FiiO D03K Digital to Analog Audio Decoder/Converter. The D03K is a digital audio analog converter which can transfer digital audio (optical / coaxial) to two channels of analog audio and output to either a line out socket or a component output. The D03K can be used to connect a wide variety of devices such as TVs and Blu Ray players which often only feature Optical or Coaxial outputs. So buy this Fiio D03K Digital to Analog Audio Decoder/Converter - Optical / Coaxial - 3.5 / Component Now £29.99.