It looks like the coaxial is an rca jack right? Well simply I would look at the Z-680 manual. You might need to use a 'y cable' with 1rca going to 2cra on the end. Im not sure about this though. However, on the breakout cable there are 2 rca jacks. One of them is coaxial in and one is coaxial out. Again Im not totally sure what you'll have to use, just download the 2496 manual and the logitech manual. One thing..the soundcard, have you actually connected anything to it, what does it sound like? I ask because im currently considering buying the card, or maybe the emu0404.