That is an excellent question! I am not sure. I can check when I get home tonight, but since I am Pacific you'll beat me to it! :-)
If I recall correctly (big IF) I have only the digital out from the PS2 to my receiver (just like my DVD player).
You will need to manually enable the digital out on the PS2 manually under settings. If you turn on the PS2 without a game in, it will allow you to get into the setup. Same place where you set date and time if I recall.
Not all games are in 5.1 but it is still pretty amazing!
jr
