How did field telegraphs help Helmuth von Moltke command Prussian armies in 1866?

During the 1866 Seven Weeks' War, the field telegraph was instrumental in allowing Helmuth von Moltke to exercise effective command over his distant armies.1

As Prussian forces were deployed across a wide front—spanning approximately 260 miles—the traditional method of issuing short, explicit orders to subordinates became impractical. The field telegraph provided a vital means of rapid communication, enabling Moltke to implement his system of "general directives". Under this approach, he provided commanders with long-term tasks in general terms, relying on the telegraph to maintain coordination while allowing his subordinates the necessary latitude to exercise initiative and discretion based on the evolving battlefield situation. This technological capability was essential for managing the complex movements of the Prussian armies, which were also supported by the strategic use of railways for deployment and supply.21