[time-nuts] RS 232

David J Taylor david-taylor at blueyonder.co.uk
Fri Jul 26 01:56:48 EDT 2013


From: Chris Albertson
[]
In just normal UNIX (including Mac OS X) and linux you can see the
difference in the log files between USB and RS232.  There is three orders
of magnitude difference.  It's micro vs. milli seconds.
[]
Chris Albertson
Redondo Beach, California
==================================================

Indeed!  You can see a similar difference in Windows as well, and a 
difference between using user-mode and kernel-mode time-stamping of the PPS 
signal.  Kernel mode is on the left, and user-mode on the right in this 
graph:
  http://www.satsignal.eu/ntp/2009-05-17-Feenix_jitter.png

and changing from user- to kernel-node on a different system:
  http://www.satsignal.eu/ntp/plot_jitter.png

These are from the page:
  http://www.satsignal.eu/ntp/NTP-on-Windows-serial-port.html

Cheers,
David
-- 
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor at blueyonder.co.uk 



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