^ 1.01.11.2Fischer, Eric N. The Evolution of Character Codes, 1874–1968. 2000-06-20 [2020-12-20]. ark:/13960/t07x23w8s. [...] In 1872, [Baudot] started research toward a telegraph system that would allow multiple operators to transmit simultaneously over a single wire and, as the transmissions were received, would print them in ordinary alphabetic characters on a strip of paper. He received a patent for such a system on June 17, 1874. [...] Instead of a variable delay followed by a single-unit pulse, Baudot's system used a uniform six time units to transmit each character. [...] his early telegraph probably used the six-unit code [...] that he attributes to Davy(英语:Edward Davy) in an 1877 article. [...] in 1876 Baudot redesigned his equipment to use a five-unit code. Punctuation and digits were still sometimes needed, though, so he adopted from Hughes(英语:David Edward Hughes) the use of two special letter space and figure space characters that would cause the printer to shift between cases at the same time as it advanced the paper without printing. The five-unit code he began using at this time [...] was structured to suit his keyboard [...], which controlled two units of each character with switches operated by the left hand and the other three units with the right hand. [...][1][2]
^ 2.02.1H. A. Emmons. Printer Systems. Wire & Radio Communications. 1 May 1916, 34: 209 [2022-02-16]. (原始内容存档于2022-02-16).