Extron Electronics VN-COMMANDER - Manual (Page 58)

Section 2: System Configuration VN-COMMANDER User Guide
48 I456GB issue 8
The following example shows what you might see if you
use Detect Sources within a Video source definition:
If VN-COMMANDER is connected to a VN-QUANTUM
Processor you can click the Detect Sources button to
display a list of the Video, RGB, DVI etc sources that are
currently connected.
Simply click on a source from the list and click OK to
create a source definition for the chosen source.