TAT-1
Encyclopedia
TAT-1 was the first submarine transatlantic telephone cable
system. It was laid between Gallanach Bay, near Oban, Scotland and Clarenville, Newfoundland between 1955 and 1956. It was inaugurated on September 25, 1956, initially carrying 36 telephone channels.
had been laid in 1858 (see Cyrus West Field
). It only operated for a month, but was replaced with a successful connection in 1866. A radio-based transatlantic telephone service was started in 1927, charging £9 (about $45 USD, or roughly $550 in 2010 dollars) for three minutes and handling around 2000 calls a year. Although a telephone cable was discussed at that time, it was not practical until a number of technological advances arrived in the 1940s.
The developments that made TAT-1 possible were coaxial cable
, polyethylene
insulation (replacing gutta percha), very reliable vacuum tube
s for the submerged repeater
s and a general improvement in carrier
equipment. Transistor
s were not used, being a recent invention of unknown longevity.
The agreement to make the connection was announced by the Postmaster General on December 1, 1953. The project was a joint one between the General Post Office
of the (UK
), the American Telephone and Telegraph
company, and the Canadian Overseas Telecommunications Corporation
. The share split in the scheme was 40% British, 50% American, and 10% Canadian. The total cost was about £120 million.
There were to be two main cables, one for each direction of transmission. Each cable was produced and laid in three sections, two shallow-water armored sections, and one continuous central section 1500 nautical miles (2,778 km) long. The electronic repeaters were designed by the Bell Telephone Laboratories of the United States
and they were flexible and were inserted into the cable at 37 nautical miles (68.5 km) intervals - a total of 51 repeaters in the central section. The armored cables were manufactured in southeast London
at a factory in Erith
, Kent
, owned by Submarine Cables Ltd. (owned jointly by Siemens Brothers & Company, Ltd, and The Telegraph Construction & Maintenance Company, Ltd).
The cables were laid over the summers of 1955 and 1956, with the majority of the work done by Her Majesty's Telegraph Ship (cable ship) Monarch. At the land-end in Gallanach Bay near Oban
, Scotland, the cable joined to a coaxial line carrying 900 inland and transatlantic circuits to the International Exchange in London
. At the cable landing point
in Newfoundland the cable joined at Clarenville
, then crossed the 300 miles (482.8 km) Cabot Strait
by another submarine cable to Nova Scotia
. From there the communications traffic was routed to the US border by a microwave radio relay link, and in Brunswick, Maine
the route joined the main US network and branched to Montreal
to connect with the Canadian network.
Opened on September 25, 1956, TAT-1 carried 588 London-US calls and 119 London-Canada calls in the first 24 hours of public service. The capacity of the cable was soon increased to 48 channels.
The original 36 channels were 4 kHz. The increase to 48 channels was accomplished by narrowing the bandwidth
to 3 kHz. Later, an additional 3 channels were added by use of C Carrier equipment. Time-assignment speech interpolation
brought a further increase in the late 1960s.
TAT-1 carried the Moscow-Washington hotline
between the American and Soviet heads of state.
After the success of TAT-1, a number of other TAT cables were laid and TAT-1 was retired in 1978.
The TAT-1 was named an IEEE Milestone in 2006.
Transatlantic telephone cable
A transatlantic telecommunications cable is a submarine communications cable running under the Atlantic Ocean. All modern cables use fibre optic technology....
system. It was laid between Gallanach Bay, near Oban, Scotland and Clarenville, Newfoundland between 1955 and 1956. It was inaugurated on September 25, 1956, initially carrying 36 telephone channels.
History
The first transatlantic telegraph cableTransatlantic telegraph cable
The transatlantic telegraph cable was the first cable used for telegraph communications laid across the floor of the Atlantic Ocean. It crossed from , Foilhommerum Bay, Valentia Island, in western Ireland to Heart's Content in eastern Newfoundland. The transatlantic cable connected North America...
had been laid in 1858 (see Cyrus West Field
Cyrus West Field
Cyrus West Field was an American businessman and financier who, along with other entrepreneurs, created the Atlantic Telegraph Company and laid the first telegraph cable across the Atlantic Ocean in 1858.-Life and career:...
). It only operated for a month, but was replaced with a successful connection in 1866. A radio-based transatlantic telephone service was started in 1927, charging £9 (about $45 USD, or roughly $550 in 2010 dollars) for three minutes and handling around 2000 calls a year. Although a telephone cable was discussed at that time, it was not practical until a number of technological advances arrived in the 1940s.
The developments that made TAT-1 possible were coaxial cable
Coaxial cable
Coaxial cable, or coax, has an inner conductor surrounded by a flexible, tubular insulating layer, surrounded by a tubular conducting shield. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis...
, polyethylene
Polyethylene
Polyethylene or polythene is the most widely used plastic, with an annual production of approximately 80 million metric tons...
insulation (replacing gutta percha), very reliable vacuum tube
Vacuum tube
In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
s for the submerged repeater
Repeater
A repeater is an electronic device that receives asignal and retransmits it at a higher level and/or higher power, or onto the other side of an obstruction, so that the signal can cover longer distances.-Description:...
s and a general improvement in carrier
Carrier wave
In telecommunications, a carrier wave or carrier is a waveform that is modulated with an input signal for the purpose of conveying information. This carrier wave is usually a much higher frequency than the input signal...
equipment. Transistor
Transistor
A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...
s were not used, being a recent invention of unknown longevity.
The agreement to make the connection was announced by the Postmaster General on December 1, 1953. The project was a joint one between the General Post Office
General Post Office
General Post Office is the name of the British postal system from 1660 until 1969.General Post Office may also refer to:* General Post Office, Perth* General Post Office, Sydney* General Post Office, Melbourne* General Post Office, Brisbane...
of the (UK
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
), the American Telephone and Telegraph
AT&T
AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...
company, and the Canadian Overseas Telecommunications Corporation
VSNL International Canada
VSNL International Canada is an international telco carrier. The company is a subsidiary of Tata Communications, part of India's Tata Group. Part of their recent work has involved the updating of the CANTAT transatlantic cable system that connects the United Kingdom and Newfoundland under the...
. The share split in the scheme was 40% British, 50% American, and 10% Canadian. The total cost was about £120 million.
There were to be two main cables, one for each direction of transmission. Each cable was produced and laid in three sections, two shallow-water armored sections, and one continuous central section 1500 nautical miles (2,778 km) long. The electronic repeaters were designed by the Bell Telephone Laboratories of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and they were flexible and were inserted into the cable at 37 nautical miles (68.5 km) intervals - a total of 51 repeaters in the central section. The armored cables were manufactured in southeast London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
at a factory in Erith
Erith
Erith is a district of southeast London on the River Thames. Erith's town centre has undergone a series of modernisations since 1961.-Pre-medieval:...
, Kent
Kent
Kent is a county in southeast England, and is one of the home counties. It borders East Sussex, Surrey and Greater London and has a defined boundary with Essex in the middle of the Thames Estuary. The ceremonial county boundaries of Kent include the shire county of Kent and the unitary borough of...
, owned by Submarine Cables Ltd. (owned jointly by Siemens Brothers & Company, Ltd, and The Telegraph Construction & Maintenance Company, Ltd).
The cables were laid over the summers of 1955 and 1956, with the majority of the work done by Her Majesty's Telegraph Ship (cable ship) Monarch. At the land-end in Gallanach Bay near Oban
Oban
Oban Oban Oban ( is a resort town within the Argyll and Bute council area of Scotland. It has a total resident population of 8,120. Despite its small size, it is the largest town between Helensburgh and Fort William and during the tourist season the town can be crowded by up to 25,000 people. Oban...
, Scotland, the cable joined to a coaxial line carrying 900 inland and transatlantic circuits to the International Exchange in London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
. At the cable landing point
Cable landing point
A cable landing point is the location where a submarine or other underwater cable makes landfall. The term is most often used for the landfall points of submarine telecommunications cables and submarine power cables. The landing will either be direct or via a branch from a main cable using a...
in Newfoundland the cable joined at Clarenville
Clarenville, Newfoundland and Labrador
Clarenville is a Canadian town on the east coast of Newfoundland in the province of Newfoundland and Labrador. Clarenville was incorporated in 1951 and is located in the Shoal Harbour valley fronting an arm of the Atlantic Ocean called Random Sound....
, then crossed the 300 miles (482.8 km) Cabot Strait
Cabot Strait
Cabot Strait is a strait in eastern Canada approximately 110 kilometres wide between Cape Ray, Newfoundland and Cape North, Cape Breton Island. It is the widest of the three outlets for the Gulf of Saint Lawrence into the Atlantic Ocean, the others being the Strait of Belle Isle and Strait of Canso...
by another submarine cable to Nova Scotia
Nova Scotia
Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...
. From there the communications traffic was routed to the US border by a microwave radio relay link, and in Brunswick, Maine
Brunswick, Maine
Brunswick is a town in Cumberland County, Maine, United States. The population was 20,278 at the 2010 census. It is part of the Portland-South Portland-Biddeford metropolitan area. Brunswick is home to Bowdoin College, the Bowdoin College Museum of Art, the Peary-MacMillan Arctic Museum, , and the...
the route joined the main US network and branched to Montreal
Montreal
Montreal is a city in Canada. It is the largest city in the province of Quebec, the second-largest city in Canada and the seventh largest in North America...
to connect with the Canadian network.
Opened on September 25, 1956, TAT-1 carried 588 London-US calls and 119 London-Canada calls in the first 24 hours of public service. The capacity of the cable was soon increased to 48 channels.
The original 36 channels were 4 kHz. The increase to 48 channels was accomplished by narrowing the bandwidth
Voiceband
In electronics, voiceband means the typical human hearing frequency range that is from 20 Hz to 20 kHz. In telephony, it means the frequency range normally transmitted by a telephone line, generally about 200–3600 Hz. Frequency-division multiplexing in telephony normally uses...
to 3 kHz. Later, an additional 3 channels were added by use of C Carrier equipment. Time-assignment speech interpolation
Time-assignment speech interpolation
In telecommunication, a time-assignment speech interpolation was an analog technique used on certain long transmission links to increase voice-transmission capacity....
brought a further increase in the late 1960s.
TAT-1 carried the Moscow-Washington hotline
Moscow-Washington hotline
The Moscow-Washington hotline is a system that allows direct communication between the leaders of the United States and Russia. It was originally designed by Harris Corporation for communication between the United States and the Soviet Union...
between the American and Soviet heads of state.
After the success of TAT-1, a number of other TAT cables were laid and TAT-1 was retired in 1978.
The TAT-1 was named an IEEE Milestone in 2006.
External links
- Reminiscences of TAT-1 by Jeremiah Hayes (in .pdf format)
- 50th Anniversary of laying TAT-1 BBC News
- 50th Anniversary of laying TAT-1 Scotsman
- http://gadgets.boingboing.net/2009/04/17/gallery-an-illustrat.html