wesk18,
The MOTO plug requires an external Optoisolator to control the Spindle Motor On/Off state.
The +5V source for Pin 1 (Anode) of the external Opto is provided from Pin 4 (Actual Pin) of the 330R RN (Pull-Up Resistor) on the Tonsen 4 "AIXS" Board.

A probe tool / digitizer can be connected to Pin 10, 11, 12, 13 or 15 (Input Pins).