Recently i purchased to friend home tatasky hd box, this is inbuilt digicard type HD settop box, this box backside no available 5.1 audio optical output port, then how to connect 5.1 audio to home theater. My home tatasky available optical port with external card type box, im using optical cable to 5.1 audio decorder to home theater. How to connect new inbuilt cardless type box, pls suggest.