caramirezr,
Are you locating the optical port? It should look something like this:
http://i397.photobucket.com/albums/pp60/samsung_hd_tech/opticalpic.jpg
--HDTech
I've recently purchased a soundbar hw c450 which brougth an optical cable AH3900779A, but when I tried to connect to either the soundbar and the tv set (LED TV SERIES 6) it didn't match with the socket of any of them. I would like advise on what to do. It's a optical cable reference AH3900779A the correct one?
Thanks.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic