Issue creating sylink for serial device on Linux (`'Inappropriate ioctl for device'`)

Mantabit 0
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I am using multiple USB devices connected to an Ubuntu machine and I would like to create a symlink to their corresponding device file so that I can read from these devices in Python.

For example, for the device "ka3305p" I created the rules file /etc/udev/rules.d/ka3305p.rules.

ATTR{idVendor}=="0416", ATTR{idProduct}=="5011", SYMLINK+="ka3305p", MODE="0660", GROUP="dialout"

When I plug in the device, I see a symlink /dev/ka3305p appear:

lrwxrwxrwx   1 root  root              15 Sep 21 10:08 ka3305p -> bus/usb/001/003

However, when I try to read from this file in python I get an error message:

def __init__(self,portname='/dev/ka3305p'):
    self.ser = serial.Serial(
        port=portname,
        baudrate=9600,
        parity=serial.PARITY_NONE,
        stopbits=serial.STOPBITS_ONE,
        bytesize=serial.EIGHTBITS,
        timeout=1
    )

SerialException: Could not configure port: (25, 'Inappropriate ioctl for device')

Can I change the rules file to avoid this error?

I can read / communicate with the device normally if I use the device file /dev/ttyACM0.

pyserial usb rules linux
1 Answers

So I was able to solve this issue, apparently, I had to use ATTRS instead of ATTR in the rules file. This fixed the problem and I can now read normally from the device using the symlink.

Mantabit0
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