[time-nuts] Thunderbolt and USB to RS232 converters

Jeroen Bastemeijer J.Bastemeijer at TUDelft.nl
Fri Jun 27 06:51:29 EDT 2008

Dear All,

I upgraded the driver for the Prolific to the latest version, now it 
works fine! Thanks!

It first used a Microsoft driver, dated a few years back. By the way, 
I'm using WinXP professional.

Jeroen PE1RGE

Didier Juges schreef:
> Hal,
> I have two Prolific adapters on a single hub, which is probably low speed
> (it was cheap). They work fine under XP, even though one of them is used
> with a program (development system) that has shown some finicky behavior
> when driving a serial input JTAG box with the old drivers. The other one
> drives my ham radio's serial port. The Thunderbolt is normally plugged into
> the hardware serial port COM 1 on this machine, I will try with the Prolific
> adapter just for grins.
> Didier KO4BB
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com 
>> [mailto:time-nuts-bounces at febo.com] On Behalf Of Hal Murray
>> Sent: Wednesday, June 25, 2008 7:03 PM
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] Thunderbolt and USB to RS232 converters
>>> That's a good point. The older Prolific drivers had a nasty 
>> habit of 
>>> crashing my laptop (Win XP would not wake up) if I put it in 
>>> hibernation with the adapter plugged into the USB socket. The new 
>>> drivers mostly fix the problem. I may occasionaly have to 
>> unplug and 
>>> replug the device after waking up, but the OS no longer crashes.
>> The SIRF GPS units use the Prolific chips.
>> I have had mixed results with them on Linux.
>> They don't work like I expect when I try to use several of 
>> them on a high speed hub.  The Prolific chip wants some 
>> guaranteed bandwidth and Linux has troubles allocating it.  I 
>> thought I found a kernel option to get around that, 
>> CONFIG_USB_EHCI_TT_NEWSCHED, but I tried to clean things up 
>> last night and mumble.  I guess it helps but not as much as I 
>> though.  Mumble.  It may be the hub-hub case that doesn't 
>> work.  I've got a 7 port hub which is really
>> 2 4 port hubs chained.
>> I haven't noticed any troubles without the hub.  I'm not 
>> doing anything fancy.
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Ing. Jeroen Bastemeijer

Delft University of Technology
Department of Electrical Engineering
Electronic Instrumentation Laboratory
Mekelweg 4, Room 13.090
2628 CD Delft
The Netherlands

Phone: +
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E-mail: J.Bastemeijer at TUDelft.nl
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