[time-nuts] Symmetricom TS2100-GPS - 1PPS has 10uS offset

Jason Rabel jason at extremeoverclocking.com
Sat May 11 15:17:53 EDT 2013

Here's some good reading you might want to check out about the PPS and different GPS modules:


I think nobody ever really bothered to fix anything since the NTP time was "good enough". Plus when all those companies got bought
out and merged managing / tweaking legacy products just wasn't a priority I guess.

The hidden "eng" menu does have some interesting stuff. I've tweaked the offset to bring time in sync with my other NTP servers,
usually around -4000 does the trick since the TS2100 doesn't use a true NTP implementation (I think it is more SNTP).

I have seen different offset settings in units, so I would think there would be *some* way to save the setting, but like you have
not found out a way to do it yet. :(


> There's hidden "eng" menu with many options. No documentation is 
> available for this menu, so I had to find things out by trial and error.
> In the "timing" menu there's offset_time option. This shows -100 at 
> default and one step is 100ns --> 10 uS. Setting this to zero the PPS 
> moves to sync with Thunderbolt!
> But the setting is not permament, it's lost with reboot. Unable to find 
> out how to "save" this permamently. And hard to understood why this is 
> even set to -10 uS!
> There's also commands to read and write the eeprom contents (it's good 
> idea to read it and copy-paste the contenst to the safe place). However 
> the offset_time is not stored to eeprom, even with JP4 in place. Too sad!

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