[rescue] USB port card for sBus?

Jonathan C. Patschke jp at celestrion.net
Fri Aug 22 21:15:23 CDT 2008


On Fri, 22 Aug 2008, Lionel Peterson wrote:

>> Whose theory would that be?  USB doesn't work that way.
>
> The *theory* that the Serial <-> USB adapter is bi-directional.

USB is a network with a multiple-tier directed graph topology.  The logic
that implements the host side of things is very different from the logic
that implements the device side of things.

There is a significant amount of data on the USB side of the EIA232<->USB
adapter that would be "out of band" relative to EIA232.  The EIA232 side
of things doesn't need to know anything about USB address arbitration,
power management, or any of that.  The EIA232 side of things is also
clocked much more slowly.

That theory is an awful lot like saying you could plug a PCI serial card
and a riser board into the console port to add a PCI card cage to an sbus
machine.

-- 
Jonathan Patschke | "There is more to life than increasing its speed."
Elgin, TX         |                                   --Mahatma Gandhi
USA               |



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