The Data III appears to be like an even bigger and heavier Data II (both based on video disc players). The ST / AT&T optical seems to what made it special. Better space and a little better resolution compared to AES, SDPIF, etc., at least when used with the Gen Va. The Data III ST / AT&T optical was the only method that proved better than the Off-Ramp5 USB to AES converter. Slightly better technicalities all around, but less analytical. It's bizarre and makes me wonder since the optical was transmitting the SPDIF format still.
It's kind of ridiculous for its size since I don't use spinners anymore. Just too difficult trying to find that CD, etc. Computer audio is just much easier to deal with. Also, DACs don't take ST / AT&T optical anymore.