Few of the communications devices we take for granted today would have been possible were it not for the work of one man. His inventions have spurned (in my opinion) the entire digital age. He was responsible for much of the communication code and hardware that have been developed into what we use today.
Jean Maurice Emile Baudot (1845-1903) was a French engineer who invented the first digital Telecommunication code* and hardware*. Working for the French Telecommunications Service, he invented the code in 1870. By 1874 or 1875 (various sources give both dates) he had also perfected the electro-mechanical hardware to send his code. In addition, his system allowed up to six operators to send messages on the same communications line. Therefore, it was the first practical use of multiplexing in telecommunications as well. The legacy of Baudot's work is alive today.
*THE CODE
The Baudot Code is the first truly digital one. It consists of only two states, both logically and electrically.
Logically, the only states are "1" and "0". Today we call the unit that can have these two logical states a
"bit". Electrically, the states are current flowing(or "1"), and no current flowing (or "0").
Each character consists of 5 bits. Two logical states and five bits allows 32 characters. (25 = 32). Baudot needed 26 characters for the alphabet, 10 for numbers, and more for miscellaneous characters. In order to have 36 + characters, he used two special characters, LTRS and FIGS, to give a total of 64 possibilities. LTRS (11111) precedes Alphabetic characters. FIGS (11011) precedes numerical and special characters such as punctuation.
*THE HARDWARE
The hardware had three main parts. They were the keyboard, the distributor, and a tape. The keyboard, seen at the
left, had five piano like keys. A spacer separated the keys into one group of two and another of three. The
operator entered the five bit code for each character at the keyboard. The keyboard input went to the distributor.
The distributor, pictured on the right, was the heart of the hardware system. Both the transmitter and the receiver used a distributor. On the transmitter end, a keyboard was connected to a set of metal brushes inside the distributor. The brushes, rotated by either weights or an electric motor, made and broke contact with stationary conductive elements called segments. Typically, each system had four to six keyboards, each connected to its own set of brushes and segments in the distributor. Each set connected to a single communications line. This was the first successful multiplexing system in electrical telecommunications.
In the receiver part of the distributor was a set of electro-magnets that stored the encoded messages. A punch mechanism transferred the stored information to a tape. The hole pattern on the tape reflected the two/three pattern of the keyboard.
Hackers all over the world use the great-grandchildren of Baudot's code and hardware daily without ever realizing it. There is an exquisite, logical, simplicity to his code that makes it the springboard for countless applications.