First, the original communication.
Before the Shang Dynasty, writing had not appeared, so communication almost depended on yelling. Before and after the Spring and Autumn Period and the Warring States Period, the writing became more mature. Flying pigeons, post stations and bonfires were the most popular methods at that time.
Although it was simpler than now, it was a great progress at that time. Although far apart, it was not until thousands of years later that the postal service was invented in the west.
Second, power communication.
Electricity, as its name implies, is the use of a large number of instruments that work with electricity.
The invention of electric power brought the history of human communication into a new era.
/kloc-After the middle of the 0/9th century, with the development of telegraph and telephone and the discovery of electromagnetic waves, great changes have taken place in the field of human communication, realizing the transmission of information by metal wires and even wireless communication by electromagnetic waves. 1837, American Samuel morse successfully developed the world's first electromagnetic telegraph. He used his own code to convert information into a series of long or short electrical pulses and transmit them to the destination. 1875, the Scottish youth A.G. Bell invented the world's first telephone, and applied for the invention patent in 1876. 1878, he conducted the first long-distance telephone experiment between Boston and new york, which is 300 kilometers apart, and achieved success.
During the period of 1888, the young German physicist H.R. Hertz conducted a series of experiments with radio circuits and discovered the existence of electromagnetic waves. He proved Maxwell's electromagnetic theory by experiments. This experiment caused a sensation in the whole scientific community and became an important milestone in the history of modern science and technology, which led to the birth of radio and the development of electronic technology. 50004+0904, British electrical engineer Frey.
1907, American physicist Fred Lester invented the vacuum triode, and American electrical engineer Armstrong invented the superheterodyne receiving device by using electronic devices. 1920, American radio expert Conrad established the world's first commercial radio station in Pittsburgh, and since then, the broadcasting industry has flourished all over the world. Radio has become a convenient way for people to know current events. 1924, the first short-wave communication line was established between nauen and Buenos Aires. 1933, the first commercial microwave radio line between Britain and France was established in Clarville, France. It promotes the further development of radio technology, and the discovery of magnetic waves also promotes the rapid development of image communication technology. 16-year-old American middle school student Philo Farnsworth designed the first schematic diagram of TV fax, and applied for the invention patent in 1929, and was awarded the first person to invent TV.
1928, Zwojin of Westinghouse Electric Company invented the photoelectric picture tube, and cooperated with the engineering teacher gas to realize the transmission and transmission of electronic scanning TV. Image fax is also an important communication mode. Since 1925, the first practical fax machine was developed by American radio company, and the fax technology has been continuously innovated. Before 1972, this technology was mainly used in news and publishing. From 1972 to 1980, fax technology has completed the transformation from analog to digital, from mechanical scanning to electronic scanning, and from low speed to high speed. In addition to transmitting weather maps, press releases, photos and satellite cloud pictures instead of telegrams, it is also used in medical care, library management, information consultation, financial data and electronic postal services in the United States.
In order to solve the problem of resource sharing, a single computer has rapidly developed into computer networking, realizing data communication and data sharing between computers. Communication media has developed from ordinary wires and coaxial cables to twisted pair, optical fiber lines and optical cables. The input and output devices of electronic computers have also developed rapidly. Scanner, plotter, audio and video equipment, etc. Make the computer more powerful and can handle more complex problems. The rise of multimedia technology in the late 1980s enabled computers to comprehensively handle various forms of information, such as words, sounds, images and movies, and increasingly became the most important and basic tool for information processing.
line telecommunications
American Morse (F.B.Morse): The telegram is about 5 kilometers (dots, dashes, spaces → letters and numbers);
American Bell (A.G.Bell): patented telephone (electric signal → voice);
Pubin, USA: communication cable;
1972 Japan: data communication and fax communication services of public communication network;
USA: Publishing Bell Data Network, UK: Image Information Service Experiment;
Modern communication systems use some centralized exchange facilities → complex information networks.
→ "exchange function" → realize signal transmission between any two points.
wireless communication
Maxwell, England, 1864: hypothesis of electromagnetic wave; 1888 H Hz: confirm the existence of electromagnetic wave;
1895 Marconi, Italy: wireless communication, the transmission distance is only a few hundred meters;
Italy Marconi 190 1: Wireless communication across the Atlantic;
Motorola was founded in 1928. During World War II, it signed a contract with the United States War Department to help it develop wireless communication tools. 194 1 year, Motorola developed the first cross-era product SCR-300, which is still the classic image of the American signal soldier in the film.
1938 French ribbon: PCM mode;
1940 CBS: color TV experiment broadcast; 195 1 American CBS: color TV is officially broadcast.
It was not until 1984 that the first generation of mobile phones invented by the famous American inventor martin lawrence cooper entered the consumer market. Since then, human communication has entered the era of wireless mobile, which is a bit of the shadow of mobile phones and an excessive connection with the era of global intelligent mobile.
The earliest "mobile phone" was 1992 26 years ago. IBM released Simon Personal Communicator, the world's first smart phone, and used a full touch-screen smart phone for the first time, paving the way for the development of modern smart phones. Take a photo with his 15-year-old iPhone:
……
Modern: Wireless communication is spread all over the world, leading to the universe. For example, the accuracy of GPS can reach tens of meters.
future
? Maybe in the future, chips will be implanted in our brains, and each chip will be automatically saved after contact, so as to avoid some harassing calls, and whoever we want to call will be automatic. Everything seems to be automatic. There is no need to bring your mobile phone every day.
Personal communication is the highest goal of human communication. It is a new communication method, and users can communicate with anyone at any time and any place by using all possible network technologies.
① Use a unique personal communication number (PTN) that has nothing to do with the network to identify users. Users can establish connections across multiple networks and charge each other, regardless of geographical location. Personal communication numbers are used in wired and wireless systems.
② The network providing personal communication is a seamless network with huge capacity, which is integrated by multiple networks (including land, ocean and space networks) by various technical means. So no matter where the user is, he can find it or be found by the other party.
(3) Fixed users or mobile users can use wired or wireless access networks to obtain communication services anywhere.
(4) It has the ability to provide various services, and the network can provide various services according to the personal wishes and requirements of users.
⑤ The mobile terminal is ultra-small, easy to carry and low in energy consumption, and can be used for several weeks after charging.
This is the ultimate goal of human communication.
-The end-
Text: Lv Yujie
Figure: Network