tailieunhanh - The Cellular Connection 1 phần 3

Cuối cùng một người nào đó nhận ra rằng các cá nhân tư nhân cũng có thể hưởng lợi từ việc có thể nói chuyện với thế giới bên ngoài từ chiếc xe của mình, và các dịch vụ điện thoại di động thương mại đầu tiên được thiết lập ở St Louis, Missouri, vào năm 1946. | The Cellular Connection A Guide to Cellular Telephones Fourth Edition. Robert A. Steuernagel Copyright 2000 John Wiley Sons Inc. ISBNs 0-471-31652-0 Paper 0-471-20340-8 Electronic 2 CELLULAR PHONE EQUIPMENT There are three parts to a cellular phone system the cellular telephone or cellphone the cell site which receives and transmits radio signals from and to your phone and the MSC or Mobile Switching Center which links cellphones to established conventional telephone services. The relationship among these is illustrated in Figure . THE CELLULAR TELEPHONE The standard portable cellular telephone is a one-piece unit that serves as the handset and includes a dial pad or keypad display microphone miniature speaker or earpiece a miniature radio receiver and transmitter or transceiver antenna and a removable rechargeable battery. The small portables available are marvels of engineering and may have a standard rectangular shape or the popular flip-phone styling which covers the keypad when not in use and is reminiscent of the communicator used in the Star Trek television series and films. Additional unique styles provide different hand-fitting shapes and additional electronic features. The Motorola Classic series for example is noted for its durability under rough 9 10 CELLULAR PHONE EQUIPMENT Figure PARTS OF A CELLULAR SYSTEM The three parts of a cellular phone system are 1 the cellular phone 2 the cell site which receives and transmits your calls to and from your phone and 3 the mobile switching center which then transmits your calls to conventional phone service. conditions and long battery life rather than small size and is nicknamed the brick because of its unique size and shape. These portable telephones have reduced power output of watt or 600 milliwatts compared to 3 watts in standard mobile cellular phones in order to reduce the battery size and thus the overall size of the unit. This power reduction may only produce noticeable reduced performance in .