, we will describe in detail the steps necessary for uninterrupted communication where normal communication is possible. GSM-signal.

What is VoWiFi and how does it work in practice?

VoWiFi (Voice over Wi-Fi) technology is the transmission of voice traffic over the Internet protocol, bypassing traditional cell towers. For the user, this process is absolutely transparent: you dial a number and make a call as usual, but the signal is transmitted through the router. This is especially true for owners of Xiaomi smartphones, who often work in buildings with thick walls or are in basements.

Unlike popular messengers, the sound quality here is provided by the operator and complies with HD-voice standards. Switching between Wi-Fi and the mobile network is automatic and without breaking the connection if you leave the coverage of the wireless network, which makes the technology ideal for office workers and residents of private homes with poor reception.

It's important to understand that the function requires carrier support and profiles in the firmware device. Without active operator-side VoWiFi, turning the slider on the phone settings won't work, and many users forget this when they try to activate the function only software-based, and they face failure.

In terms of security and pricing, such calls are usually charged as normal minutes within your fare package.Roaming may also be available if the operator provides such an opportunity, saving significant money when traveling abroad.

Verification of device and operator compatibility

The first step before setting up is to verify the technical feasibility of VoWiFi. Not all Xiaomi models and not all firmware regions have open support for this feature out of the box. Global versions usually support more carriers than Chinese ones, but there are nuances here.

It is necessary to make sure that SIM-The card is installed in a slot that supports 4G/LTE, Because VoWiFi is very integrated with fourth-generation networks, if you're using old cards that were released many years ago, you might need to replace them in the salon with new ones that support the new ones. USIM.

The list of operators supporting the technology is constantly expanding, and the largest players in the market have long implemented this option, but in some regions coverage may be limited.

You can use an engineering menu or special applications to quickly check support status, but the most reliable way is to try activation through standard settings. If you don't have an option, you may need to update your firmware or change your region.

Standard activation via MIUI and HyperOS settings

The basic method of enabling the function is available in the standard system interface, and the path to settings may vary slightly depending on the shell version, but the logic remains the same. First, you need to go to the SIM management menu.

Open Settings and find the section SIM-maps and mobile networks. This shows all the communication modules installed. SIM-Map for which you plan to activate calls via Wi-Fi.

Inside the menu of the selected SIM card, look for the Wi-Fi Call or Wi-Fi Calling Switch. If your carrier and ISP automatically identified the profile, just activate the slider. The system can request confirmation of the address for emergency services, which is standard procedure.

In some cases, especially on Chinese firmware versions, this item may be hidden, so you should try changing the region of the device to a country where the operator accurately supports the technology (for example, India or Indonesia), restart the phone and check if the option appears.

Advanced configuration through the engineering menu

If the standard method failed, you can use a deeper setup through system codes, which requires caution, because changing the wrong parameters can affect the operation of the communication module.

Enter the code ##869434##. This code is designed to unlock the VoWiFi Carrier Check menu. Once entered, you should see the message "VoWiFi Carrier Check was disabled", which means the software locking of the operator check is removed.

Once you've done this, you need to restart the device. Once you turn on the phone, go back to the settings. SIM-Now there should be an additional item that allows you to force the function to turn on, even if the operator was not automatically recognized by the system.

⚠️ Note: Using engineering codes on global firmware devices may not work as some features are already blocked at the regional limits level.

There is also code #86583##, which, on the contrary, involves checking the operator. If the function stopped working after manipulation, try entering this code to return the standard behavior of the system.

Set up network and APN settings

VoWiFi is directly dependent on the correct settings of the access point (APN), sometimes the automatic settings coming from the operator may be incomplete or outdated, in which case manual adjustment of parameters is required.

Go to Settings. → SIM-maps and mobile networks → select a SIM card → Access points (APN). You need to create a new point or edit an existing one by adding or changing the field. IMS APN. The value usually coincides with the name of the main access point (for example, Internet.mts.ru).

It is also important to check the protocol type. In the APN settings, make sure that you choose IPv4/IPv6. Switching to pure IPv4 or IPv6 can disrupt voice services over the Internet.

After making changes, be sure to save your profile and choose it active.Rebooting the device will fix the new settings and start re-registration in the IMS network.

Solution and troubleshooting

Even with the right setup, users can run into problems. It's common to see a VoWiFi icon appearing but calls fail or fail. This could be due to a router that blocks certain ports or protocols.

If your phone is constantly switching between Wi-Fi and LTE while you're talking, check the wireless signal strength, and VoWiFi requires stable ping and no packet loss, and energy saving can be a problem.

MIUI aggressively saves battery life and can kill background telephony processes, go to the battery settings, find the Phone app, and set the No Limits mode to prevent the process from being forced to end.

⚠️ Note: When using corporate Wi-Fi networks with authorization through a web portal or complex security systems (Captive Portal), the VoWiFi function may not work until the device is fully authorized on the network.

In some cases, resetting network settings helps. Go to Settings → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth. This will delete saved passwords, but often resolves software conflicts of communication modules.

Comparison of VoLTE and VoWiFi technologies

Many users confuse the two technologies as interchangeable, but there is a fundamental difference in the way they transmit a signal. VoLTE (Voice over LTE) uses fourth-generation networks for voice transmission, requiring 4G coverage.

VoWiFi, in turn, uses whatever Wi-Fi is available, which makes it indispensable in places where 4G is not enough, but there is home Internet, both technologies provide high sound quality, but their conditions are different.

• 📶 Coverage area: VoLTE depends on the operator towers, VoWiFi - on the range of the router.
• 🔋 Power consumption: VoWiFi can consume slightly more power with a weak Wi-Fi signal due to constant attempts to reconnect.
• 🌍 Roaming: VoWiFi often allows you to call as “at home” even when abroad, if there is Wi-Fi, whereas VoLTE will be charged at roaming rates.

The ideal configuration for a modern smartphone is to support both standards simultaneously, and the phone will choose the best route to complete the call depending on the availability of networks.

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If you’re often in places with poor signaling but Wi-Fi is available, turn on the “Always Prefer Wi-Fi” mode in the call menu so the phone doesn’t try to cling to EDGE/3G.

Frequently Asked Questions (FAQ)

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The main secret of success is a comprehensive check: operator support, correct APN settings and no locks on the router.

Setting up Wi-Fi calls on Xiaomi devices may seem difficult at first. By following the instructions and checking compatibility, you can significantly improve communication in problem areas, and the technology is becoming the standard, and the ability to customize it is a useful skill for every smartphone owner.

Remember that software interfaces can be updated, and the location of menu items may change with the release of new versions of HyperOS. The main thing is to understand the principle of the technology to successfully adapt to any changes in the interface.