Telephone, connect the sound of time and space

In April 1973, Martin Cooper, an engineering technician at Motorola in the United States, invented the world’s first mobile phone, the Motorola DynaTAC8000, which was launched in the world. From then on, human beings began the era of mobile communication in real sense. Since its launch 45 years ago, the development of mobile phones from 1G to 5G has become one of the most important tools in people’s lives and work.
As early as the invention of the mobile phone about 100 years ago, the telephone has already come out, and the “following ears” in the Chinese mythology reflect the reality. Today we walked into the 100-year old telephone museum in Shunyi, Beijing, to browse the history of the telephone.

In 1876, Bell (1847 – 1922) successfully applied for a telephone invention patent in the United States. In the past century and a half, the phone has undergone subversive changes. Every technological innovation brings great surprises to people.
The first generation of telephones that were first put into use were magnet-type telephones.
This type of telephone has a communication system and a calling system, and needs to have two dry batteries for power supply. Its magnet-type hand-cranked generator is used to generate an AC ringing signal. In fact, the original telephone can only be connected one-to-one through the line, even if the ringing signal is not sent, if the two parties agree on the time to pick up the microphone at the same time, the phone is in the on state, and can directly talk.

The one-to-one connection makes the communication of the phone inefficient. It is an urgent problem to increase the number of telephones connected to the line by connecting different lines through the equipment. In 1878, the manual telephone exchange was invented. With the switch as the hub, the telephone lines are connected into a network.

Along with the invention and improvement of the switch, a common telephone was introduced in the 1880s. This type of telephone is centrally supplied with signal and call power by the telephone exchange, so the hand-type magnet generator is no longer required to provide a ringing signal, and no self-supplied power source is required. When the user picks up the handset call, the attendant in front of the switch first receives the call signal (usually the indicator light or ringing), and the attendant connects to the calling machine to understand the line that he wants to connect to, according to the line condition. Pass the line corresponding to the called phone and send the ringing signal.

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Post time: Jul-24-2018
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