User's Manual

TT21/TT22 Transponder Installation Manual 13 July 2009
00560-00 Issue AF
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Page 28 Trig Avionics Limited
8 digit octal number. The TT21/TT22 only understands the hexadecimal
format, so you must first convert an octal number to hexadecimal.
There is an Octal to Hexadecimal converter tool in the support
section of the Trig Avionics web site.
Enter the 6 digit aircraft address using the rotary knob and the ENT button.
6.1.2 VFR Squawk Code
When the pilot presses the VFR button, a pre-programmed code will replace
the current squawk code. The pre-programmed code is set up here; the choice
of code will depend on the normal location of the aircraft. In the USA, the
VFR squawk code is 1200. In most parts of Europe, the VFR squawk code
should be set to 7000.
Enter the 4 digit squawk code using the rotary knob and the ENT button.
6.1.3 VFR Flight ID
The default Flight ID for an aircraft not on an IFR flight plan should be the
aircraft registration. Enter the aircraft registration using the rotary knob and
the ENT button.
Note that the aircraft registration is loaded as letters and numbers only. There
are no dashes or other punctuation marks, and no spaces can be inserted.
When you enter a space it finishes the data entry and moves to the next item.
6.1.4 Airspeed Category
Mode S transponders can transmit their maximum airspeed characteristics to
aircraft equipped with TCAS. This information is used to help identify threats
and to plan avoiding action by the TCAS equipped aircraft. The airspeeds are
grouped in ranges; using the rotary knob, select the range that corresponds to
the aircraft.