> > Perhaps this is a silly question, but how do I calibrate the clock? or
> > use an external reference signal?
>
> Andrey Sviyazov - does ClockIn works as external input in UmTRXv1?

Yes, 5V cmos level required or smaller with DC offset to get 2.5V symmetry.
Turn switches to MHz and slave positions.

Best regards,
Andrey Sviyazov.
(Sent from my mobile client)