The Beginning

We tend to think of digital communication as a new idea but in 1844 a man called Samuel Morse sent a message 37 miles from Washington D.C. to Baltimore, using his new invention ‘The Telegraph’. This may seem a far cry from today’s computer networks but the principals remain the same.

Morse code is type of binary system which uses dots and dashes in different sequences to represent letters and numbers, modern data networks use 1’s and 0’s to achieve the same result. The big difference is, that while the telegraph operators of the mid 19th Century could perhaps transmit 2 or 3 dots and dashes per second, computers now communicate at speeds of up to 1 Giga bit, or to put it another way, 1,000,000,000 separate 1’s and 0’s every second. Not long after Morse’s Telegraph, a French inventor called Emile Baudot developed a printing telegraph machine which used a typewriter style keyboard, this allowed virtually anyone to send and receive telegraph messages. Baudot used a different type of code for his system because Morse code didn’t lend itself to automation, this was due to the uneven length and size of bits required for each letter. Baudot used a five bit code to represent each character, this would normally only give 32 possible combinations (00000 to 11111 = 32). It clearly wasn’t enough for 26 letters and 10 digits but he got around this problem by using two ‘shift characters’ for figures and letters, which performed the same sort of function as a typewriter shift key. Now he had 62 combinations for letters, figures and punctuation marks. To this day, the speed of serial communications is still measured in Baud rate, after Emile Baudot.Improvements were made to Baudot’s machine by an English inventor called Donald Murray. Murray sold the rights for his machine to Western Union who gradually replaced all of its Morse telegraphs with the new ‘teletypewriters’.

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