[ntp:questions] timing issue with a HP 58534A

David J Taylor david-taylor at blueyonder.co.uk.invalid
Sat Feb 4 11:13:16 UTC 2012

"Mark C. Stephens" <marks at non-stop.com.au> wrote in message 
news:4BDE1132003994498B736B8017D15D10088EFA9E at exch2010.non-stop.com.au...
> GPS initially was selected but eventually got marked as false ticker.
> I am going to drag a silly scope down there to have a look at the timing 
> pulse, I have a vague suspicion it maybe inverted by the rs422-rs232 
> convertor which I built. Although unrelated to this issue, I came across 
> this today while building a 'gadget box' for a trimble acutime:
> TTL out of rs422 convertor goes into the max232 like this :
>                    __
> _______|   |___________
> But the rs232 comes out of the max232 inverted, like this:
> _______        ____________
>                  \__/
> The slew rate on rs232 is not so good for timing is it ):
> Mark

This is what I suggested to you yesterday.  Did you not see my post?  You 
need a positive edge on the DCD line when working normally, but there is a 
setting in the ntp.conf (for some refclock implementations) allowing you 
to select the other edge.  See, for example:



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