Documentation for Tapping Mode Holder (air)

Piezo+ is the line for bimorph shaking the cantilever in tapping mode
Extra is Analog2 channel (depending of hardware you have, you may need to toggle some jumpers/switches to route Analog2 to this pin) to bias the tip with EFM cantilever holder only
STM is the channel to route STM current signal in STM mode. It is a “free” line when operating with AFM modes
+12 and -12V are always there.

Download here PDF file with schematics: