On 2/23/21 10:43 AM, Johan Hovold wrote:

On Tue, Feb 23, 2021 at 09:58:47AM -0500, Michael G. Katzmann wrote:

quoted

Is it that we are presuming that what Prolific is telling us is true
and only Joe and I are actually measuring the data rate?  (i.e. why
does the Prolific Windows driver set the values as Joe found ???)

I'm starting to think they've added some alternate baud rate encoding in
order to make life harder for the people pushing (or unknowingly buying)
counterfeit devices.

As you say, why else would the Windows driver support this encoding?

I find that  'Halon;'s razor' is helpful in these situations...  I can't think that messing with people who use old teleprinters would be useful in protecting one's products 8-)

If Joe has some wireshark traces we can see if there are any vendor specific USB packets. If not I can try it (I'd be starting from scratch as I've only use wireshark on Linux).

I presume you can't see any differentiators in the normal USB identifiers that we can use. 

If someone has a device that works under the existing driver, it would be helpful to see if the modified scheme also works on those devices?