Polycom SoundStructure C16 Design Manual page 239

Advanced Applications
The input virtual channels that include remote audio are the "Phone In", "Pro-
gram Audio", and "VSX8000 In". These channels are routed to the "Amplifier"
channel so they can be heard in the local room.
The microphones "Table Mic 1" through "Table Mic 8" are routed to the
"Phone Out", "VSX8000 Out", and "SubMix Mics" channels using the confer-
encing signal path which includes echo and noise cancellation, and automixer
processing. The blue background of these crosspoints is the visual indicator
that the conferencing version of the input processing has been selected.
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