| Wireless is a term used to describe telecommunications
in which electromagnetic waves (rather than some form of wire) carry the
signal over part or all of the communication path. Some monitoring devices,
such as intrusion alarms, employ acoustic waves at frequencies above the
range of human hearing; these are also sometimes classified as wireless.
The first wireless transmitters went on the air in the early 20th century
using radiotelegraphy (Morse code). Later, as modulation made it possible
to transmit voices and music via wireless, the medium came to be called
"radio." With the advent of television, fax, data communication,
and the effective use of a larger portion of the spectrum, the term "wireless"
has been resurrected.
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