This is a small board for connecting "inverted" motor drives with common GROUND inputs instead of standard common +5V to the CENTIPEDE system. It also provides all required hardware to connect Slotted Optical Switches to the CENTIPEDE system for Spindle Index/Timing of Home signals. Provides 8 x "invertors" (enough for 4 axes) and 2 x Slotted Optical Switches interfaces.