Shulou(Shulou.com)11/24 Report--

Introduction: in recent years, I have been writing the history of communication development. Writing, gradually have their own understanding of the evolution of communication technology, but also have some understanding of the ups and downs of the communications industry. Today, I will just have a few words with you, and I will throw a brick to attract jade.

Since the birth of human beings, communication has been a rigid demand.

Without communication, people are isolated islands of information, unable to communicate and cooperate, unable to express feelings, and unable to form any form of organization.

Therefore, we often say that communication is not only the glue of human society, but also the cornerstone of human progress.

In the long course of development of human communication technology, 1837 is an important time node.

At this node, the history of communication development is divided into two parts: ancient history and modern history. In other words, since the beginning of this year, human communication has entered the modern era.

What happened this year? Yes, Samuel Morse, an American, officially invented Telegraph technology.

Samuel Morse Telegraph is the product of human "electrical science" research, and it can also be regarded as the early achievement of the second Industrial Revolution (Electrical Revolution).

Using "electricity" to communicate is the first epoch-making feat. Before this, people messed up for thousands of years and invented numerous means of communication (beacon, wolf smoke, carrier pigeon, post station), which could not solve the contradiction of communication information, communication delay and communication distance.

In the 1830s, human society developed to a critical point. The backwardness of communication technology has not only restricted the productive forces, but also affected the further expansion of the scale of human organizations, and even affected the world economy and national peace.

The emergence of "electric communication" is not only natural, but also timely. The transmission rate of "electricity" is extremely fast, so it is a very ideal means of communication.

In fact, Xiaozao Jun personally believes that the invention of Morse code is of more significance than the Telegraph. Because, it realizes the advanced coding of the text.

Writing is the most powerful invention of mankind. We can actually think of it as early information coding. All information can be recorded and transmitted through words, forming the history and culture of mankind.

However, the text is too complex, not to mention our complex Chinese characters, even if it is a 26-letter English alphabet system, it is difficult to simplify transmission.

What is the secret of efficient communication? It is to turn the information into simpler codes, and then to find the simplest and most efficient way to express the information symbols and carry these codes.

The historical experience at that time (early 19th century) shows that "yes" and "no", "right" and "wrong", "yin" and "yang", the binary symbol representation, is the easiest to achieve through technology. For example, lights are on and off, flags and no flags, smoke and no smoke.

Morse code turns the text into "dots" and "horizontal", achieving minimalist "quasi-binary" coding. Then, the coding expression is carried out based on the "on" and "off" of the current. This realizes the ultra-long-distance and ultra-fast transmission of text (information). The only bottleneck is the speed at which current pulses are generated-no matter how skillful a Telegraph operator is, it takes several seconds to type a word.

Before human beings solved the problem of pulse frequency, there was a "tricky" method, that is, instead of coding and decoding, acoustic information was collected directly through the thin film and magnet in the source (microphone), and then the current (simulated sound waveform) was transmitted to the handset (handset), driving the vibration of the film and magnet to reproduce sound waves.

Yes, this is the telephone invented by Alexander Bell in 1876.

From a functional point of view, the telephone is already the ultimate realization of human communication. Isn't it the highest level of communication that two people, in different places, can talk directly over the phone?

That's what people should think at that time. In their eyes, the phone has only one disadvantage, that is, it needs to be pulled. This means that construction is needed, which will incur huge costs.

After the advent of wired telephone, it brought a new concept-network, or switched network. In order to connect so many nodes, it is necessary to form a network topology and introduce switching processing.

The way of exchange processing, at first, is manual exchange. Later, with step-by-step switching and vertical and horizontal switching, a set of development route of telephone switching was formed. This is later.

Telephone communication is very powerful, but it depends on hardware construction. With the economic conditions at that time, the speed of popularization was slow, and it was easy to create a communication gap (the rich enjoy the right to communicate).

In the long 19th century, there is a hidden line, in the silent development. That is the study of radio electromagnetic waves.

The real boss of wireless electromagnetic waves is the great Maxwell.

Maxwell Maxwell is well-deserved to be called the god of wheat. At that time, no one believed in the existence of radio electromagnetic waves, only Mai God unswervingly completed the foundation of the theory.

Later, the German Hertz verified the existence of radio electromagnetic waves through experiments, which completely opened the door to a new world.

Radio magnetic waves are no longer dependent on wired media and can achieve long-distance instant communication. At that time, it was also a feat.

In 1901, the Italian Marconi realized transatlantic wireless Telegraph communication for the first time, which shocked the world.

After the birth of radio communication, with the technical means at that time, there was no way for human beings to control high-frequency electromagnetic waves, so telegram was the main way to express signals. Later, with the continuous progress of radio technology, with radio broadcasting (1920), radio also began to transmit sound.

In addition to harnessing high-frequency electromagnetic waves, there were several difficulties in radio communication at that time:

First, to obtain greater transmission power; second, to obtain more sensitive receiving capacity; third, coordinated management of radio spectrum; fourth, cost control and size reduction of wireless communication equipment.

Apart from the third, the rest are all subject to electronic technology.

Coincidentally, the two world wars between 1910 and 1950 greatly promoted the development of science and technology, including the development of the electronics industry.

With the invention of electronic tubes (1904) and transistors (Bell Laboratories, 1947), electronic technology has entered a new era. In terms of hardware, this removes the obstacles to the development of communications.

Motorola's walkie-talkie was a typical product of communication technology in that period. The communication terminal has become miniaturized and a person can carry it on his back.

At the same time, Claude Shannon of Bell Labs published a paper on information theory in time (1948).

Shannon for the first time, from the theoretical point of view, he constructed the basic model of communication, put forward the information entropy, quantified the information, and defined bits. He also introduced the Shannon formula, which clearly points out all the elements that determine communication ability.

His contribution was so important that it laid the theoretical foundation of information and communication technology. Therefore, he deserves to be the ancestor of modern communication technology. )

In the 1940s, it was in the bud of the third Industrial Revolution. This industrial revolution is represented by atomic energy technology, aerospace technology, and electronic computer technology.

In essence, the leap of communication technology in that period is the embodiment of the explosion of information technology.

We move the time pointer forward 100 years, back to the 1840s. In 1846, nine years after the invention of Morse Code and Telegraph, scientists combined perforated tape technology with Telegraph technology. Text messages are recorded through holes one by one.

Later, in 1890, the German-American Herman Holly, the founder of IBM, further perfected the technology and invented the punching watch machine.

Don't underestimate this kind of punched paper. This is actually an early storage technology. On the basis of text coding, it realizes more efficient text and digital storage, that is, the early informatization.

In the 21st century, with the invention of magnetic media storage, data storage has really entered the modern storage era.

This is very important. You think, if there is no data storage, how can there be data calculation? Without data computing, how can there be data communication?

It is war that really gives birth to the sprout of information technology.

At that time, punching tabulators were only used to calculate population data and financial statements. These calculations are not complicated.

The reason why human beings want to develop computers is the two main driving forces. One is to crack the password of the opponent in the war (refer to the deeds of Boss Turing), and the other is to calculate the trajectory of the rocket. In other words, Oppenheimer is about to be released, and the birth of the atomic bomb is, of course, thanks to computers. )

The super-complex computing requirements promote the birth of the computer. Data has been digitized, computing has been digitized, and communications have to be digitized.

After entering 1950, the whole communication technology is divided into several runways.

First, the telephone exchange network is still jogging on a step-by-step, vertical and horizontal route.

Second, wireless communications, with the emergence of transistors, the progress of electronic technology, began to move towards higher performance, smaller size, began to appear more and more vehicle mobile communications, that is, 0G (Pre-1G). In 1946, Motorola partnered with AT&T to launch the first vehicle mobile communication system (MTS) for the public.

Third, the data communication needed by information technology (computer) is beginning to sprout.

War is still driving the leap forward in data communication.

In February 1958, in order to gain competitive advantage in science and technology in the Cold War, the US Department of Defense established a mysterious scientific research department-APRA (Advanced Research projects Agency).

Later, in order to ensure that it had a certain ability to survive and counterattack under the first round of Soviet nuclear strikes, the United States Department of Defense decided to study a decentralized chain of command. It consists of countless nodes, and when several nodes are destroyed, other nodes can still communicate with each other.

As a result, ARPA teamed up with several universities in the United States to develop ARPANET (Arpanet).

The location of the early four nodes of ARPANET should be familiar with this name. Yes, it is the predecessor of Internet (Internet).

In the 1960s and 1970s, ARPANET grew, which incubated the TCP / IP protocol and built the early Internet architecture.

In the 1970s, the integrated circuit era initiated by transistors entered the first round of explosion, and the golden age of semiconductors officially arrived. The upgrade of storage technology and the leap of chip capacity have given birth to the explosion of information technology, not only mainframes blooming everywhere, but also PC personal computers.

All of these nodes need to be connected to the network. In addition to the ARPANET-related technology lines, the Xerox Palo Alto Research Center (Palo Alto Research Center) invented Ethernet, which laid an important foundation for the development of data communication.

On the other side of the fixed telephone network, under the influence of electronic technology (1950s and 1960s), network switching went from mechanical to electronic, and then from semi-electronic to full-electronic. Under the influence of computer technology (1970s), it began to enter program-controlled switching (program-controlled switching), and the switching capacity increased greatly, becoming ten thousand doors or even higher.

In wireless communications, the rapid development of integrated circuits and the maturity of the ability to control high-frequency radio electromagnetic waves eventually made radio communication devices miniaturized enough to give birth to mobile phones (Motorola, 1973).

In the 1960-1970s, we should not forget the emergence of an important role, that is, optical fiber communication.

In 1966, Chinese scientist Charles Kao published a paper predicting the emergence of optical fiber communications. In 1970, Corning pulled out the world's first fiber with a practical level of attenuation (17dB / km).

The emergence of Kao Kao's optical fiber is simply a miracle.

Who would have thought that glass would become the most powerful transmission medium for human beings? It can not only achieve super transmission rate and bandwidth, but also very cheap! If there is no optical fiber, just imagine, to achieve the current scale of network connectivity, how many precious metals do we need? How much environmental pollution will it cause? If the cost is shared among our users, how can we enjoy inclusive network services?

On the surface, optical fiber communication is wired communication, but in fact it is radio magnetic wave communication. It restricts the wireless electromagnetic waves "running about" in space in thin glass fiber, avoids the complex channel and interference of wireless communication, and realizes ultra-high rate, advanced stability and ultra-low delay. It is the real "cornerstone" of modern human communication network.

In the 1980s, the embryonic form of the Internet has been formed, and the rest is the continuous expansion of the network scale.

Fixed telephone network has basically reached the end of life. The development of mobile communication network has revolutionized the life of fixed telephone network. From 1G to 2G, mobile communication has realized the transformation from analog to digital, and has made a qualitative leap in communication capability (spectrum efficiency, anti-interference, confidentiality, stability, etc.).

The popularity of mobile communication has achieved ubiquitous voice calls. But that's not the point. Because, in the 1990s, data communication and Internet communication were the real mainstream.

In the 1990s, optical fiber communication became more and more mature and began to act as the backbone of network transmission. Due to the limited cost, on the user side, the main Internet connection medium is still telephone line and network cable (ADSL). Developed countries in Europe and America have taken the lead in stepping into the Internet era.

It is worth mentioning that in the 1980s and 1990s, civil satellite communications, as a subdivision field, also began its own road of development. The first to eat crabs is the famous Motorola Iridium project.

The outbreak of the Internet has had an important impact on mobile communications. An important feature of 3G is the support for data services. On the network side, a series of network element reconfiguration has been carried out, from circuit switching to packet switching.

Mobile communication begins to be IP, serving multimedia data services. This transformation also makes the Internet move towards the mobile Internet era.

The mobile Internet has brought about fundamental changes in human clothing, food, housing and transportation. It has created countless new business models and built the online digital world. Image, audio and video services and O2O services are still generating traffic. Traffic, stimulate the further expansion of the network.

In view of the massive business needs, computing technology began to move from centralized to distributed, giving birth to cloud computing technology. The huge amount of data further gave birth to big data technology. The growth of computing power has laid the foundation for the development of artificial intelligence.

Communication technology has always served information technology. This is true in the past, in the present, and in the future. Information technology materializes its own services and uniformly represents them as computing power. Communication, on the other hand, is incarnated as a joint force, serving the transportation of computing power, in order to realize the ubiquitous service of computing power.

In the 21st century, the biggest change in communications is not the subversion of technical principles (we don't even see a glimmer of hope), but the change of service objects. Communication no longer serves mankind as it did in the 20th century, but serves the entire physical world and the Alliance of everything.

Connect all objects, become the mapping of the digital world, become nerve endings, become control nodes, let data flow freely, let AI artificial intelligence get all data, manage everything, or an ideal state. So, is there a huge crisis behind this?

The development of communication technology has entered a turning point. In the past, it was user demand that drove technological progress. Now, it is the advanced development of technology to incubate the needs of users.

Looking back on the development of communications, every high-speed development is closely related to the upgrading and innovation of information technology. It is either the revolution in coding and storage technology, the popularity of computing needs (computers), or the construction of the online digital world.

Looking to the future, when will semiconductor-based zeros and ones be used? How long will it take to eat the dividend of wireless electromagnetic waves? Will computing or storage based on biological and quantum technology really explode?

I really want to know the answer!

This article comes from the official account of Wechat: fresh Jujube classroom (ID:xzclasscom), author: Xiaozaojun

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