David,
Q. Are you sure you have the RS232 converter wired to the sign correctly?
A. That is why I keep connecting to putty, which makes sure that I am transmitting something. As for the cabling from the converter to the sign... It's three wires. I know which one is ground so that only leaves TX/RX and each time I try I will try twice and rotate the two wires.
The programing you provided is a step beyond what I have experience with. From what I see the command is being referenced in the code. Sorry for being dumb, but I am not a programmer, just a guy with bad ideas.