[ntp:questions] Re: How to configure gps/pps with ntp?

Steve Kostecke kostecke at ntp.isc.org
Sun Mar 26 03:26:39 UTC 2006

On 2006-03-25, Chris Richmond wrote:

> Now that ntp is running, I want to get it going with my Garmin
> gps18lvc. I've got a 2.4.32 kernel with PPSKit running, linked
> /dev/ttyS0 -> /dev/pps1, and added "server prefer" to the
> config file. ntpq -p -n reports the .GPS. line, but the data isn't
> updating (all zero's except the last field is 4000.00).

The GPS-18LVC uses the NMEA driver (w/built-in PPS): 127.127.20.N

You have to symlink /dev/ttyS0 --> /dev/gps1

See http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver20.html

Here's the configuration snippet I'm using:

# GPS+PPS using Atomized Generic NMEA driver
server mode 2 minpoll 4 maxpoll 4 prefer

> I connected to /dev/ttyS0 with minicom, and I'm getting the NEMA
> sentences,

You should turn off all of the NMEA sentences other than the one you're

And you have to explicitly enable the GPS-18LVC PPS mode (it's in the

Steve Kostecke <kostecke at ntp.isc.org>
NTP Public Services Project - http://ntp.isc.org/

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