History of Communication Flashcards
Cavemen
a. Gathers around fire to discuss day to day activities.
b. Started inscribing on caves to record their activities or knowledge. The problem with this communication is it was localized.
Smoke Signal
First long distance communication
Smoke Signal : Northern America
a. Used in Northern America where each tribe has its own signaling system.
b. A smoke from the top of the hill signified danger.
Smoke Signal : Ancient China
Used in Ancient China in the Great Wall of China, transmitting messages as far as 750km within a few hours.
Smoke Signal : Vatican City
Still used in the Vatican to indicate the selection of a new Pope.
Pigeons
a. Extensively used for long distance communication because of their natural homing ability.
b. Used by Persians, Romans, Greeks, and Mughals.
Pigeons : 19th Century
Also used to transmit stock quotations from one city to another.
Pigeons : Cher Ami
Awarded the French War Cross for her services during World War 1.
October 4, 1918
Cher Ami was shot through the breast and leg by enemy fire but still managed to return to his loft with a message capsule dangling from the wounded leg. The message Cher Ami carried was from Major Charles S. Whittlesey’s “Lost Battalion” of the Seventy-seventy Infantry Division that had been isolated from other American forces. The message saved 194 soldiers.
Pony Express : Ancient Times
Kings have been using human messengers to relay messages.
Pony Express
a. First of its kind mail service delivering messages, mails, newspapers, and small packages by horseback using small relay stations.
b. Regarded as the first courier service.
Pony Express : Mid 19th Century
Used in the mid 19th century to communicate between the East Coast and West Coast of America.
Semaphore Flag
a. Derived from the Greek word ‘sema’ means sign and ‘phero’ meaning bearer.
b. The telegraphy system that is conveying information at a distance by means of visual signals with hand held flags, rods, and disk.
c. Still used during underway replenishment at sea and is an acceptable mode of communication for emergencies.
Semaphore Flag : Late 19th Century
Used in maritime during the late 19th century.
Telegraphy
The greatest breakthrough in the field of communication.
Telegraph
a. Harnessing of electricity in the late 19th century gave birth to electric telegraphy.
Morse code is still used globally as a mode of communication.
b. Most popular form of long distance communication.
2006
US discontinued the use of telegraph.
2013
India’s BSNL owned telegraph service ended and the world’s last existing true electric commercial telegraph system.
Radio
A Latin word meaning ‘beam of light’
1864
James Clerk Maxwell showed mathematically that electric waves could propagate through free space.
1886
Heinrich Hertz established the existence of electromagnetic waves.
1888
Hertz demonstrated that one could produce and detect electromagnetic waves which we today call as radio waves.
November 1894
Jagadish Chandra Bose at Town Hall of Kolkata ignited gunpowder and rang a bell kept at a distance using microwave.
1894
Italian scientist Gugliermo Marconi made an electric bell which went off during lightning.
Early 20th Century
Radio system transmitted message using continuous waves only.
Amplitude Modulation
Demonstrated for the transmission of voice and music but with little success.
World War 1
a Accelerated the development of radio for military communication.
b. After the war commercial radio broadcasting began in 1920 and was a big hit.
World War 2
Accelerated the development of radio for military, aircraft, and land communication.
Telephone
a. Confined to diplomatic purposes of broadcasting.
Telephone : Telegram
Telegram was the fastest one to one communication used by common people.
1876
Alexander Graham Bell invented the telephone.
How Telephones used to Work
a. Leased in pairs to a subscriber, who had to arrange for a telegraph contractor to construct a line between them.
b. Only rich people could afford.
PSTN
Public Switch Telephone Network
