The digital audio outputs are available on the connector labeled AES/EBU.
Each reproducer has a (-) and a (+) output on this connector. When wiring to a standard RCA coax digital audio cable, the (-) should be wired to the shield and the (+) should be wired to the tip.
When playing a video with 2-channel MPEG or AAC audio, this output generates a S/PDIF signal.