[time-nuts] Thunderbolt and USB to RS232 converters

Jeroen Bastemeijer J.Bastemeijer at TUDelft.nl
Wed Jun 25 04:04:16 EDT 2008

Dear All,

OK, thanks for the FTDI chip tip! I opened up mine, the chips they used 
are the PL2303 and the ZT213.

The PL2303 is used for the USB to serial (TTL) conversion, the ZT213 is 
comparable to the MAX232 and the like. I will try to find another USB to 
serial converter (with the FTDI chip) and see if the behaviour changes.

Best regards, Jeroen

Prologix schreef:
> While I have no experience with Thunderbolt, I have tested a lot of
> USB-Serial converters and found ones with the FTDI chip to be the most
> reliable, hardware and software wise.
> http://www.saelig.com/miva/merchant.mvc?Screen=PROD&Product_Code=U003
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Javier Herrero
> Sent: Tuesday, June 24, 2008 10:13 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Thunderbolt and USB to RS232 converters
> I've been using it with Prolific PL2303 based converters with no problem 
> at all (Aten brand, in my case).
> Regards,
> Javier
> Jeroen Bastemeijer escribió:
>> Dear All,
>> More and more people are starting to play with the Thunderbolts. I
>> already received mine :-)  Now playing around with them.
>> First I powered it up and connected it to the normal serial port of the
>> PC. The Thunderbolt behaved fine, self survey took some time, because
>> the antenna is inside a concrete building with very limited view to the
> sky.
>> However, next I did a test with the same Thunderbolt but now it was
>> connected to a USB to Serial converter (brand is Sweex). After
>> switchinhg it off and on, I expected the same behaviour as when it was
>> connected to the "real" serial port. But... it started to behave very
>> strange... instead of starting a normal survey, it started disciplining
>> after a couple of minutes (almanac was not even valid). The DAC-voltage
>> clipped to the power rail, and the SV and AMU-fields remained "?". 
>> Resetting (hot, cold, factory default) didn't make any difference.
>> When power cycling the unit and connecting it back to the normal serial 
>> port the normal behaviour returned. I assume it has something to do with 
>> the USB to serial converter. Is there anyone else with similar 
>> experience? Or who has used a USB to serial converter with succes?
>> Thank you, best regards,
>> Jeroen

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: +
Fax: +
E-mail: J.Bastemeijer at TUDelft.nl
GPS: Lat N52.00002 Lon E4.37157 Alt 46.2m

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