The first practical use of binary coding of alphabetic characters was the Baudot Code, used by Émile Baudot’s multiplexed telegraph machine in the 1870s. It was a 5 bit system: there were special characters for “erasure” (ie backspace), or to select alphabetical or numeric register.
The sender used a keyboard of just five keys, one for each bit, and had to keep time with a regular cadence. I assume they just had to learn to think in binary to operate this thing. Nonetheless it did find significant use in the UK and France as the transmission rate was higher than its predecessor, Morse Code.
In 1900, New Zealand inventor Donald Murray further developed Baudot’s system. Murray’s transmission equipment allowed an operator to enter the text on a qwerty keyboard. At the receiving end, a punched strip was produced that could be converted into alphabetic output by a second machine. Murray also rejigged the code a bit so that the most commonly used letters required fewest holes punched, and added more control characters such as line feed and carriage return.
The tape would look something like this.
Variations on the Baudot-Murray system remained common until ASCII became standard in the 1960s.
The transmission rate unit baud is named for Baudot.