[ntp:questions] Fwd: Re: NetBSD GPS/PPS using 4.2.6p3

David J Taylor david-taylor at blueyonder.co.uk.invalid
Wed Aug 24 09:00:14 UTC 2011

"A C" <agcarver+ntp at acarver.net> wrote in message
> At first I couldn't remember which way the pulse went.  But having 
> measured it now the voltage goes low (which would be an assert under 
> RS232) for 100ms and then returns to high voltage for 900ms.

The DCD line is positive active, so it needs to go high for 100-200 ms, 
and then return low.  Yes, it's the opposite of the other RS-232 


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