Alexander Graham Bell, born on March 3, 1847 Edinburgh, United Kingdom
died on August 2, 1922. The Father of Telephone.
How did it help
Before the telephone appeared, if people wanted to communicate for long distance, their only way was writing letter. It is very slow and if there was any emergency, people won't know until a few days later. Now the telephone fixed it. People could communicate with their friends, relative without weeks or even months' waiting and if anything happened, people could know immediately.
The principle of the telephone
when a person is speaking, the sound waves created by his voice enter the mouthpiece. An electric current carries the sound to the telephone of the person he is talking to.
who used it
Back to the time when the telephone was just invented, not everyone could afford one. So the people that had telephone were always middle classes or above. The telephone benefited the business. If there was emergency, the people in charge would know it very fast, even they were thousand miles from the company.