Hi Ron, thanks! I'm working with the basic green opto isolated "5 axis breakoutboard" you see everywhere. Upon further inspection I saw that this too needs external power to provide the analog 0-10V for the spindle control. So maybe it indeed boils down to the same situation as with the g540. I feel warned though by John as he stated the connections at the 5V input of the Consew controller could very well be live. Zapped myself once before during reinstallation of a bandsaw motor controller.housing....