dts connect

Hi everyone, I'm trying to get my Logitech Z506 Speakers to work over Optical cable. I bought a Panlong 5.1 Audio decoder which states it specifically works with all Logitech products (link) http://www.amazon.com/gp/product/B00AMC2J1Y?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s01 My PC...