Polycom SoundStructure C16 Design Manual page 88

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12
the output signals have a blue shading and outline to match the rear-panel
labeling. The submixes have a purple shading and outline. See the following
figures for examples of the different user controls.
It is possible to change which types of virtual channels are viewed by enabling
or disabling groups, inputs, outputs, and submixes with the controls on the
top of the Channels page as shown in the following figure.
5 - 6