You can print documents (*.pdf, *.ps, *.prn files) on a USB drive.
You can disable / enable this function in the Settings Editor.
Example of a folder structure on the USB drive
Save a file to a different location
at the left-hand side of the control panel.
to browse through the directories on the USB drive.
The locations you can select depend on your system configuration.
.
Remove the USB drive from the control panel when the USB LED on the control panel is off.