The first telephone conversation in history was made in Boston, the U.S. between the inventor Alexander Graham Bell and his assistant Thomas Watson on March 10, 1876.
"Mr. Watson, come here, I want to see you," said Bell into his experimental telephone to Watson who was in another room but out of earshot.
Bell developed an acoustic telegraph and drew up a patent application for it in 1875.
A year after his patent was issued, Bell managed to make his telephone functional.
Bell's invention originally had the same logic of operation as the electrical telegraph previously developed by the inventor Samuel Morse, but it aimed to transmit human voice naturally by encoding different audio frequencies as electrical signals instead of symbolic messages.
Bell's successful experiment initiated developments that paved the way for the practical use of the telephone. In 1877, the first telephone line was set up between Boston and Somerville, Massachusetts.
Telephone lines started to spread in the U.S. in the following years. By 1880, the number of lines of long cables carried on wooden poles reached to about 50,000 in the country.