Hood, I think you are right again, GND is connected to the GND of the (12-24V POW). I still don't understand though why I would have to connect this high periferral voltage just to be able to use the switches, and what else could that voltage be used for?. As nothing is connected to these terminals,I wonder if I could just connect this GND to the PCGND, but I think I have already tried something like that and did not get the output... So I don't intend to connect the external power supply, and certainly not connect the encoder to it...
Overloaded, BOB has the 5V supply directly from the PC power supply. I guess the USB is there for the same reason, but I did not try to use it so far, I believe the result would be the same, though. This BOB worked fine so far, until I invented this wheel problem;)
Maybe the solution with onsceen LEDs would work, I'd have to learn how to do it first, though, never tried it before. And I would be interested in Hoods solution, as this way I might be able to assemble some sort of pendant, or add some sort of box on the router itself, as opposed to having to reach for the keyboard or mouse. Sometimes it's not a problem, but sometimes it's simply too far to be able to see the tool AND use the keyboard.
I'll try both, thanks again...