Altech UEC DT 3900 - Manual (Page 22)

22
VOLUME CONTROL AND AUDIO SELECTION
The volume from the set top can be controlled via the [-/+] keys on the
remote Control.
You can also mute the audio via the mute button on the remote control.
A bar as shown above will be displayed each time volume is controlled.
Some broadcasters transmit multi track audio Mpeg and Dolby digital audio
is sometimes transmitted.
The audio button on the remote allows you selection between the two.