Harman Kardon HS 300 Owner's Manual page 25

Pressing the Open/Close Button will also select the Disc Player as the
source input, and open the disc drawer.
c) Using the remote, press any one of these buttons: TV, DISC, RADIO,
D-IN, USB 1 or USB 2, the HS 300 will select that source. See
Figure 31.
Figure 31 – Source Selectors
NOTE: Any time you press one of the Input Selectors on the
remote (i.e., TV, DISC, RADIO, AUX, D-IN, USB 1 or USB 2),
the remote will switch modes so that it will transmit the codes
programmed to operate that device.
INSTALLATION
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