19 / 20th Century Pioneer

Alexander Graham Bell (1847 – 1922).

Alexander Graham Bell's success with the telephone came as a result of his attempts to improve the telegraph.

The telegraph had been an established means of communication for over 30 years when Bell began experimenting with electrical signals. Although a highly successful system, the telegraph was basically limited to receiving and sending one message at a time using the Morse code. Bell's knowledge of the nature of sound and his understanding of music enabled him to see the possibility of transmitting multiple messages over the same wire at the same time. Although the idea of a multiple telegraph had been in existence for some time, Bell offered his own musical or harmonic approach as a practical solution.

He was granted a patent on the telephone in 1876.  His telephone was based on the principle that several notes could be sent simultaneously along the same wire if the notes or signals differed in pitch.  He also invented the photophone, a device for transmitting sound over a beam of light.