Instructions
Remove any disc from the PS3's disc tray and turn off the console.
Plug one end of the optical cable into the PS3's "Optical" port on the console's rear.
Plug the other end of the optical cable into the "Optical" port on the receiver.
Turn on the console and receiver.
Change the receiver's input to "Optical" or "Digital." Many receiver's have an "Optical" or "Digital" button on the device's front side.
Go to the "Settings" section on your PS3's cross-menu bar.
Select "Sound Settings."
Select "Audio Output Settings."
Choose "Digital Out (Optical)." Options appear for your digital out setup.
Choose the audio formats associated with your receiver, such as "Dolby Digital 5.1" or "DTS 5.1." See the receiver's manual for help if you are unsure which audio formats to choose.
Confirm the audio output settings by pressing "X."