One day in April 1973, a man stood on the street in New York, took out a wireless phone about the size of two bricks, and made a call, which attracted passers-by to stop and stare. This man is Martin Cooper, the inventor of the mobile phone. At that time, Cooper was an engineering technician at the famous American Motorola Company. Cooper placed a call to a rival at Bell Labs, who was also developing a mobile phone but had yet to succeed.
Although the mobile phone was patented as early as 1973, it was not until 1985 that the first modern, truly mobile phone was born. Although it is mobile, it still places the power supply and antenna in a box, weighing up to 3 kilograms. It is very heavy and inconvenient. The user has to carry it like a backpack when walking, so it is also called a "shoulder phone".