An electrical telegraph, or more commonly just telegraph, is a method of long-distance transmission of textual messages that uses electrical signals, usually conveyed via dedicated telecommunication circuit or radio.
The electrical telegraph superseded optical semaphore telegraph systems, thus becoming the first form of electrical telecommunications. In a matter of decades after their creation in the 1830s, electrical telegraph networks permitted people and commerce to transmit messages across both continents and oceans almost instantly, with widespread social and economic impacts.
The telephone, invented in 1876, gradually made the telegraph obsolete in everyday use by the early 20th century. However the older technology still retained usefulness for military and other specialized purposes.
The telegraph appears in numerous Harry Turtledove stories set in the 19th and 20th centuries. It is germane only to a few of them.
Telegraph in The Valley-Westside War
After the world failed to recover from nuclear war, the telegraph resumed its status as the most advanced communication technology. One notable telegraph line reached all the way between the nation-states of Vegas and Salt Lake City.
When the Valley troops first advanced down the Santa Monica Freeway in 2097, they were warned to be on the lookout for Westside scouts. Dan did so but wondered how they would be able to report back ahead of the Valley soldiers. He thought they might lay telegraph wire as they advanced and then clicked back the information from their hiding places.
Telegraph in "The Weather's Fine"
In the aftermath of an Old Front from Canada swept the upper Midwest in the 1980s and reverting the entire region to the turn of the century, communications broke down as modern telephones could not connect to telegraphs.
- Crystal ball, a communications device common in fantasy writing. In The War Between the Provinces and Darkness, the "crystal" is a loose analog of the telegraph.
- Semaphore, an Ancient Greek invention regarded as a precursor to the telegraph. In Lest Darkness Fall/"The Fake Pandemic," the terms semaphore and telegraph are used interchangeably.