Hegel H190

Can anyone help explain what the Dac+ button on the Hegel H190 does? I have purchased a new one and so far the button does nothing this leads me to believe the amp is defective. 

I believe Hegel uses the same remote for all of their units. I have the DAC + button on the remote for my HD30 and from what I can see it does nothing. It may switch the display or something to show the incoming bitrate signal, etc if certain Hegel models have a display that shows other info. My HD30 pretty much only has the LED display with the source and bitrate anyway.
Jsqt, I believe you are correct I have a h360 and some buttons do nothing, amp rocks though!