The telephone was invented by accident when Alexander Graham Bell,  a teacher for the hearing impaired was looking for a tool to teach his deaf students. His interest in sound technology was also personal, as both his wife and mother were deaf.  The telephone evolved from his invention known as a phonautograph: 'a device that draws vibrations from the human voice, to help deaf students visualize sound.' On March 7, 1876, Bell was granted his telephone patent.