On Tue, Feb 23, 2021 at 10:57:09AM -0500, Michael G. Katzmann wrote: > On 2/23/21 10:43 AM, Johan Hovold wrote: > > On Tue, Feb 23, 2021 at 09:58:47AM -0500, Michael G. Katzmann wrote: > >> 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-) Heh, guess you're right. > 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. I only have an HXD (and a GC) here. The HXD has bcdUSB as 1.10 unlike your TA with 2.00, but not sure that helps. > 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? I tried with both of mine when Joe reported this and neither works with the alternate scheme (and the GC turned out not to even support divisor encoding). Johan
