Classe Audio Sigma SSP Owner's Manual page 32

Touch any source button on the touchscreen to select it as the current source.
The selected source button is shaded. If the source you want to choose is not on
this screen (and you have more than nine source buttons enabled), press the
button for the next page of sources. Or, press the button to return to the
previous page.
The Sigma SSP comes from the factory with eighteen source buttons labeled and
enabled. To change the default settings and labels or to disable unused buttons,
see the Menu System.
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