Inventions & Discoveries20 Concepts & Facts

First Transatlantic Telephone Call: Radio Waves and Subsea Cables

The establishment of transatlantic voice telecommunications represented an extraordinary engineering achievement that surmounted immense physical and atmospheric barriers. Prior to voice transmission, international electronic communication across the Atlantic Ocean was restricted to Morse code telegraphy, pioneered by Cyrus Field and operationalized through undersea copper cables in 1866. While electric telegraph impulses could convey simple on-and-off electrical signals across three thousand miles of ocean floor, human speech required continuous analog signal fidelity that existing underwater cables could not sustain due to electrical capacitance and rapid signal distortion. The earliest experimental one-way voice transmission occurred in October 1915, when Bell System engineers transmitted speech from the United States Navy station in Arlington, Virginia, across the Atlantic to receiving antennas mounted on the Eiffel Tower in Paris.

The formal commencement of commercial two-way transatlantic telephone service occurred on January 7, 1927, linking the American Telephone and Telegraph Company in New York City with the British General Post Office in London. Walter S. Gifford, president of AT&T, initiated the inaugural call to Sir Evelyn Murray, Secretary of the General Post Office, inaugurating public transatlantic telephony. Because physical underwater cables could not yet support voice amplification, this early service operated entirely via high-power long-wave radio frequencies around sixty kilohertz. Signals originating in New York travelled through landlines to a massive fifty-kilowatt radio transmitter at Rocky Point, Long Island, beamed across the North Atlantic, and were collected at a receiving antenna array in Cupar, Scotland, before routing to London. The reciprocal British transmission departed from Rugby Radio Station in Warwickshire and was received in Houlton, Maine.

Although the 1927 radio-telephone link proved technologically successful, its operational reliability remained constrained by atmospheric weather disruptions, auroral interference, and high commercial fees of seventy-five dollars for a three-minute conversation. The true physical breakthrough in underwater telecommunications arrived nearly three decades later with the activation of TAT-1, the first transatlantic telephone cable system. Jointly deployed between 1955 and 1956 by AT&T, the British General Post Office, and the Canadian Overseas Telecommunications Corporation, TAT-1 linked Gallanach Bay near Oban, Scotland, with Clarenville, Newfoundland. TAT-1 utilized dual twin-coaxial underwater cables equipped with fifty-one flexible submerged vacuum-tube repeaters engineered by Bell Telephone Laboratories to endure deep-sea pressures. Officially commissioned on September 25, 1956, TAT-1 provided thirty-six clear, simultaneous telephone circuits, displacing unreliable radio links and establishing the modern era of submarine telecommunications.

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The transatlantic telephone service was inaugurated under a bilateral agreement between AT&T and the British General Post Office.

Commercial radio-telephony between the United States and the United Kingdom was regulated under international radio spectrum treaties.

The construction and deployment of TAT-1 in 1956 was executed through a trilateral partnership among AT&T, the British Post Office, and Canada.

The International Telecommunication Union allocated dedicated maritime radio frequencies to prevent civilian radio interference.

Bell System engineers accomplished the first one-way transatlantic voice transmission from Arlington to Paris in October 1915.

The first commercial two-way transatlantic telephone call took place on January 7, 1927, between New York and London.

The inaugural conversation was conducted between AT&T President Walter S. Gifford and British Post Office Secretary Sir Evelyn Murray.

TAT-1, the first physical submarine transatlantic telephone cable, was officially commissioned on September 25, 1956.

The 1927 voice link used single-sideband suppressed-carrier modulation transmitted on a long-wave frequency of sixty kilohertz.

#10

American signals were transmitted from Rocky Point on Long Island and received at Cupar in Scotland before landline distribution.

#11

Return voice signals from Britain were broadcast from Rugby Radio Station in Warwickshire and received in Houlton, Maine.

#12

TAT-1 utilized fifty-one flexible submerged repeaters housed inside specialized pressure-resistant steel casings.

#13

The inaugural commercial telephone rate in 1927 was set at seventy-five dollars for a three-minute call, equivalent to over one thousand dollars today.

#14

During its opening day of commercial operations in 1927, the transatlantic radio service handled thirty-one calls.

#15

The TAT-1 submarine cable spanned approximately one thousand nine hundred and fifty nautical miles across the North Atlantic.

#16

TAT-1 initially supported thirty-six simultaneous four-kilohertz voice channels, which was later expanded to forty-eight channels.

#17

Undersea telegraph cables operated as early as 1858 and 1866, but could not transmit human speech due to severe capacitance distortion.

#18

Atmospheric static, magnetic storms, and sunspot cycles frequently interrupted the 1927 radio link, necessitating a physical subsea cable.

#19

TAT-1 required two separate cables laid across the ocean floor because early subsea repeaters operated only in one direction.

#20

The Moscow-Washington hotline, established after the Cuban Missile Crisis, initially routed emergency teletype communications through the TAT-1 cable system.

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Educator's Insight

Connecting continents by telephone took far longer than doing so by telegraph. Morse code clicks could travel through early subsea copper cables in the nineteenth century, but delicate human voice waves quickly became muffled and unreadable over long distances. Engineers solved this in 1927 using high-powered transatlantic radio signals, before finally building durable underwater amplifiers in 1956 to create clear, ocean-floor telephone lines.

Examiners frequently design trick questions that conflate three distinct transatlantic milestones: Cyrus Field's 1858 subsea telegraph cable, the 1927 commercial radio-telephone call, and the 1956 TAT-1 submarine telephone cable. Do not describe the 1927 call as a cable transmission; it relied entirely on radio waves between New York and London. Remember the mnemonic WIRE: Waves carry radio in 1927, Inaugural call between Gifford and Murray, Repeaters enable TAT-1, and Electrical telegraph preceded telephony in 1858.

First Transatlantic Telephone Call: Radio Waves and Subsea Cables

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