This diagram shows the loop back function that send the received signal back  over the RS232 port to the computer so I can see what button I pressed. The FPGA is always sending the data on the 'transmit' line which is either held low (not sending anything) or if the DIP switch is high, transmits the data back to the computer. The output is also connected to an LED array and two 7-segment displays so I can verify the character being sent to the board.