I stripped a USB cable to use in a power supply and instead of the usual 4 leads inside the cable, I found only 2--red and black. I'm assuming that's 5v and ground, but I was kind of confused by what I saw. Is there another USB spec that uses only 2 leads?
Sadly, this seems to be common: USB cables that carry only power. To my knowledge that is not according to any USB spec. And it is quite frustrating because such a cable has no marking to distinguish it from a regular USB cable, so after connecting a device to my computer it takes me a lot of time to figure out that it is the &^%&&%$% cable. Needless to say, they end up in the trash can.