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How old cell phone
How old cell phone?
When I was born, my father was half my age today. In the year of my birth, he subscribed to the magazine “Technology – young people.” After ten years or filing of these magazines into the hands of me, curious Maltz. Taking shelter in an old barn, I looked at with great interest magazine articles with pictures – greetings future from the past.
Among the news about the then technical innovations and was a note on the cordless phone, which allows you to talk with the caller PSTN while driving in a car. Radiotelephone weighed about 40 kilograms consumed so much energy that it was clear: no one, other than senior management, this “pandora” need not be. Even science fiction writers radiophonics not inspired. Personal transceivers used in the bright future unless on distant planets.
Then, no one imagined that a bright future will come in the morning April 3, 1973. That morning, the streets of New York City was a man, almost nothing stands out in the crowd. Is that what he held to the ear rather impressive size of the box, a bit like a telephone. By pressing a few buttons, he said: “Hi, Joel. Imagine, I’m going on a New York street, in my hands the world’s first cell phone, and I’m calling you from it. ” It was a Vice President of the “Motorola” Martin Cooper (Martin Cooper), and he called his chief rival Joel S. Engel (Joel S. Engel), the head of the research department of the company, “Bell» (Bell Laboratories).
The company “Motorola” was developing a mobile communication system for cars. Hence the “motorcycle” in its name. Despite the bulkiness and high price (from 2 to 4 thousand dollars), the system auto radio in America found consumers. Were it not only bored millionaires, but also police, ambulance and emergency services of all kinds.
However, the creation of a complete system of radiotelephone hampered by several factors. One of these factors, the size and weight of wireless phones, there was hope in time to enter into a reasonable framework. But another factor seemed unsolvable in principle.
Every cordless telephone – a small radio station, demanding for his work certain fixed radio frequency. Several hundred concurrent cordless threatened to take the entire space of the allowed frequencies. Moreover, two close radiotelephone could interfere with each other. Not to mention the fact that if the frequency of the station is known and fixed, it can be easy to listen to. Imagine a jaunty game. The police chasing gangsters, talking on cordless phones, and bandits, being able to listen to conversations police successfully escape from his pursuers.
The controversy was evident. On the one hand, the cordless telephone becomes economically profitable if they will be in the millions and tens of millions of people. The more, the better. On the other hand, it is impossible to increase the number of customers because of the narrow range of allowed frequencies.
The solution was found. D. Ring, a member of «Bell Laboratories», offered to cover the territory of a network of transceiver antennas, each of which will serve all cordless phones that are close to her. When the signal weakens phone to switch to a neighboring zone antennas. To avoid confusion occurred, the operating frequencies of the two adjacent antennas to be different. Usually coverage of each antenna resemble hexagonal cells. Therefore, the link itself is called “cellular» («Cellular network»).
Ingenious methods of signal coding in the mid-1960s allowed a single antenna cellular service several cordless telephones. Switching equipment on transistors provide a quick and unobtrusive to the user when switching moves from one antenna in the range of another.
The introduction of integrated circuits reduced the weight of phones and their price. Also cordless phones have moved from radio broadcasts an analog signal to a digital signal transmission. Due to this increased sharply bandwidth RF channels. A cellular antenna could serve several hundred customers. It became possible to send short text messages (SMS). The digital signal is also possible to increase the privacy of conversation. And the use of computers has increased the performance of the entire network. It was a blast!
The first commercial cellular network launched in May 1978 in Bahrain. The number of subscribers in this small Middle Eastern country was small. For service 250 clients took only 2 cell with 20 channels. In 1982, the European Conference of Postal and Telecommunications Administrations has introduced a standard for mobile communications GSM (Global System for Mobile communications). Simultaneously for mobile communication has been allocated a new range of 1800 MHz. In a number of states began implementation of this standard. In 1992, the first national mobile network appeared in Finland.
In my memory there was the computer revolution. Computers from expensive and inaccessible to scientific and technical instrument in a few years become a necessity in every home a thing as television. And, apparently, are gradually replacing TVs.
Mobile communication has broken these records. The speed with which she won the countries and continents, would be the envy of any invader. Besides, as it turned out, no fundamentalists were not able to ban cell phone as they tried to ban the Internet. This little modern miracle can be found in any country in the wildest corner. If in the early 1990s, the mobile phone was a status symbol and signified its owner as a very important person, now mobilka is at all: the grandmother and granddaughter. You look, and soon she’ll need Zhuchko.Viewing:-231
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