The real dates
The first transatlantic telephone cable was not completed in 1967. It was TAT-1, which entered public service on 25 September 1956, linking Oban in Scotland with Clarenville in Newfoundland. The Atlantic had already been crossed by telegraph cables, first briefly in 1858 and then lastingly in 1866. By 1967, more than a decade after TAT-1, the Atlantic had several telephone cables, and satellites were beginning to share the traffic.
Telegraph first, 1858 and 1866
The idea of a cable across the Atlantic was pursued through the 1850s, driven in large part by the American businessman Cyrus Field. In August 1858 a cable laid between Ireland and Newfoundland carried messages, including an exchange of greetings between Queen Victoria and President James Buchanan. It failed after a few weeks, because the insulation and the way it was operated were not up to the job.
Laying a better cable was delayed by the American Civil War. A new attempt in 1865 broke during laying, but in 1866 the steamship Great Eastern, then the largest ship afloat, laid a new cable and also recovered and completed the one lost the year before. From 1866 there was a lasting telegraph link between Europe and North America. These cables carried telegraph signals, which could be sent as dots and dashes. They could not carry a voice.
Voice by radio before voice by cable
Telephone conversation across the Atlantic became possible in January 1927, when a radiotelephone service opened between London and New York. It used long-wave and later short-wave radio, which was expensive, of variable quality and affected by atmospheric conditions. Calls were short and few.
A cable that could carry speech reliably was an obvious goal, but there was a technical barrier. A voice signal fades as it travels along a wire, and over thousands of kilometres of seabed it would fade to nothing. The answer was the repeater, an amplifier built into the cable at intervals, which had to work underwater for many years without maintenance.
TAT-1 in 1956
TAT-1 stands for Trans-Atlantic Telephone number one. It was a joint project of the American telephone company AT&T, the British Post Office and the Canadian Overseas Telecommunication Corporation. The cable was in fact two cables, one for each direction of conversation, laid on the seabed between Scotland and Newfoundland. Both were coaxial designs, with a central conductor surrounded by an outer conductor, and both contained electronic repeaters spaced along their length. The repeaters used vacuum tubes, chosen for their reliability, since the transistor was still new.
Calls were then relayed overland and by radio links to connect to wider networks in Canada and the United States. At opening, TAT-1 provided 36 telephone circuits, a small number by later standards but a large gain over the radio service. The service ran for more than two decades and was withdrawn in the late 1970s, long after newer cables had been installed.
From TAT-1 to 1967
More cables followed, with greater capacity as technology improved. TAT-2 and later cables increased the number of circuits, and by the 1960s several systems were in use. Between 1965 and 1967 the Early Bird satellite and then its successors began to carry some of the same traffic, and the two technologies were seen as complementary: cables were cheaper and gave a clearer line with less delay, while satellites could carry television, which cables could not.
The question of which was better for a particular route occupied telephone engineers well into the 1980s. In the end optical fibre changed the picture. The first transatlantic fibre-optic cable, TAT-8, went into service in 1988 and had vastly more capacity than any copper cable.
The delay problem
One reason cables kept their place is a technical one. A telephone call that goes up to a geostationary satellite and back down has to travel around 70,000 kilometres, which produces a noticeable delay between speaking and hearing a reply. Early satellite telephone users often remarked on it. A cable under the sea has no such lag, which is partly why many callers preferred it. That difference showed that the Telstar satellite era and the satellite systems that followed were not simple replacements for cables.
Why the 1967 date is wrong
The title asks about a “first” in 1967. As far as the accurate record goes, none of the main milestones belongs to that year:
- 1858: first, short-lived transatlantic telegraph cable.
- 1866: first lasting transatlantic telegraph cable.
- 1927: first transatlantic radiotelephone service.
- 1956: TAT-1, the first transatlantic telephone cable.
Readers who see 1967 attached to this story are probably thinking of the satellite expansion of that period, or of later cables. TAT-1 itself was a mid-1950s achievement.