Code Window
Indicates Codevselected with the Code selectors.

TCAS / XPDR Selector

Test - Momentarily moving the selector to TEST activates the TCAS system test sequence.

STBY - TCAS and the transponders are in the warmup cycle.

XPDR - The transponder is on and TCAS is in the warmup cycle.

TA - TCAS is on but only the Traffic Advisory function of TCAS is operational.

TA/RA - The transponder is on and all Traffic Advisory and Resolution Advisory function of TCAS are operational.

Code Selector Knob
Outer knob controls the two left digits. Inner knob controls the two right digits.itle - Text.

IDENT Button
Causes the word IDENT to flash in the aircraft data block on the ATC display.

Transponder Selector

• L - Selects left transponder and LADC.
• R - Selects right transponder and RADC.

Fail Light ( Red )
Indicates a system failure of the selected transponder.

Above / N / Below Switches
Left switch controls Captain's HSI display and right switch controls F/O's HSI display.

• Above - Displays altitude reporting traffic from 2700 feet below to 9900 feet above airplane altitude.
• N (Normal) - Displays altitude reporting traffic from 2700 feet below to 2700 feet above airplane altitude.
• Below - Displays altitude reporting traffic from 9900 feet below to 2700 feet above airplane altitude.

Absolute / Relative Altitude Switches
Left switch controls Captain's HSI display and right switch controls F/O's HSI display.

• ABS - Target altitude information is displayed as three-digit absolute (indicated) altitude above sea level.
• REL - Target altitude information is displayed as relative to present altitude ( ± two digits) or 00 for co-altitude..