TEST:
-Displays all 8s in data display window and illuminates ENT and CLR keys.

TK/GS:
-Displays true track and groundspeed.

PPOS:
-Displays present latitude and longitude..

WIND:
-Displays true Wind direction and speed.

HDG:
-Displays true Heading and minutes remaining until alignment is completed.

STS:
-Displays system status message code.

OFF:
-Blanks data display window.

1/2/3:
-Displays data for associated IRS in display window.

Alpha Keys:
-Select N, S, E, W for present position entry or H for heading entry in ATT mode.

Numeric Keys:
-Key in present position or present magnetic heading in ATT mode, to the data display window.

ENT Key:
-Illuminates when and alpha key is selected. Enters keyed data into the ADIRS when pushed.

CLR Key:
-Illuminates when keyed data is of an unreasonable value. Clears keyed (but not yet entered) data from display window when pushed.

FAULT:
-Illuminates amber when a Fault affects the associated IR. Flashes if attitude and heading information is recoverable in the ATT mode.

ALIGN:
-Illuminates white when the associated IR is operating normally in the ALIGN mode.

FLASHES ALIGN:
-IR alignment fault detected.
-No present position entry has been made after ten minutes.
-Difference between position at shut down and entered position exceeds 1° of latitude or longitude.

OFF:
-Deactivates associated ADIRU. Both ADR and IR data are not available.

NAV:
-Provides full inertial data to airplane system.