Xiaomi and Redmi smartphone owners often notice a small but important icon in the screen status bar. Usually, the words VoLTE or HD appear next to the signal level division. Many users ignore this indicator, without thinking about its functional value, but it indicates a transition to a qualitatively new level of voice communication.
The appearance of this symbol means that your Xiaomi Redmi phone has switched to voice transmission via the phone. LTE-It's not just a marketing chip, it's a technology that provides crystal clear sound and instantaneous connectivity. 2G and 3G, where voice was transmitted over separate channels, here data and voice are on the same high-speed stream.
Understanding the principles of this function will help you not only save battery power, but also enjoy quality calls even in conditions of poor 3G coverage. Next, we will discuss in detail how to manage this mode, what advantages it gives and what to do if the icon is missing or does not appear at all.
Technology and Benefits of HD Voice
VoLTE stands for Voice over LTE, which literally translates as "Voice over LTE." Traditionally, mobile operators used 2G and 3G networks for voice calls, and 4G networks exclusively for the Internet. When an incoming call arrived, the phone often forced to switch to lower frequencies, causing connection delays and a drop in Internet speed.
The High Definition Voice technology that this standard implements allows you to stream audio at a much higher sampling rate, the human voice becomes natural, the effect of the robot disappears, and the metal sound disappears, and the channel width allows you to transmit not only voice, but also high-quality video without tears.
⚠️ Attention: The quality of communication depends on the tariff plan of your operator, if the account does not have enough funds or the tariff does not support the service. HD-Calls, badges may not appear, even if the phone is fully functional.
One of the main advantages is the ability to use voice and data simultaneously. You can talk on the phone and simultaneously download heavy files or a navigator without losing 4G speed. In older networks, when talking, the Internet often turned off or went into EDGE mode, making web surfing impossible.
💡
For maximum sound quality during calls, try not to close the upper speaker area with your palm, as there are additional noise reduction microphones.
Key differences from 3G and the impact on the battery
Many users fear that 4G will drain the battery faster, but in the context of voice calls, the situation is reversed: since a Xiaomi phone does not need to constantly “jump” between 2G, 3G and 4G frequencies during a call, the power consumption of the communication module stabilizes.
Third generation networks (UMTS) Voice and data were transmitted over different switching technologies, which required the device to have more processing power to transcode signals on the fly. LTE All the packages, including voice, are IP-packets that simplify processing and reduce the load on the processor.
The comparison of characteristics shows the clear advantage of the new technology:
| Parameter | 3G (UMTS) | 4G (VoLTE) |
|---|---|---|
| Connection time | 3-7 seconds | 1-2 seconds |
| Sound quality | Narrowband (3.4 kHz) | Broadband (up to 20 kHz) |
| Internet during a call | Frequently drops to 2G | It works at full speed 4G. |
| Stability in the room | Low. | High (permeating ability) |
Importantly, LTE coverage is now often denser than 3G coverage in remote areas, which means that the phone will be less likely to search for the network, which also has a positive effect on autonomy. However, if you are in a patchwork zone where 4G is coming and going, energy consumption can temporarily increase.
☑️ Testing of VoLTE Readiness
How to enable VoLTE on Xiaomi and Redmi smartphones
Activation of the feature on Xiaomi devices usually occurs automatically if the SIM card and the tariff plan meet the requirements. However, in some cases, especially after flashing or changing the region, the settings may be confused.
Walk along the way: Settings → SIM-Select the SIM card you want if you have two. In the menu that opens, find the "Use VoLTE" or Enable VoLTE switch. Once activated, the status bar should show the appropriate icon.
- 📱 Make sure that the "Network Type" is selected preferably 5G/4G/3G/2G.
- 💾 Restart the device after switching on the toggle to apply the changes.
- 📶 Check if the indicator is on. 4G or LTE near-signal.
- 🗣️ Make a test call to check the sound quality.
⚠️ Note: Some global versions of the firmware MIUI If you don't find the switch, try changing the region of the phone to India or Indonesia in the Settings menu. → Additional settings → Region, enable function and then return your region.
In some cases, carriers require the installation of a special profile or application to activate the service, which is typical for some virtual operators or corporate tariffs. If standard methods do not work, contact your provider's support team.
Hidden settings and engineering menu
If the standard MIUI interface does not provide access to VoLTE management, you can use a hidden engineering menu, which is suitable for advanced users, since carelessly changing the parameters can lead to unstable operation of the communication module.
To enter the test menu, dial the Phone application code ##4636##. In the menu that opens, select Phone Information. Here you will see a list of switches. Find "VoLTE Provisioned" or Turn on VoLTE and activate it.
The path to hidden settings:
1. Open the dialer (bell ringer)
2 Enter ##4636##
3. Select "Phone Information"
Activate "VoLTE Provisioned Flag"Once the flag is turned on, the phone may need to reboot, and if the code doesn't work, it's possible that your version of Android or HyperOS's shell will block access to that menu, and you can use Activity Launcher, which allows you to run hidden activity.
What if the code doesn't work?
Why the VoLTE icon disappeared: solving problems
It is common for an HD or VoLTE icon to suddenly disappear, most often due to an update to an operator’s base stations or a temporary failure to register a device on an IMS (IP Multimedia Subsystem).
The first thing you need to do is check if the money is out of the account. HD-Calls with negative balance, and you should also make sure you're in a safe receiving zone. 4G. If the phone shows 3G or+, The VoLTE icon will not be displayed.
- 🔄 Perform a reset of network settings: Settings → Connection and sharing → Reset Wi-Fi, mobile networks and Bluetooth.
- 📲 Replace it. SIM-card to another slot if there are two.
- 🛠 Check for system updates in the About Phone menu.
- 🗑 Remove and re-add the access point APN your operator.
Sometimes the problem lies in the very SIM-If you use an old SIM that was cut with scissors or changed many years ago, it may not support modern encryption standards. SIM-cardboard.
💡
In 90% of cases, the disappearance of the icon is solved by simply restarting the smartphone or re-registering in the network through the “Air message” mode.
Influence of region and firmware version
Xiaomi divides its devices into regional versions (Global, China, EU, Russia). In Chinese firmware, VoLTE support for foreign operators is often disabled software, and even if the operator supports the technology, the phone may not request its activation.
Global ROM users usually don’t face any problems, as they already have configurations for most global operators, but if you own a Chinese version (CN ROM) with global firmware installed, there may be certificate conflicts.
⚠️ Warning: Flashing your device from the Chinese version to the global version on its own (via Fastboot) can lead to a Hard Block if you have a phone call feature. IMEI-And you're not going to save your addresses correctly.
It’s also worth considering that some carriers require a phone model to be on their “whitelist.”If your Redmi Note or Xiaomi Mi isn’t on the operator’s certified device list, the icon may not appear, although LTE calls are technically possible.