Tcas Ii Transponder Mode Controls; Special Squawk Codes - Garmin GTN 725 Reference Manual

TCAS II Transponder Mode Controls

The GTN can also control the modes of a TCAS II system through a
GTX 3000. The TA Only and TA/RA modes are added to the transponder
control panel. Selecting TA Only or TA/RA will command the TCAS into the
selected mode, but depending on the aircraft configuration (e.g., on ground),
the TCAS may remain in a different mode.

Special Squawk Codes

As you change a squawk code, the original code will be sent until you are
finished selecting the new code.
The table below lists special squawk codes:
Squawk Code
1200
7500
7600
7700
NOTE: While 1200 is the default VFR squawk code, the installer can
configure any code to the VFR key. This is to support international
operations where 1200 may not be used.
190-01007-04 Rev. K
Default VFR code in the USA
Loss of Communications
Special Squawk Codes
GTN 725/750 Cockpit Reference Guide
Description
Hijacking
Emergency
11