Telegraphy

Telegraphy is the long-distance transmission of messages using symbolic codes. Unlike a pigeon post, where a physical object carries a message, telegraphy relies on a sender and recipient sharing a known code. This allows information to travel without the physical movement of a paper note.

While ancient signaling systems like beacon fires existed, they were often limited. Many could only send predetermined, fixed messages rather than arbitrary text. A true telegraph must be able to transmit any message a person chooses over long distances.

Ancient civilizations developed sophisticated signaling methods to communicate. The Great Wall of China used signal towers to provide early warnings. By 400 BC, signals utilized beacon fires or drum beats. During the Han dynasty, signallers used flags and wood fires. They even used dark smoke made from wolf dung during the day.

These systems were complex but lacked the flexibility of modern telegraphy. They could indicate enemy strength with colored flags, but they could not send unique sentences. Only a system like the Polybius square, which used torches to encode an alphabet, met the criteria for a true telegraph. However, there is no definite record of that system being used widely.

The first successful widespread telegraph was the optical telegraph. Invented by Claude Chappe in the late 18th century, it was used extensively in France.

This system consisted of a line of stations located on towers or high points. These stations communicated using shutters or paddles, a method called semaphore. Operators used telescopes to observe the positions of the indicators from the next station.

In 1791, the Chappe brothers successfully sent a message between Brulon and Parce. The system was vital during the Napoleonic era for transmitting government orders quickly. However, it was limited by weather and daylight, often managing only two words per minute.

In the mid-19th century, the electric telegraph began to replace optical systems. This shift changed how quickly information moved across the world. In Britain, the Cooke and Wheatstone telegraph was used primarily for railway signaling.

In the United States, Samuel Morse developed a different system. Morse's system used a specific code to represent letters.

This Morse code, along with a version developed in Germany in 1848, became the international standard in 1865. The electric telegraph was much more reliable than the optical version because it did not depend on clear skies.

Different technologies emerged to serve specific needs during the telegraphic era. The heliograph used reflected sunlight to signal over long distances.

This was common in areas without electrical wires, such as during the Apache Wars in Arizona and New Mexico. Later, wireless telegraphy emerged in the early 20th century. This used radio waves to transmit messages and became essential for maritime use.

As communication grew, submarine telegraph cables were laid under the ocean. Messages sent through these undersea lines were called cablegrams.

This allowed for international communication across vast oceans.

As the volume of messages increased, automation was developed to handle the traffic. Systems like teleprinters and punched tape transmission were created to speed up the process.

These advancements led to new ways of encoding text, such as the Baudot code.

People often sent messages known as telegrams once prices became affordable. Other specialized messages included the Telex, which used a switched network of teleprinters.

There were even wirephotos, which were newspaper pictures sent via facsimile telegraphy.

Despite its importance, telegraphy eventually faced a period of decline. Starting around 1920, the telephone began to compete by removing the speed advantage of text-based codes. Telegrams also struggled to compete with the lower prices of the letter post.

By the end of the 20th century, most remaining telegraph applications were replaced by the Internet. While the physical machines have largely disappeared, the concept of converting information into transmitted codes remains the foundation of modern global communication.