It is unlikely you have ARC on your tv but you never know.  Check the handbook for your tv and see if one of the HDMI inputs is marked ARC or spin the set round and see if any HDMI inputs are similarly marked up.

Thanks I don't think the hdmi on my tv is marked as ARC but is there any other way to use audio channel return feature and can you explain exactly what audio channel return is and how to use it 

Thanks in advance

Gaz

Your plasma is very old and so it doesn't support the ARC.

Only televisions from around 2010 and towards support ARC.

You must use digital coaxial cable or stereo RCA cinch cable if

you want to connect the sound from your TV to the Onkyo.

Hi gazman,

an ARC enables you to send audio from your TV's ARC-enabled HDMI input into your home cinema amp, thus bypassing your TV's speakers. Another benefit is that it saves you running extra cables (either a digital cable or pair of analogue interconnects) into your home cinema amp. With ARC, you just need the one HDMI cable.

Thanks Andy I understand now much appreciated

With ARC, as has been said, you get to connect things up more simply with one sort of cable.  

You also get around the B>S> of cable preferences to supply your TV based sound because an HDMI compliant cable will do it all without any differences to sound quality.  No more angst about expensive cables.