USB Cable connections

[silver-eagle]

I have a GARMIN 496 with the XM radio GXM30A antennae. The Garmin website has a USB data cable which says "Does not provide wiring for external power.". This is directly below the GXM30 USB replacement cable. I'm presuming all USB cables are not created equal?
Since I didn't label all the USB cables when they came through the front door, how interchangable are these? How do I tell a USB data cable from the powered cable?

 

[Ghery]

If you have a USB cable that doesn't provide power, a peripheral expecting to be powered won't work. Sounds like the 496 doesn't need this cabability. The wires used for data are the same in either case, so the only down side I can think of that would result from using the data only cable to connect to a peripheral that is powered from the interface is that it wouldn't work. No harm, no foul. And the 496 probably doesn't have terminations for the power wires, so going the other way shouldn't hurt, either. Garmin just saved money on the cable.

Then again, I could be wrong, but based on the USB specs I've seen at work, I THINK I'm correct.