martes, 29 de julio de 2008

THE TELEPHONE


In 1973, Martin Cooper invented the first cell phone.

As at the beginning were so big and expensive, they were only used by the military and some companies.

By 1983 were smaller and economical and could be used by the general public.


How the cell phone? The cell phone works through the union of a network of stations transmitting-receiving radio calls towers (base station, which consists of a tower, in a small building where the radio equipment) and a set of telephone exchanges.


The concept of cellular system, designed by Bell Labs in 1947, consists of a network of small transmitting towers, each tower located in a "cell" or "zone" with a radius of a few miles. Each tower a few of the frequencies designated to the system.


In what a cell travels through the cells, the so-called pass tower tower, making it possible communication between mobile phones or between mobile phones to fixed network.


Recommendations For the better functioning of this type of electric devices we recommend not expose them to heat or humendad.

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