On the Pro12 there is a USB port with a USB cable one end plugs into the tablet and the other end plugs into the back of the board in the port labeled " device". You do not use the midi in, out or thru connections or do you use the host USB connections on front and back of the board.

Steve, Ya got puzzled. “On the Pro12 there is a USB port with a USB cable one end plugs into the back of the board in the port labeled “device”.

Plugs into the back of what a board??? None of the wires go into the keyboard.
Sorry but I do not understand. Normally a wire of some sort goes from the tablet to the keyboard so that they can communicate.

John C.