Audio Zepis NumerPDC3 the first mobile telephone call was made in 1973 by Dr. Martin Cooper, the scientist who invented modern mobile phones.0:00
A mobile or a cell phone works like a radio.0:15
In fact, it is a modernized radiophone like those used in cars in the 1980s.0:20
Those car phones needed a powerful transmitter and were very expensive.0:27
Mobile phones differ from them in one important aspect.0:33
Carriers or providers cut the territory into segments or cells.0:37
As you move, you jump from cell to cell and the frequency you've just used becomes free for someone else.0:43
Each cell will, which has a base station, a tower and a building with a radio equipment, uses one seventh of all the channels it can use.0:51
In other words, lots and lots of people can talk on the phone at one time.1:01
In fact, millions of people can use the system, and that makes the cell phone cheaper to use.1:07
Another difference between mobile phones and other radio communication devices is, is that you use one frequency for talking and another for listening, so both people can talk at once.1:13
These days, mobile phones can do a lot more than make calls.1:26
People use their phones to send and get emails, take photographs, play games, surf the Internet and do many other things.1:31
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