This letter from Rockwell Manufacturing provides general information about modern voting mechanisms and lists which states use voting machines. The information was provided to enhance the label text that the curators would display with the voting machines. Compare the suggested text to the second paragraph of the display label draft text.
Raymond Anderson letter to Frank Taylor, 1898 Standard Voting Machine (Item No. 227298), March 21, 1961, Office of the Registrar, National Museum of American History.