Philips DVDR 80 Owner's Manual page 34

The back of the DVD Recorder features two digital audio output jacks
for an optical cable and
It can be used to connect the following devices:
Digital multi-channel sound provides maximum sound quality. You will
need a multi-channel A/V receiver or amplifier that supports at least one
of the audio formats of the DVD Recorder (MPEG2, Dolby Digital, and
DTS).
Consult the owner's manual of your receiver to find out which audio
formats it supports.
a
b The receiver does not support the digital audio format of the DVD
Recorder. The audio format of the inserted DVD is displayed in the
display panel when another language is switched on. Playback using
6-channel digital surround sound is only possible when the receiver
has a digital multi-channel sound decoder.
for a coaxial cable (cinch cable).
Connecting additional devices