VoLTE on Xiaomi Redmi 9: A Complete Guide to Setup and Troubleshooting

Introduction: why you need VoLTE on a smartphone

If you own a Xiaomi Redmi 9 and you notice a mysterious VoLTE switch in your settings, but you don't know what it is or how to use it, you're not alone. It's a technology that's dramatically changing the quality of voice communication, but many users don't even know it exists.

VoLTE is a standard for voice over 4G networks, not traditional 2G/3G as it used to be. For Redmi 9, with its support for modern networks, it means clearer sound, instant connectivity and the ability to talk and use mobile Internet at high speeds at the same time, but there are nuances: not all operators support this feature, and in some regions it can malfunction.

In this article, we will discuss in detail:

• 🔹 How VoLTE is better than regular calls and why it is worth it
• 🔹 How to check if your Redmi 9 supports this technology
• 🔹 Step-by-step activation instructions (with screenshots of the menu)
• 🔹 Common Problems and How to Solve Them

VoLTE vs. regular calls: what’s the difference?

Traditional voice calls use 2G or 3G networks that were developed in the 90s, which are optimized for voice, but have serious limitations:

• 📞 Sound quality – compressed audio stream with a frequency of up to 8 kHz (as in old radio phones)
• ⏳ Delays – the connection can be established before 5-7 seconds
• 📶 Switching networks - when you call the smartphone "falls" from 4G on 3G, interrupt
• 🔋 Battery consumption – frequent switching between networks consumes charge

VoLTE technology solves these problems by transmitting voice in the form of digital packets. 4G-network (LTE). It gives:

Important for Redmi 9: this smartphone supports VoLTE only on Band 3 (1800 MHz) and Band 7 (2600 MHz) frequencies. If your carrier uses other 4G bands, the feature may not work even when the switch is on.

How to check VoLTE support for Xiaomi Redmi 9

Before you set up VoLTE, make sure your Redmi 9 is technically capable of using it. Here are 3 ways to check:

1. All versions of Xiaomi Redmi 9 (including Redmi 9A, 9C, 9T) support VoLTE at the hardware level. Except for devices purchased in China (models with the CN suffix in the name), where the function can be blocked by firmware.
2. Check through settings Go to Settings → SIM-maps and mobile networks → [choose SIM] → Enable VoLTE. If there is no point, your firmware does not support the function (solution - update the software).
3. IMEI Check dial ##4636##, select Phone Information and see VoLTE provisioned. value 1 stands for support.

Attention, if you use two SIM-map, VoLTE will only work on the one that is selected as the main one for data transfer (Settings) → SIM-map → Default for mobile data).

Step-by-step: how to turn on VoLTE on Redmi 9

Activation of VoLTE takes less than a minute, but requires the correct sequence of actions.

1. Step 1. Update your firmware Go to Settings → About Phone → System Update and install the latest version of MIUI. VoLTE requires MIUI 12 or later.
2. Step 2: Activate mobile internet VoLTE only works when you are actively connected to 4G. Make sure that the status bar displays a 4G icon (not H+ or E).
3. Step 3. Enable VoLTE in Settings Open Settings → SIM-Maps and mobile networks, select your SIM-map and activate the switch Enable VoLTE. If there is no item, see the section "Problems and solutions".
4. Step 4: Reboot the phone After turning on, restart the device – this is necessary to apply network settings.
5. Step 5. Check your work. Call another phone. If the top panel shows an HD or VoLTE icon during the call, the setup was successful.

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If after turning on VoLTE calls began to be interrupted, try to disable the Wi-Fi Calling function in the settings. SIM-Cards – These two options sometimes conflict.

Common VoLTE issues on Redmi 9 and their solutions

Even after you set it up properly, VoLTE can be unstable, and here are the typical scenarios and ways to fix them:

1. VoLTE is turned on but calls don't pass

Causes and solutions:

• 🔄 Switch to 3G: Some operators are forced to transfer calls to 3G. Solution – Call Support and request VoLTE activation for your number.
• 📵 Weak signal. 4G: VoLTE requires stable coverage. Check signal strength in Settings → The phone. → Status. SIM-map.
• 🔧 Conflict with Wi-Fi Calling: Turn off Wi-Fi calls in settings SIM-map.

2.The VoLTE badge appears, but the sound is intermittent

It's because of the operator's network overload.

• 🔄 Switch to switch to 3G manually (Settings) → Mobile network → Type of network → 3G) and back.
• 📱 Reset network settings (Settings) → System system → Resetting settings → Resetting mobile network settings).
• 🔋 Remove and re-insert SIM-map.

3.Volte works, but battery goes down quickly

The problem is typical for older versions of MIUI. Update the firmware or turn off the Constant Network Search function in the developer settings (Settings → About Phone → MIUI version → press 7 times).

⚠️ If after activation of VoLTE mobile Internet disappeared, check APN-Some operators (e.g. Tele2) require manual settings. APN work-in 4G VoLTE.

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Before contacting the operator, always check if you have a mobile Internet package enabled - VoLTE will not work without an active tariff, even if the icon is displayed.

VoLTE and dual-sim mode: features for Redmi 9

Xiaomi Redmi 9 supports two SIM-maps, but with VoLTE there are important limitations:

• 📱 Only one. SIM can use VoLTE, the one chosen as the primary for mobile data.
• 🔄 If a call is received during the VoLTE call. SIM, It will be reset (function) DSDS — Dual SIM Dual Standby – does not support simultaneous calls).
• 📡 When an active VoLTE call is made, the second SIM temporarily loses contact (cannot receive calls)/SMS).

To change SIM-map:

1. Go to Settings. → SIM-maps and mobile networks.
2. Select another SIM in the Default section for mobile data.
3. Activate VoLTE for the new SIM and reboot the phone.

Comparison of VoLTE with alternative technologies

Besides VoLTE, there are other ways to improve call quality, and consider the pros and cons of the Redmi 9:

Recommendation: If your carrier supports both technologies, turn on both VoLTE and Wi-Fi Calling – the phone will automatically choose the best option depending on the coverage.

⚠️ Note: Redmi 9 with older firmware MIUI 11 simultaneous operation of VoLTE and Wi-Fi Calling can cause crashes. In this case, disable one of the functions in the settings SIM-map.

FAQ: answers to frequent questions about VoLTE on Xiaomi Redmi 9