A:Method 1:
Some DSG TCUs require permanent and switched power, which requires a switch boc to be built.
DSG bench reading you have to provide 1 X 12v permanent power hence using a breakout cable (Godiag GT107 gearbox adapter).  gt107 breakout of gt105 has switched and permanents. With gt107 you need to be able to switch power manually, gt107 has switch. You don’t need anything alse.
This adapter has automatic and manual selection for PCMFlash software. For data reading and writing, you can choose “Auto”, and for diagnosis you can choose ”Manual”. For other software kess v2, DQ200, DQ250, DQ500 you can also choose “Manual”.    Moreover, with the car battery power, the adapter can directly read and write DSG Gearbox data and you can clearly check the communication status during the data reading and writing process.
Read on bench using external power supply and it works perfectly.
Method 2:
The 2nd method using OBD connection and either PCM tuner OBD or any passthru adapter (openport, sm2 pro) and works perfectly as well but for OBD you can add 120 ohm resistor in can bus & relay for auto connect and disconnect.