USB 3.0 Use with Linux

[Kelsay, Brian - Kansas City, MO]

I believe what they mean about the USB 3 cables and connectors being compatible is that extra wires and contacts are being added, but they do not interfere with current connectors and wires.

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|  _  _  _  _   |  
_________________    old connector example    (Not even close to scale)

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|_ _ _ _ _ _ _ _|   new connector example with extra contacts between the four old ones.
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Think about RJ45 connectors on Network cables; they had 8 contacts, but only 4 were used in 10/100 networking.  After the switch to Gigabit networking, all 8 contacts and wires needed to be punched down/connected.   In the old 10/100, the extra 4 were present, but just used as ground and it one disconnected at the RJ45 end or in the wire somewhere, you would still have a network connection, just less grounding and attenuation dampening.


Brian Kelsay

-----Original Message-----
From: kclug-bounces at kclug.org [mailto:kclug-bounces at kclug.org] On Behalf Of Luke-Jr
Sent: Wednesday, August 25, 2010 7:17 PM


On Wednesday, August 25, 2010 07:00:01 pm Monty J. Harder wrote:
> On Wed, Aug 25, 2010 at 6:43 PM, Luke-Jr <luke at dashjr.org> wrote:
> > Do note in general, USB 3.0 is /not/ compatible with USB 1 or 2.
> 
> Care to explain?
> 
> > 5. Will my existing peripherals still work? How will they co-exist?
> > The good news is that USB 3.0 has been carefully planned from the start
> > to peacefully co-exist with USB 2.0. First of all, while USB 3.0
> > specifies new physical connections and thus new cables to take advantage
> > of the higher speed capability of the new protocol, the connector itself
> > remains the same rectangular shape with the four USB 2.0 contacts in the
> > exact same location as before. Five new connections to carry receive and
> > transitted data independently are present on USB 3.0 cables and only
> > come into contact when mated with a proper SuperSpeed USB connection.

Well, that's interesting! I guess I had assumed the physical connection change 
was on both ends, to avoid people mistakenly thinking it was compatible, but I 
see it in fact has another purpose. Unfortunately, some devices (such as mice) 
have the cable built-in and thus could not possibly remain compatible.
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