Is USB polarity important?

USB uses differential signaling, D- and D+ signal lines. Since it?s differential, is absolute polarity important? If, for example, I mix up the two conductors on a USB device I?m rewiring, is this critical?

Just curious?

Thanks, Dave

Reply to
DaveC
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Yes it's imperative you get it right

Reply to
TTman

Of *course* it is! Do you think you can replace every '0' with a '1' and still get the same *meaning*?

Yes.

Reply to
Don Y

because it's differential doiong that would make a "1" look like a "0" and a "0" look like a "1", that seems unlikely to end well unless USB has been designed to detect and compensate for this fault.

Reply to
Jasen Betts

On Sat, 08 Aug 2015 08:53:14 +0100, TTman Gave us:

Yes. ALL FOUR conductors, not just the signal pair.

Two are power. Does it make sense to you that reversing those would be OK?

Or mixing any from each set?

Reply to
DecadentLinuxUserNumeroUno

Yes. A - B is different from B - A.

Reply to
Tim Wescott

On 8 Aug 2015, Tim Wescott wrote

Thanks Tim. That explains it.

Reply to
DaveC

Well why the hell not? Wifi manages to sort them out... :^)

(Radio encodings not having the advantage of DC and phase correct installations, of course, so they have to make do when they're doing PSK modulations.)

Tim

Reply to
Tim Williams

On Sun, 9 Aug 2015 01:49:30 -0500, "Tim Williams" Gave us:

Make dew. Hahahahaha!

Reply to
DecadentLinuxUserNumeroUno

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