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Two critical innovations
revolutionized personal communications. When a Frenchman named Claude Chappe invented the
telegraph in 1792, it marked the first time messages could travel quickly over long
distances. It's no coincidence that the Pony Express discontinued service as soon as
Western Union began operating the first transcontinental telegraph line in 1861,
considering the very best a horse and rider could do was 250 miles a day. Not much
competition for the telegraph, which could send a message cross-country in a matter of
seconds.
Renowned Scottish-American scientist
Alexander Graham Bell took the next big step when he sent a voice transmission eight miles
over telegraph wires in the spring of 1876. By the end of that year, Mr. Bell had placed
the first long-distance telephone call in history, transmitting his voice some 143 miles.
Ever since Mr. Bell created virtually
instantaneous voice communication over long distances, we've searched for ways to make the
telephone both simpler and more powerful.
Enter cellular phones, which have one huge advantage
over the traditional telephone: they operate without wires. No more "leash." We
can now keep in touch wherever we are, whenever we want. Thanks to wireless technology,
personal communications means having flexibility, accessibility and freedom.
Wireless services started with a blueprint that
relied on cellular technology.
Cellular's name connotes that each geographic region
of coverage is broken up into cells. Within each of these cells is both radio transmitter
as well as control equipment. The first cellular services, which operate at 800 MHz, used
analog signals. Analog sends signals using a continuous stream or wave. When a cellular
phone customer turns on his phone, a signal is sent that identifies him as a customer,
makes sure he is a paying customer, then searches out a free channel to fit his
call.
PCS or personal communications services that operates at 1850 MHz,
on the other hand, followed years later. New entrants into the wireless market chose
digital technology instead of analog. These companies saw the promise in building out PCS
(personal communications services) systems based on digital, and hope to benefit from
continued growth. The may be onto something... The Strategis Group, a consulting company,
predicts that by the millennium, some 23 million folks will be PCS subscribers.
Some cellular operators did see this evolution
coming, too. They, too, looked to benefit from digital technology by backing a technique
that combined both mediums: digital analog, known as D-AMPS 136, the next upgrade from
cellular. This was intended to improve on an analog-only network. The upgrade was done to
protect their investment in the cellular network while still being able to provide some of
tomorrow's services that their customers will demand. While digital upgrades are growing
and more and more operators are switching over to digital, by some estimates half the
world's wireless users still use the basic analog system.
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