The SIB Enhancement, physically, is a plug in replacement for the existing 8032AH microcontroller that requires a very minor change in firmware. The enhancement contains a newer 80C32 microcontroller in a quad-flat package. The silk screen and the PCB design are shown below. The two main constraints upon this project are cost and ease of installation. It is crucial that the device is inexpensive and simple to install to make the enhancement worthwhile.
Size is another concern.
TD and TOL of the MAX1232 are connected to ground. Please note that when the 8032AH is mentioned here that it is actually refering to the empty 40-pin DIP socket that remains after the 8032AH is removed. A message is sent every 0.5s. The pulsewidth was about 1 microsecond. The SIB is bombarded with Control Commands.