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A comment on USB inventor explains why the connector was not designed to be reversible. Parent comment

Re:USB inventor explains why the connector was not designed ... by gzalo on Monday October 09, 2023 @04:31PM (#37825125)
> Then you implement auto crossover detection, dwhich had been around for years

Mdi-x/auto crossover for ethernet was introduced in 1999, that is after USB (1996) was designed, not sure of the technique was known at that time

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Re:USB inventor explains why the connector was not designed ... by dboreham on Monday October 09, 2023 @04:44PM (#37825259)
There were auto-crossover RS-232 boxes going back deep into the 1980s.
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Re:USB inventor explains why the connector was not designed ... by sitzkrieg on Monday October 09, 2023 @06:15PM (#37826134)
with baud rate detection to boot (down the line)
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Re:USB inventor explains why the connector was not designed ... by userbinator on Monday October 09, 2023 @10:57PM (#37828062)
You can't do "auto crossover" with USB because it needs to distinguish between D+/D- for speed selection.

https://electronics.stackexchange.com/questions/73295/in-a-u...

It works for Ethernet because the transmit and receive lanes are separate, but with USB, there's only one pair used for both directions.

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Re:USB inventor explains why the connector was not designed ... by ilyt on Tuesday October 10, 2023 @01:21PM (#37834845)
It doesn't need to.

It chose to. They could just use different way to do it. Like, I dunno, a single packet of negotiation in slow mode...

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Re:USB inventor explains why the connector was not designed ... by crote on Tuesday October 10, 2023 @05:02AM (#37829900)
Not really relevant.

Ethernet needs crossover because it has dedicated transmit/receive pairs, but USB 1.x/2.0 uses a single wire pair for both tx & rx. Ethernet crossover is pretty much identical to serial null modem cables, and those were around for a few decades by then.

USB "crossover" of the single differential wire pair would be an inversion of 0 and 1. Pretty trivial to do once you figure out a way to communicate crossover or not.

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