ADAT is an optical protocol developed by Alesis for it's ADAT multitrack digital recorders. The idea was to use the common Toslink optical media to send 8 channels of multiplexed audio data over an optical fiber. S/PDIF , OTOH, is 2-channel stereo format that can be delivered either via optical (Toslink fiber-optics) or electrical (RCA coax). The 2 formats are mutually exclusive even though you can use the same optical cable (w/c was originally developed for S/PDIF) with both.
In the case of the Delta 1010, both the full 19" rack 1010 and LT versions only use coax (or electrical) s/pdif, not optical. The ADA8000 will serve no purpose with your system. If you have a other soundcards with ADAT inputs, then the ADA8000 can and will provide you with an additional 8 analog I/O. Examples of audio interfaces with ADAT optical ports are the Emu 1820 and 1212, the M-Audio FW 1814, Creamware Pulsar/Scope, Echo Layla, and many more. Some mixers also output to ADAT, notably the Yamaha 02R and 01V, Korg 168RC, and Soundcraft Digital 328.
