Is AC3 another way of saying optical inputs and outputs for 5.1 or dolby surround sound etc and if so will they work if you run an optical cable from a Fortec LT Ultra (s/pdif) to the surround sound receiver and out to the tv. Will this work for all the channels that say AC3 or just some. I have a Yamaha home theatre that has optical features that I currently run my Bell ExpressVu thru. Thanks MK.