Xiaomi Wi-Fi Call: How Technology Works and Why You Need It

Have you ever experienced a situation where a mobile network suddenly disappears in the office, basement or outside the city, and the call still passes? Chances are that at this point your Xiaomi automatically switched to calls over Wi-Fi, a technology that allows you to call and send SMS Even without coverage, but how exactly does it work, what models support the function, and why it's sometimes best to turn it off, we'll look at this article.

Wi-Fi Calling (or VoWiFi) is not new, but it is implemented with features in the Xiaomi ecosystem, for example, on some models the function is hidden in deep settings, and operators in Russia and the CIS do not always officially support it.+, Xiaomi 13 Ultra and POCO F5, to give clear recommendations, from inclusion to elimination of typical problems.

What is Wi-Fi on Xiaomi and how does it work?

Wi-Fi Calling is a communication standard that allows you to make voice calls and send messages. SMS Connecting to the Internet, not traditional cellular networks (2G/3G/4G/5G). Technology uses the protocol IMS (IP Multimedia Subsystem, which is integrated into modern carrier networks, when the mobile signal is weak or absent, the smartphone automatically switches to Wi-Fi, retaining the ability to call.

On Xiaomi, the function works in two scenarios:

• 📶 Automatic switching: if the signal level of the cellular network falls below the threshold value (usually −105 dBm, the smartphone switches to Wi-Fi without interrupting the call.
• 🔄 Priority Wi-Fi: on some firmware (for example, MIUI 14+) You can choose Wi-Fi even if you have a good signal. 4G/5G.

It is important to understand that Wi-Fi Calling ≠ VoIP (like WhatsApp or Telegram) is where your number is used. SIM-It's not a messaging account, it means that:

• 📞 Calls come to a standard phone number.
• 💳 Tariffed at your operator's rate (free minutes, packages, etc.).
• 📡 It works even if the phone does not have internet via mobile data (wi-fi only).

What Xiaomi smartphones support Wi-Fi Calling

VoWiFi is not available on all Xiaomi devices, but the main support criteria are:

• 📱 Smartphone model: Must have a chip that supports IMS (Most flagships and mid-budget models from 2019).
• 🔄 Version. MIUI: starting MIUI 12 (for some regions only with MIUI 13+).
• 📡 Operator support: not all providers in Russia and CIS officially activated VoWiFi.

Here is the current list of models with confirmed support (as of 2026):

How to check support on your device? Go to Settings → SIM-maps and mobile networks → [yours SIM] → Wi-Fi calls. If there's no point, then either the model doesn't support the function or the operator didn't activate it.

How to enable Wi-Fi calls on Xiaomi: step-by-step instructions

VoWiFi activation process depends on version MIUI Let's look at two scenarios: standard on and manual activation for devices where the function is hidden.

Method 1: Standard incorporation (MIUI 13/14)

Open the Settings.

Move to the SIM-maps and mobile networks

Choose yours. SIM-map

Tapping on challenges via Wi-Fi

Switch the switch to the position VL.

Confirm activation (reboot may be required)

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Method 2: Manually enable via engineering menu (for older models)

If there is no Wi-Fi call option in the settings, try this method:

1. Open the Phone app and type ##4636##.
2. Go to the tab Information about the phone.
3. Scroll down and find Wi-Fi Calling Provisioning.
4. Slip on Enable and restart the device.

Important: on some firmware (for example, Redmi Note 10 Pro with the MIUI 12.5) After manual activation, the function may not work stable - calls will stop when switching between Wi-Fi and the Internet. 4G.

1. Are you connected to Wi-Fi (not mobile data)

2. whether your operator supports the technology (list above).

Does the router block ports 500 and 4500 (required for the router)? IMS).-->

Pros and cons of calling over Wi-Fi on Xiaomi

VoWiFi solves many of the problems with connectivity, but it also has drawbacks. Let's look at the key advantages and pitfalls.

Advantages:

• 📶 Stable communication in the “dead zones”: calls take place even in basements, elevators or outside the city where there is no coverage 4G.
• 🔋 Saving battery power: with a weak signal, the smartphone does not waste energy on finding the network.
• 🎧 Best Sound Quality: VoWiFi uses codec HD Voice (if supported by the operator).
• 🌍 Roaming without surcharges: you can call via home Wi-Fi abroad, avoiding roaming rates.

Disadvantages:

• ⚠️ Wi-Fi dependency: If the router shuts down, the call will be interrupted (unlike the router). 4G, where there is a backup switch to 2G).
• 🛑 Emergency Call Problems: In some countries (e.g. the U.S.) 911 does not work over VoWiFi.
• 🔒 Privacy concerns: Call traffic is routed through the operator’s network, but can technically be intercepted at the Wi-Fi level.
• 📱 Not all apps support: Truecaller may not recognize calls over VoWiFi, for example.

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VoWiFi is ideal for offices, homes with poor coverage or city trips, but it doesn’t replace cellular connectivity entirely. Always check if your carrier supports the feature before relying on it in important situations.

Typical Wi-Fi Calling Issues on Xiaomi and Their Solutions

Even if the feature is enabled, users often encounter errors, and here are the most common problems and ways to fix them:

1. Calls do not pass through Wi-Fi (no service error)

• 🔄 Solution: Switch to another Wi-Fi network (e.g., from 5 GHz to 2.4 GHz).
• 📱 Solution: Update MIUI Up to the latest version (in old firmware bugs with the IMS).
• 📡 Solution: Check if the router is blocking the IPSec protocol (required for VoWiFi).

2. calls are terminated when switching between Wi-Fi and 4G

This is a typical problem for the Redmi Note. 11/10. The fault was a bug in the module. IMS Service, solutions:

• 🔧 Enable Prefer Wi-Fi mode in VoWiFi settings (if any).
• 📲 Install alternative calling software (e.g. Google Phone from Play Market).
• 🔄 Reset network settings: Settings → System system → Reset → Resetting network settings.

3. it is impossible to enable VoWiFi (no item in the settings)

If your model should support the function but it is not on the menu:

• 🔄 Check the firmware region: VoWiFi can be hidden on Chinese versions MIUI. Change the region to Global or EEA.
• 📱 Install custom software (e.g. xiaomi.eu) where the function is unlocked.
• 📡 Contact the operator and request VoWiFi activation for your number (sometimes required). USSD-team).

⚠️ Attention: On some firmware (MIUI 12.5. POCO X3 Pro) forced VoWiFi on through the engineering menu may cause disruptions SIM-If the network is no longer defined after activation, reset to factory settings.

Security and privacy: the risks of Wi-Fi Calling

While VoWiFi is convenient, it poses additional security risks, and here's what to look out for:

1. Vulnerabilities at the Wi-Fi level

If you are connected to an unsecured network (such as a cafe or airport), an attacker could theoretically:

• 🕵️ Intercept. SIP-packets (protocol of call transmission).
• 📡 Substitute DNS and redirect traffic to a phishing server.

How do you protect yourself? Use only secure networks (WPA3) or VPN When connecting to public Wi-Fi.

2.Authentication problems

Some carriers (such as MTS) use simplified authentication for VoWiFi, which may allow:

• 🔑 Subscriber ID Substitution (IMSI-catching).
• 📞 Interception SMS (If the operator does not encrypt SMS-over-IMS traffic).

3. Geolocation leaks

When using VoWiFi, the operator can determine your location. IP-Wi-Fi address, even if GPS It's used for emergency services, but it can be abused.

⚠️ Note: If you use VoWiFi frequently in public, turn off sensitive calls (such as banking or business calls) by switching to mobile data or using end-to-end encrypted messengers (Signal, WhatsApp).

Xiaomi’s Wi-Fi Calling Alternatives: What to Use if VoWiFi is Not Working

If your smartphone or carrier doesn’t support VoWiFi, there are a few alternative ways to make calls over the internet:

1. VoIP applications

• 📞 Google Phone: Supports Wi-Fi calls on all Android devices (Settings required) → Calls. → Calls over Wi-Fi).
• 🌍 Skype/Zoom: Suitable for international calls but require registration.
• 🔒 Signal: The most secure encryption solution, but both people should use the app.

2. "Internet Calls" function in MIUI

On some models (Xiaomi) 13T, Redmi Note 12 has a separate option called Internet Calls (not to be confused with VoWiFi!) that works via the Internet:

• 📶 Mobile data (4G/5G), if the Wi-Fi is off.
• 🔄 Any internet connection but charged as a regular call.

Included in Settings → SIM-map → Additionally. → Internet calls.

3. Double. SIM + forwarding

If you have two. SIM-You can set up a call forwarding from the main number to the secondary number, which is connected to stable Wi-Fi:

1. Open the phone. → … → Settings → Call forwarding.
2. Choose Redirect if it is not available.
3. Give number two. SIM or VoIP applications.

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VoWiFi alternatives are often less stable but offer more security controls, such as Signal encrypting calls with end-to-end encryption, which is not the case with standard VoWiFi.

FAQ: Frequent questions about Wi-Fi Calling on Xiaomi