Overland Telegraph 150 Years

Overview

On 22 August 1872, the Overland Telegraph line between Adelaide and Darwin was finally connected. It was the result of years of planning and many months of arduous construction through the arid centre of the continent and the wet, mosquito-infested terrain of the Top End. This huge logistical achievement of has been called the greatest engineering feat of 19th-century Australia. It dramatically transformed the speed and breadth of communications within the country and, within two months of opening, the rest of the world via an undersea cable from Darwin to Java (Indonesia).

Charles Todd, South Australia’s Superintendent of Telegraphs and Postmaster General was the visionary responsible for bringing the project to realisation, within a mere two years of the planting of the first pole.

The Overland Telegraph involved a single galvanised wire supported by 36,000 poles across 2,839 kilometres from Port Augusta in the south to Darwin in the north. Eleven manned repeater stations constructed along a virtually unexplored route received and sent messages in Morse Code, with banks of chemical batteries at each station providing the electrical power. Communication between the cities of the eastern seaboard, via Adelaide and Darwin, now took minutes rather than weeks.

Technical specifications