One of the first telegraphs was constructed by Georges Lesage in Geneva, in 1774, using a single wire for each of the letters of the alphabet.
"C.M." - aka Charles Marshall, of Aberdeen, or Charles Morrison, of Greenock
"…The first suggestion of an electric telegraph on record is that published by one "C.M." in the Scots Magazine for February 17, 1753. The device consisted in running a number of insulated wires between two places, one for each letter of the alphabet. The wires were to be charged with electricity from a machine one at a time, according to the letter it represented. At its far end the charged wire was to attract a disc of paper marked with the corresponding letter, and so the message would be spelt. "C.M." also suggested the first acoustic telegraph, for he proposed to have a set of bells instead of the letters, each of a different tone, and to be struck by the spark from its charged wire. …George Louis Lesage, in 1782, proposed a plan similar to "C.M.'s," using underground wires. ..." (from Chapter 1 of Heroes of the Telegraph, by J. Munro)
Don Francisco Salva Campillo (1751-1828), of Barcelona (biography)"...The idea of the electrical telegraph tickled many a great mind on its way to realization. Among them was the Catalan scientist Don Francisco Salvá i Campillo. Though something of a sideline for this polymath, his proposals were significant in a number of ways. They are of particular interest because, spanning as they do from the era of the revolution to the defeat of Napoleon, they reflect, in the spirit of their mechanisms, the transitions of social franchise during this period. Salvá's first proposal is similar to the one described in Scot's Magazine. It uses a separate wire for each letter of the alphabet, a Leyden jar to transmit a spark across these wires, but peculiarly, instead of the pith ball electroscopes and indicators, Salvá specifies a number of people, one for each wire. Upon receiving a sensible shock, each of these people, presumably servants, was to call out the name of the letter of the alphabet to which he corresponded. A twenty seventh person, presumably literate, was to write down the message so shockingly spelled out. This is probably the system that Salvá operated between Madrid and Aranjuez in 1798. Whether Salvá's abandonment of pith-ball electroscopes in favor of human receivers was due to problems with electrical dissipation in the moister climate of Barcelona, a cheaper labor pool, or the relative ease of transcription of 26 vocal sources into a coherent message are questions that only further researches into his work might reveal. Nonetheless, the scene of a hall filled with the sighs, whispers and moans of humanity being shocked into literacy seems an appropriate and emblematic image for the events of 1789. ..." (from The Messenger, Paul DeMarinis, 1998)