Philips DVDR 725H/05 Operating Instructions Manual page 22

Two analog audio sockets AUDIO OUT L/R
left/right) are located at the back of the DVD recorder.
These can be used to connect the following:
Q
(audio signal output
At the back of the DVD recorder there are two digital audio output
sockets OPTICAL OUT
OUT
These can be used to connect the following:
U
for an optical cable and COAX
S
for a coaxial cable (Cinch cable).
a
b