If you are using the first layout, there is no switched output (positive or negative puls) on the board.
There is a resistor less on the old board, the one who keep the program jumper input high.
And last but not least, the is one capicitor more on the board to kill some noise.

You only need to place the resistor (10k) on the backside of the old board.
The program pin (18) must to be high if you don't have connect the RS232.