To be able to send audio from the ADA8200 to the UC you need to provide a 2nd TOSLINK cable from ADA82000 to UC:

UC--ADAT OUT ----------TOSLINK cable #1 with clocking information --------> ADA8200 -----> D/A conversion
UC--ADAT IN    <--------TOSLINK cable #2------------------------------------------ ADA8200 <----- A/D conversion from MIC/Line inputs

In the RME driver settings you need to ensure to set
- "clock source" to "internal" and
- optical to "ADAT" format

And yes, the switch on the back of the ADA8200 needs to be set to "ADAT IN" to act as "clock slave" receiving clock from ADAT IN (RME UC).

EDIT: changed 1st sentences to make it easier to understand.

The ADA8200 channels are represented by the ADAT input and output channels, as you connect the external preamp to the ADAT ports -> ADAT1..8 IN.

I only know Cubase, there you need to choose, which I/O channels you want to use in the project.
In Protools you see either all I/O ports or you need to choose the ports there as well.

Proactive proposal for further operation

You might want to read about TotalMix routing capabilities.
In some cases you might want to route through the DAW, for some monitor mixes it might be more feasible to route directly through the Interface which has a much lower latency.

I can recommend you the RME Tutorial videos to get a 1st very good overview about TotalMix FX's capabilities.
The Videos are really "to the point" (no bla bla) not much time consuming...
https://www.tonstudio-forum.de/blog/ind … al-Videos/

After that you can check, whether my TotalMix FX primer for a 1st time setup contains some points of interest for you.
https://www.tonstudio-forum.de/blog/ind … rnal-equi/

Then you should definitively download the latest version of the manual in PDF format and make yourself familiar, what this interface can do. First I would browse through the manual, to get a 1st impression what information you find where.
https://www.rme-audio.de/download/fface_uc_d.pdf
https://www.rme-audio.de/download/fface_uc_e.pdf

Then I would start with the 1st chapters which give you a good overview about the UCs capabilities and explain basic functions. I think this you should regard as "mandatory task".
The next very interesting section is about TotalMix FX.

Have fun with your new recording interface, RME products are very good.

Take your time with TotalMix, the RME videos, manual, my primer will give you a guidance what a good 1st setup could be for you.

Very important is to understand that you configure on a per output (aka "submix") base.
For every output you provide a mix of signals coming from
- either HW inputs (TM FX top row)
- and/or SW playback channels / from PC/apps (TM FX middle row).
Audio from HW inputs are per default always passed to the DAW/applications.
Audio from PC will show up 1st on the SW playback channel (an "additional Layer" between application and HW output) with the goal to give you the flexibility to route audio to different HW outputs as you like...

If you think this is all to much you can even enter DAW mode, then TM FX routing is gone (no SW playback channels anymore), then you can only route in the DAW ... tbh ... get better acquainted with TM FX routing, you do yourself a favour by this, much more flexibiltity by that.

I can not get the signal to the RME.

I can see that there is a signal in on the ADA8200 but no signal in TotalMix.
On the rear of the ADA8200 there is following options:
WC IN - Slave
ADAT IN - Slave
Master 44.1k
Master 48k

It's on ADAT IN right now.

Thank you

So you can use a single optical cable but you have to set the ada8200 the clock speed you want and then set the sync on the UC to Adat.
If the UC has word clock you can connect word clock out of the uc to word clock in of the ada8200. This way you can then set the uc to internal and ada8200 to Wcc in slave.

Next option is two optical cables (I do this with a Babyface pro fs) set the ada8200 to adat in slave. UC set to internal.

Ok .. so problem solved now ?

I have this question, too.

Then you didn't read the thread, this is possible and exactly what I proposed in posting #2.
RME Fireface UC as clock master and Behringer ADA8200 as clock slave.

My laguage is Spanish, and never heard UC.. I called it sound card or Audio Interface... You can also call it RME Fireface 802, but UC?.. I never heard UC, that is what i was asking. I suppose these two letters stand for two words.

I have done every single thing mentioned here. And I can not get the ADA 8200 to work when conecting via ADA to the  RME fireface 802.

2 tosling cables OUT TO IN. ETC. 48.00.. Inner clock in the Fireface USB settings.

And in my Totalmix.. only appears ADAT 1- in the second row, the one for software.. I do not see anything in the first Raw ( for hardware inputs or instruments) or in the 3erd raw. the one for the OUT .

The synth I have connected to the front panel LIne in 1 of the ADA820.. does not work.. I do see the green ligth on when i press the keyboard, but no signal gets into the totalmix. NO even in the software ADA1,etc..

If someone can help me by giving me a call i will appreciate.. This thread is great but much faster and better a conversation.. My number is +34 619561911.. And Whatsapp is free. Thanks a lot.

Now I understand why i did not see the ADAT hardware INPUT channels and OUTPUT channels.. I eliminated de ADAT channels from Totalmix.. There is a function that lets you do that.. I rechanged that , now they show, and it works now.

I already solved it by putting de master clock in the 8200... But, If I put the master in RME Fireface and the slave in the 8200 does not work. 

Has anyone made it work with the master clock in the RME?

Beringer's are known to have a little better specs (because of jitter) when on internal clock, as tested by SOS magazine. UC does not have this problem because of steadyclock, so Berhinger master is best anyway.

I did not try to switch the ADA 8200 first. That might be the solution. I will try tonight.
I am not sure who should be the master clock.

My intention is to have Ableton as Master clock and other external gear, in my studio,  slaves to Ableton. So I make Live performance, but BPM, and cocck is controlled from Ableton.
So... I do not know how this affects me now..¿ master clock BEhringuer?.. ¿ master clock RME?. ¿ master clock Ableton?..