Comdial 8312S System Reference Manual page 140

Using The Attendant Features GCA70–250
10.16.1 Accessing The Button Levels
The IB24X and IB48X DSS/BLF consoles have four levels of buttons,
quadrupling the consoles' button capacity. The four buttons at the bottom
of each console allow you to select which button level is currently active.
To change button levels, press one of the buttons at the bottom of the
console. The leftmost button activates level 1, the next button activates
level 2, etc. A light beside the appropriate button lights to indicate which
level is currently active.
ib48x
ib24x
Level access buttons
Level access buttons
IB24X DSS/BLF Console
IB48X DSS/BLF Console
10 – 36 LCD Speakerphone Reference Manual