Difference between USB cables

[Goi]

Hi,

I have some USB cable that have different specifications. A is not braided, B is "48 braid", and C is unspecified. They both seem to work, but B and C have "High Speed USB 2.0" printed on the cable while A is plain. B also has "28AWG/1PR and 28AWG/2C" as well as the UL # E189533 printed on it and C has "28AWG/1P and 28AWG/2C" and the UL # E238846.

All these cables seem to work, and I know I'm probably nitpicking, but I just wanna know what does "48 braid" mean, as well as the difference between 28AWG/1PR and 29AWG/1P. I know braiding helps in reducing EMI/RFI interference, but what's the 48 prefix mean?

Thanks!

 

[Zepper]

These things could mean anything and you'd have to ask the specific wire maker to find out - they may have a web site that describes their products if you can find it. 48 braid can mean either 48% braid which means it provides 48% coverage of the wires within or it might mean 8 bundles of strands at 4 crossings per inch or some such. USB 2 rated cable should have better shielding than just USB. Some of the original USB front panel to mobo wiring wasn't shielded at all - it was a 4 or 5-wire flat cable.

.bh.

 

[Goi]

So I found out that 28AWG/1PR means 28AWG/1 pair(twisted pair) and 28AWG/2C means 28AWG/2 conductor. The twisted pair is used for the D+/D- signals and the 2C is used for power and ground. According to USB specs, fully rated cables should have the twisted pair and better shielding, compared to sub channel cables which can be just 4 conductors without shielding, like you said. Contrary to what I thought, cables DO make a difference, not really for speed, but more for power delivery at least. I measured some of the cables I got, and the voltage drop can be pretty different among various cables.(100-200mV difference). Also, I tested on a Mac one of my cables with 24AWG power/ground got my 7200rpm 2.5" bus powered enclosure to spin up, whereas another with 28AWG power/ground couldn't get it to spinup despite plugging both cables of the Y cable in. Macs seem to be more picky with USB devices for some reason...