Well, I am at the conveyor belt now. I changed the parity to E, but I still get inconsistent results. I have created a much simpler form with two buttons. One for start and one for stop. Clicking on one and then the other just doesn't work all the time. Sometimes it takes two to four clicks to get one to work. Also if I click on the same button several times it can start or stop the belt eventhough it is only sending one of the commands. The input buffer does not show any data after I send the command.