"DMPORT" stands for "digital media port". You don't have anything connected to this port, so selecting this port will produce no sound output.The "digital media port" has absolutely nothing to do with the digital optical input - consult your user manual for an explanation of the purpose of the digital media port.
If you are connecting the PS3 to the optical digital input of the DAV-HDX975, you need to use the remote to select the "TV" function instead of the "DMPORT" function. The rationale for this is that Sony decided most people were going to connect the digital optical output of a TV to the digital optical input of the DAV-HDX975. No matter - in your case, you will just need to remember to select "TV" when you want to use the PS3.
Note: when "TV" is selected on the DAV-HDX975, both the optical digital and analog stereo inputs can be used. The DAV-HDX975 is designed to give priority to the digital optical input port over the analog stereo input port if both have been connected to an active source. Therefore, if you have "TV" selected on the DAV-HDX975, and if you have something connected to the analog stereo input on the back of the DAV-HDX975 and you want to listen to that sound source, make sure your PS3 is powered off.
Message Edited by hb on 12-27-2009 08:36 PM
