Terminology
A telegraph is a device for transmitting and receiving messages over long distances, i.e., for telegraphy. The word "telegraph" alone now generally refers to an electrical telegraph. Wireless telegraphy is also known as "CW", for continuous wave (a carrier modulated by on-off keying), as opposed to the earlier radio technique of using a spark gap.
Morse argued that the term telegraph can strictly be applied only to systems that transmit and record messages at a distance. This is to be distinguished from semaphore which merely transmits messages. Smoke signals, for instance, are to be considered semaphore, not telegraph. According to Morse, telegraph dates only from 1832 when the first electric telegraph was invented by Schilling.
A telegraph message sent by an electrical telegraph operator or telegrapher using Morse code (or a printing telegraph operator using plain text) was known as a telegram. A cablegram (see cablegram) was a message sent by a submarine telegraph cable, often shortened to a cable or a wire. Later, a Telex was a message sent by a Telex network, a switched network of teleprinters similar to a telephone network.
Before long distance telephone services were readily available or affordable, telegram services were very popular and the only way to convey information speedily over very long distances. Telegrams were often used to confirm business dealings and were commonly used to create binding legal documents for business dealings.
A wire picture or wire photo was a newspaper picture that was sent from a remote location by a facsimile telegraph. The teleostereograph machine, a forerunner to the modern electronic fax, was developed by AT&T's Bell Labs in the 1920s; however, the first commercial use of image facsimile telegraph devices dates back to the time of Samuel F. B. Morse's invention in the 1800s. Morse and his partner Alfred Vail also invented morse code).
A diplomatic telegram, also known as a diplomatic cable, is the term given to a confidential communication between a diplomatic mission and the foreign ministry of its parent country. These continue to be called telegrams or cables regardless of the method used for transmission.
Read more about this topic: Telegraphy