The MakerBot Motherboard is a shield for the Arduino MEGA. This board is the heart of your MakerBot and controls all the other boards. Its all about connectivity. The Arduino MEGA provides the USB interface, and the motherboard has an SD card slot for storage. For motion control, it has headers for 5 stepper drivers, so it can drive your XYZ positioning system and have room left over for controlling 2 extra stepper motors. Along with steppers, it has headers for 6 endstop cables (X+/-, Y+/-, Z+/-) and an e-stop switch. The interface connector is can be connected to an interface board for controlling the machine without a computer. To control the extruders, it comes with 2 rs485 ports and can support up to 5 rs485 ports. It accepts a standard ATX header for power.