On 25 September 1956, the first transatlantic telephone cable was launched signing the beginning of the modern era of global communications. The purpose was to connect the United Kingdom to Canada and the United States, with some lines leased to European countries too.

To begin with there were 30 telephone circuits linked to the United States and 6 linked to Canada. They were mainly destined to communicate with the United Kingdom with just a few reaching Europe via direct access with London.

The project was completed in 3 years, costing about £12.5 million (equivalent of £255 million today – see “source”:http://www.thisismoney.co.uk/money/bills/article-1633409/Historic-inflation-calculator-value-money-changed-1900.html). It was developed through the creation, manufacture and installation of the system, with evolutions in technology to allow deep underwater cables.

In 1927 the first commercial radiotelephone service was introduced between United Kingdom and United States. At the beginning the number of calls made was around 2,000 per year, but the price was quite high. For instance, a 3 minutes call to New York had a cost of £9 – the equivalent of £480.00 today.

The switching point was due to an improvement in the equipment with the introduction of coaxial cables insulated with polyethylene, the improvement of carrier frequency equipment and the diffusion of broadband submerged repeaters just before the World War Two.

The cable ship Monarch, belonging to the Post Office, laid the entire transatlantic telephone cable. At the time, it was the only ship capable of carrying 1,500 nautical miles of cable which required to be laid in one piece between Clarenville in Newfoundland and Oban in Scotland, across the deepest part of the Atlantic. In its first year of service, the new system TAT1 succeeded in carrying the double of the calls that the radio circuits had done in a year. The numbers of calls were about 220,000 between Britain and United States, and about 75,000 between Britain and Canada, generating revenues of £2 million £45 million in todays value) to be shared between the three involved countries .

The introduction of the first transatlantic telephone cable in 1956 was regarded as a major technological achievement and recognised as an important base for future improvements and research. It was the breakthrough that opened the path for future innovations such as digital fibre optic transatlantic cables, which allow the transmission of tens of thousands of calls simultaneously.

Written by: Pietro Paolo Frigenti