Optical telegraph codes
Prior to the electrical telegraph, a widely used method of building national telegraph networks was the optical telegraph consisting of a chain of towers from which signals could be … See more

In 1931, the International Code of Signals, originally created for ship communication by signalling using flags, was expanded by adding a collection of five-letter codes to be used by … See more

• Commercial code (communications)
• Great Western Railway telegraphic codes See more

• Beauchamp, Ken, History of Telegraphy, IET, 2001 ISBN 0852967926.
• Bouchet, Olivier, Wireless Optical Communications, … See more

Baudot code
Early printing telegraphs continued to use Morse code, but the operator no longer sent the dots and dashes directly with a single key. Instead … See more

The teleprinter was invented in 1915. This is a printing telegraph with a typewriter-like keyboard on which the operator types the message. Nevertheless, telegrams continued to be sent in upper case only because there was not room for a lower case character set … See more

Comparison of flag codes
Table 1 notes
1. ^ Left and right are the message sender's left and right. The neutral position is with the flag … See more