The quest for centralization of military communications goes back to World War II (WWII), with a push for the development of military communications that were common-user. Military communications of WWII centered on three main technologies: wire, radio (wireless), and radar. Systems were general purpose in nature, serving the needs of a host of users at a number of geographic locations and capable of sending message traffic of all types and precedence. The global scale and rapid pace of actions during WWII required large-scale coordination within the U.S. armed forces as well as between our forces and those of our allies.
While common-user communications systems had distinct advantages over those communications systems that were “dedicated” to a single use (and were frequently viewed as inherently limited), not all were in support of the common-user communication systems. Most notably the military services were unhappy with common-user systems for the precise reason that they were designed to serve the communications needs of others and were thus not fully under one’s own respective control. In short, common-user systems necessitated accommodation by the services and this was viewed as undesirable. For more details http://www.disa.mil/About/Our-History