IT conveyed news from home of births, deaths and marriages to emigrants in America just 20 years after the Great Famine.
It also related news of the Easter Rising and other important events in Europe.
And now one man is hoping to recover the transatlantic telegraph cable 145 years after it was laid under the ocean from Valentia Island, in Co Kerry, to Heart's Content in Trinity Bay, Newfoundland.
For Joe C Keating, from Cahirsiveen, in Co Kerry, recovering the cable has been his life's dream and something he has dedicated over 50 years to. He has already recovered more than 120km of it in two separate salvage operations in the 1960s and 1980s.
Now 80, Mr Keating has been approached by Scottish salvage company Haliburton Salvage, which is part-owned by former US vice president Dick Cheney.
They want him on board as a consultant to help them recover the cable. Mr Keating is the only one with the experience, the charts, the know-how and the contacts to ensure the operation is successful.
Crucially, he secured permission from the Commercial Cable Company in London -- who holds the rights -- in the 1960s to salvage the cable, which is worth a fortune due to its copper, steel, brass and gutta percha (a valuable rubber) components.
"There was a lot of money in it in 1963 when I first started salvaging the cable but the price of commodities has gone through the roof now and there's millions of tonnes still under the sea," Mr Keating said.
Joe C Keating and Sons Ltd's first attempt to recover the cable hit disaster when his ship the 'Salvage Venture' was shipwrecked on Reenroe Beach in Ballinskelligs, Co Kerry, in November 1964.
By then he had salvaged about 1,000 tonnes.
In 1989, he bought a semi-submersible oil rig, the Petrolia, and used this to bring up another 2,000 tonnes. He insists the project is now feasible given advances in technology and underwater camera equipment.
His son, Joseph Jnr, worked with him on the Petrolia hauling cable on to the rig. He says the real hidden gem is the booster box that was fitted to the cable, which contains platinum.
"It really is like buried treasure and it would be a great bonus to find one of these boxes, but even the copper used in the cable was the finest copper. The key is finding an economic way of processing it," Joe Jnr said.
Despite his age, Mr Keating hasn't lost his appetite for salvage and is ready to go to sea again when the time comes -- which he hopes will be in about six months.