[ntp:questions] help with setting up NTP on windows with a USB GPS

David J Taylor david-taylor at blueyonder.not-this-bit.nor-this-part.co.uk.invalid
Mon Nov 30 16:06:59 UTC 2009

"jack" <> wrote in message 
news:b15dd4f8-2611-4e3f-9ace-ad21c5f78892 at f20g2000vbl.googlegroups.com...
> RGB:
> I tried the serial port on my B&B serial board and the 1PPS signal is
> not detected. I don't how how serialpps.sys sees the signal and am
> thinking the DCD signal is not sent over the PCI bus.
> jack


Dave Hart is obviously the man who knows most about this, but my 
understanding is that the DCD transition should create a hardware 
interrupt, which then creates a software interrupt, which serialpp.sys 
handles and notes the time of the transition, which the DLL/ntpd.exe can 
later retrieve.  Even without the special serialpps.sys and DLL, ntpd.exe 
can note the time of the transition, only just not as accurately.  We're 
talking microsecond-level differences here.

I suspect that you may find an option to enable or disable DCD.  You seem 
to have other COM-port issues from your next post.


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