Civil War Era
Signal Corpsmen served throughout the Union Army, with the largest number of officers assigned to the Army of the Potomac and the Departments of the Cumberland and the Tennessee. When Myer was chief signal officer of the Army of the Potomac, he urged that signal personnel be centralized and that the chief signal officer of the army, after obtaining details of coming operations at headquarters, direct the signal parties to wherever they were needed. Instead, commanding generals usually determined the employment of the signal parties, most often assigning them to army or corps headquarters. When inclement weather or unfavorable terrain made visual signaling impossible, signal officers often served commanders as aides.
As new additions to the Army, signal soldiers did not immediately gain universal acceptance and recognition. Commanders had to become familiar with the Signal Corps' mission and accustomed to calling upon its services. An example of this situation occurred during the battle of Shiloh in April 1862 when Maj. Gen. Ulysses S. Grant unwittingly rode through a signal station belonging to the Army of the Ohio, apparently unaware of its purpose. Not recognizing the intruder (as Grant disdained the badges of his rank), the lieutenant guarding the station called out: "Git out of the way there! Ain't you got no sense?" The general quietly apologized and removed himself from the signal officer's line of vision. Grant was among those who were slow to include signal parties in their commands; his Army of the Tennessee did not have an active signal detachment in the field until March 1863.
In the field, confusion over how best to employ signal personnel had been evident from the start. During the war's first major encounter, the battle of Bull Run, the chief signal officer reached the battlefield, but the Union Signal Corps did not. Myer had intended to command a balloon detachment at Manassas, but a delay in the receipt of his orders left him with little time for preparation. Although he requested signal personnel from Fort Monroe to assist him, there was not enough time for them to reach Washington before the fighting began. Consequently, the eve of the battle found Myer rushing toward Manassas with a balloon and a detachment of twenty men from the 26th Pennsylvania Infantry. In their haste, the balloon became caught in some trees and was badly damaged.
Find out more in "Getting the Message Through" at http://www.history.army.mil/books/30-17/Front.htm#toc