Coba jelasin Signal Corps History dari Signal Corps (Angkatan Darat Amerika Serikat) dong

Getting the Message Through: A Branch History of the U.S. Army Signal Corps, R.R. Raines, 1996, Ctr. of Mil. History, US Army, 438 pp.

Feb 1919 Popular Science article about a method to replace semaphore flags with a swinging dot signal: Wigwagging is Now Done by Machine, Popular Science monthly, February 1919, page 82

Service: Story of the Signal Corps

Unit komunikasi militer dan pasukan Amerika Serikat