On this day, 149 years ago, March 10, 1876 (February 15, 1876, the lunar calendar), Bell invented the telephone. 1892 Telephone lines were opened in New York and Chicago. Bell, the inventor of the telephone, was the first to audition: "Hello, Chicago." This historic voice was recorded. Today, people living in different places need to contact directly without sending letters or rushing to each other's place in person. They can do it through the phone. Who was the telephone as a communication tool and when was it invented? The inventor of the telephone was called Bell. He was originally Scottish and was born in 1847. He moved to the United States at the age of 24 and soon became an American citizen. In 1873 he was already professor of language physiology at Boston University. Once, he attempted to transmit several messages simultaneously through a telegraph line. His vision won his wife Mabel. Hubbard and his father-in-law's support. Mabel is deaf and used to be a student of Bell's. Her father, who was relatively wealthy, generously donated money to his son-in-law's scientific experiments and provided necessary financial support. Many of Bell's friends wanted him to study telegraphy. But the inventor disagreed. The only thing he cared about was to complete the task of transmitting human voices. He first tried to make a "harmonic telegram"-a collection of two harp-like harps made of charged reeds connected on a single wire. Each reed has a counterpart at the same frequency on the other end of the wire. Bell hung two "harps" on magnetic films. The membrane is a device that mimics the human ear. One day, Bell's assistant Thomas Watson fiddled with the clamped reed, but Bell heard the plucking of strings from the adjacent room through the wire. He noted the facts, which led to further experiments. During the test, Bell encountered many difficulties. But he was an open-minded and studious person, so when he asked for advice from others, he received guidance and help from some famous scientists, including the famous physicists Helmholtz and Joseph. Henry, Edison, etc. On March 10, 1876, Bell shouted through the intercom: "Mr. Watson, please come here! I need to talk to you!" Watson's assistant in the laboratory heard the call and jumped out of the laboratory like crazy and ran to the bedroom where Bell was shouting. He shouted all the way: "I heard Bell calling me! I heard Bell calling me!"... In this way, mankind had the first phone call and opened a new chapter in the history of communication. In 1877, the first telephone-based press release was sent to the Boston Le Monde, marking the adoption of the telephone by the public. In 1878, Bell Telephone Company was officially established. Early manual telephone exchanges. It can serve 50 phone users. Mobile phones used by the U.S. military during the Vietnam War. Since the use of repeaters, it has become possible to connect phones between the United States and continental Europe. Telegraph and Telephone's watch-type phones are becoming smaller and more powerful. 1882, magnetic wall-mounted phones 1969, videophones 1938, telephone switchboard 1949,"500" desk phones