Wiring Harness, 1 m (3.281 feet), For connecting a Trig TT22 Transponder Unit to a TC20 Control Unit and TN72 GPS Unit
This is a pre-wired wiring harness which makes installation faster and trouble-free.  It may also save you delays and repair bills should you accidentally connect something incorrectly.  This wiring harness is assembled and tested using a cable tester by Larry Goddard.  It has a DB-9f connector at the TC20 end and a DB-25m connector at the TT21 or TT22 end and DB-9m connector at the TN72.  It also includes power leads for 10 to 30 VDC. The power input leads exit the DB-25m connector at the TT21 or TT22 transponder end. The wiring from the TT22 to the TC20 is 1 m long. The wiring from the TT22 to the TN72 is 1 m long.
Note: Wiring for external "Squat" and "Ident" switches is not included.  The squat switch input is only for aircraft with built-in squat switch circuitry.  It is my understanding that a landing gear switch in a glider can not be used as a squat switch because it would cause the transponder to send incorrect information while the landing gear is down during aerotow and in the landing pattern.  The "Ident" switch is not necessary because the "IDT" pushbutton on the TC210 control unit has the same function.