Code Selection
Code selection is done with eight keys (0 – 7) providing 4,096 active identification codes.
Pushing one of these keys begins the code selection sequence. Digits that are not yet entered
appear as dashes. The new code is activated when the fourth digit is entered. Pressing the CLR
key moves the cursor back to the previous digit. Pressing the CLR key when the cursor is on
the first digit of the code, or pressing the CRSR key during code entry, removes the cursor and
cancels data entry, restoring the previous code. You may press the CLR key up to five seconds
after code entry is complete to return the cursor to the fourth digit. The numbers 8 and 9 are not
used for code entry, only for entering a Count Down time, and for adjusting contrast and display
brightness.
When the transponder code is changed, a notification is sent to ATC by the GTX 330.
This notification is temporary and will not be sent if the GTX is inactive (i.e., set to STBY)
when the code is changed.
NOTE: On a dual transponder installation, change the code on the active
transponder. This ensures the notification is transmitted to ATC.
Keys for Other GTX 330 Functions
IDENT Pressing the IDENT key activates the Special Position
Identification (SPI) Pulse for 18 seconds, identifying your transponder
return from others on the air traffic controller' s screen. The word IDENT
will appear in the upper left corner of the display during this time.
VFR Sets the transponder code to the pre-programmed VFR code
selected during installation configuration (this is set to 1200 at the
factory). Pressing the VFR key again restores the previous identification
code. If the VFR Key is pressed when disabled (dependent upon
installation configuration) a VFR Key Disabled message appears to
indicate that no operation took place.
FUNC Changes the page shown on the right side of the display.
Display data includes Pressure Altitude, Flight Time, Altitude Monitor,
Count Up, and Count Down timers. Also displays Outside Air
Temperature, Density Altitude, Contrast, Display, and ADS-B Operation
(dependent upon installation configuration).
START/STOP Starts and stops the Altitude Monitor, Count Up,
Count Down, and Flight timers.