User's Manual

TT21 Transponder Installation Manual 19 January 2009
00560-00 Issue AA
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6. Installation Setup and Test
The TT21 uses a simple setup system to program important system parameters, including the Mode S
address. In the original factory configuration, the setup screen is the first thing that runs when you
switch on the transponder. If the transponder has already been configured, and you want to access the
setup screen again, simply hold down the FN button while switching on the transponder and the setup
system will run.
The script will prompt for the following configuration items:
 Mode S Address
 VFR Squawk Code
 VFR Flight ID (Registration)
 Aircraft Maximum Airspeed
 Aircraft Category
 Squat switch source, if fitted
 GPS position source, if fitted, and ADS-B parameters
This setup mode also allows the recalibration of the altitude encoder.
All the programming is accomplished using the right hand rotary knob and the ENT and FN buttons.
Make all input selections using the rotary knob. Pressing the ENT button accepts the current input and
advances to the next input item. Pressing the FN button moves directly to the next screen.
6.1 Configuration Items
6.1.1 Aircraft Address Programming
The Mode S Address is a 24 bit number issued to the aircraft by the registration authority for the
aircraft. These addresses are usually written as a 6 digit hexadecimal number, although you may also
encounter one written as an 8 digit octal number. The TT21 only understands the hexadecimal format,
so you must first convert an octal number to hexadecimal.
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.
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