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This arrangement ensures that the dedicated plugs can all plug into an ordinary ("non-dedicated") socket, but that the various dedicated plug and socket combinations are not interchangeable (nor can a non-dedicated plug be inserted into a dedicated socket). Group B2 of the GOST 7396 standard describes BS 1363 plugs and sockets. The earth pin is too large to be inserted into the line or neutral sockets by mistake. They thought atmosphere current, connected with a return path using "Earth currents" would allow for wireless telegraphy as well as supply power for the telegraph, doing away with artificial batteries. In the United States, Thomas Edison, in the mid-1880s, patented an electromagnetic induction system he called "grasshopper telegraphy", which allowed telegraphic signals to jump the short distance between a running train and telegraph wires running parallel to the tracks. Also, the relatively short distances that a practical Preece system could span meant that it had few advantages over underwater telegraph cables.

Western Union gave up its patent battle with Alexander Graham Bell because it believed the telephone was not a threat to its telegraph business. This service kept Western Union in business long after the telegraph had ceased to be important. In fact, the electric telegraph was as important as the invention of printing in this respect. Several wireless electrical signaling schemes based on the (sometimes erroneous) idea that electric currents could be conducted long-range through water, ground, and air were investigated for telegraphy before practical radio systems became available. Up to 25 telex channels could share a single long-distance telephone channel by using voice frequency telegraphy multiplexing, making telex the least expensive method of reliable long-distance communication. 253 Ironically, the invention of the telephone grew out of the development of the harmonic telegraph, a device which was supposed to increase the efficiency of telegraph transmission and improve the profits of telegraph companies. The British government censored telegraph cable companies in an effort to root out espionage and restrict financial transactions with Central Powers nations. News from war correspondents kept the public of the nations involved in the war informed of the day-to-day events in a way that had not been possible in any previous war.

Railway use quickly led to private telegraph companies in the UK and the US offering a telegraph service to the public using telegraph along railway lines. In America, the end of the telegraph era can be associated with the fall of the Western Union Telegraph Company. These poles are owned by, and located on property owned by, a railroad company. A telegram service is a company or public entity that delivers telegraphed messages directly to the recipient. CATV cable for public cable TV network. Telex (telegraph exchange) was a public switched network of teleprinters. Historically, telegrams were sent between a network of interconnected telegraph offices. Where telegram services still exist, the transmission method between offices is no longer by telegraph, but by telex or IP link. As alternating current is used with high voltages, this method of electrification is only used on overhead lines, never on third rails for safety reasons. Preece first noticed the effect in 1884 when overhead telegraph wires in Grays Inn Road were accidentally carrying messages sent on buried cables. The electric telegraph freed communication from the time constraints of postal mail and revolutionized the global economy and society. Other attempts were made to send the electric current through bodies of water, to span rivers, for example.

For example, for Preece's station to span the English Channel from Dover, England, to the coast of France would require sending and receiving wires of about 30 miles (48 kilometres) along the two coasts. The length of those sending and receiving wires needed to be about the same length as the width of the water or land to be spanned. However, his induction system required extensive lengths of antenna wires, many kilometers long, at both the sending and receiving ends. During the Great Blizzard of 1888, this system was used to send and receive wireless messages from trains buried in snowdrifts. The average length of a telegram in the 1900s in the US was 11.93 words; more than half of the messages were 10 words or fewer. As telegrams have been traditionally charged by the word, messages were often abbreviated to pack information into the smallest possible number of words, in what came to be called "telegram style". 277 In the modern era, the telegraph that began in 1837 has been gradually replaced by digital data transmission based on computer information systems.

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