David Wright <deb...@lionunicorn.co.uk> writes: > As it happens, I find I have (but don't use):
> $ grep -i ttyusb /lib/udev/rules.d/* I actually found this in 50-udev-default.rules: KERNEL=="tty[A-Z]*[0-9]|ttymxc[0-9]*|pppox[0-9]*|ircomm[0-9]*|noz[0-9]*|rfcomm[0-9]*", GROUP="dialout" So that should set the group for ttySx and ttyUSBx also to dialout and in fact I see exactly that happening in my Debian 11 router which has devices ttyS0-ttyS3 and ttyUSB0-ttyUSB4: $ ls -l /dev/ttyUSB* /dev/ttyS* crw-rw---- 1 root dialout 4, 64 Jun 13 12:12 /dev/ttyS0 crw-rw---- 1 root dialout 4, 65 Jun 13 12:12 /dev/ttyS1 crw-rw---- 1 root dialout 4, 66 Jun 13 12:12 /dev/ttyS2 crw-rw---- 1 root dialout 4, 67 Jun 13 12:12 /dev/ttyS3 crw-rw---- 1 root dialout 188, 0 Jun 13 12:12 /dev/ttyUSB0 crw-rw---- 1 root dialout 188, 1 Jun 13 12:12 /dev/ttyUSB1 crw-rw---- 1 root dialout 188, 2 Jun 13 12:12 /dev/ttyUSB2 crw-rw---- 1 root dialout 188, 3 Jun 13 12:12 /dev/ttyUSB3 crw-rw---- 1 root dialout 188, 4 Jun 13 12:12 /dev/ttyUSB4 I didn't find a rule which sets the perms for these to 0660 but something does that for me. This rule comes with the udev package itself so it should be always installed in a Debian installation. Still, it seems for Gene these are overwritten somehow but I don't know why or how. I have exactly one USB-to-serial cable I can try to plug in and see what happens. However it's a CP210x and I think Gene's stuff is FTDI.