Các tế bào connetion P1

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Các tế bào connetion P1

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AN INTRODUCTION TO CELLULAR PHONE SYSTEMS The first mobile communications system began in 1921 when the Detroit Police Department installed two-way radios in its cars. The equipment was bulky, awkward, and a drain on automobile batteries, but it proved its worth. Soon police and fire departments throughout the country were installing two-way radio equipment in their fleets. Eventually someone realized that private individuals could also benefit from being able to talk with the outside world from their cars, and the first commercial mobile telephone service was instituted in St. Louis, Missouri, in 1946. Early mobile phone service was more like using...

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