Computers typically are not designed to switch power on USB ports. If they did, how would a device be detected the first time - when the power is off it doesn't start up...
The USB ports power lines are always connected to the 5V power lines. There might be exceptions in that some devices disable the port when power negotiations fail, but I don't know of any. Your best guess could be a powered USB hub, whose power supply you could control (but this requires hardware).
What I am looking for is a SW equivalent, by running win script, that will
simulate an unplug/plug re-negotiation cycle for a specific USB port,
of my choosing.
It seems like 'devcon' from the Winowd driver kit is what you need:
- devcon.exe disable <_ID with wild cards_>
- devcon.exe enable <_ID with wild cards_>
You can also look at http://stackoverflow.com/questions/916296/how-can-i-cycle-a-usb-device-from-c/919836#919836 to find a windows scripting solution.
It looks like googling for "windows software usb unplug" yields some more detailed information.
But this still assumes that the USB-renegotiation will properly re-init the affected devices.
Thanks hli, thats exactly what I need.