User Guide
Series III Avionics
Pilot's Guide
Page 23
CD-422B Display
In normal operation, the upper display is the
transponder code. It is selected either by the
CODE SELECT knobs or by setting the FUNCTION
SELECTOR to VFR.
The displayed code is active only when the
annunciation ACT is present in the display.
When a displayed code is changed, the new code
will appear on the display for 3 seconds before the
annunciation ACT appears. This allows the code to
be manually changed before it becomes active if it
is in error, or while "tuning through" one code on
the way to another one. It is not necessary to go to
SBY to change codes.
In addition to a 3-second delay before becoming
active, emergency codes (7500, 7600, or 7700) will
blink on and off during the 3-second delay, alerting
the pilot that transmission of an emergency
transponder code is imminent.
If the IDENT pushbutton is pressed while the
FUNCTION SELECTOR is in TST mode, the top
line of the display indicates 8888 while the bottom
line indicates 88888.