Just thought I would share this schematic I have.
It is for the NH3200 but the ep controller is pretty much the same as the 3400.
In the schematic the z axis is shown with a solenoid operated axis, the wiring is still valid for a stepper motor.
I forget it has been a long time since I made this but the schematic shows from the driver board ribbon cable to the rectangluar connector on the back to the table cable and the connecting jacks for each motor or limit switch.