Xiaomi WiFi Calling: What It Is and How to Set It Up

Modern smartphones, particularly popular Xiaomi models, offer numerous features to improve call quality that many users aren't even aware of. One such technology is the ability to make calls wirelessly, which is especially useful in areas with weak cellular signal. This feature is often hidden deep within settings or requires operator activation, which raises many questions among device owners.

In this article we will take a detailed look at what they are. calls via WiFiHow VoWiFi technology works in the Xiaomi ecosystem and how it differs from traditional messaging calls. You'll learn how to activate this feature, which phone models and routers support it, and how to resolve common issues with the handset icon appearing on a wireless network.

Understanding how this technology works will help you avoid missing important calls in areas with poor coverage, such as basements, remote offices, or country houses. We'll cover the technical nuances, router settings, and the specifics of working with SIM cards from different carriers.

VoWiFi Technology: How It Works on Xiaomi Devices

The technology in question is called Voice over WiFi Or VoWiFi for short. Unlike popular apps like WhatsApp or Telegram, which use the internet to transmit voice data through their servers, VoWiFi is integrated directly into your smartphone's standard dialing interface. This means you dial a number as usual, and the system automatically reroutes the voice stream over the internet if cellular coverage is unavailable or signal quality is poor.

On devices Xiaomi, Redmi And POCO The implementation of this feature depends on the MIUI or HyperOS operating system version, as well as the regional firmware. The smartphone automatically switches between 4G/5G and Wi-Fi networks without interrupting the connection, ensuring uninterrupted calls. This technology requires support from your mobile operator and a stable broadband internet connection.

A key advantage is high sound quality and the absence of echo, which is often encountered when making calls through third-party apps. Furthermore, WiFi calls use your home or office data plan's data rather than your cellular data plan's minutes, which can be cost-effective when roaming or on limited plans.

It's worth noting that for proper operation, the IMS (IP Multimedia Subsystem) profile must be correctly configured on the SIM card. In Xiaomi smartphones, this is handled by a system module that checks for service availability each time a wireless network is connected.

Differences between WiFi calls and instant messaging calls

Many users confuse VoWiFi technology with regular calls via internet apps, but the difference between the two is fundamental. Firstly, to make a call via VoWiFi not required, so that the other person has the same messenger or even smartphone. You call a regular phone number, and the call is routed just like through a cell tower.

Secondly, VoWiFi connection quality is often more stable, as voice traffic is prioritized by the operator's network settings. Messengers, on the other hand, operate on a "best effort" basis, meaning quality depends on the current load on the channel and the app's servers.

⚠️ Note: When using VoWiFi, your phone number remains the same, and the other person sees it on their screen. In messaging apps, the profile name or account linked to the app is often displayed.

Another important difference concerns emergency services. Telecom operators are required to transmit the subscriber's location when calling emergency services (112, 102, etc.) via VoWiFi, whereas messaging apps don't provide this guarantee and may transmit an IP address, which doesn't always correspond to your physical address.

Resource consumption is also worth mentioning. Xiaomi's native calling system is better optimized than the background operation of heavy messaging apps, which positively impacts battery life during long calls.

How to enable WiFi calling on Xiaomi

VoWiFi activation on Xiaomi smartphones typically occurs automatically if the carrier supports the service and the SIM card profile is updated. However, in some cases, especially on global firmware versions or when using SIM cards from specific regions, the settings may be hidden or disabled by default.

To check and enable this feature, go to the settings menu. The path may vary slightly depending on the MIUI version, but it usually looks like this: Settings → SIM cards and mobile networks → Select your SIM card → WiFi callingIf you see this switch, simply enable it.

If the option isn't in the menu, it doesn't always mean the phone doesn't support the technology. Sometimes activation is required via the engineering menu or a code request from the operator. Also, make sure that in the section Settings → Connection & Sharing → Wi-Fi Hotspot restrictions blocking voice traffic are not enabled.

In some cases, resetting network settings helps. To do this, go to Settings → Connection and sharing → Reset Wi-Fi, mobile networks, and BluetoothAfter rebooting, the phone will request profiles from the operator again, and the desired option may appear.

It's important to understand that even with this feature enabled, the handset icon above the Wi-Fi icon may not always appear. It only appears when the phone is actually using the wireless network for voice, not data.

Using Xiaomi routers for calls (Mi Router Call)

The function deserves special attention Mi Router Call, which is implemented in some Xiaomi router models. This technology allows a smartphone connected to a Xiaomi home network to make calls via the router's internet connection, even if there is no cellular service.

This feature requires a compatible router model (usually flagship series with VoIP support) and installation of the corresponding plugin in the application. Mi HomeIn this case, the router acts as a gateway, converting the voice signal into internet packets.

Setup is done through the Mi Home app. After adding the router to the list of devices, find the "Mi Router Call" plugin in the plugin store and activate it. Then follow the on-screen instructions to link your phone number.

The advantage of using Xiaomi routers is the ability to create a unified smart home ecosystem, where the phone automatically switches to the home network for calls, saving battery power while searching for a cellular signal.

Common problems and solutions

Despite its convenience, users often encounter situations where the feature is advertised but doesn't work. One of the most common issues is the absence of a handset icon above the Wi-Fi icon, even when the setting is enabled. This could mean the phone is in a strong cellular coverage area and is prioritizing it, or the carrier hasn't transmitted the IMS profile.

Another common issue is connection drops or the inability to make outgoing calls. This is often related to router security settings. Some routers block ports required for SIP protocols by default or use strict NAT settings. In this case, it's recommended to check the DHCP and DNS settings on the router.

⚠️ Note: If you're using a third-party DNS (such as Google 8.8.8.8 or Cloudflare 1.1.1.1), try switching to automatic DNS resolution from your carrier. Carriers often use specific DNS resolution for routing VoWiFi traffic.

It's also worth checking whether power saving mode is enabled for your phone's system services. Aggressive battery optimization in MIUI can "kill" background registration with the IMS network, preventing incoming calls over Wi-Fi.

If all else fails, try removing the SIM card, wiping the contacts, and reinserting it. Sometimes physical contact can interfere with the operator profile. Also, make sure your SIM card has sufficient balance, even if you have an unlimited data plan, as some carriers block additional services when your balance is empty.

Operator compatibility and tariff plans

VoWiFi technology requires support not only from the phone but also from the telecom operator. In Russia and the CIS, the major operators (the "Big Four") have already implemented this technology, but conditions may vary depending on the region and specific plan.

Activating the service often requires sending a special USSD code or confirming consent in your operator account. Without this network-side procedure, even the most modern Xiaomi phone will not be able to initiate a call over Wi-Fi.

It's important to note that VoWiFi usage rules can vary significantly when roaming internationally. Some operators allow you to receive calls free of charge over Wi-Fi abroad, treating them as incoming calls from your home number, while others charge them as regular incoming calls when roaming.

Below is a table with examples of support statuses (relevance may change, check with your operator):

If your carrier claims support, but the feature doesn't work on your Xiaomi, contact technical support and request a remote SIM card service profile update. This often resolves the issue of incompatibility between older profiles and new IMS standards.

Frequently Asked Questions (FAQ)