This is a pretty old thread, but I figured I might as well ask anyway...
Since the price of the Xoom and accessories has dropped dramatically, I recently picked one up on the egg and a standard dock on amazon for around ten. Just like most on this thread, I couldn't believe that moto didn't design a female plug on the back of the dock (how much easier would it have made things if they had put a simple female microusb on the back?).
Anyways, I quickly stripped an old usb cable, popped off the dock cover, and wired her up in regular USB mode (non-host). I did add an additional wire plug from an old cordless phone battery pack and connected it to my brown and black wire -- this way I could easily "short" brown and black with paperclip to send it to usb host mode.
So after I get this all done, I test -- non-host mode works great. Now, I insert the paperclip and test using my keyboard/mouse (which works fine with a regular OTG adapter) and bingo -- nothing! Boo!
I then get out my multitester and discover that the red and white wires/pins are reversed on the OTG cable. Can anyone else confirm this? From what I have read online, it does not appear to be, but since I stripped everything apart, I can't test unless I am willing to sacrifice my one remaining OTG adapter.
Thanks,
CY