It was once a tailwind of ancient Chinese imagination. In 1793, the French Chape brothers set up a 230-kilometer-long carriage line between Paris and Lille to transmit information via relay. This is a communication system consisting of 16 signal towers. The signal operator uses ropes and pulleys to manipulate the different angles of the bracket to express relevant information. At that time, France and Austria were at war, and it took only an hour for the signaling system to reach Paris with news of the victory over Condé-sur-Ais from the Austrian army. Later, Belgium, the Netherlands, Italy, Germany and Russia also established such communication systems. One of the two Chape brothers is said to have been the first to use the word "telegraph."
European research on long-distance sound transmission began in the 17th century. The famous British physicist and chemist Robert Hooke first proposed the idea of ??transmitting voice over long distances. In 1796, Hughes proposed a method of transmitting voice messages via microphone relay, and called this communication method Telephone, which is still in use today.
In 1832, the American doctor Jackson explained the principles of electromagnets to passengers on a mail ship sailing in the Atlantic Ocean. Among the passengers, the 41-year-old American painter Morse was deeply attracted. At that time, the signal system in France could only communicate within a few miles of sight. Morse dreamed of using electric current to transmit electromagnetic signals and send messages thousands of miles away in an instant. From then on, Morse's life changed radically.
Morse was inspired by the fact that the current flowing in the wire will burst out sparks when the wire is suddenly cut off: if the current is cut off for a moment, the spark is used as a signal, and the current is turned on without sparking. As another signal, the longer the current is on also acts as a signal. The combination of these three signals can represent all letters and numbers, and the text can be transmitted to distant places through the current in the wire. In 1837, Morse finally designed the famous Morse code, which uses different combinations of "dots", "dashes" and "spaces" to represent letters, numbers, punctuation and symbols. On May 24, 1844, in the meeting hall of the Federal Supreme Court in the Capitol Building in Washington, Morse personally operated the telegraph machine. With a series of "dot" and "dash" signals being sent, the telegraph reached Baltimore 64 kilometers away. Received the world's first telegram consisting of "beep" and "dah" sounds.
[Edit this paragraph] The invention of the telephone
The inventor of the telephone-Antonio Meucci
It has been a mess for several years. On page 75 of "History and Society" in the third year of junior high school, it is mentioned about "Technology and Culture in the 19th Century": "The invention of the telephone by the American Bell fundamentally changed the way human communication is done." Regarding the inventor of the telephone, the textbook was written Due to the relationship of time, the traditional view is still used to attribute the invention of the telephone to Bell. However, there is controversy in history about the real inventor of the telephone, which involves three related figures: Bell, Gray and Meucci. The following material provided to students is not meant to subvert our teaching materials, but I just hope that through in-depth exploration of this issue, everyone can have a more comprehensive and detailed understanding of it.
For most people, when they think of the invention of the telephone, they think of Alexander Graham Bell. Bell conducted extensive research exploring the components of speech and analyzing the vibrations of sound on precision instruments. In the experimental instrument, the vibration on the diaphragm is transmitted to a glass piece coated black with carbon, and the vibration can be "seen". Next, Bell began to think about whether it was possible to convert sound vibrations into electronic vibrations. This allows sound to be passed through the wire. Over the years, Bell tried to invent several telegraph systems. Gradually, Bell came up with the idea of ??inventing a machine that could transmit several messages simultaneously through a single line. He envisioned coordinating different frequencies through several armatures. On the transmitting side, these armatures interrupt the current at a certain frequency and send a series of pulses at a specific frequency. At the receiving end, only the armature matching the pulse frequency can be activated. During the experiment, Bell accidentally discovered that sound signals could be transmitted by transmitting electromagnetic waves along lines. After several experiments, the sound can be transmitted stably through the line, but it is still unclear. Due to Bell's heavy teaching workload, his research did not progress for a long time. In 1876, on the eve of Bell's 30th birthday, the idea of ??transmitting sound through wires was unexpectedly patented.
Bell rekindled his passion for research. On March 10, 1876, Bell's phone call heralded the arrival of a new era in human history.
But Bell was not the only person working on the invention of the telephone. A man named Elisha Gray once launched a legal battle with Bell over the telephone patent. Gray and Bell applied for patents on the same day, but because they were a little later than Bell in terms of specific time (only about 2 hours later), they ultimately lost the case.
In fact, regarding the invention of the telephone, we should also think of another unknown Italian, Antonio Meucci, who immigrated to the United States in 1845. Meucci was obsessed with the study of electrophysiology, and he inadvertently discovered that radio waves could transmit sound. From 1850 to 1862, Meucci produced several different forms of sound transmission instruments, called "telephones." Unfortunately, Meucci was too poor to protect his invention. At that time, applying for a patent required a filing fee of US$250, and the long-term research work had exhausted all his savings. Meucci's poor command of English also prevented him from understanding how to protect his invention. Then, fate dealt Meucci an even bigger blow. In 1870, Meucci became seriously ill and had to sell the telephone device he invented for a mere $6. In order to protect his invention, Meucci tried to obtain a document called a "Request to Protect an Invention." For this, he needs to pay a fee of US$10 per year, and needs to be updated every year. Three years later, Meucci was reduced to living on social welfare benefits, unable to pay the processing fees, and the application became invalid.
In 1874, Meucci sent several "long-distance transmission microphones" to the American Western Union Telegraph Company. Hoping to sell the invention to them. However, he didn't get an answer. When requesting the return of the original parts, he was told that the machines were missing! Two years later, Bell's invention was unveiled and he signed a huge contract with the Western Union Telegraph Company. Meucci sued, and the Supreme Court agreed to hear the case. However, Meucci died in 1889 and the lawsuit was dropped.
Until June 15, 2002, the U.S. Congress passed a bill recognizing Antonio Meucci as the inventor of the telephone. Today, there is a monument in Florence, Meucci’s birthplace, which reads, “Here lies the inventor of the telephone, Antonio Meucci.”
At present, Bell is generally recognized as the inventor of the telephone. He applied for a telephone patent at the U.S. Patent Office on February 14, 1876. In fact, just two hours after he filed his application, a man named E. Gray also applied for a telephone patent.
Before the two of them, many people in Europe were already carrying out ideas and research in this area. As early as 1854, the principle of the telephone had been conceived by the Frenchman Boussard, and six years later the German Reiss repeated this idea. The principle is: two thin metal sheets are connected with wires. When one side makes a sound, the metal sheet vibrates, turns into electricity, and is transmitted to the other side. But this is just an idea. The problem is the structure of the transmitter and receiver. How can the mechanical energy of sound be converted into electrical energy and transmitted.
Initially, Bell used an electromagnetic switch to form an opening and closing pulse signal, but this method was obviously not feasible for such a high frequency of sound waves. The final success came from an accidental discovery. On June 2, 1875, during an experiment, he connected a metal piece to an electromagnetic switch. Unexpectedly, in this state, the sound magically turned into an electric current. According to the analysis principle, it turns out that the metal piece vibrates due to sound, which induces a current in the electromagnetic switch coil connected to it. It seems now that this principle is known to even a student who has studied junior high school physics, but at that time it was undoubtedly a very important discovery for Bell.
Gray's design principle is different from Bell's. It uses the resistance change of the liquid inside the microphone, while the receiver is exactly the same as Bell's. In 1877, Edison obtained a patent for the carbon microphone. At the same time, many people were making various improvements to the way the phone worked. The patent dispute was complicated and did not come to an end until 1892. One reason for this situation was that the Western Union Telegraph Company, the largest in the United States at the time, bought the patent rights of Gray and Edison to compete with Bell's telephone company.
The result of the long-running patent dispute was that the two parties reached an agreement. Western Union Telegraph Company fully recognized Bell's patent rights and would no longer be involved in the telephone industry. In exchange, it shared 20% of Bell Telephone Company's revenue within 17 years.
[Edit this paragraph] Development of telephone technology
In the decades after the invention of the telephone, a large number of patents were applied for regarding the management and technology of telephones. Strowger’s “ The "automatic dialing system" reduces various problems caused by manual wiring, the application of dry batteries reduces the size of the phone, and the application of loaded coils reduces signal loss in long-distance transmission. In 1906, Lee De invented the electronic test tube, and its loudspeaker function led the direction of telephone service. Later, Bell Telephone Laboratories made an electronic triode based on this. This research was of great significance. On January 25, 1915, the first interborough telephone line opened between New York and San Francisco. It used 2,500 tons of copper wire, 130,000 poles and countless loaded coils, and three vacuum tube amplifiers along the way to strengthen the signal. On July 1, 1948, scientists at Bell Labs invented the transistor. This is not only of great significance to the development of telephones, but also has a huge impact on all aspects of human life. In the following decades, a large number of new technologies emerged, such as the production of integrated circuits and the application of optical fibers, which all played a very important role in the development of communication systems.