blackcobra487

I just bought a powered USB hub from a local computer store. The only issue is that the data cable slits into two plugs and the second one is where it draws power. I split open the second cable to find that there are more than two wires, since the manual said it was for power only I only expected two. My question is, with the second USB plug, is it safe to assume the red wire is positive power while the black is negative and the other two would be for data?
The hub does have a spot for a barrel connector, but there's no way to tell what's + or - so making a wire seems out. Unless somebody is pretty sure which one would be which. Any help guys?