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Asked: 2024-09-24T17:45:56+05:30 In:

I am having trouble getting my device to recognize /dev/ttyUSB0 on Ubuntu 22.04. It seems to be missing, and I’m unsure how to resolve this issue. Can anyone provide guidance on how to troubleshoot or fix this problem?

I’ve been feeling pretty frustrated trying to get my device recognized on my Ubuntu 22.04 setup, and I’m hoping someone can help me out. I’ve got this USB device that should show up as `/dev/ttyUSB0`, but for some reason, it’s just not appearing at all. I’ve plugged it in, and I can see the light on the device blinking, so I know it’s getting power. But when I run the `ls /dev` command, there’s no sign of it anywhere.

I’m not sure if I need to install any specific drivers for this thing, or if it’s just a matter of some settings I might have missed. Also, I’ve checked the USB cable and ports with a different device, and they seem to work fine. It’s definitely something related to the configuration or recognition in Ubuntu since I’ve used this device on Windows before without any issues.

I’ve tried a few things already, like checking the dmesg logs after plugging in the device (`dmesg | grep tty`) to see if there are any messages about new devices being connected, but the output doesn’t show anything related to `/dev/ttyUSB0`. I even looked into the `lsusb` command to see if the device is recognized at all, and it shows up there, which is a small relief, but not exactly the solution to my problem.

I’ve thought about maybe running the `modprobe usbserial` command to see if that helps, but I’m not familiar with how these modules work. Is there anything else I should do to troubleshoot further? Am I missing a step, or is there something else I should check in the settings? If anyone has faced a similar issue or knows some common fixes for getting USB devices recognized in Ubuntu, I would really appreciate your insights. I just want to get this device working so I can move forward with my project! Thanks!

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    2 Answers

    1. Sounds like you’re having a tough time with your USB device on Ubuntu. I’ve been there!

      First off, since you can see the device with lsusb, it definitely means the system recognizes it at some level, which is good! The fact that it’s not showing up as /dev/ttyUSB0 is a bummer, though. Seems like it might be related to drivers or kernel modules.

      Here are a few things you could try:

      • Check your user permissions: Make sure your user account has the right permissions to access the device. You might need to be in the dialout group. You can do this by running:
        sudo usermod -aG dialout $USER
        After running this, log out and back in.
      • Try loading usbserial module: You mentioned modprobe usbserial, and that’s a good thing to try! Just run it like this:
        sudo modprobe usbserial
        Then check dmesg | grep tty again to see if anything changes.
      • Search for drivers: Depending on what the device is, it may need specific drivers. Do some Googling for your device model and check the Ubuntu forums for any tips. Sometimes, manufacturers provide Linux drivers!
      • Check the kernel version: Sometimes updating your kernel can help with device support. You can check your version with:
        uname -r
      • USB power settings: Check if your USB settings are causing issues. You can try disabling USB power management using:
        echo 'on' | sudo tee /sys/bus/usb/devices/usb*/power/control

      If you still can’t get it to work, consider rebooting your system after trying the above steps. Sometimes, a good reboot can reset things enough for the device to be recognized.

      Hope something here helps you out! Keep poking at it!


    2. It sounds like you’re facing a common issue when working with USB devices on Ubuntu. Since your device appears in the output of `lsusb`, it indicates that the system recognizes the USB hardware at some level. However, since you’re not seeing the `/dev/ttyUSB0` entry, it may be related to kernel modules or the specific type of USB device you are using. Many USB to serial devices require the `usbserial` module to be loaded, which you can check with `lsmod | grep usbserial`. If it’s not listed, running `sudo modprobe usbserial` may help. Additionally, ensure that any additional drivers specific to your device are installed. You can often find these on the manufacturer’s website or in the Ubuntu repositories, especially if your device is common.

      Beyond checking the kernel modules, look into permissions as well. Sometimes, the device node appears but isn’t accessible due to lack of sufficient privileges. You can check and potentially change the permissions with `sudo chmod 666 /dev/ttyUSB*` after the device is connected. If the device requires specific user group access, adding your user to the appropriate group with a command like `sudo usermod -aG dialout $USER` might be necessary, followed by a logout and login to refresh your session. Additionally, trying the device on another USB port or using a different USB cable can sometimes resolve connectivity issues, as there can be physical layer incompatibilities. Continue checking `dmesg` and `lsusb` after every change to verify progress towards resolving the issue.


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