Canadian Transcontinental & Other Significant Northern Open Wire Facilities

Canadian Open Wire Facilities


 Our Canadian open wire fanatic, Erik, atop a  remaining relic of the Chicoutimi lead, Quebec, Canada.

Canadian Power Lineman at the International Lineman’s Rodeo in Bonner Springs, Kansas

Canadian Open Wire Facilities section will be devoted to advancements in open wire outside plant in Canada from the earliest periods of telegraph to the line wrecking of lines today.  We seek to publish any information you might provide us regarding our northern neighbors’ contributions to the great art of open wire design, construction, maintenance, ownership, and operation.  Look for exciting information regarding Canada’s own systems whether it be with Bell Canada and Northern Electric or the Canadian Pacific Railway, Canadian National or other ownership within the provincial networks.

Erik Boucher’s creative take on the The Great Canadian Rockies with an approaching CP locomotive.

Views of British Columbia Telephone Open Wire,  Anarchist Pass and Princeton, B. C., Circa 1989

Photos and Commentary Reported By Arend Gregor

I added some images of a road trip I made in 1989 and the final year of BCTel roadside poles.  Due to the mountainous terrain, underground cables were supported on the old telegraph poles instead of trenching through solid rock.  Later, the tops were cut off and only the poles and cable remained.  It is nice to know that there are more people who enjoy these relics and even worked on them.  Enjoy the old photos!


BCTel poles aside Highway 3, Anarchist Pass, c. 1989.


BCTel poles, Highway 3, Princeton, British Columbia, c. 1992.


 The Great Canadian Transcontinental Open Wire Lead, Opened in 1932

Route of Trans-Canada Telephone System

No discussion of Canadian open wire technique would be complete without mentioning the most ambitious construction project in this northern country’s national history: The Trans-Canada Telephone System.  Let’s travel back in time to the late 1920s when a long distance telephone call from Ontario might be routed through the United States in order to reach Vancouver, British Columbia, for example.  This project came about because the seven largest telephone systems in Canada voiced their concern about this situation and firmly predicted a transcontinental Canadian route was required to meet this future traffic need and to avoid the complex switching needed to connect eastern Canada to the western coast and points in between.   Since long haul toll service was routed over U. S. lines, this also caused extra expense and Canadian phone companies were not adequately serving, nor obtaining the profits, from a line exclusively on Canadian soil.  More importantly, too, was the need of a Trans-Canada lead which would coordinate with the North American Switching Plan.  Now, this project didn’t emerge overnight.  Because seven phone companies in Canada were involved, significant pre-planning commenced years before January of 1932, to embark on this aggressive effort to tie the nation together.  There were many obstacles.  Among them were the technical tribulations of operating a highly extended system between coasts (circuit design), the physical obstruction posed by the Canadian Rockies (construction forces) as well as financing and budgeting the immense project

Let’s start with how the phone companies assembled their teams for the task before them.  Canadian population centers are mainly (as in the United States) concentrated in major cities of the eastern seaboard and western coasts.  Between are cities of varying sizes and many small towns.   To define the “west” in Canadian terms is to consider the provinces of British Columbia,  Alberta, Saskatchewan and Manitoba.  In the “east” we find Ontario and Quebec as well as the Maritime Provinces, Prince Edward Island, Nova Scotia and New Brunswick.  Each possessed their own individual telephone operating companies.  These were: The British Columbia Telephone Company, the Alberta Government Telephones, the Saskatchewan Government Telephones, the Manitoba Telephone System, The Bell Telephone Company of Canada (Ontario & Quebec), the New Brunswick Telephone Company, and finally, the Maritime Telegraph and Telephone Company (Nova Scotia & Prince Edward Island).  Cooperation of all was deemed essential if the project was to move forward.

Before the Trans-Canada, toll service in Canada was treated in this manner.  Each regional telephone company or governmental authority contained its own toll service boundaries at first.  Oddly enough, no means existed to connect them fully without going through United States interconnected circuits.  The Bell System and other Independents provided the means to communicate between Canadian Provincial boundaries.  Part of the Canadian problem was due to finances.  Up until 1932, finances weren’t available to provide these links.  Because these provincial systems isolated themselves to toll interconnection, it was a major dilemma.  So, the leadership of these organizations decided to make some major changes with each others’ cooperation.  Thus, the  formation in 1921 of the Telephone Association of Canada (TAC) became reality.

When formed, the seven systems agreed to protect their investment, establish uniformity in construction and maintenance plans, come to agreement on uniform construction, maintenance, operation and accounting procedures, share technical information, and do what was necessary to maintain an efficient all-Canadian telephone system.

The group met annually.  Without doubt, the problem of trans-Canada call routing came up immediately and a committee was assigned to investigate and recommend a means to rectify this difficult challenge.  By the next year, 1922, the committee announced its findings.  At this Second Annual Meeting, the project’s ambitious nature was explained to the audience.  Mainly, the Rocky Mountains were the most formidable physical barrier to construction, and among the suggestions made were to utilize the Canadian Pacific and Canadian National Railways’ pre-existing aerial wire routes and lease circuit space.  Between Sudbury and Winnipeg was a distance to cover of about 1,000 miles.  Additionally, pole line construction in the east, where intersecting Quebec to St. John, had to cover very rocky, difficult terrain, where lines confronted numerous water and coastal geography.

For several years the the project seemed quite impossible.  The dream  languished for many years until 1928 when technology both in construction and circuit design caught up with the project’s potential.   The TAC’s Annual Meeting, the Bell Telephone Company of Canada’s leadership revisited a need for the project to commence by suggesting a full engineering study recommending all the needs for a true Trans-Canada route and subsequent service.  Meanwhile, the various telephone companies devised and coordinated efforts to interconnect their toll services between provinces and with only three regional service gaps being closed by 1927, it appeared the only remaining gap was the “big one”; bridging the Canadian Rockies.

So, here’s how it all began.  With a preliminary report by the Executive Committee of the TAC, April 1929, using extensive information garnered from the previous study years prior.  Building on this, the Executive Committee reviewed how the circuit requirements may have changed in the proceeding years, whether the proposed earlier route necessitated any changes, transmission requirements and how these may have been altered in light of new technologies, maintenance studies and what evolving features might be included in the new facilities.

By the end of 1929, the final study, with all new considerations added, was now accepted by the Executive Committee and presented at the September Annual Convention to members.  With firmly acceptable budget numbers and costs climbing every year this project was held in abeyance, it was decided by membership to green light the project.  1930 would be the start date.  The best means to accomplish the major effort was for each telephone entity to provide the future facilities which were expected to be a part of the final plan in each territory.  Completion date was scheduled for early 1932.  The total proposed length was about 4200 miles.

Circuit requirements for the line and number of pairs necessary to be included in the route was based on traffic data.  By reviewing the years of routed toll calls prior to 1929 for about a decade, this provided a good estimate.  Furthermore, the individual telephone companies undertook studies which looked at micro data as well as macro data on each system, which furnished further predictions on what the new system might be expected to bear in the decade 1932-1942.  Flexibility was considered crucial.  The line design expected to lay twelve circuits, however by 1932, only seven were actually built and heated up.

The circuit layout up to then, as we mentioned, was piecemeal.  The Rockies was the major barrier to the western Canadian population; in the east, there was the Sudbury-Winnipeg gap and one which was daunting between Quebec and St. John.  Around mid-1928, these gaps were nearly completely closed, although more work was required to put finishing touches on them prior to the transcontinental opening.   The Telephone Association of Canada and its members reviewed the situation where there appeared to be very little profitability and business by closing these gaps.  Instead of viewing these as “little used” facilities, it was thought perhaps the increased ability to link these cities might manufacture more traffic.  If congestion in the east was eliminated and new lines opened up, perhaps traffic would grow–not diminish.  They would be proven . . . correct . . . in the final analysis.

So to prove a point, the Canadian Pacific Railway Company’s aerial wire line route, provided a leased circuit over the Rockies from Calgary to Vancouver.  This was around November of 1928.  The same transportation company also leased a circuit between Sudbury and Winnipeg.  This further closed a gap.  But these were simply a test of the potential prosperity of such a future project.  In the east, the rocky landscape of the Maritime Provinces were bridged partly by new line construction and other connecting Independent companies’ lines.  Thus, New Brunswick Company’s line at Edmunston was connected by two circuits by December of that year and St. John was now part of the complete system.  Case closed?  Not quite.  This was a transitory medium prior to building the “big one.” 

The major problem remained: while the continent was bridged, the circuits remained voice-frequency types.  Adding to this technical limitation was the need to switch from one system to another, including railway facilities.  With all the switching, it was both inconvenient and time-consuming.  Transcontinental toll calls were very expensive with this process.  It was predicted that with the new project’s completion, only two switch operations would be encountered by toll customers when calling on the new Canada Transcontinental Lead in 1932 and after.

Now, before you correct me, there were operating carrier systems on these transcontinental calling routes.  I was able to obtain some interesting data regarding the different segments of the “initial” Trans-Canada configuration.

Vancover – Calgary: three (3) direct circuits to Halifax

Calgary – Regina: three (3) direct circuits to Halifax

Regina – Winnipeg: three (3) direct circuits to Halifax

Winnipeg – Toronto: three (3) direct circuits to Halifax

Toronto – Halifax: three (3) direct circuits to Halifax

Montreal – Halifax:  four (4) direct circuits to Halifax

St. John – Halifax: four (4) direct circuits to Halifax 

The Grand Route is Selected

Open wire was the chosen medium for the majority of the new facility which crossed many plains of western Saskatchewan, Alberta before entering the Rocky Mountain passes.  Many existing right-of-ways were utilized in rehabilitating the existing structures or replacing them.  This was done for several reasons.  Inductive exposure to near-by electric transmission and distribution lines was largely mitigated because those earlier routes had avoided potential problem and that existing structures had repeaters and where cable was involved, loading coils, installed.  The new repeater points would be using existing poles and where necessary, new ones on the same right-of-way easement.  Doing this avoided an entirely new route in the Northern Great Plains sections of this new route.

However, the onslaught of the Rockies faced a new and critically different situation.  Up to then, no existent civilian (non-railway) communications links traveled over the Northern Rocky Mountains.  Only railway ROWs and easements had made the traverse across the high country.  While it may have been convenient to have leased further easement from the railways to place this new non-transportation communications link, this was not done.  Instead, one hundred and fifty miles south of the Canadian Pacific Railway’s easement, a new route was selected.  Several technical problems confronted designers of the new Transcon: open wire would have to be terminated with complex termination structures, toll calls loaded onto multi-pair copper cables for lengthy railroad tunnel routes, only to emerge on the opposing side at similar termination structures, risers, filters and converted to open wire medium.  While the new route was almost two hundred miles longer, the susceptibility of these circuits to reflection losses, various degrees of echo effects, and other technical problems associated with open wire to cable and back again, made the decision much easier to accept.  Another reason was the fact that the more lengthy route took the open wire through settled territories in the mountains: towns and villages which occupied the route and allowed maintenance to be easily accomplished on these intermediate locations.

The situation was somewhat different on the Eastern Plains side of the Rockies, where between Brandon and Winnipeg, the existing main lead of four ten pin crossarms was avoided and a new line routed 40 miles so as to avoid power contact and the necessity of adding arms to the existing lead.  There were points where the poles would have carried up to eight (!) arms for new and existing toll and exchange circuits.   This would be avoided in the new venture.  Yet, there was enough re-building to do in order for the existing lines to carry this project’s traffic: about 2,000 miles of pole rebuilding work!

Incorporating the Finest in Transmission Design Techniques

While most Canadian facilities had been built in sections, connecting points within each province, these were shorter haul facilities.  Instead of a Bell System Long Lines Division where the local operating companies were linked by a separate entity of transmission furnishing long distance routes, Canada had no such similar organization.  So, it was now a new endeavor to link the entire Canadian nation by a new lead incorporating long haul facilities.

The first thing to go was using voice frequency transmission methods for the new Canadian Transcon.  There were far too many problems associated with voice frequency systems and in view of the long distances involved, this would only cause inefficiencies and too many losses in the system operation.

Crosstalk, transmission equivalent, attenuation (noise), and distortion at splices and between entrance cables and termination points would rise to an unacceptable level.  This dictated the use of high frequency carrier on open wire pairs.  Along with any switching losses, carrier was deemed necessary.

As in the DBR (Defense Backbone Route) lead in the United States ten years later, the highest quality design, procurement and construction was undertaken to achieve low loss and high efficient operation.  For example, the conductor chosen was 165-guage hard drawn copper placed on CS tempered glass insulators at eight inch spacing.  This conductor has high strength in storm conditions.  In British Columbia, these were commonly used.  Because temperature and humidity changes were acute where mountains versus lower elevations were encountered, this combination of crossarm design was desired.  Furthermore, larger gauge conductor along with more efficient insulation gave considerable advantage where repeater spacing was planned.   No phantomed circuits (voice frequency) were undertaken; avoiding additional complexity.  Crosstalk was eliminated through point-type eight-inch brackets.   This involved placing over 1500 miles of new transposition bracket sections and made this project a major effort.  67 percent–over half–the route was electronic carrier design limit outside plant.

Standard C. S. Design for Carrier

“C-Carrier” (3-channel Western Electric) was chosen for the Transcontinental Canada Lead which led to some interesting considerations.  Where repeaters were undertaken to regenerate signal strength on these conductors of eight inches, it was found no existing (at that time) repeaters could work on this spacing selection.  Instead, it was ingeniously discovered that if you modified the C4.1 and C4.8 systems, one could eliminate the problem and obtain the values necessary for efficient transmission reproduction. 

Consideration was given to these circuits carrying network programming across Canada.  For this allowance, the filters at termination points along this line have a cut-off frequency of 5,000 cycles, so that if desired, such programming can be transmitted along them.  Because these lines were so important to national civilian and business communications, a redundancy system of alarms were built in to them.  Should an emergency have occured on one of the Transcon’s carrier systems, there was a coordinated system between repeater points.  The 2-A Automatic Pilot Channel regulator was installed on the 1,250 mile Oshawa-Winnipeg Carrier sections and also on the Calgary-Winnipeg Carrier Section, which in total equaled 925 miles.  13 to 14 db variations occurred on the carrier system and with the automatic system in place all corrections and compensations were done without human interference.

As noted, the major portion of this lead was built in open wire construction.  While there were some toll entrance cables and terminal poles, these don’t amount to more than one percent of the entire 4200 mile length.  Most of the pre-existing Transcon circuit design was based on utilizing existing cables in the Toronto and Montreal areas.  This was about 78 total miles of multi-pair copper lead-sheathed cable.

Transposition styles were dictated by the eight inch conductor spacing decision.  These were known as “K8”.  Some “K10” were also used between Winnipeg and Halifax, but the majority of new construction was of K8 design.  Each joint, including transpositions, were soldered together, ensuring a proper and efficient connection which eliminated (for the most part) unbalances which were caused by high resistance.

Point Type Transposition Bracket

Naturally, the Western Cedar Poles were Class 2 and 3 for a majority of the line’s route.  This was required for storm resistance.  Creosoted Pine was also used, but these were planted mostly east of Winnipeg, Manitoba.

One final note: for stringing wires, a Stone-Boat was used, pulled by a horse team in some sections of the line route.

Let’s Examine Maintenance on the Trans-Canada Lead

Lost circuit time is money.  Unlike a single player, such as Long Lines in the U. S., the Canadian lead was operated across the boundaries of many different telephone organizations.  But, hold on.  Did I mention that each of the seven systems had different testing methods?  This is where they all joined to adopt policies where interconnecting facilities, continuing education of maintenance personnel, adoption of uniform testing practices and equipment becoming paramount.

To improve the situation yet further, the TAC’s  creation of a Management Committee, whereby they were responsible for a new financial department where funneling Trans-Canada revenue was properly disbursed among the operating companies involved in the line’s investment and use.  Clearly, this eliminated the troubling problem of each Canadian telephone system undertaking separate settlements with each neighboring system.

Testing equipment consisted of No. 5 toll test boards and 7-A and 7-B transmission test boards.  Portable test equipment was also available where convenient locations allowed personnel to take it into the field.  Each month, trouble reports were submitted to the Chairman of the TAC.  Here a Management Committee, formed in 1931, to oversee the operation of the system and to also coordinate the work of constructing, maintaining and operating the Trans-Canadian masterpiece. 

Trans-Canada Alberta Pole Head

This is the Alberta Group pole head design, 1932.  Note the use of side brackets.  Drawing by D. G. Schema

As in existing Provincial cities and towns, each circuit had a “control office” located at one terminus.  This Control Office was dedicated to maintenance of the speech quality and transmission efficiencies along its part of the route.  Physical maintenance of the outside plant was a different matter.  Hence, facilities along the Transcon route were separated.  An office at one terminal responsible for section length toll plant work, whether cable, open wire or carrier systems.  Where repeaters were located, this was divided among the two section offices depending upon the bay of equipment for their individual section.   When training the personnel involved at each of these section offices, they underwent Bell System education in transmission maintenance.  This insured uniformity in equipment and training procedures.

Trans-Canada BC Pole Head

This is the style of structure which crossed the Canadian Rockies in British Columbia, 1932.  Drawing by D. G. Schema.

What was even more important to learn, beyond the actual construction and completion of the line, was in its continued use into the late 1930s and World War II period.   Traffic reports, circuit orders, alterations in existing circuits, and special circuit design, fell to the newly organized TAC Engineering Committee.  There, periodic reviews of the system performance and traffic congestion revealed potential improvements in the existing plant and suggested improvements in them.  It took three long years for the Trans-Canada Lead to become reality and while the original is gone today, its pioneering efforts furthered the progress of Canada and opened a new vista in North American communications development.

Summing Up The Immense Project
  • At completion of the Transcontinental Canada Toll Route in 1932, not more than two switches were required between any two of the main switching points in Canada.  This was an important milestone.  Here’s a glimpse of the Trans-Canada communications highway in numbers: four groups of circuits with almost 8,000 circuit miles of length. 
  • Vancouver-Calgary – 3 circuits @ 819 miles
  • Calgary-Regina – 3 circuits @ 507 miles
  • Regina – Winnipeg – 5 circuits @ 418 miles
  • Winnipeg – Toronto – 3 circuits @ 1278 miles
  • Montreal – St. John – 3 circuits @ 622 miles.

Quite an achievement, eh?

 DP and Toll Insulator Cross-section

Some of the existing insulator styles incorporated into the new Canadian Transcontinental line.

Our Quebec Editorial Contributor Speaks About Canadian Communications History 

By Erik Boucher

St. Lawrence Street, Montreal, Quebec Canada, c. 1900. Photo courtesy of the McCord Museum Collection of McGill University, Montreal.


Fascination, what an epic telephony in Canada.It is introduced by the telegraph network and the system will open wire and insulators, the most fascinating and effective first communication system deployment in North America.The phone comes in Eastern Canada and especially in Quebec.It is in this perspective and also to render honor to this fabulous technology transmission by wire bare insulators, which gave the largest communications service all the history of mankind.

Telegraphy In My Telephone Homeland:

Definitely, telegraph technology was a haven for telephony. Moreover we find multiple experiments will be on the network even telegraph poles and son.1898 copper wins effectiveness in terms of transmission over the galvanized wire.CPR (Canadian Pacific) will be the first to install the copper facilities and they will on telegraph lines from Montreal to Vancouver.Very quickly it propels the diffusion rate to such an extent that the transcript paper became overwhelmed. Technicians opt for sending the sound (knocking) which went from 45 to 50 minutes. Is already sends a signal through a wire which is interpreted by specific sequences and adorned with silences that constitute communication. The constant search gave engineers a search to send a signal over a single wire. A man named Thomas Alva Edison will develop the transmission system in four phases (quadruplex system). This system allows a single thread the possibility of four separate and independent signals.  This multiplexing is very important to remember because it is a key and it will be broadcast on other forms later.In time, Emile Francis Baudet invented the binary code that will perform five times transmissions over 150 characters per minute plus multiplexing 4 phases for a total of 600 words per minute.

The Telephone Arrives in Canada:

In foremost thing we need to note, the excellent engineers and inventors of the MIT [Massachusetts Institute of Technology]. This is the heart of telephony northern end of the 19th century and 20th century America.  This technology is definitely Bostonians who excels in his mastery1878-1879, The phone is ready for entry into Canada . She has maturedand telegraph company is currently of great interest . Montreal Telegraph and Dominion Telegraph armed themselves for the necessary telephony seeing it as a natural extension to the telegraph technology.These companies using switches serve the telephony service even on their telegraph poles . They are dignitaries and governments and doctors who benefit exclusively.Meanwhile in Boston, an idea germinates . Seeing the enthusiasm of telegraph companies become a bitter war of competition. Hugh Backer worried that war could jeopardize the future of the phone. That’s when he found an idea that was to fetch the National Bell Boston support to buy the two companies telegraph in self-destruction .Backer is a support to William Forbes. With the support of Boston, wrote it during the winter 1879-1880 the charter of a new business.  It will be called “The Bell Telephone Company of Canada .Later, Hugh Backer recruited a former insurance agent named Charles Sise seller. Charles was a good negotiator and he had a charisma that generates confidence among investors. This acquisition Backer allowed his dream to become embedded even in the heart of Montreal . That means the establishment of a headquarters of the new ” The Bell Telephone Company of Canada” Company. Note that Charles Sise chair the company from 1890 to 1915. It is also officially the father of Bell Canada.The Bell Telephone Company of Canada was composed of 75% American Belland actions of Canadian Telephone 44.2% of Bell Telephone.  What makes a company mainly supported at the time by U.S. companies.It is now the Bell Telephone Company installed securely and with purchasing power on the two largest companies are telegraph: “The Montreal Telegraph Company and Dominion Company”The dream of Hugh Backermay be running.  The two companies will betransferred to Montreal Telegraph American Bell which in turn yield the BellTelephone.This is the official technology telephone entry.  This has become possible bythe purchase of two telegraph networks previously converted the phone. This acquisition will become the spinal column of a telephone network.

Deployment:In 1881 Bell Telephone Sise hada telephone network representing a value of 400,000 dollars CAD.  Making ita solidcraftsman for future exploitation.Indeed, given the enthusiasm of governments and physicians and otherwealthy, developed at Bell Telephone entry point in the city.Traders were thefollowing to conquer consumers, and this was the case.

This is the largest deployment of telephon in the city.The appearance of thepoles and their lines stand in the main streets.  This is seen by some as a symbol of modern and prosperityand other threats…

Photo below: Montreal 1904

See description numbers below in article. Photo courtesy of McCord Museum Collection, McGill University.

The establishment of the Bell network faced some obstacles. The deployment of lines and poles occurred quickly within 2 years.  In this fast installation time, urbanites there saw appearing an imposing web of copper wires. These entanglements of wires became an increasingly acute problem in the middle of downtown areas.Indeed it was precisely at this point, poles for power supply shops, tramway poles stood as well, and poles owned by a private telephone company and ultimately poles of Bell.
Note figures in the photo: St Lawrence: 1 – Lines of Bell; 2 – Power lines for the shops; 3 – Tramway poles; 4 – Telephone lines to a private company.
For urban and surrounding environments, installations of Bell lineswere best seen.  They were less invasive due to the fact that there areno lines previously installed in their areas, so there were fewer poles.
The climax came to this situation when a great ice storm arrived at the city of Montreal in 1893

1 : Linemen, lines with ice C: Bell Canada
Photo 2 : 1893 Montreal ice storm C: Bell Canada

Note that facilities open wire lines are highly resistant to various vagaries of climate. However, lines can withstand a large load of ice.  But, when a wire is quadrupled its diameter by ice, the weight stretches the line and it breaks.

Furthermore, the structures and poles, become too heavy and they crash under the weight.

Another fact about early open wire lines was they were easy to navigate and locate the problem. A network could be quickly back on his feet by several team assemblers repairing those sections of the line which were damaged.
And shattered poles, their lines cut and laying prostrate in the middle of the main roads, generated a real anger of the population which the mayor had to endure.

Mayors were pressing the Bell Telephone to find a solution to this dilemma.

The laboratory technicians and researchers of Boston Bell System created a cable that could be buried. And from 1901, progressively over the years, aerial telephone networks were buried in the soil of city centers.

Photo: 3 Winnipeg Street, Canada, 1903 C: Bell Canada

Technology of the open wire lines on insulators were still present around this time and continued to provide a great service. They did not finish their goal yet, but they were beginning an evolution…

Evolution Of The Open Wire:

Openwire line gets modernized and refined.   In this part, we ask you to indulge us in regards to the technical data.   Here, [an open wire circuit] must be seen in their simplest possible expressions.
See Figure 1 below, where the phantom circuit “C” is stacked on both physical circuits “A” and “B” by a diversion which consists of the resistances
” R1 ” and “R2”.  So the initial current of the circuit “C” is divided into two by a diversion of a resistance. This current was also on both wires of the circuit “A” and so the way of return “ the circuit ” B “.
The result was that the current which borrows the circuit “C” or phantom becomes in a way divided between both wires of the real circuit which then goes to the circuit return and makes the interference impossible.

This halving is also a technical trick. So the interferences are caught up by the resistances (as filtered) and a cleaning of the signal is carried out successfully.

In 1886, John J. Carty of American Bell labs replaced the resistances by repeaters. They resulted, not only a clearer signal, but also stronger signal.

To have more of detail, invite you to us to consult the section of the site:
 Transpositioning brilliantly as explained by Doug Schema.

Pupinising” of the lines:On the long distance systems, the signal attenuation paused a problem.Indeed, lines could pass transmit a suitable signal but the line owed exceeded no more than 621milles. Thus the engineers had to find a solution to maintain a good signal on the long distance.  A scholar of Serbian origin, by the name Michael Idvorsky Pupin at the University of Columbia in U.S, invented the coil ( featuring the inductance) idea.The term “to load” (“charge”) the line would become an expression in the convention of practical electricity. But what is “to load (“charge”) and to what lines or “pupinising” did this accomplish?

To have the same efficiency as a bigger copper wire, the reel so creates one them (an informed illusion) which believes to pass in a bigger driver. It causes not only an acceleration but a continuation of the quality of the electric signal. We have a lighter and more effective thread for a thread in bigger diameter. It is “pupinising” a line or, “to load,” or charge it.A Pupin placed coil placed 600 feet in approximately 1200 milles allowed a very good efficiency for transmission on a long distance line and allowed the phone wires to divide by two the diameter.  This made practical transmission possible.

Figure 1: Open wire in practice

How The Vacuum Tube (Triode) Impacted Canadian Communications

The Tube Vacuum (Triode)Communications electronics appear at the beginning of the 20th century. Lee De Forest, an ex-employee of Western Electric in 1906 sought to manage exact control of the flow of electrons in a vacuum tube.  This vacuum tube would be called a triode. We also call this triode an amplifier because it allows keeping the integrity of the signal.1913 would mark the repeaters first ones in triode. They would be installed on the section of the line between New York and Baltimore.From 1914, the incorporation of repeaters in triode would allow a long-distance call between New York and San Francisco.From now on, telephony goes into an adulthood.  It is spectacular progress so much at levels of efficiency and of the performance (quality). The first transcontinental conversation took place in May 1914 between Montreal and San Francisco. 1916 saw the first conversation between Montreal and Vancouver before a public of 4500 people. It was also the last appearance of the founder of Bell Canada, Charles Sise, at this big event.

 The beginning of the 1920s, marked with a good expectations for Bell. To such a point that the CN called on to the Bell Labs of Boston, who to send in Canada a talented engineer, J.C Burkholder to preside over the installation of the system with carrier current. From April, 1927, it was now possible to send 13 signals, telegraphic 12, and a telephone to a single thread.