Am 07.05.2012 23:58, schrieb Michael Scherer:
> meaning the controller then needs different outlets for 3.0 and 2.0 
> cables,
> so I need to use 3.0 cable on the 3.0 one, but 2.0 cable on the other.

Not quite :). A 3.0 USB client (like a 3.0 HDD) will usually come with a 
new 3.0 USB cable with additional contacts. The client head is different 
than with a USB 2.0 cable. The master head (that plugs into the 
controller, your computer or hub) is backwards compatible - if you plug 
it into an USB 2.0 port, the additional contacts won't connect and the 
HDD will speak USB 2.0. The same goes for a 2.0 client in a 3.0 port.

So, controller side, you can plug everything into everything. Only 
client side you have a new outlet (which is good because it prevents you 
from using an old 2.0 cable and falling back to slow speed if both your 
PC and client speak USB 3.0)

Regards,
     Thomas