The digitizer's main function is to protect the fragile LCD, as well as to transfer all of the touch functions (swipe, press, zoom, etc.) to the LCD. The touch action on the Digitizer glass is transferred through the Digitizer flex cable, so the LCD image can respond accordingly. The Digitizer flex cable should already come installed on the glass digitizer. This is where things can get confusing- an LCD Digitizer assembly is actually these two parts fused together. Usually, the glass is called front glass or touch panel but not the digitizer.