From the owners manual..Pg14
Quote:DIGITAL AUDIO COAXIAL jacks
For digital audio signals transmitted via coaxial digital
audio cables.
DIGITAL AUDIO OPTICAL jacks
For digital audio signals transmitted via optical digital
audio cables.
Notes
• You can use the digital jacks to input PCM, Dolby Digital and
DTS bitstreams. All digital input jacks are compatible with
digital signals with up to 96 kHz of sampling frequency.
• This unit handles digital and analog signals independently. Thus
audio signals input at the digital jacks are not output at the
analog AUDIO OUT (REC) jacks.
• Pull out the cap from the optical jack before you connect the
fiber optic cable. Do not discard the cap. When you are not
using the optical jack, be sure to put the cap back in place. This
cap protects the jack from dust.