How to activate USB-modem

In conditions of unstable cellular coverage or in the absence of access to Wi-Fi networks, the use of external USB-The modem becomes the only way to get online for owners of Xiaomi, Redmi and Poco smartphones. MIUI or HyperOS doesn't always automatically identify the connected device as the source of the Internet, requiring the user to manually intervene. OTG-adapter device exclusively as a drive or completely ignores it, which causes bewilderment among inexperienced users.

The activation process depends on many factors: the version of the operating system, the model of the modem itself and the availability of the necessary drivers in the Android kernel. In this article, we will discuss in detail the algorithm of actions that will turn your smartphone into a full-fledged terminal for receiving 4G/LTE It's important to understand that the success of an operation often lies in choosing the right modem and setting the parameters. APN.

Before you start complex manipulations, you need to make sure that your equipment is physically fit and compatible. Xiaomi smartphones have a wide range of supported devices, but the specifics of the firmware can make their own adjustments. We will look at both standard methods and advanced methods through the engineering menu that will help in the most difficult cases.

Compatibility check and equipment preparation

The first step is to physically connect and make an initial diagnosis. USB-modem (e.g. from operators) MTS, Beeline, Tele2 or universal Huawei, ZTE), fit OTG-Not all Xiaomi models support the function OTG at the level of iron, although in 2026-2026 In the past few years, these devices have not been used in active use.

When you plug your modem into your smartphone connector, look at the LED light, and if the modem flashes blue or green, it means that the power is running correctly. But the lack of Android interface response doesn't always indicate a malfunction, and the system could recognize the device as a CD-ROM with drivers, which is typical of older modems, or as a Mass Storage.

⚠️ Note: When connecting powerful 4G/LTE modems through cheap OTG-In adapters, the smartphone can issue a warning about "large current consumption", in this case, using an external recharge (through a splitter). USB) It is mandatory, otherwise the power controller may block the port.

For successful activation, the condition is critical SIM-A card installed in the modem, make sure it doesn't have a card on it. PIN-code, as Android can't ask for it when you connect an external modem. Also check the balance and availability of the tariff that supports the distribution of Internet, as some operators block modem operation on third-party devices.

Owners of devices with global firmware Global ROM are less likely to face the problem than users of China ROM, where the necessary certificates and drivers for European or Russian telecom operators may not be available, and in some cases, it is necessary to flash the modem on the computer before connecting to the phone.

Basic settings through the developer menu

The standard MIUI interface often hides the USB mode switch. To activate the necessary functions, you need to access hidden settings. Go to Settings → About Phone and quickly click on the MIUI version seven times. Once the notification “You became a developer” appears, return to the main settings menu.

In the "Advanced" or "Extended Settings" menu that opens, look for the "Developers" section, which is the default USB configuration section, the standard "Charge Only" or "File Transfer" value will not allow the modem to start, and you need to select RNDIS or ECM mode if available on the list.

After choosing the right mode, connect the modem. If a message about a new one appears in the notification curtain USB-In some versions of the HyperOS shell, it may be necessary to manually run the modem service through special assistant applications that emulate the system requests.

It is important to note that the debugging regime USB (USB Debugging) is better not to include in this menu unnecessarily, as it can conflict with modem drivers. USB Default: Experiment with the options MIDI, PTP, if standard do not work, although for modems it is rare.

Using applications to manage modems

Android is not always a feature of the Android device, especially if the modem driver is not built into the core, and in such cases, Google Play comes to the rescue, and one of the most effective is the USB Modem or PPP Widget 2 program, which takes over the connection.

These applications work on the principle of network interface emulation. Once the program is installed and given Root permissions (if required) or special permissions through ADB, the software finds the connected device itself, reads the signal data, the balance, and allows you to create connection profiles with the desired APN parameters.

A popular solution is also the use of terminal emulators such as Termux. You can manually run a modem initialization script through the command line if you know its VID and PID. This method is suitable for advanced users who understand the principles of Linux, on which the smartphone OS is built.

When using third-party software, it is important to monitor energy consumption.Constant survey USB-It is recommended to keep the device on charge or use Power Bank during long sessions of operation through an external modem.

Solving problems with drivers and network modes

One of the common problems is that the modem is not working properly; by default, many devices are defined as flash cards with installation files. AT-On computers, this is done by a switching program, and on Android, this function is taken over by the apps mentioned above.

If the modem is detected but the Internet is not working, check the settings of the APN hotspot. Operators use different addresses to access the network. Incorrect APN settings are a common cause of connection failure even when the hardware link is established. You can find current settings on your carrier's website or in the application help.

In situations where standard methods don't work, you can try changing the network mode in the engineering menu ##4636## in dialer (calling app) in the section "Phone information" or "Information about the phone" USB-Try switching your preferred network type to LTE Only on GSM/UMTS/LTE (Sometimes coercive regime 3G Works more consistently in areas of poor reception.

Configure through the Engineering Menu and ADB

For users who are not afraid of the command line, there is an activation method through ADB (Android Debug Bridge), which allows you to embed commands directly into the system, bypassing the limitations of the graphical interface, you will need a computer, a USB cable and an installed ADB driver.

Connect your smartphone to your PC, turn on debugging USB And you can type in a command to check the list of connected devices: adb devices. If the device is displayed, you can try to send a command to activate an Ethernet connection, which is often emulated. USB-modem:

adb shell svc usb setFunctions rndis

This team is forcibly translating USB-port to network adapter mode. In some cases, the function switch command helps USB:

adb shell am start -n com.android.settings/.usb.UsbSettings

Using ADB requires caution. Incorrect commands can lead to a freeze in the interface or temporary loss of communication with the device. If after you input the smartphone stopped responding, just restart it. This method is especially effective on devices with custom firmware, where standard settings can be cut down.

⚠️ Attention: Teams ADB It can vary depending on the version of Android and the manufacturer of the chipset (Snapdragon, MediaTek, Exynos). there is no universal command, so you should experiment only with understanding the essence of the actions performed.

Frequent errors and ways to fix them

Even if all instructions are followed, specific errors may occur «USB-The device is not supported" often appears on older Xiaomi models with limited current in the port.The solution is one - use of active USB-feed-in.

Another common problem is cyclical reconnection, which is that the modem is constantly plugged in and out before it can be initialized, which can indicate power shortages or driver conflict. USB-devices, reduce the brightness of the screen (to save energy) or use a cable shorter than 20 cm.

💡

Use quality. OTG-Cheap thin cables create resistance, which causes voltage to drop and unstable operation. 4G-modem.

If the modem is working but the internet speed is extremely low, check if it has switched to 2G/EDGE mode. In the modem control app or in the engineering menu, force LTE Only or 4G Preferred mode. It is also worth checking whether traffic is not exhausted, since operators often cut the speed after reaching the limit.

Rarely, the problem lies in the smartphone file system itself. A crowded cache of system services can interfere with the proper functioning of network interfaces. Clearing the cache of Phone, Settings and Downloads applications sometimes works wonders.

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Stability of work USB-Xiaomi modem directly depends on the quality of the port power and the correct settings APN, It's not just cell tower signal strength.

FAQ: Frequently Asked Questions