Why did World War I armies need much larger communication systems than earlier armies?

World War I armies required significantly larger and more complex communication systems because commanders could not effectively control, coordinate, or direct such massive, modern forces without efficient, high-capacity signal networks.1

The scale of these armies created an enormous load on existing systems, which were initially inadequate. As the conflict progressed, the need for improved electrical communication became critical, leading to the development of intricate grids involving thousands of miles of wire, including buried cables and telephone lines that extended from rear headquarters to forward-most outposts and even front-line platoons.1

This expansion was driven by several factors:
* Command Distance: Commanders had shifted from leading on the battlefield to operating from distant headquarters, relying on reports rather than direct observation.2
* Coordination Failures: Inadequate communication led to significant military setbacks, such as the miscarriage of the German Schlieffen Plan and the defeat of Russian forces at the Battle of Tannenberg.1
* Redundancy: Because intense artillery fire frequently severed wire lines, armies were forced to develop radio and other auxiliary methods to ensure reliable contact.13