Comdial and FXT Owner's Manual page 94

Other Advanced Features
Accessing The DSS/BLF Console 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.
IB24X DSS/BLF Console
86
IB48X DSS/BLF Console
Large Screen Display Speakerphone Station User's Guide
GCA70-349