Theta Digital Casablanca


Need help. How do you identify the DTS card in the back of a Casablanca series I. I only have some pictures and I can see two digital in cards:

1. marked ac3 (so I belive this is the Dolby Digital one) with two RCA inputs, an aes/ebu, a BNC, a tos link in and an optical in.

2. 6 RCA inputs, 2 toslink, two optical and two digital tape out RCA connectors.

the rest are the analog in card, a balanced Right, center left card and a balanced sub, surround right and surround left.

Hope somebody can help.
The DTS card enables the box to take a digital feed in DTS format and turn it into multichannel audio. It should work on any of the digital inputs. At least that is what I thought...