Reference

Edward Porter Alexander played a significant role in the early Signal Corps. He was tasked by Jefferson Davis to establish the Confederate States Signal Corps, a responsibility he executed effectively. Alexander was instrumental in developing a flag signal system for the U.S. Army, which was a notable early assignment in his career. His work in the Signal Corps was crucial during the Civil War, where he served as a signal officer on the staff of General Pierre G.T. Beauregard and was involved in the first signal message during the Battle of First Manassas.

For more detailed information, you can refer to the New Georgia Encyclopedia and the American Battlefield Trust.

Here is an image of Edward Porter Alexander: