there are four cable types supported by the S/PDIF specification. See S/PDIF. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction requires permission.

[Andrew Jeddeloh] got curious about the standard after contemplating some long cable runs in his home ... which had no SPDIF decoding hardware on board. Instead, [Andrew] tinkered with the ...

S/PDIF, and more specifically optical TOSLINK ... you can simply use a red LED pointed just right into the optical cable. The end result? Lossless transmission of CD-quality audio from an Arduino ...