Please try connecting an HDMI device to the system. Once connected, go to Control Panel > Sound, and let us know what options do you find. If possible, provide us with a screenshot.
Thanks for the reply Jose but does this mean that the correct port is only displayed when it is in use? If so, IMO clearly that is wrong.
I currently do not have any HDMI devices to try out your suggestion but I can't see why an HDMI port couldn't be displayed there instead of the wrong S/PDIF port. A previous Intel driver on this board did offer this and my HP Touchsmart 2 with IDT Audio Codec correctly displays an HDMI port in the IDT Control Panel, so what I'm wanting is very possible. Maybe someone else with this board and an HDMI device is able to give the test results you asked for but in the meantime, I'd like this looked at anyway please.
The difference between the Intel(R) Desktop Board DG45ID and the systems you have mentioned, is the fact that the Intel(R) Desktop Board DG45ID does offer an optical output in the back, that needs to be handled by the IDT Control Panel somehow. Most HDMI audio settings are available in the Control Panel.
Thanks for the further reply Jose but the S/PDIF Optical output on the rear panel is already handled by the optical port shown higher up the IDT Control Panel Screen shot I posted above (there's another one in the top clump of ports - all representing the rear panel).
A previous driver version had an HDMI port exactly where the lower S/PDIF port is shown on the DG45ID so it is possible. Does that make things any clearer?