I've build a simple distribution amplifier for my GPSDO.
My SYMMETRICOM GPSDO 090-03861-03 with firmware release 184.108.40.206-01 has a bunch of commands available:
I've done some long term measurements on my GPSDO. The GPSDO has a RS232 based simple command interface.
To have a stable 10MHz reference in my shack, I've ordered a SYMMETRICOM based GPSDO from an Chinese eBay seller. It was delivered in kit form, so no issues with missing CE marking etc.
The GPSDO is build into a sturdy aluminium case with a PCB front panel and an aluminium back panel.