GREENWICH – CENTRE FOR GLOBAL TELCOMMUNICATIONS SINCE 1850
By Steve Hill and Alan Jeal
The history of submarine cable is about to celebrate the 150th anniversary of the first international telegraph cable.
As a tribute to all those people who have been involved in the development, manufacture and deployment of submarine cable systems, this paper has been put together as a brief reminder of their dedication which has led to the global success story of cables. This success initially centred around Greenwich but, as will be seen, other locations, notably Woolwich and Erith, have all played major parts in the overall story.
The Greenwich site graduated from a rope factory in the early 1800s into communications in the late 1840s thanks to the development of the telegraph and the desire to communicate with other countries not connected by land. Today the Alcatel site is the location for one of the leading telecoms exporters in the UK.
Throughout the 19th and 20th centuries the site has continued to be home to world leaders in undersea communications. In recent years the site occupants have won the Queen’s Award to Industry six times; four times for Export and twice for Technological achievement. The site was reclaimed from marshland and Bendish Sluice runs through it. The sluice exits through a flap valve in the sea wall. About 10 years ago the valve stuck and with the rising tide of the river parts of the site, including the basement of Enderby House, were flooded. To this day the site has scavenger pumps continually running to keep it relatively dry.
This paper briefly traces the history of the site and the achievements of the dedicated engineers who have, and are still, playing a key role in the global communications revolution.
Greenwich and the Telegraph from 1840 to 1890
The Greenwich Peninsula was a major centre for industry. As far as the development of the cable industry is concerned, good transport via the river probably accounted for this. The area also had a lot of industrial coal tar available and it is interesting to note that a lot of this is used on the armour wires around the cable.
It is believed that Charles Enderby moved to the newly constructed Enderby House on the present site in about 1830. The house is preserved on the site to this day and is a listed building. From the octagonal room on the first floor the Enderbys possibly controlled their Antarctic whaling fleet.
At the same time the Enderbys began to set up a rope and sail-making factory on the undeveloped fields of East Greenwich. The map of 1835 clearly shows the ropewalk, a long narrow building through which a long length of rope could be taken in one stretch.
In 1837 the Enderby brothers were approached by the pioneer inventor of the telegraph, William Cooke for help in developing specially insulated ropes for use as telegraph cables. This was for the first experiments in which Cooke wanted to establish an electric telegraph across the Thames. As far as we can tell this was not developed further at that time.
The Enderby Hemp and Rope works was destroyed by fire in 1845 and never re-opened
William Kuper had been granted rights to develop the Morden Wharf site (just along the river from Enderby Wharf) and some of the early attempts at undersea cable manufacture were carried out here. These were probably based on hemp impregnated with tar for insulation.
Key to the future development of submarine cables was the availability of a new insulator, gutta percha. The Gutta Percha Company was set up in 1845. Dr William Montgomerie, who was on the staff of the Governor of Singapore, noted that the Malaysian natives were using a rubber-like substance that they obtained from a local tree and he wrote a long paper on the properties of the substance and its uses.
The gutta percha was sliced up and used to mould a whole range of items from ornaments to golf balls and buckets.
The new material could be moulded into shapes at high temperature and when cooled solidified. It was in fact an early type of plastic.
It was the pioneering physicist Michael Faraday who suggested the use of gutta percha as an electrical insulator. By 1849 two miles of gutta percha insulated undersea cable had been tested and schemes were proposed to provide a telegraph cable between the UK and France.
The Gutta Percha Company received an order for 25 nautical miles (nm) of cable for the first link to France. Some of the cable was delivered to the Kuper works for armouring. The cable was laid in 1850 but was a failure because of a then unknown effect called induction, which jumbled up the messages so that they could not be deciphered. The cable which, as far as we can tell, was made from copper wire covered by gutta percha had to be weighted to keep it submerged. These weights probably contributed to its premature insulation failure. The cable was abandoned and left to the mercy of fishermen who thought that they had hooked a new kind of seaweed stuffed with gold!
A second attempt in 1851 using armoured cable was more successful and cross-Channel communications were established. This cable had four cores for more than one message path. The cable landed at Sangatte where today there is the Channel Tunnel terminal!!
Glass and Elliot took over the Morden Wharf site about this time from the original owner William Kuper and their first commission was to make a cable for installation between Northern Italy and Corsica using gutta percha insulation. In 1854 they purchased the Enderby Wharf site from the Enderby family.
Initially, Enderby Wharf was shared with the WT Henley Telegraph Works Company. Henley was also in the submarine cable manufacturing business but the association of the two companies on the same site proved unworkable and Henley moved to North Woolwich where the company continued to make undersea telegraph cables, albeit in small quantities, until the end of the century.
With the success of the cables laid at this time it was inevitable that attention should focus on the possibility of laying a cable across the Atlantic. As we shall see with every new technology the measure of its success has been, “Can we use it across the Atlantic?”
Cyrus West Field, a retired businessman, persuaded the British and US governments to put money into the venture of a transatlantic cable and raised the rest from British merchants.
A total of 2500 nm of cable were required and half of this was made at Greenwich by Glass Elliot.
The HMS Agamemnon (lent by the UK government as its contribution to the project) laid the first cable across the Atlantic in 1857 but unfortunately it broke in mid-ocean. Grappling techniques to recover cable were not perfected at this time and so the cable was abandoned.
Work on a second cable started immediately and was completed in August 1858 after many setbacks. These included storms, that nearly destroyed the ship, and several cable insulation faults, which had to be repaired en route.
Messages could be sent at a rate of only a few words a minute because of the long length of cable which tended to smear the dots and dashes. This meant that long (relatively) intervals were required between the dots and dashes so that the operator could be sure that he had decoded the pulse correctly.
A few messages were sent in August 1858 including an exchange between Queen Victoria and the US President of the time, President Buchanan. A notable message cancelling a request to send two regiments from Canada to Kashmir India as the crisis was over, saved the British Government £50,000 – about 25 of the cable cost. The success of the cable was short-lived as, after only two months, the signal became so weak that it became unusable. It was not helped by the application of 3000V pulses from the induction coils developed by Wildeman Whitehouse one of the engineers working on the cable which further affected the insulation
Lord Kelvin (then William Thomson), was assigned the task of investigating the failure of the transatlantic cable. He proposed that more stringent testing was necessary and to that end large underwater tanks were constructed on the Enderby Wharf site so that the cables could be coiled and continuously electrically tested. These tanks provided more stable temperature conditions for storage of the completed cable lengths before loading onto the ship. By 1862 a new and improved cable design was available and proposals for a third attempt were put in hand.
About this time, 1864, Glass Elliot and the Gutta Percha Company merged to form the Telegraph Construction and Maintenance Company (Telcon) and offered to make the new transatlantic cable at Greenwich.
The finished cable was bigger and heavier than the previous attempts and a bigger ship would be required to lay it. Three types of cable were made for different depths of water. The solution for the cable-laying vessel was found with the Great Eastern, designed and built by Brunel. This ship had not been a success for general shipping but was ideally suited for cable- laying.
The cable was loaded from the factory into a small vessel and transferred to the Great Eastern at Sheerness.
Laying the cable began in July 1865 and 1186 nm were laid successfully but imagine the disappointment when 717 miles from Hearts Content in Newfoundland, the cable broke and all attempts at recovery were fruitless. Once again the cable was abandoned on the seabed.
Further plans were made, for a fourth attempt, using Glass Elliot cable made in Greenwich and on 27 July 1866 successful communication was established once again between Valentia in Ireland and Newfoundland.
The Great Eastern then went back to look for the broken ends of the cable from the previous attempt. On 2 September the telegraph instruments at the Valentia end of the cable began to move as the two ends of the cable were joined.
There were two cables now connecting the New World to Europe!!
The success of the Atlantic cable promoted a steady growth in the deployment of the undersea telegraph business and by 1874 a further three Atlantic cables were laid by the Great Eastern for Telcon.
A further five transatlantic telegraph cables were also made by Telcon before the end of the century. Cables linking the Commonwealth were rapidly installed and the RED ROUTE telegraph cable network, linking all the major commonwealth countries, was completed by 1902. Telcon played a major part in this achievement and can be classed as a truly global company at this time.
Sending and receiving techniques were improved and up to 50 words per minute could be achieved. From 1850 to the widespread introduction of telephone cables in the mid 20th century, Telcon in Greenwich was involved in the manufacture of some 130,000 nm of cable (enough to go 6 times round the earth).
To provide for installation and maintenance of these cables, the cable makers also purchased and maintained a fleet of cableships. From 1866 to 1935 Telcon owned and operated a total of 18 different laying vessels. One, the Colonia, laid more telegraph cable than any other ship in the fleet. In more recent times the Ocean Layer was notable because of a fire which destroyed the ship whilst she was laying a cable in 1959. The company’s last cableship, the John W Mackay, was moored at Greenwich until 1988. Te vessel laid its last cable in 1975 between Australia and Papua New Guinea before being retired as unseaworthy after 55 years of sterling work. The vessel (now owned by STC – more later) was sold for the princely sum of £1 to The John W Mackay Trust in 1989.
The plan was to preserve the vessel as a working example of British technology. As a matter of interest, prior to selling the vessel to the Trust, consideration had been given to selling the ship as scrap for medical instruments. The reason for this was that the ship had been built before any nuclear explosions had taken place and therefore the metal was considered ‘pure’ and free of radioactivity. Unfortunately, the John W Mackay Trust did not prosper and the last we heard of the vessel was when she lost her tow in the Bay of Biscay en route to Turkey. She is believed to have sunk so perhaps she was unseaworthy!
Loading of the cable onto the laying vessels was achieved directly from the factory and even today if you amble along the river walk you can see that some of the loading gantries remain. Looking at rite 1891 accounts the company was worth about £1 million.
The Early Telephone Era 1890 to 1950
In 1876 Alexander Graham Bell invented the telephone which changed all our lives. Initially its acceptance was slow in the UK but in 1891 Siemens Brothers, based at Woolwich, supplied the first cross-Channel telephone cable. Telcon applied for their first patent in undersea telephone cables in 1896 and laid the first telephone cables across the Solent and the Irish Sea. These cables were made at Greenwich on the Enderby site as the Morden Wharf site had been run down and abandoned in 1895.
The distance over which a telephone conversation could be made was limited because of the loss of the cable. To improve this a technique known as loading was developed, first on land routes and then on submarine cables. The technique required the addition of magnetic tape into the cable construction. The first cross-Channel telephone cable of this type was supplied by Telcon in 1912.
This technique was also applied to telegraph cables and by 1924 transatlantic cables supplied by Telcon achieved 1500 words per minute. Further developments in magnetic tape technology increased the capacity to 3000 words per minute in 1928.
The industry continued to innovate and the addition of a copper outer conductor to telephone cables to reduce the resistance of the sea return path increased the transmission distance still further. This development was the direct precursor to coaxial cable design upon which the industry thrived in more recent times. Gutta percha was still used for insulation. Major investment in new equipment for processing the material, such as hydraulic cleaning and vacuum- drying, improved the overall performance of cables made during this period.
The site processed large quantities of wire used for strengthening the cables and it also continued to armour large quantities of cable for submarine use.
Still the majority of cables carried only one telephone conversation although Siemens brothers developed the first multi-cored submarine telephone cable at Woolwich with loading – a technical feat unmatched at the time.
The invention of thermionic tubes (commonly known as valves) meant that not only could speech signals be amplified but also carrier frequencies could be used to carry several simultaneous conversations over a single cable. To receive a particular conversation you tuned into the right frequency like you do on a radio.
This technique together with the coaxial cable technology already developed rendered loading of cables unnecessary. Telcon at Greenwich still used gutta percha insulation and was the first to manufacture submarine coaxial cables in the UK. Similar cables were also being produced in America. The invention of the thermionic tube also brought about an increase in the development of ‘wireless’ telegraphy. The first successful transatlantic telephone call using this technology was made in 1923 from the Western Electric (later STC) laboratory in Southgate. Between 1930 and 1935 wireless telegraphy led to the decline of the telephone cable companies with falling orders as a lot of the traditional cable telephone traffic was now being sent by radio.
In 1935 the only two remaining submarine cable companies in the UK, Siemens and Telcon, agreed to pool their resources and form a jointly owned company, Submarine Cables Limited (SCL), to be based at the Greenwich works of Telcon. The development and deployment of co-axial cables was soon to undergo its next growth phase thanks to a new insulator developed by ICI in 1933. The new insulator was based on the discovery of polyethylene and offered much lower signal loss than cables made with gutta percha. This meant that higher and higher frequencies could be used on the cable which in turn meant more and more simultaneous conversations on a single cable. At first only minute quantities of the material were available but by 1937 a small amount was made available for experimental use. In 1939, after extended research by the SCL engineers at Greenwich, a trial polyethylene cable of 1 nm was made.
Then came the Second World War years during which some 1000 nm of cable were made by Telcon and laid around the British Isles and unoccupied parts of Europe. In addition nearly 1000 miles of coaxial cable were accumulated for D-Day together with a large amount of gutta percha telegraph cable. In spite of heavy bombing of the docklands area the Greenwich works kept in full production throughout the war, 24 hours a day seven days a week, although it was damaged the day before the Duke of Kent visited the site.
The site was also the leading location manufacturing Telcothene, the SCL trade name for polythene covered cables, which were a key part of the new radar installations that sprang up during the war. SCL continued to be a major supplier of telephone cable until 1950 when intercontinental telephone traffic – still being largely carried by radio – was to undergo a major new innovation.
The Modern Era 1950 to 1985
The advantage of repeaters, or relays, for receiving weak signals and re-transmitting them with renewed strength were of course realised very early in submarine cable history That is why so many small islands, unimportant in themselves, were used as telegraph relay stations. The application of electronics to repeatered telephone cables was about to take off.
A repeatered submarine cable would include amplifiers spliced at intervals along the cable. These would be powered from the cable ends using a power feeding equipment. The telephone traffic would be assembled into the right packages and transmitted along the cable also from each end.
With the development of stable electronic amplifiers, and particularly the introduction of negative feedback amplifiers by HS Black in 1934, it became possible to consider laying broadband repeaters with valve amplifiers in the submarine cable.
This was not without difficulty as protection would be required for the electronics to withstand the sea- bottom pressures and reliable components would be needed to ensure long and fault-free operation without the need for maintenance.
Two techniques were developed initially for protecting the electronics. A rigid repeater in a steel housing was developed by the British Post Office and first inserted in a cable between Anglesey and the Isle of Man in 1943. The cables came out of the same end of the repeater, which made laying both difficult and slow as the repeater had to be lowered over the side of the ship.
In America work by Bell Telephone Laboratories concentrated on producing a flexible repeater contained under a bulge in the armour wires of the cable suitable for deep water and capable of being laid on the sea-bottom by the normal telegraph cable- laying gear of a cableship. With this technique only one way amplification could be provided because of the space restrictions.
The scene was now set for the development of long distance, high capacity repeatered submarine cable systems, capable of spanning transoceanic distances. Starting at about 40 circuits on a single cable the technology in 1978 was placing up to 5520 circuits on a single cable!
The co-operation of SCL with the BPO on cable and repeater design and manufacture was strengthened by the entry into the market of Standard Telephones and Cables Ltd (STC).
STC was inaugurated in 1883 with the opening of a London office of the Western Electric Company (W.E.Co) for the sale of telephones. W.E.Co purchased the North Woolwich site in January 1898 from the ailing Fowler-Waring Cables Company for £87,000. By 1909 the site employed 1,000 people. This site was just across the road from the WT Henley factory (mentioned previously) and continued to make a wide range of telephone cables until its closure in 1977.
The company was named STC in 1925 and in the 1920s and 1930s was a supplier of equipment for submarine cable systems. STC had overall responsibility for a number of cable systems and sourced cable from Siemens or Telcon. Entering the repeatered cable market in 1950, STC supplied repeaters for the system between the Netherlands and Denmark. The four repeaters for this system were made in an open shed on the site with ordinary components! This system was followed in 1954 by the UK-Norway system for which the repeaters were made in clean area conditions. Woolwich was the home of the STC transmission divisions until the landline division moved to Basildon in 1963 and the microwave division moved to St Mary Cray in 1965.
The first transatlantic repeatered submarine cable was a joint project involving SCL, STC and Bell Telephone and initial discussions started in 1952. SCL anticipated that it might be required to provide a large proportion of the submarine cable and began building a new factory at Erith in 1953. The factory was designed to store 2400 nm of cable (enough to cross the Atlantic). To allow loading of cable into the largest cableships available, the river was dredged and new wharves built. The cable-making equipment was electronically controlled for the first time. The new cable called TAT-1, supporting 36 simultaneous telephone conversations, went into service in 1956 and was an immediate success. In this system were almost 400 nm of cable manufactured at the Greenwich and Erith factories. This was followed in 1959 with a second cable for which SCL supplied 2000 nm. Up to this time the coaxial cables were based on the old telegraph cable design which incorporated external armour wires to provide strength to the cable. In 1951 the BPO proposed a new lightweight cable design whereby the cable strength was concentrated at the centre of the cable.
This cable was successfully trialled between 1956 and 1958 and was selected for the first cable to be laid from Europe to Canada known as CANTAT (CANada Transatlantic Telephone).
The cable for this system was made at Greenwich and Erith with repeaters from SCL and STC. The system was in service in 1961 and had a capacity of 80 circuits and was notable for two reasons. The repeater had cable entries at each end so could be laid with the cable in a continuous operation and also contained two-way amplification so requiring only one cable for both directions.
About this time STC realised the importance of supplying complete systems and opened their own cable factory in Southampton in 1956.
There now followed a period of growth in repeatered cable systems over the next 10 years with SCL and STC operating from sites just across the river from each other. The rivalry at the technical and marketing levels was intense. SCL was now owned by the UK electronics giant AEI. In 1970 as part of the rationalisation process within AEI the submarine cable business was sold to STC. Thus STC became the sole UK supplier of submarine cable systems and one of only four in the world.
With the rationalisation of the UK industry into a single company the cable factory at Erith was closed. All cable for the group was then made at Southampton and Greenwich. STC in North Woolwich became the leading site for the design, development and manufacture of repeaters. North Woolwich also made telephone cables but with a downturn in the market this activity was transferred to Newport Gwent and the site closed in 1976. All the submarine cable activity was again concentrated at Greenwich.
But there was a new threat to the business. Rockets capable of putting satellites into a synchronous orbit routinely and cheaply provided another means of communication. The communication satellite era had arrived.
The traditional communication agencies decreed that long-haul transoceanic facilities should be provided by satellite on a 50-50 basis with cable. The demise of submarine cables was widely predicted by this new technology!!
The cable industry responded with greater and greater capacities, and cheaper cost per circuit mile. However, orders did decline and the last cable was made on the Greenwich site in 1975 for the Columbus system between Venezuela and Spain. The last shipment of cable and repeaters leaving the Greenwich factory was eventful. The tugs assisting departure pulled the cableship from the dolphins and steamer off. As the cableship navigated the bend in the river around the Peninsula it became stuck on a mud bank. The tugs were recalled and the ship was towed off under the river pilot’s directions. The value of the equipment on board was several million pounds so the tugs put in a claim for salvage. They did not get it as they were technically still under contract, but it was a nice try!!
The system was inaugurated on Columbus Day 1977 – 12th October. The problem of how to use the now redundant cable storage tanks on the Greenwich site was solved by the managing director late one evening while he was walking through the factory. He had the idea of using them to rear trout! With an artesian well on site there was a good cheap supply of fresh water and with the tanks indoors the temperature would be ideal for the rapid growth of the fish. The trout grew at an astonishing rate and kept the site and the local market well supplied with fish for a long time.
During this period STC at Greenwich was the largest supplier of submarine cable systems in the world. With 97 of the total output going abroad STC was awarded the Queen’s Award to Industry for Export four times and by 1986 STC and its predecessors had manufactured and laid over 270,000 km of coaxial cable.
Optical Cables 1986 to present
In 1966 Kao and Hockham at the STC research laboratories proposed the use of optical communications networks operating on glass fibres to replace traditional copper cables.
The installation of the world’s first land-based system for the BPO in 1976 had a profound effect on the future of all telephone communication systems, including submarine cables. The first effect was a downturn in new system orders after about 1982 whilst the traditional telephone operating agencies anticipated the arrival of all optical undersea cable systems.
The Greenwich site of STC was in a unique position in the development and deployment of the new technology. With the strong lead gained from the research laboratories in the new technology and the opening of Europe’s first optical fibre production unit in Harlow by STC, the engineers at Greenwich developed the world’s first undersea optical cable and repeater. An experimental system was laid in a sea water loch in Scotland, Loch Fyne in 1980.
This experimental system showed for the first time that a fibre optic cable could be successfully manufactured and installed by a conventional cable- laying ship. Six months after the installation of the cable it was recovered and a single repeater inserted. The cable was re-laid on the loch bed. This demonstrated for the first time that fibre optic cables could be laid and subsequently recovered for repair in sea water conditions and optical signals could be regenerated underwater.
With the last copper cable system being installed in 1986, STC on the Greenwich site secured the world’s first order for an international fibre optic cable system from British Telecom, Deutsche Bundespost, and the Netherlands and Belgium PTTs. The system, known as UK-Belgium No 5, would cross the English Channel for 112 km and contain three repeaters.
Fibre optic cable has the ability to carry more than one transmission path. The old copper cables had a single transmission path and the send and receive signals were separated in frequency and could run in opposite directions along the cable. Fibre optic cables were initially designed to contain up to 6 fibres so that three could be used to carry traffic in each direction. The UK-Belgium cable, commissioned in 1986, had six fibres and the cable could carry 12,000 simultaneous two-way telephone conversations. All the electronics and optical parts of the system were designed and manufactured at the Greenwich factory using specially engineered components from the UK’s leading suppliers. Once again reliability of service was required and with the use of a large array of new components rigorous testing was employed to ensure at least 25 years of trouble-free service. More components were tested to destruction than used in the first two or three actual systems! The reliability of the components is being proven in real time now as the system is still operating after 13 years.
Once again, after the initial feasibility of the new technology had been proven on relatively short routes, inevitably the question was asked, “Can we use this new technology across the Atlantic?” A programme of co-operation between Greenwich and the US and French suppliers of submarine cables began in 1983 and led to the deployment of the first fibre optic transatlantic cable in 1988 called TAT-8. This system was developed and supplied as a result of commercial and political pressures from the owners of the system and laid the foundations for the growth of the technology in the US, France and the UK. This system had a cable capacity of just under 10,000 telephone channels.
The acceptance of the new technology was sealed and the race was on for further innovation. De-regulation of the communication service providers started about now and in the UK Cable and Wireless emerged as a rival to BT. STC on the Greenwich site unilaterally set about increasing the capacity of cables in 1986 and this resulted in the first privately sponsored transatlantic cable, PTAT-1 in 1989. This was the first complete transatlantic fibre optic cable to be supplied by a single contractor and had a cable capacity of 18,000 telephone channels.
The cable was notable because it had more service channels (these are channels that are used by the system for ‘housekeeping’) than the total capacity of the original TAT-1 system. STC was awarded the Queen’s Award to Industry for Technological achievement in 1990 for this development.
These initial systems were termed regenerative systems. Here the optical signal is received at each repeater and turned back into an electrical signal. The electrical signal is processed to remove accumulated degradations and then converted back into an optical signal before being transmitted to the next repeater.
The telephone traffic is assembled at the terminal stations into large groups and digitised to enable them to be transmitted to the submarine cable. The equipment to achieve these functions was again designed and manufactured on the Greenwich site. In addition, the repeaters have also to be provided with electrical power to enable them to operate and this is achieved by feeding electric current along the centre conductor of the cable.
For the longest systems a total system voltage of 9000 Volts has to be supplied from one end of the cable. The equipment to do this required 18 cubicles. It is fully duplicated so that there would be no interruption to the traffic in the event of a component failure over the 25-year design life of the system.
The specialised equipment to carry out this vital function was also designed and manufactured at the Greenwich site.
Cable was initially produced at the Southampton factory but as demand grew STC opened a new cable factory in the USA in Portland, Oregon. This factory was opened primarily to service the rapidly expanding Pacific and Far Eastern markets. Once again STC was awarded the Queen’s Award to Industry, this time for Export achievement in 1993. Some 97 of all manufactured products were exported.
In 1992 STC won a contract for a transatlantic system, CANTAT-3, as sole supplier. The system would have a capacity of 30,000 channels on a single fibre. This was a major increase in capacity compared to other suppliers. The cable was completed in 1994, connected 6 countries and remains the largest capacity regenerated undersea fibre optic system in commercial operation to this day
During the late 1980s a group of scientists at Southampton University combined to form the leading group in the UK on fundamental optical communications technology. This group had the concept of creating a technology for telecommunication systems that eliminated the requirement for the electrical regeneration of signals and replacing it with direct amplification of light. The concept of optical amplifiers was not new but the technology that they developed was novel and extremely simple. The concept was based on the use of a glass fibre in which minute traces of a special rare earth element called Erbium were embedded. This is termed doping. In operation this rare earth is excited with a laser and made to amplify light entering the fibre at one end.
The advantage of this type of technology was that unlike electrical amplifiers the number of telephone channels it (.an carry is virtually unlimited. The limiting factors in these systems are the generation of noise and the relative strength of the signals along the system.
STC set about using this new technology initially on very short submarine cable systems. These systems are termed un-repeatered systems and are characterised by short cable links initially of up to about 120 km in length. The use of all optical amplifiers in the terminal stations could increase the length of the unrepeatered links to over 200 km at that time. The development of these amplifiers in Greenwich won a major Northern Telecom award for the engineers responsible for their introduction as well as a Queen’s Award to Industry for Technological achievement to the company in 1995. Links of 400 km are now possible with the latest technology.
Once again it was not long before there were proposals for spanning the Atlantic with large capacity systems using optical amplifiers. The optical regenerative systems had by this time progressed to TAT-9, TAT-10 and TAT-11 all carrying almost 8000 channels per fibre and the proposal was now to provide two systems, TAT-12 and TAT-13, which would carry 64,000 channels per fibre. Because of the very large capacity of each cable the effect of any damage would be disastrous to the overall transatlantic telephone business and so two cables were proposed in a ring configuration with one cable protecting the other.
Once again these systems were developed in collaboration with the US and French suppliers and commissioned in 1995. This collaboration ensured quick delivery of the technology from the feasibility stage to supply and commissioning of the complete system through the combined expertise of the three companies.
These early systems demonstrated the capability of the technology but not the events that were to unfold as we progress towards the end of the millennium. Global rationalisation and expansion of key business areas play an important part in the history of the submarine cable system industry. The three initial players in the business AT&T, SC1 and STC were followed by the French company, CI (later Alcatel) and the Japanese in the form of NEC and Fujitsu who formed a powerful national alliance. With the amalgamation of SCL and STC in 1970 there were effectively four major suppliers for a period of over 20 years.
STC, originally part of the giant US company ITT, partially floated on the UK stock market in March 1982. In October 1982 ITT reduced its ownership in STC to 35 by offering for sale another 40 of its stock. In 1987 ITT announced that it was selling its whole worldwide ownership of telecommunication companies. The remaining share of STC was sold 1 Canadian company Northern Telecom (later North and its other worldwide interests were sold to the French company Alcatel. In 1991 Nortel acquired ; the stock of STC within the UK and so the submarine cable business at Greenwich became part of the Canadian company.
Under Nortel the business prospered due to the generally high demand for submarine cable system and the de-regulation of the telecommunications industry which encouraged more and more private companies to start investing in the ownership and operation of cable systems. In 1993 Nortel decided on a rationalisation of its key business areas and decided to divest itself of the submarine system business based in Greenwich. After a protracted Monopolies and Mergers Commission enquiry the STC business was sold to Alcatel in March 1994 for approximately US$900 million and Alcatel then became the world’s leading supplier of undersea systems.
Since the amalgamation of the two businesses the supply of submarine cable systems has reached an all-time peak in terms of length of system manufactured each year, the sales value and more recently the increase in the amount of traffic that can be squeezed onto a single fibre. By the end of 1999 the total fibre optic cable supplied by Alcatel will be in excess of 230,000 km. The most recent technology advances have been based on a technique known as wavelength-division multiplexing (WDM). WDM effectively increases the number of fibres in the cable by combining traffic streams onto a single fibre. Each traffic stream has a different wavelength or colour and can be combined and separated using optical components. This is analogous to splitting white light into the colours of the rainbow using a prism.
This technology development has accelerated at an ever-increasing rate as shown by the fibre capacity capability, and projections show that this will continue.
So where is all this telephone capacity being used? A lot of you will be connected to the
Internet at home and at work.
The measured 100 million connected users in 1998 is continuing to expand at a high rate due to the reducing cost and increasing speed of today’s computers. With the vast amount of information from Web sites around the world available in your own home for the cost of a local telephone call, predictions show that the demand for international capacity will continue for the foreseeable future.
Alcatel at it’s worldwide manufacturing sites has increased it’s production capacity and has now consolidated itself as the world’s No 1 supplier of submarine cable networks.
Whilst cable is no longer manufactured on the Greenwich site repeaters, branching units and power feeding equipment for the company’s systems are still designed and built there. Development of the highly sophisticated terminal transmission equipment that assembles the telephone traffic into the right optical signal format for transmission over the submarine cable is also carried out in Greenwich. The rapid development of fibre optic cable technology is being exploited to its limit in the new equipment designs in which the young Greenwich engineers are currently engaged.
And what about the future? Well, to date, the technology has progressed from sending electrical dots and dashes over a copper cable to sending highly encrypted and error correcting laser-generated light pulses over glass fibres. The cable capacity in terms of channel connections has increased from 1 to 15 million channels!!!
From point-to-point cables we now supply multi- landing cables with built-in ring protection so that if one segment of the cable is damaged the cable link is restored automatically in a few milliseconds so that the connection is not lost. These links are predicted to grow further in capacity and become more and more sophisticated in their connectivity and operation. The early pioneers of cable development and manufacture on the Greenwich Peninsula 150 years ago would now be astounded with the achievements that have been made by their successors.
Despite the predicted demise of cable communication on two occasions, by wireless and satellite, the submarine telephone cable industry in Greenwich is alive and well. With the current placement of about four billion dollars worth of new business each year worldwide, it will continue to be so for many years to come.
It is a sobering thought to consider that the first transatlantic telegraph cable could transmit only a few words per minute whereas the new cable systems Alcatel are developing at the same Greenwich site are capable of transmitting 10 million copies of the Daily Telegraph every second!!
The dedicated people employed in Greenwich have been responsible for many “firsts” in the field of submarine cable systems and can claim to be the Global Centre for telecommunications for over 150 years.
List of Firsts
1850 First cross channel telegraph cable
1858 First transatlantic telegraph cable
1912 First loaded cross-channel telephone cable
1939 First polyethylene coaxial cable
1961 First Canada – Europe telephone cable system CANTAT
1976 Highest capacity coaxial cable system in the world installed
1980 First optical repeater installed
1983 First order for an international optical cable system
1989 First transatlantic single supplier optical regenerated system
1995 Highest capacity optical regenerated system installed
1998 First transatlantic single supplier optically amplified system installed GEMINI
We would like to thank Dr. Mary Mills, Sally Jenkinson and the Science Museum for permission to use some of their material, and Andy Collins for compiling the presentation.
Greenwich Marsh – t he 300 years before the Dome by Mary Mills
Whaling, Rope making and the Atlantic Telegraph -Enderby Wharf by Sally Jenkinson
Submarine Telegraphy. The Grand Victorian Technology by Bernard S. Finn (Science Museum)
Cableships and Submarine Cables by K.R. Haigh
Power of Speech -A history of Standard Telephones and Cables 1883-1983 by Peter Young
The Telcon Story – One hundred and ten years of undersea telecommunications by Submarine Cables Ltd
Various publications produced over the years by Alcatel and its predecessor companies
Published Alcatel 2000 reproduced with permission
Return to Enderby Wharf
3 thoughts on “Greenwich Centre for Global Telecommunications”