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From: "Michael G. Katzmann" <michaelk@IEEE.org>
To: Johan Hovold <johan@kernel.org>
Cc: charles-yeh@prolific.com.tw, linux-serial@vger.kernel.org,
	linux-usb@vger.kernel.org, Charles Yeh <charlesyeh522@gmail.com>,
	Joe Abbott <jabbott@rollanet.org>
Subject: Re: non-standard baud rates with Prolific 2303 USB-serial
Date: Tue, 23 Feb 2021 10:57:09 -0500	[thread overview]
Message-ID: <f63df659-6cdf-bba6-f892-1012b98f82e2@IEEE.org> (raw)
In-Reply-To: <YDUiuLtwRkZ0D0Mi@hovoldconsulting.com>

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-)

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?



  reply	other threads:[~2021-02-23 15:59 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <3aee5708-7961-f464-8c5f-6685d96920d6@IEEE.org>
     [not found] ` <dc3458f1-830b-284b-3464-20124dc3900a@IEEE.org>
2021-02-22  8:52   ` non-standard baud rates with Prolific 2303 USB-serial Johan Hovold
2021-02-22 12:39     ` Michael G. Katzmann
2021-02-22 13:18       ` Johan Hovold
     [not found]         ` <fb1489c2-b972-619b-b7ce-4ae8e1d2cc0f@IEEE.org>
2021-02-22 15:34           ` Johan Hovold
2021-02-22 15:42             ` Michael G. Katzmann
2021-02-22 15:50               ` Johan Hovold
2021-02-22 16:37                 ` Michael G. Katzmann
2021-02-22 16:48                   ` Johan Hovold
2021-02-24 23:08                     ` Joe Abbott
2021-02-25  8:44                       ` Johan Hovold
     [not found]                   ` <43da22ced8e14442bbc8babea77e4ed7@MailHC2.prolific.com.tw>
2021-02-23 10:18                     ` Johan Hovold
2021-02-23 13:25                     ` Michael G. Katzmann
2021-02-23 14:58                 ` Michael G. Katzmann
2021-02-23 15:43                   ` Johan Hovold
2021-02-23 15:57                     ` Michael G. Katzmann [this message]
2021-02-23 16:14                       ` Johan Hovold
2021-02-23 16:30                         ` Michael G. Katzmann
2021-02-23 16:52                           ` Johan Hovold
2021-02-23 19:15                             ` Michael G. Katzmann
2021-02-24 17:04                               ` Johan Hovold
2021-02-24 18:13                                 ` Michael G. Katzmann
2021-02-25  8:42                                   ` Johan Hovold
2021-04-08 15:35                                     ` Johan Hovold
2021-02-24  7:34                             ` Charles Yeh
2021-02-24 17:00                               ` Johan Hovold
2021-02-24 17:12                                 ` Michael G. Katzmann
2021-03-05  9:32                                 ` Charles Yeh
2021-03-05  9:36                                   ` Johan Hovold
2021-03-06 20:18                                     ` Michael G. Katzmann
2021-03-07  4:15                                     ` Michael G. Katzmann
2021-03-11 16:08                                       ` Johan Hovold
2021-03-12 13:17                                         ` Michael G. Katzmann
2021-03-12 13:44                                           ` Johan Hovold
2021-03-12 20:29                                             ` Michael G. Katzmann
2021-03-13  1:28                                             ` Michael G. Katzmann
2021-03-15  9:07                                               ` Johan Hovold
2021-03-15 10:07                                                 ` Charles Yeh
2021-03-15 10:24                                                   ` Johan Hovold

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