why is usb specified as 90-ohm transmission lines anyway, when almost everything uses either 50, 75, or 300 ohm transmission lines
-F
@zetasyanthis I wonder if usb 3 is different, since it's meant for higher speed stuff
usb 1.1 didn't specify an impedance, i don't think, because it's too slow for impedance matching to really matter
-F
No, 2.0 and 3.0 both call out 90 +/- 7 ohms. What on earth. Why would that be different from everything else made? XD
I am going to have to ask on StackExchange tomorrow and hope someone answers.
(Longer, properly worded question = more energy than brain has right now. :P)
Displayport and HDMI are 100 ohms too, look like.
@Felthry
High speed data cables often use 100 ohms. (SATA, SAS, QSFP DAC cables, for example). Why 90 for USB? I have no bloody idea.