How to turn on and set up USB-Modem on Xiaomi Redmi 9: Full guide

Connection USB-The modem for Xiaomi Redmi 9 may seem like a trivial task, but in practice users face a lot of nuances: from the lack of drivers to problems with device recognition. MIUI) This article will help you understand why your Redmi 9 can’t see. USB-modem, how to enable data transfer and what parameters need to be changed for a stable connection.

Features of Xiaomi Redmi 9 (model M2003J15SC/M2004C3LGG) It is a limited support USB OTG The manufacturer turns off this feature to save battery power, but it can be activated manually. We'll look at everything from checking modem compatibility to fine-tuning. APN and solving typical errors like «USB-Device not identified" or "No access to the network».

1. Verification of compatibility USB-modem with Xiaomi Redmi 9

Not all. USB-Modems work with Xiaomi smartphones due to firmware limitations MIUI. Before you buy or connect a device, make sure it is supported:

• 🔹 List of compatible modems: Huawei E3372, ZTE MF823, TP-Link M7350, Megafon M150-2. Modems on Qualcomm chips MDM9207 or HiSilicon Balong 711 They usually work without problems.
• 🔹 Incompatible devices: old modems based on Option GlobeSurfer or Sierra Wireless MC8700 may not be recognized.
• 🔹 Firmware requirements: Redmi 9 must be installed MIUI 12.5 or later, in older versions (e.g, MIUI (11) lack of support USB Ethernet.

To check compatibility without connection:

1. Download the USB Device Info app from Google Play.
2. Connect the modem to the smartphone through OTG-cable.
3. Launch the app and see if the device is detected in the USB Host section.

⚠️ Note: If the modem requires the installation of drivers on the PC, it is 90% likely not to work on the Redmi 9. USB-driver.

2.Preparation of Xiaomi Redmi 9 to connect

Before you physically connect the modem, you need to activate the hidden USB OTG and USB Ethernet settings in MIUI. These options are disabled by default to save power.

Preparation steps:

1. Turn on Developer Mode: Go to Settings → About Phone. 7 times click on the MIUI Version until the notification “You are a developer!” appears.

USB OTG

• Return to Settings → Additional → Developer Mode.
• Find the default USB configuration option and select File Transfer (MTP).
• Turn on the USB OTG switch (if any).
• Install the USB Ethernet app (if the modem requires this type of connection): https://play.google.com/store/apps/details?id=com.arpruss.usbeth

Developer mode is on|Activated. USB OTG|Annex installed USB Ethernet (if necessary)|Verified version. MIUI (12.5+)-->

Critical detail: if the developer's settings do not have a clause «USB OTG», Your firmware does not support network connection. USB-The solution is to update. MIUI prior to the latest version or use alternative methods (see Section 5).

3. Physical connection USB-modem

To connect the modem to Redmi 9, you will need:

• 🔌 OTG-cable (preferably externally powered, as modems consume a lot of energy).
• 📶 USB-modem SIM-card and active tariff.
• 🔋 Charger (it is recommended to connect the smartphone to the network during setting up).

Step-by-step:

1. Connect. OTG-You can use the cable to your smartphone and the modem to your cable. USB-C Redmi 9.
2. Wait for the notice «USB-If it's not there, check the cable or reset the modem.
3. Open Settings → Connections → Mobile Network.
4. In the section Access Point select USB-modem (if no item is available, see section 4).

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If the modem requires PIN-code SIM-Cards, enter it through the application USB Ethernet or in Mobile Network settings → Name of the access point (APN)

4.Tune in. APN for USB-modem

Without the correct APN (Access Point Name) settings, the modem will connect to the network, but the Internet will not work.

How to add APN manually:

1. Go to Settings → Connections → Mobile Network → Access Point Name (APN).
2. Click Add and fill in the fields according to the table below.
3. Save the settings and restart the modem (disable/connect it again).

If the Internet does not work after setting up the APN:

• 🔄 Reboot your smartphone and modem.
• 📱 Check the balance. SIM-Cards (some operators block access at zero balance).
• 🛠️ Install NetMaster app for network diagnostics.

5. Solving common mistakes

Even after setting up correctly, Redmi 9 users are faced with errors.

Mistake: «USB-device not identified»

Causes and solutions:

• 🔌 The problem with the cable: use the original OTG-Xiaomi cable or certified analogue. Cheap cables often don't transmit data.
• 🔋 Lack of power: connect your smartphone to charge or use OTG-feed-in.
• 📱 Firmware conflict: Update MIUI Up to the latest version or roll back to a stable assembly.

Error: “No network access” when you are actively connected

Possible causes:

• 🌐 Blocking by the operator: some tariffs prohibit the use of USB-Check the terms of your rate.
• 🔒 Wrong settings APN: remove all saved APN Add a new one (see section 4).
• 🛡️ firewall VPN: turn off VPN and temporarily deactivate the Defender MIUI In Settings → Annexes → Application management.

⚠️ Warning: If after connecting the modem, the smartphone begins to warm up strongly or discharge quickly, this is normal — USB-Modems put a lot of stress on the processor, so to reduce heat, close all background applications and reduce the brightness of the screen.

Mistake: “It’s connected, but there’s no internet”

Try the following steps:

1. Turn off the modem, wait 30 seconds and reconnect.
2. In the APN settings, change the APN type to default,supl.
3. Install the PdaNet+ app and activate USB Tether mode.

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If the modem is running on other devices but not Redmi 9, the problem lies in the firmware or MIUI settings. Try resetting network settings to Settings → Connections → Resetting Wi-Fi, mobile network and Bluetooth settings

6. Alternative ways of connecting

If USB-The modem cannot be connected directly, consider alternatives:

• 📡 Access Point Mode: Connect the modem to a laptop or router, and then distribute the Internet over Wi-Fi on Redmi 9.
• 🔄 Back Tether: Use the ClockworkMod Tether app to distribute internet from PC to smartphone via USB.
• 📶 External router: buy 4G-router (e.g. Xiaomi Mi Router) 4G) And connect to it via Wi-Fi.

Advantages and disadvantages of alternative methods:

If you use it often USB-modem, consider buying OTG-power hub (e.g, UGREEN USB 3.0 Hub. It will provide a stable connection and protect the smartphone from overheating.

7. Optimization of connection speed and stability

USB-Redmi 9 modems often run slower than PCs due to Helio processor limitations G80. To improve speed:

• 📈 Turn off background apps: Use Settings → Annexes → Autostart and disable Autostart for unnecessary programs.
• 🔄 Change the network mode: in the settings APN set the network type to LTE only if the modem supports 4G).
• 📡 Update your modem firmware: Some modems (e.g. Huawei) E3372) Allows you to use alternative software to increase speed.

To check the actual speed, use:

1. Speedtest by Ookla app.
2. Netflix fast.com (optimized for mobile devices)

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If the speed is below 10 Mbps, try changing the modem location – sometimes even moving 1-2 meters improves the signal.

FAQ: Frequent questions about USB-modems on Xiaomi Redmi 9