The telegraph and the telephone were both wire used electrical systems. He came upon the invention of the telephone at a failed attempt at changing the telegraph. The telegraph had been a way of communication for 30 years. it was a very successful system, but it limited a person to only recieving and sending one message at a time. He is vast knowldge on sound helped him to put together the way you can send and recieve messages all at one time.
Significance
Alexander Graham Bell was so significant because he changed our world forever by furthuring communication. We learned about him in Chapter 26 because he was apart of the Era of Progress. His impact today was that he took his ideas and made an invention, and now we have built off of it to have what we do today.