On Sun, 29 Jul 2007 04:21:14 -0700, you wrote:

>> Does anyone know of a "reverse" USB to serial adaptor?  
>
>I've never heard of such a beast existing.  Some comments...
>
>> That is, one into which a USB peripheral is plugged, and which
>> produces a serial output - in  this case it's a GPS receiver
>> with a USB interface
>
>So the GPS unit has a device/peripheral side USB connection
>(probably B or mini-B connector)?  Does the manufacturer provide
>a driver for the PC (or Mac or Linux) side?  If so, how will you
>simulate that in a reverse USB to serial adapter?
>
>> and I want to use it with something that isn't a PC and which
>> expects RS232.
>
>If this something is expecting to talk to a GPS unit via serial
>port, does it use (somewhat-standard) NEMA sentences or does it
>rely on a proprietary protocol to the GPS unit?  Proprietary
>would make this whole lash-up less likely to work.
>
>You could conceivably have 2 proprietary protocols here -- one
>on the GPS USB link and a second on the serial link.  How fun.
>
>> I suppose it's a tricky thing to do, since the USB interface
>> is intelligent,
>
>And USB is non-symmetrical.  You need host-side USB connection
>to master the link to the GPS unit.
>
>You could build one with a Cypress SL811HS USB host controller
>and a PIC with UART, but it wouldn't be a trivial exercise.
>
>Good luck.
>						Lee Jones

The Vinculum VNC1L chip is almost exactly this - I don't know to what extent it yet supports devices
other than memory and FT232's.

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