Samuel Finley Breese Morse (1791-1872), perhaps best known as the inventor of the first practical telegraph instrument, began his career as an artist and enjoyed a secure reputation as a portrait painter. By 1837, however, Morse decided to devote all his time to the development of electromagnetic telegraphy. During the course of a visit in 1838-39 to Europe to secure patents, he developed an application of his telegraph for railway signaling that was designed to report automatically the presence of a train anywhere on the railway line. 

An electrical telegraph was a point-to-point text messaging system, used from the 1840s until the mid 20th century when it was slowly replaced by other telecommunication systems. At the sending station switches connected a source of current to the telegraph wires. At the receiving station the current activated electromagnets which moved indicators, providing either a visual or audible indication of the text. It was the first electrical telecommunications system and the most widely used of a number of early messaging systems called telegraphs, that were devised to communicate text messages more rapidly than by physical transportation. Prior to the electric telegraph, semaphore systems were used, including beacons, smoke signals, flag semaphore, and optical telegraphs for visual signals to communicate over distances of land.

Electrical telegraphy can be considered to be the first example of electrical engineering, and was used by the emerging railway companies to develop train control systems that minimized the chances of trains colliding with each other. This was built around the signaling block system with signal boxes along the line communicating with their neighboring boxes by telegraphic sounding of single-stroke bells and three-position needle telegraph instruments.

Text telegraphy consisted of two or more geographically separated stations (often called telegraph offices) connected by wires, usually supported overhead on utility poles (originally called telegraph poles). There were many different electrical telegraph systems invented, but the ones that became widespread fit into two broad categories.