[time-nuts] Symmetricom TymServe 2100-GPS currently fails with GPS offset

Andrew Lindh andrew at netplex.net
Fri Jan 30 11:17:15 EST 2015

Esa Heikkinen <tn1ajb at ...> writes:

> Robert Watzlavick kirjoitti:
> > I'm seeing the same thing with my TS-2100 - it is one second behind WWV 
> > based on the front panel display.   My ET-6000 appears to be in sync.
> Ok - then this is verified...
> So the only way (for me) is to run this with 1PPS from Thunderbolt. Good 
> thing is that Tymserve itself support leap second and when 1PPS is used 
> it can be set manually. I did some quick tests and noticed that correct 
> command to set the leap second event is:
> tim leap 1 07/01/2015 00:00:00
> SPOLER ALERT - if you want to see the leap yourself, stop reading...
> It did not go 23:59:60, it was stopped at 23:59:59 two seconds.

I have a nice set of TS2100 GPS Rubidium boxes as primary servers
that provide time and PPS to more current NTP servers. It's too
bad the firmware is so old and this bug won't be fixed.

I see the same 1 second offset against my other time sources used
by NTP on my test machine: Motorola Oncore M12+T, Garmin 18x LVC,
Trimble Resolution T. 

Looking at the TS2100 menu you can see that it is using the GPS
offset leap second early and reports 17 rather than the current
correct setting of 16.

I found you can use the engineering menu to hack temporary changes
to the offset. These changes are unsupported, use at your own risk.
Good luck!

Telnet to your TS2100 and login.

You can check the current offset using:
 root timing gps utcoffset
 root timing utils tfp 1

It will show 17, which is a bug because it's early.

Use an engineering command to set it to 16:
 root engineering timing early_utc_leap 16

You can also set the TS2100 to add a leap second at the correct time:
 root timing leap 1 07/01/2015 00:00:00

I gave this a quick test by setting the leap to a minute from now
and it did change the offset from 16 to 17. I guess it will only
add 1 second when the time comes as instructed, but who knows...
Maybe it will add 2 because of the manual setting and the GPS
message change, or maybe it will just be correct when the GPS
message changes.

This fix does NOT survive a system restart as it syncs with GPS again.
It  does survive a GPS reset, but if the leap second message updates
it may reset the offset.

You can clear the manual offset and use GPS:
 root engineering timing early_utc_leap 0

Clearing the offset tells the system to use the default GPS offset.
You can check the offset again with the above commands.

Clearing the offset hack and leap settings after the real leap
second and restarting would be a good idea (it's the only way to sure).

This early_utc_leap setting hack does not require a restart and the
TS2100 changes time (adjusts to the new office) in about a minute.

 - Andrew Lindh

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