We know that it will allow output of EQ curves (before and after) from the Trinnov processing. That's the only thing we've seen officially confirmed. If we assume that it will also be comparable to what the 990's USB port does, it would also support firmware updates and let the 997 act as an external sound card for a PC. The 990's USB input is limited to PCM stereo (no DD or DTS bitstreams). I seriously doubt that it would support video, and I doubt it would allow the 997 to output audio via USB.