Modern standards of mobile communication require not only a stable connection, but also high quality voice, which is especially important for owners of popular smartphones series Redmi Note 8. Voice over LTE technology allows you to transmit voice calls through networks of the fourth generation, providing crystal clear sound and almost instantaneous connection of subscribers. Many users are faced with a situation when the operator provides a service, but on the screen of the gadget the cherished icon does not appear, forcing doubts about the correct settings.
Xiaomi device owners often wonder why the feature is not activated automatically, even though the plan is fully compliant with the operator’s requirements. In most cases, the problem lies in software limitations of the firmware or regional features that are easily circumvented by correct manipulations in the engineering menu or system settings. Understanding the principles of the IMS (IP Multimedia Subsystem) will help you not only include a tick in the menu, but also ensure stable communication in areas of uncertain reception.
In this article, we will take a closer look at all the possible ways to activate high-speed voice on your device, from standard methods to using hidden engineer codes. You will learn how to check the support of the technology with your SIM card, why 4G may not work during a conversation, and what hidden switches are available in the MIUI shell. Properly configuring these settings will significantly improve the user experience and allow the capabilities of your smartphone.
Checking the compatibility of the operator and SIM card
Before you start to manipulate complex system files or engineering menus, you need to make sure that your equipment and tariff are compatible. VoLTE technology requires support from a cellular operator, availability of the appropriate service in the tariff and proper registration of the SIM card on the network. Even if your Redmi Note 8 is technically capable of working on 4G networks, without active service on the provider side, communication will switch to 3G or 2G during the call.
The first step should always be to check the status of the service through USSD-Large Russian and foreign providers often require a separate connection option, even if it is free for subscribers from the operator. 4G-Sometimes you need to replace your old SIM card with a new one with support. USIM, Older chips may not have the necessary profiles to run the multimedia subsystem.
- 📱 Make sure that the network type is selected in the mobile network settings 4G (LTE).
- 💳 Check if your SIM card supports the standard 4G/LTE (usually indicated on a plastic basis).
- 📞 Contact the operator support to clarify the status of the service connection HD Voice or VoLTE.
- 🌍 Make sure that in your area of network coverage, the operator has deployed voice transmission equipment through the network. LTE.
⚠️ Note: If after connecting the service by the operator and restarting the phone icon HD or VoLTE didn't show up, don't rush to reset settings. In some cases, it takes up to 24 hours to update profiles on network hardware.
It is also important to consider that different carriers use different frequency bands for LTE operation, and your Redmi Note 8 should support specific bands (Band 3, 7, 20 and others) used by the provider in your area. Global versions of the smartphone usually support a wide range of frequencies, while Chinese versions (China ROM) can have range restrictions, which indirectly affects the stability of voice services. Checking the model specifications on the official website or through applications like Cell Info Lite will help to eliminate hardware incompatibility.
Standard activation via the settings menu
The easiest and safest way to enable the function is to use the regular menu of the Android operating system with a shell. MIUI. In current firmware versions for the Redmi Note 8, this switch is often hidden in the depths of the settings menu. SIM-But if you run a check manually, you can force the device to register. IMS-operator.
To access the necessary settings, you need to go to the settings section responsible for wireless networks, and it is important not to confuse the settings for different SIM cards if the device has two sets. SIM-If the switch is active and available to press, just turn it on and wait for the corresponding indicator to appear in the status bar.
☑️ Algorithm of inclusion in the menu
In some versions of the MIUI shell, the path to setup may vary slightly depending on the firmware region (Global, EEA, Russia). If you do not find the switch right away, search for settings by typing in a “VoLTE” or “Mobile Networks” request. The system will redirect you to the desired section, which is especially useful when updating the interface or using custom design themes that can hide standard controls.
If the switch is missing completely or inactive (serrated), this indicates that the smartphone software has not determined the support of the service by the operator or the device model, in such a situation, standard methods will not be possible to do, and you will need to move to more advanced activation methods through the engineering menu or hidden codes, which we will discuss next.
Use of the Engineering Menu to Activate
When standard methods fail, the engineering menu, a hidden part of the system designed to test equipment and set up a radio module, comes to the rescue. Redmi Note 8 is logged in through a special code that allows access to deep telephony settings. Be careful: changing unknown parameters can lead to unstable operation of the communication module, so follow the instructions strictly.
To enter the test menu, dial ##4636## in the Phone app. If the code doesn't work (which is possible on some versions of MIUI), you may need to install a special activator application or use the #86583## command to unlock hidden features. After successfully logging in, select Phone Information, where you will see a list of switches that control the radio module.
Sequence of action:
1.Type ##4636###
2. Select Phone Information
3.Look for the VoLTE Provisioned item
4. Switch to ON stateThe key here is VoLTE Provisioned. If the switch is turned off, turn it on. This action tells the modem that the device is authorized to use it. IMS-After switching, be sure to restart your smartphone so that the changes take effect and re-register on the network. In some cases, you may also need to switch the network type to mode. LTE Only for a short time, then return back to force the connection to be renewed.
⚠️ Note: Do not change other parameters in the engineering menu, especially those related to band selection, without knowing exactly what they are intended.
What if the code doesn't work?
Set up via Xiaomi’s Hidden Menu (CIT)
In addition to the standard Android engineering menu, Xiaomi smartphones have its own hardware testing utility known as CIT (Customer Information Test), which often contains additional switches that are not available in the standard Android interface. It is also accessed through dialing, but the functionality is focused on the diagnosis of hardware Redmi.
To get to this menu, dial the code ##6484## or ##64663##. Here you are interested in the section related to the following: SIM-map or network status, depending on the version MIUI, There may be a VoLTE Carrier Check or similar option that allows you to ignore the operator check, which is especially useful if your operator is not listed on the white list of supported Xiaomi devices, which causes the system to block the display of the function.
Use of the CIT-The menu is safe for user data, as it does not affect personal files, but only works with the modem configuration, but as in the previous case, after making changes, a complete restart of the device is required. If after all the manipulations the icon did not appear, perhaps the problem lies in the incompatibility of frequencies or the need to flash the radio module, which requires a deeper knowledge.
| Access code | Appointment | Risks of use |
|---|---|---|
| ##4636## | Phone information, VoLTE Provisioned | Medium (possible loss of network) |
| ##6484## | Equipment Testing (CIT) | Low (diagnosis only) |
| ##86583## | Unlocking Hidden Functions | Low (temporary change) |
| ##726633## | VoLTE Display/Hide (depending on region) | Low. |
Solving problems with displaying the 4G icon
A common problem with Redmi Note 8 users is when the phone switches to 3G (H+) while talking, even if the feature appears to be on, meaning that voice transmission is via the old CSFB (Circuit Switched Fallback) protocol, rather than VoLTE, a behavior often seen when moving between towers or in buildings with thick walls where the LTE signal is weakened.
You can use the setprop command via ADB or special applications to force 4G retention, but on MIUI it is easier to use the hidden "Preferred Network Type" switch. Select the LTE/TD-SCDMA/CDMA/EvDo/GSM/WCDMA mode, which provides maximum compatibility. If the phone still resets the network, try to extract the SIM card, wipe contacts and paste into another slot, as one of these may be a priority for LTE operation.
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Try temporarily disabling the second SIM card. Often a conflict of resources when two active SIM cards are running in 4G+4G (Dual 4G) mode leads to a VoLTE reset on one of them.
It's also worth checking if you have a power saving mode that aggressively limits the radio module. MIUI has an ultra-energy saving feature, or just hard battery settings for the Phone app and system services. Allow background work for system communication processes so that the phone doesn't strangle the connection to save charge, which is especially true for older batteries.
Impact of the firmware region on the work of VoLTE
One critical factor affecting the feature's availability is the firmware region (ROM).Global versions (Global) usually have the most comprehensive list of supported carriers, while Chinese (China) or Indian (India) versions may ignore European or Russian providers.If you bought a phone brought from abroad or re-furbished the device, this may be the reason for the lack of option.
Owners of the Chinese versions of Redmi Note 8 often face the need to change the region in the system settings. Go to Settings → Advanced Settings → Region and select the country corresponding to your operator (for example, Russia or Ukraine). After changing the region, the phone will reload carrier profiles and may suggest updating network settings, which often solves the problem. However, if the firmware is “sharpened” only for Chinese operators, changing the region may not help.
In such cases, the only solution is to flash to the global version (Global ROM) or install custom firmware (Xiaomi.eu), which is free of regional restrictions and contains full lists of operators for all countries. Xiaomi.eu firmware is based on the Chinese version, but has built-in multilinguality and unlocked bootloader, making it an ideal choice for activating hidden functions. Before you start the firmware, be sure to unlock the bootloader to avoid problems with starting the device.
⚠️ Warning: Flashing the device voids the warranty and carries the risk of turning the phone into a brick in case of violation of technology.
Additional nuances and frequent errors
Even after successful activation, users may encounter artifacts such as intermittent sound, connection delay, or increased battery consumption, often due to the LTE network in your area being overloaded and the prioritization of voice traffic is not working properly, in which case the phone may try to hold a weak 4G signal instead of switching to stable 3G, which impairs the quality of communication.
Another common mistake is using older versions of the carrier’s applications. Make sure your provider’s application is updated to the latest version, as it may contain current configuration files for setting up the Internet and multimedia services. Also check if you have a contact ban on HD-Calls for specific numbers, although this is a rare setup.
- 📶 Make sure the cover is covered 4G stable in your location (check through Speedtest).
- 🔄 Reset network settings: Settings → Connections and sharing → Reset Wi-Fi, mobile networks and Bluetooth.
- 📲 Update the security app and system components of Google Play.
- 🔋 Turn off the power saving mode to check the impact on communication.
If nothing helps, your Redmi Note 8 may have a hardware defect in the antenna module that is not visible externally, and a drop or moisture could damage the tracks responsible for high LTE frequencies, while 2G/3G continues to work normally, in which case the software methods are powerless, and you will need a diagnosis in the service center.
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Successful activation of VoLTE depends on a combination of three factors: operator support, proper smartphone configuration and regional firmware compatibility.