Chapter 16 - TELEGRAPH AT WAR 1854 - 1868 of Distant Writing by Steven Roberts outlines several battlefield usages of the telegraph prior to the American Civil War.
The British, French and Spanish all employed telegraphs systems on the battlefield prior to the start of the American Civil War.
The Crimean War is the first time that the telegraph ...
When was the first electrical intra-battlefield communication?
Broadly, the United States Civil War.. Definitely Sept 17, 1862, arguable July 21, 1861.
July 21, 1861 Battle of First Manassas Confederate Generals Beauregard and Johnston coordinated the convergence of their two armies to meet a Union ...
The first time an electric mean of communication was used on the battlefield is the American Civil War. The first time it was used for military communication purpose, but not intra battlefield, is the Crimea War.
About Civil War, you can notice that the US Telegraph Corps was specially created whe the war began. This was already quite a reliable technology....