Sony DVS-9000 User Manual page 22

Colors of lit cross-point buttons
In a particular row of cross-point buttons, only the last pressed button is
effective, and lights amber or red. The amber indicates the "low tally" state,
and the red indicates the "high tally" state, to indicate whether or not the
selected signal appears in the final output video.
Color
Amber
Red
22
Signal Selection
Significance of colors of lit cross-point buttons
State
Low tally
High tally
Significance
Does not appear in final output video
Appears in final output video