USB header pinout, connecting a poorly marked cable

Question

I have a "USB Cable" (http://www.evga.com/support/manuals/files/120-PG-1500.pdf pg 5 is all the info I can find on it) that connects my PSU to my computer for communication. My problem is the USB header on my MOBO and the "USB cable" do not matchup pinouts in a logical manner.

The standardized USB header pinout is such (?)

I can see around the heat shrink on the USB cable and can see a Red, White, Green, Black cables. There is no blocked pin that might represent the "key" position, and those are the only four wires.

I take it I need to align it so the Red wire sits on one of the +5v pins, but which one?

Answer 1

The above is a connector for two USB ports as you often see on the front panel. So it really won't matter if you use pins 1,3,5,7 or 2,4,6,8 but I guess the former being port zero is the way I'd go. The USB specification has the following official colours that should be used (although it's not always the case):

• Red = Positive
• White = Data-
• Green = Data+
• Black = Negative

So your cable order seems to match the motherboard connector so you should be right to attach it with the red wire to either of the +5V pins. I would hope / expect the black and red are the supply voltage but if you did happen to get erratic operation it might be that the data lines are reversed. That won't cause any hardware damage but you can find more information on that side of things in the question In a USB cable, is it OK to swap the D+ and D- wires?

Answer 2

The motherboard USB header you posted, is a typical 2 port header. Either one will work. While cable color does not always match what it should be, Red is 5v, White/Green is USB data, Black is ground, like the USB Standard Dictates (Section 6.6.2). Without an official pinout, this is just an educated guess.