Alexander Graham Bell his grandchildren. "U.S. patent images in TIFF format" Alexander Graham Bell Alexander Graham Bell (March 3, 1847 – August 2, 1922) was a Scottish-born scientist, inventor, engineer, and innovator who is credited with inventing and patenting the first practical telephone. He also founded the American Telephone and Telegraph Company (AT&T) in 1885. Bell's father, grandfather, and brother had all been associated with work on elocution and speech and both his mother and wife were deaf, profoundly influencing Bell's life's work. His research on hearing and speech further led him to experiment with hearing devices which eventually culminated in Bell being
Invention of the telephone to the pressure. Thus, the grains could vary their resistance as the plates moved in response to sound waves, and reproduce sound with good fidelity, without the weak signals associated with electromagnetic transmitters. The carbon microphone was further improved by Emile Berliner, Francis Blake, David E. Hughes, Henry Hunnings, and Anthony White. The carbon microphone remained standard in telephony until the 1980s, and is still being produced. Additional inventions such as the call bell, central telephone exchange, common battery, ring tone, amplification, trunk lines, and wireless phones – at first cordless and then fully mobile – made the telephone the