I don’t think the 2-pin digital connector on the back of the optical drive is an INPUT, but an OUTPUT instead. But I could be wrong. If it’s an input, I’m sure you can get a TOSlink or coax connector and install it to the external case, but you will need some level matching components depending on the digital format. You are basically looking for a portable DAT or MD recorder, but just with CD format. I can only think of professional audio may have an equipment like that, and it would be expensive.