Hi Daniel. Thanks for your reply, much appreciated!
You're right it is straightforward, or should be at least
I've done some more testing, still no luck though...
You mentioned formats so I've tried 1080i50 and 1080p25 program output from the TriCaster to the studio fiber converter return 1 - in both cases I get pictures at the studio and camera converter end but no tally. Also in both cases pressing the return 1 button on the camera fiber converter shows the pictures on the studio viewfinder and LCD, as it should, plus the physical SDI return output 1 works too. But no tally. (I changed the settings on the camera to suit the format).
If I take the same TriCaster output direct to the Ursa SDI input I get tally, plus it passes through all the way back to the studio fiber converter.
Program out from the ATEM gives me tally, plus program audio if I turn it on in the Ursa menu.
No audio direct from the TriCaster though... presumably as it's not routed to 15-16 as it is with the ATEM (not sure how to achieve that). I just wonder if that's part of the issue... i.e. maybe the fiber converter needs 15-16 to be "alive" to pass the control signals?
It's a weird one that's hugely frustrating. I even started trying different sync options as I thought that may be relevant, think it's more basic than that though.
Going slightly crazy with this now
If you have any other ideas they'd be most welcome!