Some misinformation here. The ADAT in will not read a SPDIF signal, it is for ADAT only. Some may expect it to since many audio interfaces can do both. Only the coaxial port on the SPDIF board will read/output SPDIF. You would need a toslink to coax converter to work with an optical output.
I didn't have a digital cd-rom cable either, ordered one online and it didn't fit. Oh well, maybe there isn't a single standard? I do most of my sample organizing on the computer so haven't bothered since. BTW, the only purpose for that cable is to digitally sample from audio CDs (which is better than relying on the CD-ROMs DA conversion).