Acoustic telegraphy

Acoustic telegraphy was also known as harmonic telegraphy. During the 1800s inventors tried to find ways of sending multiple telegraph messages simultaneously over a single telegraph wire by using different audio frequencies for each message. These inventors included Charles Bourseul, Thomas Edison, Elisha Gray, and Alexander Graham Bell. Their efforts to develop acoustic telegraphy to reduce the cost of telegraph wires led to the telephone.^[1] Acoustic telegraphy was similar in concept to FDMA, Frequency Division Multiple Access, used with radio frequencies.

See also

• Telegraph
• Invention of the telephone

References

• US patent 166,095 -- Electrical Telegraph for Transmitting Musical Tones -- Elisha Gray, July 27, 1875
• US patent 182,996 -- Acoustic Telegraph -- Thomas Edison, October 10, 1876
• The Victorian Internet, Tom Standage, Berkley Books, New York (Penguin), 1998, ISBN 0-425-17169-8
• The Great Telephone Mystery by Devid Robertson
• Telephone Patents by Brooke Clarke

1. ^ Standage, pages 195-199