How does the 123/TUNE (USB) function? The 123/TUNE (USB) electronic ignition is easily to program with the optimal needed advance curve. Using a (shielded) USB cable and notebook this version of the 123 ignition product range enables you to tune your engine yourself. Particularly apt when you are (also) driving on LPG: in this unit you can programm two sets of curves that can be selected by placing power on the yellow wire from the 123/TUNE. By using this function you will be able to switch between two pre-programmed curves without having to use a computer. Please select the right brand below to see which 123/TUNE is suitable for your classic car.