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

A C agcarver+ntp at acarver.net
Fri Aug 26 06:00:35 UTC 2011


> I will try to capture the outgoing serial data sometime either this
> weekend or the next when I have a bit more time. I'll send it along to
> the list as soon as I do. For now I'll leave things using PPS only and
> see how it works. But I still want to eventually get the GPS refclock
> working along with PPS just to have a backup clock for network outages.

Ok, so I've spliced up a serial tap cable to snoop on the data heading 
out towards the GPS.  Unfortunately I can't seem to decode it.  No 
amount of changing baud rates, stop bits and parity seems to show me 
anything but a stream of unreadable binary data.

It seems to be coming out at 4800 baud although stty says the output 
speed of the port is 9600.  The data seems to have a regular pattern to 
it with a few of the bytes changing.

If anyone can think of a utility that will attempt to autosync to the 
data I'm open to suggestions.  Otherwise I can try to capture the raw 
data if anyone wants to look at it.  Either way, it only transmits while 
ntpd is using the port.  If ntpd is shut down the data stops.



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