Pete is correct. Why are you telling ME this?? I already know this stuff, and, frankly, would NEVER use a parallel port to control anything as it's too easy to blow the port up. I'd use hardware dedicated to the purpose like something from Phidgets or a Netduino or Arduino. Since the original poster never specified what they were using as an "LED display" the question is unanswerable. I really don't feel like going through every possibility of scrolling an image on every type of "LED display" as it would take a small book to describe them all. A guide to posting questions on CodeProject[^] Dave Kreskowiak