My motorolla HD/DVR cable box with RCN converts the analog channels to 2-channel Dolby Digital output. Even better, it downconverts HD signals so that I can watch them, letterboxed, on my normal TV! It's amazing how much clearer the signals are, even without a high-resolution picture tube.

I have the SA Explorer 3250HD which sends all audio to the optical out (the DVI is disabled). SD channels are DPL, HD channels are DD.

Since Cablevision was out of Cablecards, I currently have an SA Explorer 4200HD in the house, and it converts analog audio to digital PCM streams, the 950 plays audio on ALL channels through the coax digital input with this box.

I'm still going with the cablecard when it shows, as the picture is supposed to be better and it saves me $6 a month vs. renting the box.

My new SA 8300HD DVR as well as the old SA 8000 DVR would output everything as digital PCM through the coaxial output.