Can I use SPDIF digital for loopback?

[Uberverbosity]

Using a Behringer UMC1820, I can output via SPDIF RCA without issue, but I'm unable to get "Ref In" signal.

 

[Uberverbosity]

As always, just needed to give up and ask the internet in order to figure it out on my own...
Apparently the "Output" and "Timing Ref. Output" need to be dissimilar.

 

[Wayne A. Pflughaupt]

Don’t think you can do loopback via SPDIF. Just follow the instructions in the REW Help Files and you can’t go wrong.

Regards,
Wayne