The history of the Edge Lane plant in Liverpool

Originally written in the centenary year of the Strowger automatic system (1989) for GPT Ltd by ANDREW EMMERSON and not since updated. Copyright 1989.



  1. Strowger Works and its place in history
  2. The beginnings of Edge Lane
  3. The prehistory of automatic telephony
  4. The first British Strowger installations
  5. A British Strowger company is born
  6. Epsom and afterwards
  7. On active service
  8. The 1920s—Decade of decision
  9. The 1930s—Expansion and a new name
  10. World War II—To battle again
  11. Post-war regeneration
  12. The 1960s and 70s—A period of crisis
  13. System X and the 1980s

Further reading

Abbreviations used


This brief survey tells the story of the Edge Lane site, long known as Strowger Works, and the telecommunications industry in Liverpool, a long and proud tradition. Products made here have shaped the development of telecommunications in Britain, have been exported all over the world and can truly be said to have benefited every citizen of our country.


The timing of this study is not accidental: it is issued at the time of the 100th anniversary of machine (as opposed to manual) telephone switching, and commemorates the original invention in 1889 by Almon B. Strowger of the first 'real' automatic exchange. One hundred years on, we can see how this developed into the world's most successful telephone system and note the role played in this by the workers of Liverpool. The successive owners of the Liverpool site, culminating in GEC-Plessey Telecommunications (hereafter referred to as GPT) have had close associations with the Strowger organisation since early times and have played a significant part in world telephone development through the productions of the Strowger Works in Liverpool.

Although the early production of the Liverpool factory was influenced by its American parent, the works soon turned out products of entirely British conception and helped influence the separate development of automatic telephone switching in Great Britain. Over the years the American influence declined, and the UK company achieved complete independence both in the conception of its products and in its economic structure.

The importance of this work should not be under-estimated. There is an unfortunate trend nowadays to belittle British achievement, but the story of the Strowger Works is no such tale of gloom. The Liverpool organisation can lay claim to a story of continuous innovation and success, not only in the home market but world-wide.

The timing of this study (just after the 75th anniversary of the opening of Britain's first public automatic exchange in 1912) also allows us to correct the impression that automatic telephony was slow to take root in this country. Britain is often accused of being slow to adopt new technology for its telephone service, and the delay of twenty years between the introduction of the first automatic telephones in the world (La Porte, Indiana, USA) and Epsom's inauguration is sometimes cited as evidence. A little research, which grew into a lot of research, led the author to uncover new facts that now alter and correct that impression.

For the first time in print it can be reported that Britain's automatic telephone history goes back somewhat further than assumed, in fact to 1898, when the first dial telephone installation was ordered. The Strowger organisation was involved throughout the whole era, from the outset in 1898 to the present day. The rest, as people say, is history - and most of it is in this little history.



To keep the size and scope of this work within bounds, it does not go into any great technical detail, though it does point to the appropriate references. Nor does it attempt to provide a history of the telephone service or industry in general, and the broader background as well as the commercial and social development of the telephone in Britain is left to be found in the reference books cited.

References have been given to the most useful material used. Many abbreviations are used in the text, and all are explained at the end of the text. Acknowledgement is readily made to all previous authors on this subject whose texts have helped so much to produce this history. I am also please to acknowledge the assistance of colleagues in GPT and British Telecom and my thanks to Eddie Birch and to Stan Swihart for taking time to criticise and check the text. Any errors that remain are mine alone.




Strowger means several things to people: to the public at large he is remembered at the man who invented the automatic telephone to avoid losing business to a rival; to telephone engineers world-wide his name denotes a type of switching mechanism which even a hundred years after its invention is still used in most countries. And to people who work and have worked at what was known as the Strowger Works in Liverpool, the name has an even more special meaning. We have many reasons to be grateful to Mr Almon Brown Strowger of Kansas City, USA.

Strowger gave his name not only to a telephone switching system but also to a group of companies, the most famous of which for most of its existence has been based in Chicago and was known as Automatic Electric (now GTE Automatic Electric, a major subsidiary of General Telephone and Electric). Automatic Electric established a number of subsidiaries and licensees which used the Strowger name, but none was more successful than the British concern, known over the years as the Automatic Telephone Manufacturing Company (ATM), Automatic Telephone and Electric (ATE), Plessey Telecommunications Ltd. (PTL) and now GEC-Plessey Telecommunications Ltd. (GPT).

With headquarters at the Strowger Works, Edge Lane, Liverpool, these companies have made primarily telephone, telegraph and other telecommunications apparatus, and over the years they have also manufactured domestic electrical appliances, essential war products, traffic lights and many other appliances for home and world-wide use.

Changing political and economic influences outside the companies' control have meant that not all former world markets are still open, although Eastern Europe and China are once again considered potential opportunities. In a historical outlook, taking into consideration the separate development and progression of telephone switching technology at Edge Lane and its spread world-wide into the former British empire and spheres of influence, it can be argued that British practice eventually had more influence on world telephony than did Chicago.

This study traces the history of this productive output, which in fact has two sources. We begin therefore with two separate stories, first that of the company which started the Liverpool telecommunications industry long before the advent of the automatic telephone, and second the progression of events in the development of the dial telephone which led to formation of the ATM company in the Strowger Works.



Long before Strowger Works was built at its present site in Edge Lane records show that the first beginnings of Liverpool's telecommunications industry can be traced to two brothers by the names of J. and G. Crosland Taylor, who founded a small company in Helsby, Cheshire with the grand title of the Telegraph Manufacturing Company.

The two brothers commenced business in 1884 using a small shed to produce batteries and gutta-percha insulated cables under the control of a gentleman called Slater Lewis whose only previous management experience had been to organise the Cheshire Agricultural Shows.

Within two years the primitive shed had been replaced by a two-storey brick building which became known, somewhat inevitably for the time, as the 'Mill' and which was used by the company to celebrate the occasion of Queen Victoria's golden jubilee with a special dance organised by the intrepid Mr Slater Lewis.

One year later, in 1888, when it was realised that the company's fortunes were declining, Mr Slater Lewis was replaced by Mr Alfred Whalley, an energetic and enterprising man who held the title of Engineer and Manager. It was he who diversified by using the company's gutta-percha expertise to introduce the manufacture of golf balls, which became known to a generation of golfers as the 'Helsby Brambles' or the 'Helsby Green Dot'.

Almost from the beginning, the firm had a small telegraph instrument-making section requiring precision work of a type then unknown in the North West, and because of the shortage of skilled men locally, the company tried to attract instrument makers from London. It was not easy, however, to attract suitable men to stay in the then-quiet rustic atmosphere of Helsby. Even the company itself had a quaint simplicity about it. Advertisements for cable hands, for instance, would include the condition that the applicants 'must be a good cricketer' and there was a cup awarded annually to the winner of a race to the dizzy summit of Helsby Hill.

In 1892, therefore, it was decided to move the instrument section from the 'dead and alive hole' of Helsby to Liverpool, into premises just off Renshaw Street - the beginning of the long association between the city of Liverpool and the company.

Under the direction of the enterprising Mr G. Crosland Taylor the firm produced an amazingly wide range of products including even cycle tyres. More significantly, they supplied large quantities of telephone wire and 26-pair cable for the National Telephone Company, as well as power and lighting cables for Brussels and for St Petersburg.

It is interesting also to note that the energetic Mr Crosland Taylor also floated with a M. Ville the Crosville Motor Company, a local bus company of many years standing, which was managed by the family for many years.

In 1902 the Helsby concern amalgamated with the British Insulated Wire Company of Prescot, which held the British patents for the manufacture of dry-core cable - a very timely move in view of the fact that rubber or gutta-percha insulation for conductors was now being seriously threatened by the cheaper dry-core paper system. (BICC - British Insulated Callenders Cables - is the lineal descendent of these companies.) Meanwhile the instrument section in Liverpool had widened its scope and by the early part of this century the company was securely established with the manufacture of manual telephone exchange equipment. Work increased to such an extent that by 1903 the Renshaw Street premises became quite inadequate for the number and complexity of jobs, and a move was made to the once prosperous residential suburb of Edge Lane, then on the outskirts of the city. The company purchased a good stretch of land lying between the road and the railway and began to build a new factory. This plant was expanded progressively, as was production which was by 1905 supplying large quantities of exchange equipment for use both at home and overseas (Shanghai, Fremantle and other cities). This was achieved latterly under the enterprising management of a Mr Dane Sinclair, and we shall return to his foresight in chapter 5.




Although the credit - and fame - for inventing the automatic telephone exchange rests with Strowger, he was not the first to apply his mind to the problem of switching telephone calls by machine. Although finding labour to put calls through was not generally a problem during the latter part of the nineteenth century, there were situations where machine switching would be desirable, for instance in remote locations and when human operators were asleep or otherwise occupied. Moreover the joy of invention does not always require a problem before it finds a solution!

Accordingly a number of schemes were devised for controlling a telephone switch remotely; one of these came from the Ericsson firm in Sweden and others in America and Britain. It is commonly agreed that the first fully automatic switchboard used in Britain was one patented by Mr D. Sinclair, when engineer for the National Telephone Company in Glasgow. Although it predated the well-known work of Strowger in America, it was not such a significant development. This is because Sinclair's invention was not a complete telephone exchange, more of a remote-control switch. Today we would call this concept a line-connector or a remote concentrator unit. The apparatus was for single wire circuits only, and was efficient for one junction line and five subscribers' lines. When a subscriber called his indicator made contact with a sliding bar which connected the calling line to the junction line leading to the central exchange, and insulated all the other lines.

According to a paper read by Aitken in 1911 and his Manual of the Telephone, the first of Sinclair's switches was installed in Glasgow in 1883 and a few of these were in use in Scotland for a while. Parts are believed to survive in the National Scottish Museum, Edinburgh.

Before this time, the concept of a complete automatic telephone exchange had already been contemplated in the USA, the home of the telephone. Already in 1879 a patent was issued to Connelly and McTighe for a system embodying step-by-step mechanisms controlled by impulses from the telephone, but it was crude and impractical. In the same year Westinghouse described an auxiliary exchange which, like Sinclair's, enabled suburban telephone users to obtain the sole use of a junction circuit to a city exchange.

In 1883 a Mr A.S. Paul acquired the English rights of a step-by-step system invented by the Swedish Ericsson company, but this too was only a remote-controlled selector or auxiliary exchange enabling a city operator to call a particular rural subscriber.

The breakthrough came in 1889 when Almon B. Strowger of Kansas City, USA devised the germ of the automatic telephone exchange that even now bears his name. It was Strowger's switching system that was the first to embody the complete concept of replacing all the functions of a manual telephone exchange.

He was a businessman, in fact an undertaker, who suspected that calls intended for him were being diverted by switchboard operators to a business rival. "Too many would-be clients were given (when they asked for Almon B. Strowger) a wrong number - which, quaintly enough, was usually that of his rival, whose wife, so remarkable is the chain of coincidence, happened to be an operator at the local exchange. Mr Strowger vowed - and this is a story which all good telephone engineers believe implicitly - that he would invent a machine which would entirely eliminate manual working in the business of setting up a telephone connection." [J.H. Robertson, The Story of the Telephone.]

From basic principles he attempted to devise a system that would put the connection of the phone call under the sole control of the person making that call. Somehow the function of plugging a cord into a one of a selection of jacks had to be imitated by a machine.

He had an idea that, by arranging a metal finger on a central shaft and rotating it by means of an electro-magnet he could evolve a mechanism which, when perfected, could complete telephone connections without human aid. The first realisation of this scheme saw Strowger sitting at his desk carefully placing pins around the inside edge of a collar box. In 1891 he obtained his first patent for an automatic means of communication between two subscribers. This contained the basic idea of a selector finger moving both vertically and horizontally to reach any one of 100 lines arranged in ten rows each containing ten lines. The selecting finger was moved by electromagnets which, in turn, were controlled by current impulses sent by tapper keys on the calling subscriber's telephone. At this stage separate wires were required for speech and for the hundreds, tens and units keys, making five wires in all. (Later on the system was much improved, the number of wires reduced and the key switches replaced by a circular dial. Strowger patented his system in 1891 and went on improving it until 1896, then in ill health went to Florida and died there in 1902.)

Thus the chance result of an undertaker's lost business led to the gradual refinement of what we now know as the Strowger system into a commercial dial telephone system.

The next significant event occurred in 1892 with the opening of the first public automatic exchange in La Porte, Indiana. The dial telephone was yet to come, though, and an important innovation was made in 1896 when the keys used for tapping out numbers to the exchange were replaced by a dial, in essence no different from the one used today. In the following ten years more than seventy automatic exchanges were installed in the USA.

The advent of fully automatic telephone systems did not, however, extinguish interest in so-called semi-automatic operation. For a decade or more argument raged as to whether subscribers were capable of "spelling out" their numbers to automatic equipment and whether control of sophisticated apparatus was not better left to trained operators. Indeed, some foreign installations made subsequently relied on subscribers passing their wanted numbers to operators, who then dialled and rang the numbers. There were many experts, too, who considered that the process of dialling a number, the risk of human error ("finger trouble") and waiting for the automatic equipment to complete its machinations was tedious and could be beaten easily by human operators.



The commercial development of Strowger's system began to follow an involved path and it was not long before a company was formed to exploit this in Britain. In 1896, because of failing health, Almon B. Strowger left the employ of the Strowger Automatic Telephone Company, which had been formed to exploit his invention. The following year, the Automatic Telephone Exchange Company Ltd. of Washington D.C. was formed for the purpose of carrying on the automatic telephone business. Previous to this incorporation it had gone by the name of the "Drawbaugh Telephone and Electric Appliance Company Ltd of Baltimore Md. and London England". This is the first reference I can find to the presence of a Strowger company in Britain.

The purpose of the new Automatic Telephone Exchange Company was to market the apparatus made by the Strowger company and in the USA it acted as agent of the Strowger firm on a royalty basis. (This arrangement ended in 1900 when the Washington company sold everything back to the Strowger organisation.) In the meantime the Strowger company devoted itself actively to development work and to promoting the system overseas.

The first introduction of the Strowger automatic telephone to the United Kingdom thus came about in March 1898, when representatives of the Strowger Automatic Exchange Company of Chicago started on a sales trip to Europe and took with them some demonstration exchanges. First stop was London, where a working exhibit of 200 lines capacity was set up at Winchester House, 66 Old Broad Street in the City of London. This was the first time the Strowger system had been exhibited on this side of the Atlantic.

This particular installation provided for each subscriber's line to terminate on a two-motion switch and a multiple of all the subscribers' lines appeared in front of each switch mechanism. The exhibit attracted considerable interest, but on account of its capacity being limited by the size of the multiple, it was considered impractical for large installations.

A company called the Direct Telephone Exchange Corporation Ltd., based at 84 Winchester House, was formed to exploit and popularise the Strowger system. It published an informative booklet and arranged for a demonstration of the system at the Royal Institution in June 1898. Exchanges for 100 and 400 lines, also for 1,000 and 10,000 subscribers were described. By November 1898 demonstration systems for 100, 200, 400, 1,000 and 10,000 subscribers were on display: presentations were made in that month to delegations from the national German and Bavarian administrations, who had come specially to London in 1898 for this purpose. Representatives of the Automatic Telephone Exchange Company of Chicago were also present on these occasions.

It was at this time that the first sale was made of what the Americans at that time widely called "the girl-less, cuss-less telephone". This episode does not appear to be mentioned in the contemporary literature. Research in the archives of Glasgow City Chambers, however, indicates that the town council approved at a meeting held on December 13, 1898 draft heads of agreement between the corporation and the Telephone Construction Co. of 85 Winchester House, London. The company was to install an 'automatic telephone exchange system for twenty-five instruments', and maintain it for three months, all at their expense. If the corporation wished to have instruments placed in municipal offices outwith the City Chambers, however, this would be at their expense. At the end of the three months the corporation would have an option to purchase.

On January 13, 1899 the town clerk reported to the Special Committee on the Telephone Service that the company was prepared to proceed with the installation. Later, on October 13 a letter from the company was submitted, stating that the three months had expired and enquiring whether the corporation proposed to purchase. The committee agreed to wait until offices outside the City Chambers had been connected before coming to a decision. On March 27, 1900 they recommended that the installation be purchased, and this went ahead. The principal archivist of the Strathclyde Regional Archives notes that in July 1900 there are references to negotiations with the Strowger Automatic Telephone Exchange Co., Chicago, apparently in connection with a different system. This may, however, been for acquiring further components.

It is interesting to note that a municipal body was the first to adopt this new-fangled system of automatic telephony—perhaps it was a case of civic pride. Remarkably it contrasts with the rather outmoded call-wire system adopted for the Corporation's (manual) municipal telephone service; it would be interesting to research the background reasoning behind the two radically different decisions.

In 1899 another Strowger exhibit was received in London from Chicago, which embodied the principle of trunking and grouping used in all subsequent installations. This paved the way to systems of virtually unlimited capacity and was introduced simultaneously into France and Germany. A further private installation was made during this period, at some time before 1906 when it was mentioned in that year's edition of Poole's Practical Telephone Handbook. This was at St Bartholomew's Hospital, London, but extensive searching of their records has revealed no details of the exchange.

A fresh impetus to automatic telephony was given at the start of the new century in America. In 1901 the well-known Automatic Electric Company of Chicago was organised to carry on the business of making and selling automatic telephone apparatus, while the Strowger Automatic Telephone Exchange company retired from activity apart from holding the patents under which Automatic Electric operated.

Another automatic installation followed. In a publication of 1906, The Electrician, recorded (on July 13) "It is stated in the Western Electrician that Mr Andrew Carnegie has purchased from the Automatic Electric Co. of Chicago a complete private automatic exchange equipment of 20 lines for his estate at Skibo Castle in Scotland. The first 13 lines are to be working by August." The system replaced an old manual magneto one and is described in greater detail in the July 1906 issue of Telephony.

All these installations so far can be considered curiosities, whereas automatic exchanges were by now numerous in the USA. Some 73 had been installed by May 1907. Also, up to now all the Strowger installations in Britain had been imported from Chicago, but this was soon to change. What had happened, incidentally, to the companies based in Winchester House in the meanwhile is not clear, but their lack of large-scale sales may have a bearing on their demise. Alternatively they may have always been short-term creations of the American parent, which later was more amenable to licensing foreign manufacture to local operations. This is what occurred in Germany, where a German concern had secured the right to exploit the Strowger patents throughout Europe except Britain and France.




Our story moves forward to 1908, a most significant year. The birth of Britain's own telephone industry in general - and of the Strowger Works, Liverpool in particular - can be traced to the Exposition at the White City, London, in 1908 where a demonstration exchange embodying all the latest improvements was put on display. Although not stated, this must have been under the auspices of Automatic Electric in Chicago.

At this exhibition it would have been clear to observers that the automatic telephone now on display was highly refined compared to the primitive efforts of the 1890s. The telephone line circuit had been simplified to just two wires (like a normal CB manual telephone) and the clumsy and unnaturally large 'half-moon' dial with oval slot-shaped finger holes was now replaced by the small round dial with which we are still familiar. Automatic ringing, though without ringing tone for the calling subscriber, was provided together with busy tone on connection to engaged numbers.

It was also here at this exhibition that a British company first saw the potential of automatic telephones and became interested in manufacturing them. Indeed, the growing conviction that machine switching, as it was also called, was the thing of the future which led the British Insulated and Helsby Cables Ltd. to set up a company to manufacture equipment of the Strowger pattern.

The key figure in this activity was Dane (christened Daniel) Sinclair. As mentioned in chapter 3, he had patented Britain's first automatic switchboard in 1883 and clearly he had retained his interest in automatic switching after his early work. Sinclair had been Engineer-in-Chief of the National Telephone Company, which was due to be taken over by the Post Office (in 1912) and he had now left that firm to go as General Manager to the British Insulated & Helsby Cable Company (now BICC). Having long been concerned with the idea of automatic telephone systems, he now urged his employers to acquire from Automatic Electric in Chicago the British and colonial patent rights of the Strowger system. (The Continental rights were by then in the hands of the (French) Thomson Houston Company, Paris and Messrs Siemens & Halske, Berlin, who manufactured this equipment for the territories allotted to them.)

His new employers shared his faith, for they set up a new company - the Automatic Telephone Manufacturing Company - to exploit these rights, which were acquired in November 1911 - a few weeks before the National Telephone Company's operating licence expired. This new Automatic Telephone Manufacturing Company was independent of, but had a reciprocal arrangement with, the Helsby cable company. [Some conservative individual in the Post Office must have pretended not to note the distinction between the companies, since he allotted to ATM the manufacturer code H - for Helsby - and this was forever after used for ATM products.] Two directors of ATM were from Automatic Electric and as well as the rights to the Strowger patents and designs, the new ATM company could draw upon the extensive technical and manufacturing experience of the Chicago company.

The first action, made in November while the patents were still in the hands of the cable company, was to arrange a press demonstration of the automatic equipment. Illustrated features appeared in The Sphere and the Illustrated London News, together with sentiments such as "Every man his own exchange' and a system "which will entirely dispense with telephone girls". The Sphere's photographs indicate the table and wall phones used at the time, which used the old 'sunburst' eleven-hole dial. In this pattern, which was slightly smaller than those which followed, the finger wheel was disconnected from the dial mechanism once the user's finger had reached the finger stop and returned to normal at a high speed. The eleventh hole was purely decorative and served only the purpose of symmetry. The centre of the dial had a pressed sunburst pattern and no provision for a number and instruction label, a feature which was, however, introduced on the instruments used at Epsom.

Dane Sinclair was managing director of the new company, which took over the already existing Edge Lane, Liverpool works and relevant staff of the B I & H Cable company. The new firm began its effective life on January 1, 1912 and set about designing and making press tools and jigs for the mass-production of automatic telephone equipment. The Automatic Telephone Manufacturing Company was thus the first firm to undertake the manufacture of automatic telephone equipment in this country. (Initially the operation was confined to assembly of components mostly produced in Chicago. The first public exchange apparatus produced at Edge Lane was for Newport, opened in 1915.)

Despite, or perhaps notwithstanding, the experience of the early small private installations, 1912 thus stands out as the watershed year in the development of automatic telephony in Britain. This was the year when the ATM company opened for business and when the expanded Post Office (incorporating the NTC) ordered and opened two automatic exchanges. The time was now right for commercial exploitation of dial telephones on a proper scale.




The ATM company's faith in machine switching was soon justified. By 1912 the Post Office had determined it was time to give automatic telephone switching a full investigation and a fair trial under practical conditions. In fact the decision was made to order three exchanges, two for public use and the other for internal application. Since ATM was the only company actively offering auto equipment in Britain it was natural that the Post Office should turn to them for the supply of apparatus, but the Strowger technique was not the only system of machine switching in vogue at the time. Three other automatic exchange systems, the Rotary (American), the Betulander (Swedish) and the Lorimer (Canadian) were being exploited elsewhere and the Post Office decided to make a trial of two of these also. In the event, none of these systems caught on in Britain, and the Strowger system was the one that was standardised. But this is to anticipate our story.

The two ATM exchanges were to be installed at Epsom in Surrey, just south of London, and at Post Office headquarters in London, while the Lorimer would serve the Caterham Valley. The observation of the performance of these two techniques would supply the answers to some fundamental questions and enable a long-term policy to be established.

The trials were to determine:

According to equally authoritative sources, Epsom auto exchange opened on March 13, May 18 or May 26, 1912, (the dates probably relate to contractor's handover, actual and official opening). This was followed on July 13 by the opening of the "Official Switch" at PO HQ, St Martin's le Grand. The opening of the Caterham Valley exchange was delayed, owing to the difficulty the contractors found in delivering the necessary plant. Its story is told in the next chapter.

Both Strowger exchanges followed standard USA practice in most respects, including telephone instruments embodying a direct current-energised magnet in the receiver (to save weight) and no induction coil. These arrangements were not retained in later systems, nor was the polechanger arrangement for producing the ringing current and buzzer and pendulum device for busy tone. It was realised that other arrangements could be modified to advantage, and engineers of the PO and ATM company started the long train of development that gradually led British automatic practice away from that of the USA.

The two 1912 exchanges used the current Strowger two-wire system and, not unexpectedly, gave very adequate service all told. Epsom provided for 500 subscribers initially, with an ultimate capacity of 1500. The Official Switch also had a long-term capacity of 1500 and was first equipped for 900 users. Using plunger-type Keith line switches and 'vertical' pattern group and final selectors, both exchanges were fitted out along similar lines, and in fact when Epsom was eventually closed, some equipment recovered from there went to augment the Official Switch.

Being the first public automatic exchange, Epsom attracted considerable press attention and some detailed descriptions of the technical arrangements of these two exchanges are given in the literature and are therefore not repeated here [see bibliography]. A novelty was the dialling instruction card and that given to Epsom customers had a map showing all the exchanges in the Metropolitan district, divided into three areas. Subscribers requiring connection to numbers in the central or northern area were instructed to call up 15 for a line to the city exchange (Central). They would give the number required to the operator there for connection in the normal manner.

For connection to the south-eastern district of London customers dialled 16 and were connected automatically to the operator in Croydon, while 17 seized a junction to Sutton where calls to the south-western district would be connected. The taboo on numbers starting with 1 had obviously not set in at this time. Subscribers' numbers started at 200 (or 211 if you prefer) and operator calls (enquiries and trunks) were made by dialling 0 (marked 'Long Distance' on the dial, following normal American practice).

In the two years between 1912 and the start of the Great War several further private installations of Strowger equipment were made and the first export orders were fulfilled. The ATM Company was one of the early suppliers of purely internal automatic systems (PAXs) and its first private customer was Messrs Tweedale & Smalley of Castleton, near Rochdale, who had a 100-line installation in 1913. The following year they supplied Messrs Davidson & Co. Ltd. with a system of automatic telephones throughout their Sirocco Engineering Works, Belfast. In addition orders were secured for several other private installations of 25 to 100 lines and upward for telephone intercommunication in factories, offices, collieries, etc..

The company also proceeded with the exploitation of the system abroad and was successful in securing contracts for the equipment of two exchanges in the Argentine (at Cordoba and Rosario) and an initial installation at Simla, India, for the Indian government. This last was supplied in 1914.

As a footnote, it is interesting to speculate whether any other installations of automatic exchanges were made before the formation of ATM in 1911. The Electrical Times of November 30, 1911 remarks "The British Insulated and Helsby have taken the automatic under their wing, and already one hears of two or three exchanges worked on these lines in this country." Certainly my colleague Norman Pearce, who has had an interest in telephones for many years, recalls almost acquiring some early Strowger telephones before the last war. The system was in an office in the City of London and the phones were said to have had the large "half-moon" dials characteristic of early American Strowger installations. It should be noted that Siemens & Halske maintained production of this pattern of dial in Germany for some time, and the first Siemens Brothers auto installation (1913) employed dials of this kind. So "half-moon" dials do not necessarily indicate an early Automatic Electric installation, but the thought is intriguing.



Just as the ATM company was beginning to reap the rewards of its efforts in introducing automatic telephony to the British empire, its work was confounded by the outbreak of war. The 1914-18 war, with its insatiable demand for munitions, seriously interfered with the further development of the company's objects and most of its production facilities were used to make shell-fuzes, anti-submarine gear and so on. Major changes to plant and methods had to be made. Upwards of 2 3/4 million fuses were manufactured for the Ministry of Munitions at the Liverpool factory, as well as various other urgent war materials such as gunsight mountings, hydrophones and field telephones.

All this was achieved with a skeleton workforce. The military services made heavy calls on the company's technical engineers for officer material, while its workmen were eagerly sought for service in the special corps, particularly the signal branch.

As far as telephony was concerned, the war profoundly disrupted the plans of the Post Office for further experimentation with new types of automatic exchange; it also impeded the efforts of ATM to complete its automatic exchange contracts. The outbreak of war must have caused even more problems for ATM's main competitor, Siemens Brothers. This firm was trying to introduce their first public exchange for the Post Office despite the lack of contact with the main design department in Berlin and this meant that the opening of this exchange, Grimsby, was considerably delayed and did not open until 1918.

The ATM company was the only other manufacturer in a position to supply telephone equipment during the war and it performed this role admirably. In the defence arena it supplied private exchanges (PAXs) to War Office and Admiralty installations at Crombie, Wylies, Rosyth, Blackbank and Port Edgar. It also continued to equip public exchanges in a number of other towns, largely with apparatus (and installation staff, known as switchmen) imported from the USA. In at least one exchange this led to the adoption of a sort of pseudo-Yankee jargon, which infuriated the senior supervisors! Thus the more go-ahead British staff now said 'grounded' rather than 'earthed', 'open' for 'disconnected' and 'hook-up' for 'temporary connection'. A faulty inter-switch circuit was now a 'bum link' or 'phoney trunk' and the portable telephone used by the exchange faultsmen was a 'butt-in-ski'. The test clerk became the 'wire chief' and men on switch adjustment duties were known as 'trouble-shooters'.

The Post Office exchanges installed at ATM in this period included Chepstow (1915); with 65 lines it was the smallest installation and the first unattended exchange with remote manual board. The list continues with Newport Mon. (1915) plus Accrington (1915) and Blackburn (1916). Newport was the first exchange furnished with equipment actually manufactured (rather than assembled) at Edge Lane, while the latter were the first two exchanges to have inter-dialling. Portsmouth and Paisley followed in 1916. With all these exchanges the Post Office could evaluate auto working in small and medium towns, but it had no experience yet of major ones. Leeds was chosen to be the site of its largest experiment.

Leeds, equipped for 6,600 lines with an ultimate capacity of 15,000, was one of the largest exchanges in Europe (only Germany had larger) and the first in Britain to adopt five-digit subscriber numbers. Work began in 1915 and continued throughout the rest of the war period. It was finally opened on May 18, 1918.

We thus reach the end of the first twenty years of automatic exchanges, a period of considerable progress. From the earliest private installations the switching techniques had been refined to a state capable of serving satisfactorily a major conurbation.

To reach this level of development several techniques had been tested, but only the Strowger was considered to have the flexibility and simplicity suitable for British application. That the trials were considered successful is evident from a report made by the Engineer-in-Chief of the Post Office in 1925. He said "All have given, and continue to give, good service at reasonable maintenance cost."

Moreover, the Strowger system originally imported "raw" from the United States had been refined and redesigned to meet British requirements. Significant improvements had been made to the first American designs, and the start had been to the task of developing the British Post Office's own practice of engineering design. Even more significant, Britain now had an automatic telephone equipment manufacturing industry of its own, removing the early reliance on American imports and creating an export market of its own.



The period following the Great War was crucial to most nations - industrial and communications facilities of all kinds were run down and had to be built up once more if prosperity was to be regained. Telecommunications were essential to this regrowth: most countries were under-telephoned and were crying out for the renewal and improvement of their networks. Here was a golden opportunity for the British telephone industry, one that it grasped firmly.

At this time Britain and the USA were the only countries with telephone industries which could satisfy this insatiable demand for new telephone facilities, and the British and American Strowger companies were well placed to exploit this. Between them, they shared the world market for automatic systems and proceeded to export keenly.

For a company which had only started actually making its apparatus in 1915, ATM rapidly established export markets. By 1922 it had already provided the following installations:

Country Lines fitted ditto Lines under construction ditto
British Isles 22,590 4,058 10,580 1,435
Mesopotamia 1,000      
India 3,700 25 11,300  
South America 17,300 165    
South Africa   80    
China 8,000 588 200 50
Japan   205    
Straits Settlements   40    


Canada was one part of the British Empire where Strowger equipment was supplied from Chicago; New Zealand and Australia were similarly largely American preserves. South America, however, was served by the Liverpool plant and in 1922 the first start was made on the conversion on Buenos Aires and the territory of the United River Plate Telephone company to automatic working, a task completed 15 years and 150,000 subscribers later. The government of India ordered ATM automatic equipment for Simla, Lahore and Amritsar, as did the Bombay Telephone Company for that city. Other overseas cities similarly equipped by ATM in this period were Harbin and Dairen in Manchuria.

A major export order in 1924 was born of necessity. In September 1923 an earthquake almost totally destroyed the cities of Tokyo and Yokohama. The decision was taken to rebuild them on modern lines and the Strowger automatic telephone system was chosen for Tokyo. The first five new exchanges were supplied by ATM Liverpool, as well as one of the subsequent order for another five (the other four being provided by Automatic Electric in Chicago).

The following year ATM fulfilled a major order for the city of Sydney, Australia's largest seaport. Two new exchanges expanded a Strowger system first installed in 1914 by the Chicago organisation.

In 1924 ATM proudly stated "Of approximately 1,000,000 automatic telephones now in service throughout the world, 90 per cent are on the Strowger principle. This fact speaks for itself - there is no need to experiment - install the system already adopted by the world's leading telephone administrations: The Strowger Automatic Telephone System."

One country that had not made that decision was Great Britain. Over the years since the first public automatic exchange was installed at Epsom, Post Office engineering chiefs had been studying the performance, behaviour and running expenses of the new exchanges. In 1925 the Engineer-in-Chief of the Post Office said "All have given, and continue to give, good service at reasonable maintenance cost." Despite the delays and difficulties caused by the war, it was proven that automatic telephones were acceptable to the British public and provided the solution to most of Britain's telephone problems. Thus the Strowger system was formally adopted as standard in Britain.

This decision, while very satisfactory, did not give ATM any monopoly over the supply of Strowger-type systems to the Post Office. Other firms were active in the supply of automatic exchanges and the Post Office insisted on a scheme of patent pooling. This meant that each company's patents were thrown open to the others, contracts were evened out and each firm's engineers worked in close contact with those of the Post Office. This led to the standardisation and optimisation of equipment design, which was good for the Post Office and its customers, but initially the benefit to ATM's competitors must have exceeded that to ATM itself.

Major orders for expanding the inland system were placed by the BPO in this period: major ATM installations included Cheltenham, Gloucester, Gosport, Nottingham, Paignton, Shrewsbury, Torquay, Southport and York as well as further exchanges at Leeds. All this increased demand from home and abroad meant that production capacity had to be increased: the Edge Lane plant was enlarged and two further factories were acquired in Liverpool, Beech Street, near Edge Lane, and Victor Works, Broadgreen. Telephone exchange production was not transferred to automatic equipment exclusively, of course: manual exchanges were still made for applications where these would suffice.

The largest telephone problem facing the British Post Office at the beginning of the new decade was London: its telephone system simply could not cope much longer. Many studies were made, industry was approached, and the considered opinion of the BPO was that London should adopt the American (Western Electric) 'Panel' system of automatic working which had been selected to solve a similar problem in New York.

This decision, however, did not appeal to the directors of the ATM company, who were not slow to realise that the adoption of a foreign country's technology would be disastrous to the interests of ATM and British industry. Accordingly the chairman of ATM, Sir Alexander Roger made urgent overtures to the Secretary of the Post Office and alerted him to the full implications of choosing panel. It was suggested that Parliament would never sanction such a proposal in a period of serious unemployment, and accordingly an urgent study was made of an alternative Strowger system that the ATM company claimed could be made in Britain.

In Chicago the engineers of Automatic Electric had invented a device on Strowger step-by-step principles which was called the 'Call Director' and which stored and redirected the calling information dialled by the subscriber. This, it was claimed, gave the Strowger system the same flexibility of numbering and system design possessed by the Panel system. Furthermore, it would be produced in Liverpool. After many months of study and evaluation the BPO came to its conclusion and in November 1922 the Engineer-in-Chief recommended the adoption of the Director system. The first automatic director exchange in London opened five years later in November 1927: this was HOLborn, supplied and installed by ATM.

The Director system introduced to telephone users the metropolitan numbering system of a three letter exchange code and a four digit number, such as TEM 4506 (TEMple Bar 4506, ATM's London number). Another Strowger innovation employed in London was the 'Coded Call Indicator', which enabled subscribers to dial calls to manual exchanges in the system which had not yet been converted to automatic operation. The number dialled was passed forward to the distant manual exchange, where it appeared on illuminated indicators, enabling the operator there to complete the call without having to speak to the calling subscriber.

Another significant development occurred in 1929 when a British company won the concession from the Portuguese government to run part of the country's telephone system. The Anglo-Portuguese Telephone Company (APT) was established and operated in Lisbon, Porto and surrounding areas, later becoming Telefones de Lisboa e Porto (TLP). ATM set up a subsidiary known as Automatica Electrica Portuguesa (AEP) which for many years supplied the apparatus needs of these companies. Thus the Monophone, and later the 332 and 706 type telephones, became as familiar in Portugal as in Britain - and now these old black Bakelite telephones are being imported back to Britain to fill the demand for antique telephones here!

Speaking of fashions in telephones reminds us that by the end of the 'twenties subscribers were no longer satisfied with the shape and inconvenience of telephone instruments which owed their design to the 19th century. The candlestick table instruments and wooden wall telephones had separate mouth and earpieces which were inconvenient and distinctly old fashioned. In 1925 Strowger engineers in Chicago developed their first successful telephone of the handset type and this - known as the Monophone - was also offered by ATM to its British customers. The Post Office, however, was not yet ready to adopt this innovation, so the Monophone was used only on private contracts. From this metal and plastic combination evolved the Strowgerphone, a moulded Bakelite table telephone of advanced styling used on some private exchanges and exported to Ireland and other countries. By this time the Post Office had adopted another firm's design as its handset phone and ATM accordingly supplied the BPO design on public and major private contracts.

(The distinction for introducing the first handset-type dial telephones in Britain goes, however, to Siemens Brothers, who supplied German Siemens phones of this type on private installations in 1913.)

Not all the automatic exchange contracts secured by ATM during this period were for public use. The requirement of industry for instant, 24-hour communication led many firms to introduce private automatic exchanges (PAXs). These provided reliable intercommunication without the need for a switchboard operator and ATM was well established in this market with systems from five lines upwards. Special advanced features provided on Strowger PAXs included (a) the conference line, whereby a number of stations may be connected with one another automatically for conference purposes, (b) the code call, whereby an officials away from their telephones may be summoned by lights or buzzers, (c) watchman's service, (d) executive break-in to an existing conversation, (e) fire and emergency alarm and (f) tie-lines to link two or more internal private exchanges.



Notwithstanding other economic factors, business expanded throughout this decade with the growing automation of telephone networks in Britain and abroad. The Director system installed in London was a major success and this encouraged the Post Office to apply this technique to other major provincial centres. The first to follow London was Manchester and in June 1931 the first three 10,000-line units, known as BLAckfriars, CENtral and VICtoria, were cut into service. Appropriately they were supplied by ATM, although as part of the patent-sharing agreement, director equipment was also being made by the other telephone manufacturers.

Other provincial centres, which were not large enough to warrant director exchanges, also benefited from modernisation. One was Bristol, whose manual system could not match the expansion of this commercial city. Early in 1930 the Post Office telephones department placed a contract with ATM for ten exchanges comprising Bristol Central and nine satellite exchanges within a five-mile radius. A uniform five-digit numbering scheme was employed and this installation (opened in 1931) was the first in the country to employ the entire Strowger equipments mounted on shelves on single-sided racks. The significance of this innovation was that the complete assembly and testing of racks could be completed at the factory as well as simplifying maintenance and offering up to 30 per cent saving in floor space together with greater flexibility in adapting equipment to any exchange.

In the years 1930-32, stimulated by the trade depression of the period, there was much interest shown in the search for new systems that would be more economical to install than the standard Strowger system. Trial exchanges of such systems, for example the Strowger Common Control exchanges as Wigan and ARNold (London), were installed but did not succeed in persuading the Post Office to depart from their established standard. Indeed, the episode may have strengthened that organisation's desire to press on with complete standardisation.

The 1930s were very much a decade of automation. In London an all-automatic snack bar was opened, while automatic ticket and slot machines, automatically opening doors, and self-operated lifts became familiar to the public in public buildings and on public transport. Automation was also applied to other fields, one being horse racing. The ATM company's all-electric totalisator was developed in response to the inadequacy of the manual method of calculating the 'tote' money following the adoption of totalisator betting here in 1929. At the request of the British Race Course Betting Control Board ATM devised an electric totalisator working on normal Strowger principles which combined the calculation equipment, display indicator and ticket-issuing machines. It was first installed at Thirsk racecourse in Yorkshire in 1930 and was a complete success.

ATM also installed Liverpool's first traffic lights (at the corner of Lord Street and Church Street), having been active in this field from 1932 onwards, using the name Electro-Matic. The first vehicle-actuated traffic signals in Europe were installed by the company, in London. Another creation of this era was the country-wide electricity supply organisation and supervisory control and remote indication systems were also supplied for this new National Grid.

The tremendous expansion in the size and scope of activities of the company between the wars was to no small extent due to the managerial skill of its managing director, Mr T. A. Eades (later Sir Thomas Eades) and to the technical management skill of its local director, Mr A. F. Bennett, who had joined the ATM concern in 1921 as its chief engineer. Mr Bennett came from Automatic Electric Company Inc. of Chicago and was responsible for negotiations with the Post Office that led to the adoption of the Strowger system as its standard.

Mr Bennett also obtained agreement in 1931 for the supply of automatic exchange equipment to several Polish cities and towns and for establishing a production plant in Warsaw (where some of this exchange apparatus is still in use). In that year the Minister of Posts and Telegraphs told the Diet of Poland that the Strowger system had been chosen following exhaustive investigations of all available systems by a number of prominent Polish telephone engineers. A financial arrangement made by the Telephone and General Trust Ltd., an AT&E subsidiary, may have assisted this choice. In any case automatic conversion commenced in May 1933 with the Baltic port of Gdynia, and by the following year 22 exchanges had already been installed. Later on equipment was also supplied and installed in Warsaw but the full completion of the ambitious plan, designed by Edge Lane engineers, was prevented by the war in 1939. Another Baltic country that took Liverpool exchanges before the war was Lithuania, which ordered 11,200 lines in 1933.

An important development, in terms of company history, occurred in 1936 when the name of the company was changed to Automatic Telephone and Electric Company (AT&E). That said, the old device or 'logo' with the letters ATM in a circle was retained as it was so familiar and had been applied to so many castings and pressings. For a while the new name was frequently shortened to Automatic Electric in advertisements. The new title better reflected the widening activities of the firm, whose products now included road traffic signals (Electro-Matic), remote supervisory and indication equipment, totalisators, street lighting control equipment (Rhythmatic), carrier line transmission systems and mining signalling and communication apparatus. Also included were Xcel domestic electric appliances such as electric irons, cookers and immersion heaters.

"The Strowger Dial rotates with the World" ran an AT&E slogan of the mid-1930s and advertisements recorded further export successes. Somewhat remarkably, Canada had ordered 11,000 lines for the city of Victoria (B.C.) in 1930. More exchanges were supplied to Portugal, in particular Lisbon (Norte) in 1934 and Estrela in 1937. In the British West Indies automatic exchanges were installed at Halfway Tree and Kingston, Jamaica, the latter being converted to fully automatic working in 1933.

Further exports were made within the British empire, a major contract being the trunk exchange and a complete 26-exchange director system for the local network of Johannesburg, South Africa. South Africa adopted the Strowger system for the whole of the Transvaal and in 1936 a new system comprising 12 exchanges was brought into operation in and around the township of Durban. Inner Durban was served by three municipal exchanges and the outer area by nine exchanges operated by the Postmaster General. A linked numbering scheme embraced all twelve exchanges, which were of both the attended and unattended variety. This system was an early user of the very new concept of a single emergency number for fire, police and ambulance, which was introduced in London the same year.

At home the Post Office proceeded with further standardisation. Having fixed upon a single pattern of relay and uniselector, the BPO now adopted a new, optimised two-motion selector: this, the 2000 type, originated as the AT&E type 32A, the name by which it is still known in Poland. First used on a large scale in 1936, it marked the completion of the BPO's full standardisation of equipment, circuits, maintenance procedures and rack layouts. Complete inter-changeability of all manufacturers' products was now at hand.

In addition, the update in design enabled manufacturing costs to be reduced and made for more reliable exchange operation and simpler maintenance on site. The redesigned exchanges were also around 40 per cent more compact than the 'standard' American Strowger version.

A growing market of the 1930s was for the smaller pattern of PABX. Hitherto private branch exchanges had needed bulky switchboards, a battery room and the constant attendance of an operator, which smaller businesses did not find feasible. The only alternative was the PAX, an self-contained automatic exchange which required no operator but could not handle external calls, either outgoing or incoming. The company's type 349 PABX solved all these problems.

Mounted in a compact steel cabinet and requiring no special accommodation, this device ran entirely from the mains using a battery eliminator. Incoming exchange calls were answered by one or more extension users, while all users could dial their own outgoing calls by prefixing them with a single code digit (unless they had outside access barred, another facility). Exchange calls could be passed between extensions by the pressing of a button and dialling another extension number. Though commonplace today, these facilities were considered revolutionary in the late 1930s.



The late thirties had seen a transformation in the fortunes of Edge Lane. Notwithstanding any public acceptance of 'Peace in our Time', the AT&E factory was gearing up for increased production. Some workfolk were signing Official Secrets documentation, the workforce was back on full time and the largest ever building extension programme was put in hand. Floors were added, buildings were extended and new buildings were put up, one being known as the 'air ministry' block.

War effort was well under way by 1939 and in late 1939 the staff were having to give up their weekends to make sandbags and practice evacuation drill to the new underground shelters. The factory lost its militia men, its territorials and some volunteers, but after this it was designated a war industry, with reserved occupations. The majority of employees now signed the official secrets act and Edge Lane recruited its own home guard and air wardens. All external windows were provided with black out curtains, which were used in earnest during the 'blitz' of 1941. Although the factory was a prime target nothing stopped its war efforts.

As in the First World War, the Strowger Works made navigational instruments, and a story often told concerning the company's World War II work involves a woman who used to push a pram full of laundry down Edge Lane. So ordinary a sight would never even provoke a second glance as she pushed the pram to a villa a quarter of a mile from Strowger Works. Had a curious onlooker cared (or been allowed) to peep under the pile of laundry, however, he would have discovered a vitally important, most secret piece of aircraft equipment - the RAF's distant reading gyroscopic compass. Special apparatus to test it had been set up away from the factory to be free of magnetic disturbances. Some 30,000 of these instruments were produced for allied aircraft.

Other vital productions were telephone equipment for home defence networks and military field use. The government introduced a system of licensed supply for private exchanges: only companies involved in war work could obtain equipment, and even then renovated and second-hand equipment was supplied whenever possible. All the time pressure was increased for additional production to aid the war effort and the factory was visited regularly by Air Ministry liaison teams and by Allied military missions. In order to manufacture more transmission equipment a section of Crawfords' biscuit factory was taken over.

As a result of all this Edge Lane was able to make a significant contribution to the war effort. At the same time commercial telephone engineering had to take a back seat and development of new systems for public network use ceased. As with much of the remainder of British industry, a valuable commercial edge was lost, and despite the national victory, the devastation and suspension of supplies during the war years left the company in a depleted position at the end of the war.



Top priority after the cessation of hostilities was to renew the run-down production facilities that had served the company so well during the war. Throughout the world there was a great demand for improved telephone facilities and this fuelled the country's necessary export drive. At home too, there was a pent-up demand for industrial telephone facilities that had been unfulfilled during the war.

Private automatic exchanges and branch exchanges were in great demand in 1946 and the sales department was quickly organised to snap up these orders. Within a few months the business taken for these pent-up orders equalled the whole of the pre-war business in numbers of exchanges. In such a market margins were good and the industry at this time had a price cartel under which all of the major suppliers charged similar prices. This scale of this business was such that a separate company, Communication Systems Ltd., was formed in 1947 to look after private exchange contracts. The only problem, maybe not fully appreciated at the time, was that considerable capital investment was needed to service these new orders, while payback was slow, since the PAXs and telephones were generally not sold but leased under fourteen year agreements.

Main exchange business was equally buoyant, although the growth of the home market was hindered by government restrictions on the Post Office's capital investment programme. The arrangements between the British Post Office and Commonwealth administrations included a Bulk Contracts Committee and a 'costs plus' price system which ensured an adequate distribution of orders to the British manufacturers for both main exchanges and stores together with guaranteed profits. The captive Commonwealth countries with the Post and Telegraphs departments staffed by expatriate 'Brits' continued to buy British and the orders rolled in.

So great was the demand for equipment, the company continued to sponsor overseas production. In 1948 its director Mr A. F. Bennett negotiated an agreement with the newly independent Indian government, which wished to set up its own telephone manufacturing facility. This was to be divorced from international finance but using negotiated patent rights, and the factory set up in Bangalore as a result now flourishes as Indian Telephone Industries (ITI), employing thousands of workers. It was laid out as a Strowger manufacturing unit and was designed by experts from Edge Lane. Liverpool also secured a fifteen year trading agreement in helping ITI organise and run its factory, and in later years ITI was to supply Strowger equipment to Edge Lane to meet an unexpected demand and to challenge its progenitor in its overseas markets.

The encouraging start of the post-war period continued throughout the 1950s and well over a million lines of Strowger equipment were manufactured at Liverpool. Around half of this output was for export, moreover. Foreign destinations of this apparatus included the traditional, pre-war countries (the Colonies, South America, Portugal and Poland) but also new markets such as Egypt, the Netherlands and the USSR.

In some of these countries it was recognised that local manufacturing was necessary and the first external factory to be set up was in Brazil in 1948, followed in 1950/1 by Portugal. There was, however, a significant difference between the two ventures: Automatica Electrica Portuguesa (AEP) was to establish itself as a competent, Government-recognised organisation whereas the Brazilian factory was run more or less as a loss-leader and had been opened as a condition for tendering for that country's network.

The Strowger equipment that was the mainstay of manufacturing at Edge Lane and elsewhere had been honed to a high degree of perfection but it no longer represented the state of the art, as it had done on 1936. While it met the requirements of the BPO and of other British-influenced administrations there was no mistaking the fact that many other telecommunications operators were turning to Crossbar. In some parts of Europe and in North America all major new installations were of this latter technology and AT&E wisely chose not to ignore this trend.

As a result manufacturing rights were secured for the so-called 5005 Crossbar equipment of ITT and engineers and development resources diverted to this project from Strowger. Brazil was one of the company's first sales markets for Crossbar, though it must be said that many teething and equipment design troubles were experienced initially. In the meantime the resources for Strowger development were reduced, while the demand for this inevitably began to decline.

If improvements in switching technology characterised the inter-wars period, then the breakthrough of the fifties was the development of inter-continental telecommunications, starting with the opening of TAT-1, the first transatlantic telephone cable in 1956. Together with international standardisation of specifications this led to a new boom in transmission equipment, and a new 'Golden Mile' production facility for manufacturing this was set up at Edge Lane.

Another new development area was the application of electronics to telephone switching, with the development in 1955 of the magnetic drum later used as a look-up table in register-translators for subscriber trunk dialling and the like. This reflected the trends of thought within the Post Office, which the following year set up a Joint Electronic Research Committee (JERC) in conjunction with AT&E and the other major British manufacturers. With this, the first steps were taken towards achieving a British electronic telephone exchange.

By the end of this decade the AT&E company had reached the peak of its expansion programme and was operating at the full extent of its resources. The group product portfolio covered MAX, PAX and PABX exchange equipment, telephones, voice frequency signalling equipment, line and data transmission equipment, VHF and UHF radio systems, telegraph equipment, remote control supervisory equipment, power line carrier telephony equipment, crystal control equipment, traffic signals, machine tools, plastic mouldings and mine signalling equipment. In conjunction with GEC and British Ericsson overseas manufacturing organisations had been set up in South Africa (TMSA) and Australia (T&EI). Associations with BICC Ltd., Telecommunications Research Ltd. and the Telephone & General Trust Ltd completed the picture.





If the 1950s had seen a golden era of limitless orders and assured profits for AT&E, this period was now at a close. It is acknowledged that the company was not in a healthy state by 1960. Grasping new opportunities in the market place had involved major investment, maintaining an elite group of engineers was costly, finished goods stores were full and production was not at peak efficiency - a complete contrast to the situation of 1950.

Many of the company's products were dated and had been designed specifically to meet BPO standards, which seldom lent themselves to economic production and competitive overseas marketing. Meanwhile Swedish Ericsson and ITT Pentaconta Crossbar exchange systems had a firm grip in Europe and a threshold for world-wide exploitation, particularly in the developing countries.

The successful senior management team of the early post-war period had reached retirement age and the top team was ripe for replacement. A vacuum now occurred, the link with BICC Ltd (the company's progenitor, so to speak) was severed and the company was open to be taken over. This major development duly occurred in 1961 when the merger took place between the Plessey Company Ltd., Automatic Telephone & Electric Company Ltd. and Ericsson Telephones Ltd. Subsequently, with the formation of the Plessey Major Product Groups, ATE and Ericsson Telephones became the nucleus of Plessey Telecommunications Group, later Plessey Telecommunications Ltd.. (Ericsson Telephones Ltd., while originally founded as the British L. M. Ericsson Company Ltd., had been independent of the Swedish concern for many decades.)

Initially the old AT&E and Ericsson Telephones (ETL) firms continued trading under their old names, with little material change. Major reorganisation followed then: many of the existing senior management resigned while new expertise was brought in from the Plessey empire. New accounting and management techniques were introduced and gradually a new era of greater efficiency was brought in. This was nonetheless hard-won and not achieved overnight.

In 1964 Strowger Works became the headquarters of Plessey Telecommunications, controlling the activities of some 30,000 employees in the North West, the North East and the Midlands, as well as in Brazil, Portugal, Ireland, Africa, Singapore, Canada and Nigeria. The Liverpool production facilities were now to concentrate on the manufacture of all main exchange equipments for the group, leaving the former Ericsson works at Beeston to make private exchanges, telephones and transmission equipment. Traffic signal production was moved to Poole, while loading coils, street lighting and remote control manufacturing was discontinued. And most important of all, the business was becoming viable once more.

During this period the company kept open its arrangement with AEP (Automatica Electrica Portuguesa) and imported telephones and other equipment. This plant continues to make BPO-style telephones of the 700 type as well as electro-mechanical PABXs.

At the same time the Post Office was making long-term plans for the modernisation of the UK telephone network. Inevitably these included electronic switching (which the collaborating companies of the JERC had been developing with the Post Office since 1956) and recognised that the days of Strowger step-by-step technology were numbered. It became clear, however, that no simple or immediate transition from electro-mechanical technology to electronic was possible, and instead a halfway house solution or solutions had to be found. Plessey companies provided three such solutions, Pentex and 5005 (or TXE2 and TXK1 in Post Office parlance), and subsequently TXE4.

For large exchanges the only new technology available immediately was Crossbar, and Plessey was the sole British manufacturer with a product offering. Indeed Plessey (AT&E) had been alone among the British manufacturers to realise the potential of this system, a decade previously, and was now in a position to supply the needs of the BPO and meet the increasing demand for telephone exchanges throughout the world.

In recognition of this Plessey further developed the 5005 Crossbar switching system to meet the Post Office's requirements. Approval was first given in 1962 for a trial exchange to be installed at Broughton near Preston, and further examples were installed at many BPO exchanges, following its adoption in the 1966 at the BPO's official 'interim system'. (The Post Office gave it their designation TXK1.) This gave the firm its first real opportunity to break into the major home market from a position of strength and to recover some development costs.

In a parallel field the company had acquired the first British patents on electronic switching systems and developed the magnetic drum Register Translator for use in the growing Subscriber Trunk Dialling (STD) network. From STD evolved direct international dialling and again the company was early in this field by supplying the 5005 Crossbar international 'Gateway' exchange. The London Gateway exchange at Wood Street was in its day the largest of its kind and switched 5,000 incoming and 5,000 outgoing circuits to all parts of the world. The maintenance and accounting equipments associated with it included a considerable amount of advanced electronics developed in the laboratories at Strowger Works.

BPO recognition of the 5005 equipment enabled Plessey to sell the system overseas and its first 5005T gateway exchange was supplied to Sydney's international trunk switching centre in Australia. In 1965 the first local Crossbar exchange was supplied and installed in Lisbon and the following year the BPO adopted the 5005A version for local non-director areas pending the arrival of electronic exchanges.

Crossbar equipment of the 5005 variety was also used to modernise official telephone facilities in London and formed the nucleus of the present Government Telephone Network. Known as the Central Branch Exchange or CBX scheme it provided push-button telephone facilities in the Houses of Parliament government ministries and departments. Another 5005 system was installed at Post Office Telecommunications Headquarters, and other exchanges of this type were supplied to Nigeria and Brazil.

For smaller exchanges the selected solution was another Plessey product, Pentex. Pentex was an electronic switching system employing reed relays as the switching element that had been developed by Ericsson Telephones Ltd and now came under the Plessey Telecommunications Group wing. Following field trials at Leamington and Peterborough in the mid-sixties it was adopted by the Post Office as its TXE2 exchange and was a major vehicle for exchange modernisation.

Subsequently a further reed relay system was developed for larger exchanges, known as TXE4. This was based on existing world telecommunications practices and was adapted for the British network, being adopted by the Post Office in 1972. Plessey was not the prime contractor initially but set up a brand new factory at Huyton for its production, opened in 1974.

Crossbar and reed relay systems were intended only as transitional, and throughout the sixties and seventies work was also proceeding on all-electronic, stored program control exchanges in which the operation of the exchange is controlled effectively by a computer running a predetermined program. The first of these was the 'System 250' processor which was ready for field trials in the middle of the 1970s. Another logic-controlled system was fluidics, which for a short while held out a promise but was abandoned after the construction of an experimental fluidic exchange at the Roke Manor research establishment.

The long-term goal of the Post Office and industry team that made up JERC was to develop a world-beating all-electronic exchange and as time progressed it became clearer that this would perforce employ digital technology. In time it would be known as System X and its immediate genesis was in a Post Office report into the telecommunications systems of the future, presented in 1966. A more detailed study, completed in 1971, came to the conclusion that the only future was a digital one. By 1975 agreement was reached with the leading manufacturers to collaborate on System X, the new generation of advanced switching systems. Its story is continued in the next chapter.

The transition from the 1960s to the 1970s began promisingly and 1971 saw the installation of Wood Street international exchange in London, the first Plessey installation to use a computer as part of its control equipment. The telecommunications industry now looked forward to a period of full order books, having responded to its major customer's requirements and scaled up capacity in accordance with the Post Office's stated forecasts. Instead it had to suffer a cut in orders, as the Post Office became the victim of Treasury cuts. Plessey Liverpool was able to obtain a small measure of compensation by negotiating to take over the balance of main exchange contracts that Pye Telecommunications was willing to relinquish.

The Telecommunications Group was at the crossroads but the company was determined to fight its way out of its difficulties. Strowger resources were trimmed; all manufacturing units within the Group were scrutinised and compared one against another in the wish to make savings. Edge Lane, with its heavy overheads. Inefficient space utilisation and surplus capacity looked a prime candidate for 'rationalisation' but instead it was modernised and remained telecommunications HQ within the Group. The new TXE4 factory at Huyton has already been mentioned but otherwise the cuts led to the closure of several satellite factories and compulsory redundancy for many workers.

Those remaining saw the fruits of an imaginative reconstruction plan for Edge Lane. This recognised that the new technology would require less space and fewer production staff and at the same time, more specialised technical staff. Some older buildings were demolished, a new building was completed and the System X team moved in. The future was perhaps the toughest challenge to face Edge Lane in its history but the rewards of success could be its finest chapter.



The present decade has seen perhaps the most dramatic changes at Edge Lane since the initial establishment of telecommunications production at the site. Organisationally, too, the site has come under new ownership, with the amalgamation of the telecommunications interests of Plessey and GEC into the new company of GEC-Plessey Telecommunications (GPT) in 1988. In this period Strowger, the one-time staple product, was phased out as were the 'interim' main exchange products Crossbar and TXE4. At the same time a major period of renewal was undertaken to adapt the Edge Lane site for the new high-technology products, the most significant of which has been System X.

System X indeed has been not only the largest single development project in British telecommunications during the past decade: it has also been the Liverpool site's largest ever success. Following the early joint development stages, Edge Lane is playing the main role in its continuing development of System X, which is now produced exclusively by GPT.

System X is the spearhead of a total approach to telecommunications. It is a comprehensive family of products embracing all types and sizes of exchange, from small local ones to trunk transit and international gateway exchanges. The technology can be integrated into any existing network, analogue or digital, or it can be used to create a completely new telecommunications system. In addition to voice services, System X can provide non-voice digital services on a single integrated network, making ISDN a reality.

From the outset System X was designed as a co-ordinated range of products which would integrate with each other without making any existing parts obsolete. The programme provided for the development of a comprehensive range of switching applications—local, trunk and international for voice, data and other services—designed to a common technological base. In it three major system concepts—stored program control, common channel signalling and digital switching—are exploited in a carefully organised system architecture based upon a repertoire of modular subsystems which can be replaced for updating independently of each other, without necessitating complete replacement of the exchange. The latter enables advantage to be taken of new devices and techniques as they become available, avoiding premature obsolescence of the exchange as a whole. Prime objectives have been to provide systems that provide for easy growth, are adaptable to the different requirements of different networks and administrations and provide the necessary flexibility for the progressive expansion of services.

This family of advanced digital switching systems evolved from the JERC agreement of 1956 as a co-ordinated project between British Telecom (first the Post Office) and industry. The original System X collaborators were GEC, Plessey and STC but with much of the development work completed and following a review of the technical partnership in 1982, the last-named company withdrew and Plessey (now GPT) was named as prime contractor for the continuing System X development programme.

Since then System X has formed the foundation stone of British Telecom's digital modernisation strategy and has also been sold into 14 other administrations' networks on four continents at home and abroad, including those of Kenya, Gibraltar, the Falkland Islands, China, Colombia and St Vincent. In all, in excess of 12 million lines have been ordered to date.

The first milestones along the System X road to success were passed in 1979 when the first public demonstration of a System X exchange took place, at the international communications exhibition in Geneva, together with the placing of initial orders for a first tranche of eight exchanges, including local, trunk and tandem exchanges. These came into service between 1981 and 1983. Since then, production and installation has continued apace and as well as providing public networks for British Telecom, Mercury Telecommunications and others, it has also been adapted for switching optical fibre private circuits (in the Flexible Access System and City Fibre Network projects) and as the switching infrastructure of a mobile radio network.

Most recently the product has achieved a world record, unequalled by any other telephone switching system. In front of independent observers and assessors a System X exchange carried 1.5 million "busy hour call attempts" or the equivalent of 415 people making phone calls each second. As well as setting a new standard for British technological achievement, this sets the seal on the success of System X and demonstrates its unrivalled ability to perform in situations where processing power per call must grow to meet customers' increasing demands for advanced services. Even this, however, will not be sufficient in the new century and the Edge Lane engineers are working on an even more advanced concept, described below.

Fundamental to this is the takeover of Stromberg-Carlson. In 1982 the Edge Lane organisation acquired the public switching activity of the American telecommunications company Stromberg-Carlson. This company (S-C) had made a successful business out of supplying the needs of the USA's independent telephone companies, and its acquisition has given GPT a valuable springboard into the North American market.

More importantly it has made possible what is the firm's most significant and exciting development of the decade, namely DCOX or GPT's global switch programme. This is a new digital main exchange engineered to 'global' standards to make it equally suited to use in both the North American T1 and CCITT international standard networks. Currently the company makes two different digital switches, System X in the UK and the DCO (Digital Central Office) at S-C's plant at Lake Mary in Florida. The new switch, however, will be a merger of the architectures of System X and the DCO, combined with a new high power central processor.

The DCOX 'converged' switch will be equipped with a processor operating significantly faster than existing systems and will use standardised fibre-optic interfaces between modules to ease the interconnection of systems from other vendors. It will also make extensive use of technologies already designed into the latest SEP4 version of System X, including 32-bit microprocessors, high capacity memory chips and high performance subscriber line circuits.

While System X and its family have dominated the present decade for GPT, a few other significant events deserve mention, if only to complete earlier stories. The Strowger era came to its inevitable close in 1985 when the last rack of this equipment was produced at what had been Strowger Works—the last of 300,000 racks produced over a period of 70 years. In the same year the manufacture of TXE4, the company's first electronic MAX, was discontinued. It was made at Huyton and Chorley and during its eleven-year life (1974-85) 16,000 racks were produced. Many of the production techniques later used on System X were first introduced on TXE4. Already the previous year production ceased of Crossbar. It had been engineered at Edge Lane, although it was manufactured in the North East. In 20 years of production some 50,000 racks were supplied, the last one being delivered in October 1984.

The 100th anniversary of the invention of practical automatic telephone switching thus sees the principal site of telephone switching development and manufacturing in Britain in a powerful position and poised to supply the increasingly demanding needs of the next century. The changes in technology have made their impact on both the site and upon the workforce. The company has changed from being a relatively 'low technology' manufacturing site which once made most of its own components—relays, switchboards, even nuts and bolts—to an advanced 'high-tech' design and assembly site where the components are all sourced outside. With ever-increasing automation the number of employees has reduced and their skills have changed drastically. The site has also changed to reflect the new technology; it is pleasing to report that in 1985 the firm gained a national award for improvements to the environment.

The next century will see developments in telecommunications switching we can hardly guess but it is a reasonable supposition that the Edge Lane site will be involved in them.



Telephones and their history in general

Earl R. & Povey P., Vintage Telephones of the World. Peter Peregrinus, 1988.

Emmerson A., Old Telephones. Shire Publications, 1986.

Robertson J.H., The Story of the Telephone. Scientific Book Club, 1948.


Automatic telephony

Aitken W., Automatic Telephone Systems. Benn, 1922.

Atkinson J. Telephony. Pitman, 1948.

Baldwin F.G.C., The History of the Telephone in the United Kingdom. Chapman & Hall, 1924.

Chapuis R.J., 100 Years of Telephone Switching. North-Holland Publishing Company (Amsterdam), 1982.

Fagen M.D., A History of Engineering and Science in the Bell System. Bell Telephone Laboratories, 1975.

Herbert T. and Procter W., Telephony. Pitman, 1932.

Kingsbury J.E., The Telephone and Telephone Exchanges. Longmans Green, 1913.

Lawrence J.A., Fifty Years of Automatics (in Post Office Telecommunications Journal, Autumn 1962).

Murray L.J., Development of Automatic Telephony in Great Britain, in ATE Journal, 1954, pp 271-293.

Poole J., The (Practical) Telephone Handbook. Pitman, several editions.

Post Office Electrical Engineers' Journal. Special editions marking the 50th and 75th anniversaries of the institution, October 1956 and October 1981.

Robertson J.H., The Story of the Telephone. Scientific Book Club, 1948.

Smith S.F., Telephony and Telegraphy. Oxford University Press, 1978.


The first Strowger systems

Childhood of Automatic Telephony (in Post Office Electrical Engineers' Journal, pp. 296-300, 1930).

Journal of the Institution of Electrical Engineers, vol. xlvii p. 651.

Smith A.B., History of the Automatic Telephone (in American Telephone Journal, June-August 1908 and Telephony, September-December 1908.


Epsom and other early exchanges

Daily Mail, May 23, 1912. (Drawing of the interior of an exchange.)

Electrical World, June 15 1912. (Epsom, pp. 1325/6.)

The Illustrated London News, December 2, 1911. (Illustrated feature on p. 913.)

Post Office Electrical Engineers Journal, July 1912. (Epsom.)

ditto, January 1939. (Portsmouth, p.321.)

ditto, October 1939. (Official Switch.)

Post Office Telecommunications Journal, Summer 1964. (article by Bonnard J.A., Blackburn: The Oldest Automatic Exchange.)

The Sphere, December 2, 1911. (Illustrated feature on p. 197.)

The Strowger Journal, October 1951. (Portsmouth, pp. 20-29.)



ATM .......Automatic Telephone Manufacturing Company

AT&E .....Automatic Telephone & Electric Ltd.

Auto ....... automatic

BICC .......British Insulated & Callenders Cables Ltd.

BI&HC ....British Insulated & Helsby Cable Company

BPO ........British Post Office

BSI ........ British Standards Institution

CB ......... central (or common) battery

CBX .......central branch exchange

GPT .......GEC-Plessey Telecommunications Ltd.

IBTE ......Institution of British Telecommunication Engineers

IPOEE ....Institution of Post Office Electrical Engineers (now IBTE)

MAX .......main automatic exchange

PAX ........private automatic exchange

PABX ......private automatic branch exchange

PBX ........private branch exchange

PMBX .....private manual branch exchange

PO ......... Post Office

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