Yamaha O2R Owner's Manual page 196

Display Screens
There are four screens in the AUX display functions. Two screens access the
channels to send to the effects buses, the other two screens allow you to
select and set-up the effects.
Shown below is the first – MIC/LINE 1 through 16 and LINE 17/18
through 23/24:
Select this screen by pressing a SEL button for one of the MIC/LINE
channels.
Shown below is the second screen – TAPE 1 through 16, and EFFl or EFF2:
Select this screen by pressing a SEL button for the tape or effect returns
channels.
Note: The AUX functions for AUX 7 and AUX 8 are restricted in their
assignments to the effects buses. AUX 7 can only route to Effect2 and AUX 8 can
only route to Effect1.
Internal Effects 93
Digital Recording Console 02R User's Guide