The telephone was invented by American A. g. bell in 1876. He uses two wires to connect two transmitters and receivers with the same structure and a vibrating diaphragm on the electromagnet to realize the communication between the two ends. But the communication distance is short and the efficiency is low.
Today’s mobile phone has completely overturned the old times. Nowadays, there are few families with fixed telephone. Telephone represents the development and progress of the past 40 years. Have you ever seen these phone tattoos?