This is quite possibly the simplest S/PDIF receiver and DAC available. It uses the absolute minimum of parts, and also minimises the connections and control functionality usually provided. It is still a serious project, and is not recommended for beginners. As shown, the connection is COAX (but will almost certainly handle TTL just as well). If you want a dedicated TTL to COAX converter, there is an adapter shown at the end of this article. The spare gates in the 74HC04 package may be used for the adapter if desired.
http://sound.westhost.com/project85.htm
