Invention of the telephone
The carbon microphone was independently developed around 1878 by David Edward Hughes in England and Emile Berliner and Thomas Edison in the US. Although Edison was awarded the first patent in mid-1877, Hughes had demonstrated his working device in front of many witnesses some years earlier, and most historians credit him with its invention.
Dictation machine
Alexander Graham Bell and his two associates took Edison's tinfoil phonograph and modified it considerably to make it reproduce sound from wax instead of tinfoil. They began their work at Bell's Volta Laboratory in Washington, D.C., in 1879, and continued until they were granted basic patents in 1886 for recording in wax.
Thomas A. Edison had invented the phonograph in 1877, but the fame bestowed on him for this invention — sometimes called his most original — was not due to its efficiency. Recording with his tinfoil phonograph was too difficult to be practical, as the tinfoil tore easily, and even when the stylus was properly adjusted, its reproduction of sound was distorted and squeaky, and good for only a few playbacks. Although Edison had hit upon the secret of sound recording, immediately after his discovery he did not improve it, allegedly because of an agreement to spend the next five years developing the New York City electric light and power system.