FrontLine BPA LOW ENERGY, Hardware User Manual

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A.2 Bluetooth® low energy Security
Figure 16 - Chappe's Optical
Telegraph
"Paris is quiet and the good citizens are content." Upon seizing
power in 1799 Napoleon sent this message on Claude Chappe’s
optical telegraph. Chappe had invented a means of sending
messages line-of-sight . The stations were placed approximately
six miles apart and each station had a signaling device made of
paddles on the ends of a rotating “regulator” arm whose positions
represented code numbers. Each station was also outfitted with
two telescopes for viewing the other stations in the link, and
clocks were used to synchronize the stations. By 1803 a
communications network extended from Paris across the
countryside and into Belgium and Italy.
Chappe developed several coding schemes through the next few
years. The station operators only knew the codes, not what
characters they represented. Not only was Chappe’s telegraph
system the first working network with protocols, synchronization
of serial transmissions but it also used data encryption. Although
cryptography has been around for millenniums—dating back to
2000 B.C. — Chappe, was the first to use it in a wide area network in the modern sense.
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