Xiaomi’s Redmi line of smartphones has been at the forefront of the budget and mid-market segments for many years. The Redmi 9 has been a hit because of its balance between performance and price, but the MIUI software shell sometimes requires a careful approach to configuration. In particular, standard telephony settings may not fully meet the expectations of users accustomed to pure Android or other interfaces.
The quality of voice communication depends not only on the coverage of the cellular operator, but also on the correctness of the device's software parameters: the wrong codec, the lack of support for VoLTE or a malfunction. SIM-Maps can turn communication into a challenge. In this article, we will discuss in detail how to optimize the communication module on your device.
You will learn how to activate hidden functions, eliminate interference and adjust call automation for maximum comfort. Competent configuration will make the most of the hardware capabilities of the Redmi 9, providing crystal clear sound even in unstable signal conditions.
Basic configuration SIM-maps and nets
The first step to quality communication is to properly install and configure SIM cards. Redmi 9 supports two. SIM-Nano-SIM cards are simultaneously available, allowing you to flexibly manage your rates. Before setting up, make sure the cards are inserted into the right slots and fit tightly to the contacts.
To access the main options go to the Settings menu, then select the item SIM-And there's a key switch that's often ignored by newcomers, if your carrier supports the technology. 4G, You need to activate the option to Use VoLTE, which will allow you to transmit voice in a format. HD, Keeping high-speed internet while talking.
You can also set a priority menu SIM-The system offers three options: ask every time, use always the first card or always the second card.
- 📱 Make sure the network type is selected in the settings. LTE maximum speed connection.
- 🔒 Check if outbound calls are banned from the access restriction menu.
- 🔄 When changing the operator, reset the access point settings APN for the proper operation of the Internet.
⚠️ Note: If after activating the VoLTE icon HD It doesn't appear in the status bar, but the calls pass, it doesn't mean it's a mistake. Some operators hide this indicator, but the technology works at the network level.
Set up a one-touch call and quick calls
MIUI offers convenient features to speed up dialing, which saves you a lot of time in everyday use, and one of the most useful options is One-touch Call, which allows you to make calls to contacts on your desktop or widgets without having to open your phone book.
Another interesting feature is a quick call by long-pressing the number in the "caller," so you can assign a number from 2 to 9 to a particular contact. To make a call, just open the dialer and hold the assigned key, which is especially convenient for emergency contacts or communication with loved ones.
To activate these functions, go to the Phone app, click on the three dots in the upper right corner and select Settings. In the Additional Settings section, you will find Quick Call, and you can divide contacts by digital keys.
☑️ Quick call checks
Remember, the number 1 is reserved by the system for voicemail access, and you can't change that by standard means, because it's a global standard. GSM-If you don't need voicemail, you can delete it in the operator's settings.
Managing forwarding and waiting for a call
Redirection features prevent important calls from being missed even when you are busy or out of network coverage. On Redmi 9, these options are managed via the system menu or USSD-Standard forwarding can be configured in case of line occupancy, lack of response or unavailability of the subscriber.
In parallel, it's important to set up call waiting, and this service allows you to hear the second caller's beep while you're talking to the first caller, and without activating this option, the second caller will hear the "busy" signal, even if the line is free software.
To set up, go to the phone. → Settings → Call accounts. Choose the one you want. SIM-You can find the additional settings section, and you can find the switches for all kinds of forwarding, and you can manually enter the number to which the call will be redirected.
| Type of forwarding | When it works. | Recommended action |
|---|---|---|
| Always. | Any incoming call. | Use only when the main number is not available. |
| If it's busy. | During the current conversation | Good for business lines. |
| If there is no answer | After 4-5 horns | Optimal for skipping spam calls |
| If not available. | Phone off or off the network | Basic setting for all users |
Keep in mind that forwarded calls may be charged by the operator as outgoing calls to the number where the forwarding is going.
Improved sound quality and noise reduction
The quality of voice transmission on Redmi 9 depends on the operation of noise reduction algorithms built into the processor and microphones of the device. In some cases, the standard settings can be too aggressive, "eating" part of the frequencies, or, conversely, skipping too much background noise. There is an engineering menu for fine-tuning the sound.
To get into the test menu, open the dialer and dial the combination ##6484##. This will trigger the CIT (Customer Interface Test), where you can check the performance of each microphone and speaker. However, changing the audio parameters often requires access to coki settings through the Engineering Mode application, which can be downloaded from official sources or installed via ADB.
In standard operating mode, the system automatically detects the noise level and adjusts the sensitivity of the microphone. If the interlocutor complains of a quiet voice, check whether the lower end of the smartphone is closed with a finger. In Redmi 9, the main microphone is located right there, next to the charging connector.