Communications (Cromwell the Great)

The history of communications or more specifically telecommunications in the Modern World can be traced with the invention of the printing press, national postal services, semaphores and telegraphs. Of these the main developments were the semaphore and telegraphs.

Semaphores
An optical semaphore is a system of conveying information by means of visual signals, using towers with pivoting shutters, also known as blades or paddles. Information is encoded by the position of the mechanical elements; it is read when the shutter is in a fixed position.

All optical semaphore systems consists of lines of relay towers with a semaphore rig at the top were built within line-of-sight of each other, at separations of 5 to 20 miles. Operators at each tower would watch the neighboring tower through a spyglass, and when the semaphore arms began to move spelling out a message. They would pass the message on to the next tower. This system was much faster than post riders for conveying a message over long distances, and also had cheaper long-term operating costs, once constructed.

Semaphore lines were a precursor of the electrical telegraph, which would replace them, and would also be cheaper, faster, and more private. The line-of-sight distance between relay stations was limited by geography and weather, and prevented the optical telegraph from crossing wide expanses of water, unless a convenient island could be used for a relay station.

There are four major rival semaphore systems in service and one obsolete.
 * 1) Chappe's system (Sémaphore). Built in 1792 between Paris and Lille in France. Later it served the main french cities.
 * 2) Edelcrant's system s (Optisk telegraf) 1793. First line built was Copenhagen-Korsør. Later it covered the Danish straits, Stockholm-Goteborg,
 * 3) Murray's six-shutter system (1794-1807) was used until it was replaced by Popham's semaphore. First line built was London-Deal and later the English Coast.
 * 4) Betacourt's system (1795) First line built was Madrid-Cádiz, and later communicating Spain and Portugal.
 * 5) Popham's semaphore (1807) replaced Murray's system using the same previous lines.