Precursors
Prior to the electric telegraph, visual systems were used, including beacons, smoke signals, flag semaphore, and optical telegraphs for … See more

Cooke and Wheatstone system
The first commercial electrical telegraph was the Cooke and Wheatstone system. A demonstration four … See more

The ability to send telegrams brought obvious advantages to those conducting war. Secret messages were encoded, so interception alone would not be sufficient for the opposing side to gain an advantage. There were also geographical constraints on … See more

• Beauchamp, Ken (2001). History of Telegraphy. London: The Institution of Electrical Engineers. ISBN 978-0-85296-792-8 See more

Main article § Section: History of longitude § Land surveying and telegraphy.
The telegraph was very important for sending time signals … See more

In America, the end of the telegraph era can be associated with the fall of the Western Union Telegraph Company. Western Union was … See more

• 92 Code
• Aurora#Historically significant events
• American Telephone and Telegraph Company (AT&T)
• Bell Canada
• Geomagnetically induced current See more