12VDC TO POWER THE BOARD. To keep optoisolation, this current must come from th VFD, or a source different from the what is poweing your other devices.
Direction control is not implemented in the Sieg X3 Speed Control.
The final voltage must be adjusted to 7VDC.
The P1 and P2 must be disconnected to GND and analog output on the C6 board.
Step, direction, and GND from the parallel port or breakout board.