How to turn on VoWiFi on Xiaomi Redmi Note 9: step-by-step instructions with error solutions

Calling over Wi-Fi (VoWiFi) on Xiaomi Redmi Note 9 It allows you to make calls even when you don't have a mobile network -- a fairly stable Internet connection -- and it's particularly useful in places with poor coverage. 4G/3G: In basements, outbacks or country houses, however, not all users know that the feature is hidden in the settings and requires the correct activation.

In this article, you will find 3 working ways to enable VoWiFi (including an engineering menu for advanced users), a compatibility table with Russian operators, as well as solving errors such as “Not supported by an operator” or “No registration on the network”. We tested the instructions on the Redmi Note 9 with firmware MIUI 12-14 – all steps are relevant to models M2003J15SC (global version and M2003J15SS (China).

What is VoWiFi and why is it needed on the Redmi Note 9?

VoWiFi (Voice over Wi-Fi) is a technology for voice calls over the Internet instead of traditional cellular networks. It works on a protocol. IMS (IP Multimedia Subsystem) and integrated into modern smartphones at the firmware level. 9 The function is supported by hardware (Meditek Helio chipset) G85 compatible VoLTE/VoWiFi), but often disabled by default.

The benefits of VoWiFi for users:

• 📶 Stable signal in areas with poor coverage (for example, in the subway or in the country).
• 🔋 Saving battery power: the smartphone does not waste energy on finding a cellular network.
• 🎧 Better sound quality thanks to codec HD Voice (if supported by the operator).
• 🌍 Free roaming calls (when connecting to Wi-Fi abroad).

It's important to understand that VoWiFi is not the same as VoIP (Skype, WhatsApp). SIM-map, not through third-party applications, so:

• ✅ The number is defined as mobile (not “unknown»).
• ✅ Operator services work (redirection, waiting for a call).
• ✅ No additional Internet costs (no traffic is charged).

Checking your operator’s VoWiFi support

Before you set up your smartphone, make sure your mobile operator supports the technology. In Russia, VoWiFi is officially available from four providers, but with reservations:

To check for support on your SIM-map:

1. Send. USSD-request: MTS: *111*586# Beeline: *110*180# MegaFon: *105*00#

If the answer is “VoLTE is active,” then VoWiFi should work too (they use the same infrastructure).

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⚠️ Note: If the operator does not support VoWiFi, you will not be able to turn on the function on the smartphone - the settings will be an error "Not supported by the operator", in this case, you only have to wait for updates from the provider or change the tariff.

Method 1: Enabling VoWiFi through standard settings MIUI

This is the easiest method that works on most Redmi Note 9 with firmware. MIUI 12 and newer. Follow the instructions:

1. Open the Settings app (cog icon).
2. Go to section. SIM-maps and mobile networks.
3. Choose yours. SIM-card (if two of them).
4. Slip on the call item via Wi-Fi (or VoWiFi).
5. Activate the switch in the "On" position.
6. Confirm the inclusion in the dialog box.

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If VoWiFi calls are not turned on, try to turn off the phone. VPN Proxy servers, they can block IMS-traffic.

Method 2: Activate VoWiFi via the Engineering Menu (for advanced)

If the standard method didn't work, you can turn on VoWiFi through a hidden engineering menu, which requires caution - incorrect settings can disrupt the network.

Instructions:

1. Open the Phone app and type the combination: ##4636## Some firmware may require ##869434## or #86583##.
2. Select Phone Information (or Phone Information).
3. Scroll down to the VoWiFi section or IMS Service Status.
4. Activate the options: VoWiFi enable → Enable IMS over WiFi → Enabled WiFi Calling Provisioned → Yes

Network settings

Network Setting

Restart Radio

After rebooting the module, check for the appearance of the VoWiFi icon. If the function is not activated, try:

• 🔄 Reboot your smartphone.
• 📶 Reconnect to Wi-Fi.
• 🔧 Reset network settings (Settings) → Reset → Resetting network settings).

⚠️ Note: Do not change other options (e.g. Band Selection or the Menu) in the Engineering Menu. LTE Mode: This can cause network loss. If the mobile Internet is lost after manipulation, reset. APN (Settings → Mobile network → Access points (APN) → Reset).

Method 3: Manual addition APN VoWiFi (unless the operator determines the settings)

Sometimes the operator does not transmit automatic settings. IMS For VoWiFi, you can add them manually:

1. Go to Settings. → SIM-maps and mobile networks → [Yours. SIM] → Access points (APN).
2. Put the badge on «+» (add APN).
3. Fill in the fields according to the table below (options for MTS, Beeline and MegaFon).
4. Save your settings and select a new APN in the list.
5. Reboot your smartphone.

After addition APN Check the work of VoWiFi:

1. Connect to Wi-Fi.
2. Turn off the mobile data.
3. Try making an outgoing call.

If the call does not pass, check what is in the settings. SIM-The card includes the option “Use the Internet for calls” (can be called “Enhanced”). 4G» Or "VoLTE"). VoWiFi won't work without activated VoLTE.

Solving common VoWiFi errors on Redmi Note 9

If after all the manipulations VoWiFi does not work, we will analyze the typical problems and their solutions:

Error: “Not supported by the operator”

Causes and solutions:

• 📱 SIM-The card does not support VoLTE → Replace it with a new one in the operator’s cabin (free of charge).
• 🌐 Region not supported → Check VoWiFi coverage on the operator card.
• 🔄 Outdated settings IMS → Reset network settings (Settings) → System system → Reset → Reset Wi-Fi, mobile network and Bluetooth).

Error: “No registration on the network IMS»

Action:

1. Turn off Wi-Fi and connect again.
2. Turn on/off the “In the Plane” mode for 30 seconds.
3. Check that the date and time on the smartphone are set automatically (Settings) → Additionally. → Date and time).
4. Update the firmware to the latest version of MIUI.

Calls are cut off or not made

Possible causes:

• 📶 Weak Wi-Fi signal → Connect to another network or approach the router.
• 🔋 Battery savings block background work → Add the Phone app to exceptions (Settings) → Battery → Optimizing the battery).
• 🛡️ firewall VPN hinder → Turn them off temporarily.

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If after all the manipulations VoWiFi did not work, contact the operator with a request to check the binding. IMS Sometimes the problem is in the ISP's databases, not the smartphone.

Additional settings to improve VoWiFi quality

To make Wi-Fi calls sound clearer and more stable, set the following settings:

1. Priority of Wi-Fi for Calls

By default, the Redmi Note 9 can switch between VoWiFi and VoLTE automatically to prioritize:

1. Enter the dialer: ##869434##
2. Choose. IMS Service Status.
3. Activate WiFi Preferred (WIFI priority).

2. Codec optimization

For better sound, turn on codec support HD Voice:

1. Go to Settings. → Sound. → Quality of call.
2. Choose. HD Voice (VoLTE/VoWiFi).
3. Activate the option to Always use HD.

3. Roaming setup

If you travel frequently, set up VoWiFi for roaming:

• B Settings → SIM-map → [Yours. SIM] → Roaming enable Data in roaming and VoWiFi in roaming.
• Make sure that your roaming partner supports VoLTE (the list of partners is available on your operator’s website).

We also recommend turning off traffic savings in Wi-Fi settings – this can worsen the quality of communication.

FAQ: Frequent questions about VoWiFi on Xiaomi Redmi Note 9