Dial or dash?
Union forces used two types of telegraphy: the dial (or Beardslee) and the Morse. The dial telegraph could be set up quickly, giving it great flexibility. Operators needed to be literate but not as highly trained as Morse operators. Chief Signal Officer Albert Myer advocated the dial system; the Military Telegraph Service used the Morse system. In his letter, Capt. C. M. McClure praised the capabilities of the Beardslee system, which had been successfully employed at Fredericksburg. By the end of 1863, however, the Signal Corps moved towards the Morse system with its relatively stronger signal strength. When Secretary of War Stanton removed Myer as chief signal officer in November 1863, the military primacy of the Morse telegraph was complete.
National Archives, Records of the Office of the Secretary of War