This board adds one additional analog port identical to that on the main board, for a second repeater or adding a link.
It also implements 3 sense inputs that can be used to modify the flow of the state machine to send different CW messages, such as when running on backup power instead of AC.
The board also has a general purpose 8-bit output port that can be controlled by DTMF tones.
The picture below shows a 3D rendering of the board.
