S/PDIF

[5] A common use is to carry two channels of uncompressed digital audio from a CD player to an amplifying receiver.

The S/PDIF interface is also used to carry compressed digital audio for surround sound as defined by the IEC 61937 standard.

This mode is used to connect the output of a Blu-ray, DVD player or computer, via optical or coax, to a home theatre amplifying receiver that supports Dolby Digital or DTS Digital Surround decoding.

Optical provides electrical isolation that can help address ground loop issues in systems.

Instead, the data is sent using biphase mark code, which has either one or two transitions for every bit, allowing the original word clock to be extracted from the signal itself.

[11][12] The receiver does not control the data rate, so it must avoid bit slip by synchronizing its reception with the source clock.

[13][14][15] If the DAC does not have a stable clock reference then noise will be introduced into the resulting analog signal.