The stacking LEDs indicate the unit's position in the stack. As shown in the front panel illustrations at the start of this section, the stacking LEDs are numbered
1 through 6. Each unit in the stack has one stacking LED lit, indicating its position in the stack. When stacking LED 1 is lit, the unit is the master unit. When one
of the stacking LEDs numbered 2 through 6 is lit, the unit is the corresponding stacking member unit.