Here's a video about the usual audio optical ports.

by R. Proffitt Moderator - 11/18/12 9:01 AM

In Reply to: QUestion on intermittant audio dropouts by fdm2000

http://www.youtube.com/watch?v=yEdtxaquGXI

Yes, it's for a PC or Apple but it's clear enough for folk to see the cable and such.

If you don't use optical you'll have to tell more.
Bob