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Letter pigeons
Another very old communication network is
the system of messenger pigeons. Pigeons
often had a small piece of paper written
with important messages. This was
attached to their leg. Sometimes they
carried the results of sporting events,
for example from the Olympic games.
In modern times, white pigeons
are released at the beginning of
each Olympics to remind us what
an important role they used to have.
Pigeons were also very important during
times of war when there was no other way
to get messages between places.
Morse code
Morse code is a sound system that can be used
to send messages. It is a series of tones
representing a letter of the alphabet. From
the 1890s it was widely used on board
ships for communication. A special
tool was used to create the sounds,
for example, one short sound and
one long sound represent the letter
A. Three short, three long and
three short (for SOS) represent
emergency conditions and a call
for help. This code is international.
Pilots and air traffic controllers are
often familiar with Morse code.
