By default the Rosetta is set for ADAT optical. If you want to switch to S/PDIF optical, use the following procedure:

• Hold down the "Sample Rate (AES FMT)" button. Now on the digital output source, you should see that the LEDs for ADAT and AES will be lit up.

• Hit the "Source (SRC)" button and that will switch it to "S/P OPT". If you want to go back to ADAT, hit the "Source (SRC)" button again while holding down the "Sample Rate" button.

*Keep in mind that if you re-set the Rosetta 200 (holding down the sample rate button while powering on) it will re-set to ADAT optical.