[time-nuts] TimeProvider 2700 PTP UTC offset issue.

[Andrew Back]

Hoping that someone may be able to shed some light on a PTP issue I'm experiencing, which could well be a simple configuration issue or, as I suspect, somehow related to the grandmaster firmware.

I have a Symmetricom TimeProvider 2700, with firmware which I think dates from ~2014, connected to a BeagleBoneBlack running Debian and Linux PTP. A direct Ethernet connection with no switches in between. The TP2700 has the 1588 Annex J Default profile active, with all default configuration. Linux PTP client is configured for utc_offset 37. The GM is referenced to GPS and "show clock" returns "Leap Seconds : 37". However, when ptp4l is started on the client I get the running in a temporal vortex message and "updating UTC offset to 35", despite not seeing an offset of 35 configured anywhere.

I did also run "pmc -u -b 0 'get TIME_PROPERTIES_DATA_SET'" on the client, which similarly confirmed a UTC offset of 35.

I don't seem to be able to manually configure UTC offset on the TP2700 and when I try, it complains that this is not possible with the current mode, since it's referenced to GPS I guess.

Other than this perhaps being a grandmaster firmware issue, I'm out of ideas.

Andrew