The Telegraph:
The telegraph was invented by Samuel Morse in 1844. During the Civil War 15,000 miles of telegraph cables were laid for military purpose only. With the use of the Telegraph, Abraham Lincoln was the first president to be able to communicate with the officers on the battlefield. President Lincoln would regularly visit the telegraph office to get the latest news, monitor battlefield reports, lead strategy meetings, and deliver orders to his men. The confederate army was at a disadvantage with this. They lacked the "technological and industrial" ability to control such a large-scale communication offensive.