Calrec SUMMA User Manual page 168

At this point you can toggle on/off the routing of any path to the selected bus by pressing its fader ACCESS button.
Paths on layers other than the currently visible layer can also be routed by using the layer buttons to access their fader
controls. The following image shows how the fader displays will change to indicate routing. Once you have finished
viewing contribution for the chosen bus, tap DONE VIEWING CONTRIBUTION on the touch screen.
FIGURE 3 - CONTRIBUTION—FADER DISPLAYS
168 SUMMA ROUTING
Networked Audio Production System