Early in the twentieth century, detailed commercial codes (systems of rules for replacing a piece of information such as a letter, word, or phrase with an arbitrary symbolic equivalent) were developed for communications purposes. One such code was the Baudot code (pronounced baw-DOH), a simple five-bit alphanumeric coding scheme. It was originally developed for telegraphy (a system of communication using an electrical apparatus to transmit and receive pulses), but principally used for telex transmissions (a system for sending and receiving typed messages electronically). The Baudot code mapped complete phrases to single code words (five-bit groups). However, this type of code later proved inadequate for radio and other, more advanced forms of communications that were soon developed.

Baudot code is a character set (a mapping between characters and bit strings) that preceded the more sophisticated character set EBCDIC (Extended Binary Coded Decimal Interchange Code), which was developed...