dbmtb":2r9w11ty said:
There will be coax and optical digital outs even on the cheapest blu-ray machines.
If your 5.1 system is so old it predates DVD you are screwed but otherwise it will also have coax and optical digital IN.
It's just a question of configuring your receiver so it can find the signal. It will automatically decode the DTS channel for playback.
If you don't have an AV receiver then I don't understand why you are asking this atall.
As you mention, receivers / amps from DVD days - not all of them, then, decoded DTS - in fact in the early days, not all DVD players dealt with DTS.
From what I can remember, though, DVD-Video had to have something like a DD2.0 audio track as a minimum to be spec compliant.