[ntp:questions] GPS_NEMA, but high offset and jitter?

David Lord snews at lordynet.org
Sat Feb 27 10:57:49 UTC 2010

David J Taylor wrote:
> "David Lord" <snews at lordynet.org> wrote in message 
> news:7ur6r2Fac0U1 at mid.individual.net...
> []
>> Thing is there appears to be a problem with the PPS so
>> I was suggesting a more sensitive circuit should a scope
>> or moving coil meter not be available.
>> David
> Isn't there software for the OS which emulates a breakout box and would 
> give a simple indication of the DCD line or parallel port bit used? 
> Obviously you may not be able to use such software at the same time as 
> NTP, but it might be enough as a a test tool.
> For Windows, I could find:
>  http://www.windmill.co.uk/serial.html
>  http://www.taltech.com/freesoftware/breakout.htm
>  http://www.sinnovations.com/htdocs/siscope_rs232_analyzer.htm
> although I've not used any of these, and some require two serial ports.

I mentioned radioclkd(2) both of which in debug mode
display state of selected pin (dcd cts dsr or rng).

radioclkd -s poll -d -v ttyS00:dcd

This gives time at each pulse edge.

I'm sure there are other programs that do a better job
for debugging serial data.

For serial data on Windows, I've captured serial output
by  using second serial port and a two headed (9pin + 25pin
at both ends) modem cable that splits the cable for you.


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