got mail from KBtalking guy i think:
"only USB interface , this keyboard without PS/2 interface
And I have explain what is N-Key meaning !!
For N-Key meaning is , this keyboard won't have any anti-Ghost key ,
But in USB interface , (according to USB protocol keyboard just can sent 6 KEY to System , but I can use another way to make full N-Key in the same time , but in USB N-key still have some little bugs , maybe in new motherboard BIOS , Unix system , Mac OSX system ......)
So , I have sorry tell you
KBT Pure only have USB interface , I think you can find in User Manual
Have fun , and good day"
tired and that didnt make me any smarter lol