This time a USB (full speed+high speed) opto isolator.
It is based on the ADuM 3160 chip and can generate isolated 5V from the USB input or be powered from 5-12V externally.
The PCB is version 1.2 or a design by CircuitsAtHome. It is larger then version 1.1 and quite easy to solder by hand.
I still have a 1.1 PCB here that I plan to do another day.
I plan to use it on my CNC to further reduce electric noise leaving the spindle VFD and interfering with the rest of the equipment.