I’ve updated my tooling to use these paths ( /dev/usbserial/3/1.4.3) instead of the kernel names ( /dev/ttyUSB0), and it has greatly simplified things. Now as long as I attach a specific device to the same USB port on my system, it will have the same device node. You can see the new symlink in the DEVLINKS value, and looking at /dev/usbserial we can see the expected symlinks: # tree /dev/usbserialĪnd there have it.

Looking at the available attributes for a serial device, we see: # udevadm info -a -n /dev/ttyUSB0 While that sounds conceptually simple, it took me a while to figure out the correct udev rules. Ouch.Ī common solution to this problem is to create device names based on the USB topology – that is, assign names based on a device’s position in the USB bus: e.g., when attaching a new USB serial device, expose it at something like /dev/usbserial//. ive used the modprobe trick, nadetect nya naman yung cable and used the generic driver, nakakapagdial pero hindi umiilaw yung TR (Terminal Ready) LED sa modem ko. On more than one occasion, I have accidentally re-flashed the wrong device. im trying to make my modem work thru USB-Serial cable wala na kasing serial port yung unit ko, but im sure my modem works kasi nagamit ko na before sa lumang pc. This by itself would be a manageable problem, except that the device names assigned to these devices aren’t constant: depending on the order in which they get plugged in (and the order in which they are detected at boot), a device might be /dev/ttyUSB0 one day and /dev/ttyUSB2 another day. Unfortunately, they have a cheap CH340 serial adapter on board, which means that from the perspective of Linux these devices are all functionally identical – there’s no way to identify one device from another.

I like to fiddle with Micropython, particularly on the Wemos D1 Mini, because these are such a neat form factor.

Hl 340 usb to serial driver ubuntu