Hi Folks, i added the udev rules already 1. lsusb: Bus 003 Device 004: ID 16c0:0483 Van Ooijen Technische Informatica Teensyduino Serial 2. ls -l /dev/ttyU* /dev/ttyA* crw-rw-rw- 1 root dialout 166, 1 Sep 2 18:58 /dev/ttyACM1 3. picocom -eq -b9600 /dev/ttyACM1 :GU# nNpHzE0# :GR# 03:06:34# :GD# +90*00:00# So it seems to work. I think the trick was in restarting the onstep, and not only in rebooting the system. Many thanks! Regards, GerritRead More...