Cable hookup to DVD Player

I have an older Sony Stereo Receiver.  It has a digital coax cable hookup
for audio to a DVD player.  I have a question about hooking up the audio
cables.  If I use a digital coax cable for the DVD player, do I also need
to connect the L-R RCA cables?  Or is the digital coax cable all I need to
get surround sound?  The manuals for both the DVD player and the Receiver
are not real clear on this. The Sony Receiver is an STR-DB840 with Dolby
Digital, DTS and Pro-Logic.  The DVD Player is a Sony BDP-S301 Blu-ray
player.

Thanks!

Patty