I'm getting my first 7.1 audio setup tomorrow and want to get this set up.

Is the optical digital out not a 5.1 signal? I'm primarily confused about that. It would be my first choice as the audio system has a few optical digital ins.

Otherwise I will need a demodulator for the RF to interface with a modern 7.1 audio system, right? What sort of output/connections do they use? The audio system I'm getting is mostly audio through HDMI but has some other inputs..

Thanks!

Don't know this model, but the optical output will almost certainly be digital stereo. The only 5.1 output will be the AC3 RF.

The Yamaha APD-1 I'm currently using has coax and optical digital outputs. The Onkyo ED-901 I used to own had an analogue output for each channel. It also had digital and analogue inputs for the other channels from the player, so you didn't have to connect it directly to the amp three times.

Optical digital out should deliver DTS, without RF-demodulator.
Played The River Wild with DTS and my receiver handled it with no problems.

You'll need a coaxial cable (preferably well insulated) with an RCA connector to connect the LD player's RF output to the RF demodulator. From there it depends on the RF demodulator. Some only have coaxial out. Some have both coaxial and optical/TOSLink out.

A short composite video cable usually works for the RF output. Needs to be a good one, to minimise RF interference etc.

Stereo RCA connectors:(Both from Digital and Analog tracks)
-Mono
-Stereo
-Matrixed Surround Modes Below
-Dolby Surround
-DTS Stereo
-Chase Surround
-Ultra Stereo
Digital Optical and/or Coaxial Connectors(Only 1 needed)
-All above except analog tracks
-DTS Surround(5.1 Discrete)
RF Output(Only when RF track is available)
-Dolby Digital
-Dolby Digital EX

Thanks for all the answers guys!

I'll play around with the DTS as I have some optical audio cables around. Next, I'll have to budget and shop for a demodulator with optical out.