To add to what Paul wrote: Here is a oneliner to check for usb serial ports on a linux machine: $ ls -l /dev/tty[ACU]* (the initial '$' is the prompt, don't include it in the command) run this before and after you plug in your usb serial device, and you will find it - if it is detected.
If the device only works as user root, you need to create a file to set ownership, group and permissions on the device when it is plugged in. This is commonly done through udev / udevadm on linux. On Sun, Aug 2, 2026 at 4:00 AM Paul Berger via cctalk <[email protected]> wrote: > > Well the first thing to do is make sure the USB serial device gets > configured, when you plug it in, you should see the serial device listed > in the output from 'lsusb' and there should be messages about it in > 'dmesg' (requires root authority). It is possible that the naming > convention for the tty device that get created is different between the > two versions of linux. The usual way is the device gets created > dynamically when you plug in the USB serial device. on my linux, > Devuan which is debian based but unencumbered by systemd, it creates a > device /dev/ttyUSB0 most modern distributions I have seen use names like > this. > > Paul. > > On 2026-08-01 21:41, Jon Elson via cctalk wrote: > > Well, everything is a fight! > > > > The project I'm working on is to get a VMS MicroVAX system working at > > VCFMW. The plan was to have serial comm on a Linux laptop connected > > to the MicroVAX. I have the serial comm working on a Dell desktop > > machine, so I just plugged the same USB serial cable into the laptop, > > and NO COMM! I plugged back into the desktop, and serial data works > > fine! I'm totally mystified! The desktop is running an OLD Debian > > kernel (7.11), the laptop is running a late Ubuntu (24.04.4). > > > > I have no idea why the laptop doesn't communicate. I have tried > > minicom, picocom and cutecom, same result on all of them. > > > > Thanks for any help you can suggest. > > > > Jon > > -- mvh Torfinn
