I have a logitech z-5500 suround sound system. I bought the advanced av pack with the optic slot. I juast recently found a cheap optic cable off of ebay. put it in the system and the box, didn't work. I( flipped the input on the system to optic and it said no digital data. I went into the x-box settings and changed all of it to digital and dolby surround sound. The surround sound is fine it works on my comp all the time. but nonetheless it still soays no digital data. Is the cable broke or am I not doing something?