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Communications Revolution |
Communications Networks |
Optical Fibres |
Photonic Devices |
Future of Communications | Credits |
The first telegraph lines were made of iron: at that time, copper was not strong enough!
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Thomas Doolittle
developed a new process to draw
strong copper wire. Because of
its better electrical conductivity over iron,
copper wires became the standard in telephony.
The first improvement came with the wire pair: a second wire was used instead of using the ground.
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The next improvement was the use of the
twisted-pair cable:
two independently insulated wires
were twisted around one another.
One wire carries the signal
while the other wire was grounded
and absorbs signal interference. Twisted-pair cables are still in use by older telephone networks and is the cheapest cable.
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