WW1 US Army Signals Corps Collar Disc with nut

During World War I. Chief Signal Officer George Owen Squier worked closely with private industry to perfect radio tubes while creating a major signal laboratory at Camp Alfred Vail (Fort Monmouth). Early radiotelephones developed by the Signal Corps were introduced into the European theater in 1918. While the new American voice radios were superior to the radiotelegraph sets, telephone and telegraph remained the major technology of World War I.