How to set up calls on Xiaomi Mi 9: from basic settings to troubleshooting

Xiaomi Mi 9 is still a popular device due to its powerful hardware and flexible settings, but many users have problems setting calls, from basic volume parameters to difficulties with VoLTE or a secondary microphone. This article will not only explain how to set a call on the Mi 9, but also help optimize communication quality, eliminate echoes, adjust vibration and even restore performance after resetting.

We'll take a look at the official and hidden settings, and we'll give you checklists to diagnose malfunctions, and we'll focus on issues after a MIUI update, which often cause a loss of sound or an inability to make a call, and if you just bought a used Mi 9 or upgraded your firmware, this will save you hours of searching for solutions.

Unlike Xiaomi’s newer models, where calls are automatically customized, the Mi 9 (especially on custom firmware) requires manual calibration, for example, there is no separate volume control for conversations — it needs to be activated through an engineering menu. And if you lose sound in the speaker during a call, it may be not only the software that is to blame, but also the physical disconnection of the second microphone due to the oxidation of the contacts after moisture.

Before you go to the settings, make sure the problem is not in the SIM-Try calling from another phone to the same number -- if the call doesn't go through, call the mobile operator. If the problem is only on Mi 9, read on.

1. Basic call setup in MIUI

Start by checking the basic parameters. Open the Phone app and go to Settings → Calls. Here are the key options:

• 🔔 Call volume: adjustable by slider or volume buttons during a call. The Mi 9 doesn't have a separate profile for conversations - it's tied to the overall media level.
• 📞 Auto dial: turn on if you want the phone to automatically call back when a call is dropped (useful for poor communication).
• 🔄 Call forwarding: Set up a redirect to another number if your Mi 9 is not available.
• 🎵 Call melody: select a standard signal or download yours through Settings → Sounds and vibrations.

Note the option for additional settings – there are options for displaying the number (hide / show your subscriber ID) and recording conversations. The latter function only works when manually enabled during a call (automatic recording is blocked by law in some regions).

If the settings are changed, check to see if the Do Not Disturb mode is activated (the crescent icon in the notification curtain) and can block incoming calls from unknown numbers.

2.Sound problems: speaker and microphone

The most common complaint of Mi 9 owners is that the sound is lost during the call or the interlocutor does not hear you, the reasons can be both software and hardware.

1. Call a voice number (e.g. 112 – it works even without a voice number). SIM-maps) and check if you can hear the autoinformer.
2. Turn on the tape recorder and record a few seconds of speech, play back the recording -- if the sound is distorted or missing, the microphone is the problem.
3. Put your headphones on and repeat the call. If it sounds, the main speaker is malfunctioning.

If tests show a hardware fault, try cleaning the connectors:

• 🧹 Use a toothpick with cotton wool dipped in alcohol to clean the speaker mesh (it is located in the lower part of the body).
• 🔊 For the microphone (located next to the main camera and on the lower end), use a compressed air canister.

If the problem is software, reset the sound settings:

Settings → System → Resetting settings → Resetting sound settings →

Checked speaker for music playback

Tested microphone through a voice recorder

Dust connectors cleared

Resetting of sound settings performed

Checked work in headphones-->

3. VoLTE setup and communication quality

Xiaomi Mi 9 supports VoLTE (voice over 4G), which improves communication quality, but by default it can be disabled.

1. Go to Settings. → SIM-maps and mobile networks.
2. Choose yours. SIM-map and turn on the VoLTE call switch.
3. If you don’t have an option, update your firmware or contact the operator – some tariffs don’t support VoLTE.

After activating VoLTE, check the quality of the connection:

• 📶 In the status line should appear an icon HD or VoLTE during the call.
• 🔊 The sound will be cleaner, without noise and interruptions (if the cover is covered). 4G stable).
• ⚡ The connection time will be reduced with 5-7 second 1-2.

If VoLTE is not working, try manually selecting the network:

→ SIM-maps and mobile networks → Network type → 4G (preferably)

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If after turning on VoLTE the Internet disappeared during the call, disable the option Use. 2G call-in SIM-map.

4. Hidden settings of the engineering menu

If standard methods don't work, use the engineering menu, which allows you to test hardware components and change parameters that are not available in MIUI.

1. Enter the combination in the Phone app: ##4636##.
2. Select the item Phone Information.
3. Scroll down to the Set preferred network type block and set LTE only (if you need to force 4G on).

To test the microphone and speaker:

1. In the engineering menu, select Hardware Testing.
2. Go to Audio and run the Normal Mode (for the main microphone) and Loud Speaker Mode (for the speaker).

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Note: Do not change the settings in the engineering menu unless you are sure of their purpose. For example, the wrong setup of Band Mode can lead to loss of the network.

5. Solving problems after the MIUI update

Firmware updates often break the work of calls to the Mi 9.

• 📵 Calls are dropped through 1-2 seconds.
• 🔇 The sound is lost in the speaker, but the music is playing normally.
• 📞 Impossible to dial the number – buttons do not respond.

The first thing to do is to clear the cache of the phone application:

Settings → Applications → Application Management → Phone → Storage → Clear cache

If this does not help, reset your network settings:

Settings → System → Resetting → Reset settings Wi-Fi, mobile network and Bluetooth

For advanced users: if the problem occurred after upgrading to MIUI 12.5+, try to retrace to the previous version via Fastboot.

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Note: The rollback of the firmware will void the warranty and may result in the device being locked if the bootloader is not officially unlocked.

6. Alternative methods of making calls

If the standard Mi 9 call doesn’t work, use the following workarounds:

• 📱 Google Phone: Install an alternative app for calls from Play Market.It's often better optimized for older devices.
• 💬 Messengers: WhatsApp, Telegram or Viber support voice calls over the Internet.
• 🌐 IP-Telephony: services like Zoiper or Linphone allow you to call through SIP-Account (suitable for corporate users).

To set up Google Phone:

1. Install the app and make it standard for calling Settings → Apps → Default Apps.
2. In the Google Phone settings, enable Sound Improvement and Call Recording (if necessary).

If you make frequent calls abroad, consider rates with unlimited calls over the Internet (like Tinkoff Mobile or Yota).This is cheaper than roaming and doesn't require additional settings on the phone.

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Alternative calling apps (Google Phone, WhatsApp) often solve problems with standard MIUI calling, especially after updates.

7. Hardware malfunctions: when to contact the service

If all the software methods have been tried and the calls still don't work, the problem could be the hardware.

• 🔌 Oxidation of contacts after moisture hits (even if the phone didn't sink, condensation could damage the microphone).
• 📱 Detachment of speaker plume or microphone (often after falls).
• 🔋 Failure of the audio codec (the microchip responsible for sound processing).

Signs of hardware breakdown:

• 🔊 The sound disappears only in the dynamics, but works in headphones.
• 🎤 The microphone does not work in any application (dicamer, camera, calls).
• 🔌 After cleaning the connectors, the problem returns in a few days.

Cost of repairs in service centers:

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Warning: If the Mi 9 stopped ringing after falling or getting moisture, don't turn it on again - it may cause a short circuit. SIM-Card and battery (if possible) and take to the service.

FAQ: Frequent questions about calls on Xiaomi Mi 9