I have a koss surround sound sytem with one optical in. I have a bright house pace high definition box with an optical out. When I run the optical cord from the cable box to the surround sound no sound will play. If u plug the red and wite cables from the cable box to the surround sound box then it will work but i want OPTICAL. The only modes the surround sound sytem has are AV 1 and 2(which are the red and whie cables), DVD, and tuner(radio). How in the world do I get it to put out the sound being transferred through the optical cable?