Telegraphy

Instead of exchanging a tangible item containing the message, telegraphing is a method of sending communications across large distances that relies on the sender using symbols that the receiver understands. Pigeon post, on the other hand, is not a kind of telegraphy. Despite the fact that ancient signalling systems, such as those in China, were capable of delivering arbitrary text messages, they were typically incapable of doing so. These technologies are not real telegraphs since the possible messages were preset and fixed.

Claude Chappe's optical telegraph was the first real telegraph to be widely used in the late 18th century. During the Napoleonic period, the system was widely implemented across France and the European states under French control. In the mid-19th century, the electric telegraph began to displace the optical telegraph. The Cooke and Wheatstone telegraph was the first to be used in the United Kingdom, and was first used primarily for railway signalling. It wasn't long until Samuel Morse devised a new method in the US. A slower pace of progress for electric telegraphs in France was owing to the country's long-standing usage of optical transmissions, but an electrical transmission that was code compatible with the Chappe system was eventually put into service. When the worldwide standard was established in 1865, a modified Morse code produced by Germany in 1848 was used.

Using reflected sunlight as a signalling medium, the heliograph was an early kind of telegraph. Aside from locations where the electrical telegraph had not yet been developed, this kind of telegraphy was often utilised. During the Apache Wars, a massive heliograph network was built throughout Arizona and New Mexico. As recently as World War II, the heliograph was a regular piece of military equipment. For maritime application, the early 20th century's wireless telegraphy emerged, and it competed with electrical telegraphy utilising underwater telegraph cables for worldwide communications.

Once the cost of sending a telegram had decreased, it became a common method of communication. Teleprinters and punched tape transmission were developed as a result of an increase in traffic. The Baudot code was the first of several new telegraph codes developed as a result of these systems. Even though they could not compete on price with the letter post, they were eventually pushed out of business by telephone competition that obliterated their speed advantage. Towards the end of the twentieth century, internet alternatives mainly replaced the few remaining telegraph uses.