Comment 4 for bug 1243728

Internal I/O Connectors

1 x S/PDIF Out Header

node 0x2d may be the internal S/PDIF Out header

http://www.intel.com/support/motherboards/desktop/sb/CS-032871.htm

S/PDIF onboard headers

You can also connect the onboard header to an S/PDIF input header available on some graphics cards using an S/PDIF cable. This connection routes digital audio to the HDMI output of the graphics card.