I have a Motorola Digital Cable Set Top box. It has an orange-coded Coax output that appears to be a digital audio output. I connected this to a digital audio coax input to my Onkyo receiver, but can't get it to work. I tried turning on the digital audio capablity on the set top box setup, even tried swapping out the box that I had on my TV upstairs. Even connected it to the same coax input that my DVD was hooked up to no avail. Suddenlink tech support has been useless. What am I doing wrong?