It was during the 19th century that French telegraphy took off: the arrival of such great names as Samuel Morse and Édouard Branly revolutionised the country’s technologies. It is Émile Baudot‘s “multiplex system” that Dufy chose to depict in his fresco. 

Invented in 1874, this was the first model able to distribute the same telegraph line to several operators, thanks to a precision clock system. It used the Baudot code, which comprised only five keys but could transcribe the entire Roman alphabet as well as all punctuation marks and machine functions. Remarkably fast for its time, it was capable of sending 60 words per minute. It was adopted by the French telegraph service in 1877, notably for the Paris-Bordeaux line.

Improved in 1890 to require only a single wire, Baudot‘s device remained in use until the 1950s.