Telephone History Introduction
Telephone History January 04, 2006
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Telephone HistoryJanuary 04, 2006Part BAt this point we need to look back a few years. In 1906 Lee De Forest invented the three element electron tube. Its properties led the way to national phone service. Long distance service was previously limited to 1,500 miles or so. Loading coils and larger, thicker cables helped transmission to a point but no further. There was still too much loss in a telephone line for a voice signal to reach across the country. Transcontinental phone traffic wasn't possible, consequently, so a national network was beyond reach. Something else was needed. In 1907 Theodore Vail instructed AT&T's research staff to build an electronic amplifier based on their own findings and De Forest's pioneering work. They made some progress but not as much as De Forest did on his own. A nice De Forest biography is at: http://www.acmi.net.au/AIC/DE_FOREST_BIO.html (external link) The site also includes the photograph below. 
The most popular book on De Forest is Empire of the Air : The Men Who Made Radio by Tom Lewis. Try searching for it with the Powells.com search engine at the bottom of this page. AT&T eventually bought his patent rights to use the tube in their telephone amplifier. Only after this and a year of inspecting De Forest's equipment did the Bell Telephone Laboratory make the triode work for telephony. Those years of research were worth it. Electron tube based amplifiers would make possible radiotelephony, microwave transmission, radar, television, and hundreds of other technologies. Telephone repeaters could now span the country, enabling a nationwide telephone system, fulfilling Alexander Graham Bell's 1878 vision. Recalling those years in an important interview with the IEEE, Lloyd Espenschied recounts "In May [1907], several of us had gone to a lecture that Lee De Forest had given on wireless at the Brooklyn Institute of Arts and Sciences. In this lecture, he passed around a queer little tube to all the audience. It was the first three-element tube to be shown in public, I found out afterwards. He passed this around and everybody looked at it and said, "So what!" Even De Forest said that he didn't know what it was all about. He looked on it as a detector. [an early device to pick up radio waves, ed.] Actually it was an evolution of the Fleming valve, but he would never give credit to anyone." Later in the interview, Espenschied gives an opinion of De Forest shared by many at the time, "No, he was no engineer. He was just a playboy all his life. He's just plain lucky that he stumbled into the three- element device. Just plain lucky. But that was handed to him for persevering; he kept at it, grabbing and grabbing at all the patent applications without knowing what he was doing." For more quotes like the above and a great oral history of early electronic and vacuum tube experimenting:
Luck or not, De Forest was first to build and then exploit the the three element tube. It later enabled the vacuum tube repeater which ushered in telephony's electronics age. A triode is sometimes called a thermionic valve. Thermions are electrons derived from a heated source. A valve describes the tube's properties: current flows in one direction but not the other. Think of a faucet, a type of control valve, letting water go in only one direction. This controlled flow of electrons, not just electricity itself, marks the end of the electrical age and the beginning of the electronic age. Go here for more on de Forest and how the triode works (internal link) For more comments, read Ray Strackbein's comments below Armstrong later developed the regenerative circuit which fed back the input signal into the circuit over and over again. In electronic books of the era many called him "Feedback Armstrong." His circuit amplified the signal far more than original designs, allowing great wireless or wireline transmission signal strength. The feedback circuit could also be overdriven, fed back so many times that supplying a small current would develop an extremely high frequency. The circuit would thus resonate at the frequency of a radio wave, letting the triode receive or detect signals, not just transmit them. DeForest later claimed to have invented regeneration; this was a lie. DeForest invented the three element tube by trial and error; he did not even understand how it worked until five years later when Edwin Armstrong explained it. More on this regarding radio is here (internal link) As evidence of the triode's success, on January 25, 1915 the first transcontinental telephone line opened between New York City and San Francisco. The previous long distance limit was New York to Denver, and only then with some shouting. Two metallic circuits made up the line; it used 2,500 tons of hard-drawn copper wire, 130,000 poles and countless loading coils. Three vacuum tube repeaters along the way boosted the signal. It was the world's longest telephone line. In a grand ceremony, 68 year old Alexander Graham Bell in New York City made the ceremonial first call to his old friend Thomas Watson in San Francisco. In an insult to Lee de Forest, the inventor was not invited to participate. This insult was carried over to the 1915 World's Fair in San Francisco, in which AT&T's theater exhibit heralded coast to coast telephone service without mentioning the man who made it possible. [Morgan] Professor Michael Noll, writing in Signals: The Science of Telecommunications, says a three minute coast to coast call cost $22.20. That's $411.47 in 2004 dollars. In 1919 Theodore Gary and Company bought the Automatic Electric Company. Years later, when A.E. became AG Communication Systems, the AGCS website said "Theodore Gary aimed to cash in on the accelerating trend of replacing manual labor with machinery, and saw great potential in the Bell System market. Gary formed a syndicate that secured an option on the majority of Automatic Electric Company common stock. In 1919, he exercised his option to purchase the company." Since Automatic Electric didn't manufacture for the Bell System the words "potential in the Bell System market" means licensing potential. Indeed, the AGCS site goes on to say that, "By the mid-1920s, AE was licensing about 80 percent of the automatic telephone equipment in the world. It became the second largest telecommunications manufacturer in the United States after Western Electric." Finally, on November 8, 1919, in what must have been a humiliating experience for the telecommunications giant, AT&T at last introduced large scale automatic switching equipment to their telephone system. Using step by step equipment made, bought, and installed by Automatic Electric. The cut over to dial in Norfolk, Virginia was a complete Bell System policy change. No longer would they convert automatic dial systems to manual as they bought independent telephone companies, but they would instead embrace step by step equipment and install more. More on the many mergers of Automatic Electric is here
In 1921 the Bell System introduced the first commercial panel switch, a very odd invention. Developed over eight years, it was AT&T's response to the automatic dialing feature offered by step by step equipment. It offered many innovations and many problems. Although customers could dial out themselves, the number of parts and its operating method made it noisy for callers. Ironically, some switchmen say it was a quiet machine inside the central office, emanating "a collection of simply delightful 'clinking,' 'whirring' and 'squeak, squeak, squeak' noises." Working like a game of Snakes and Ladders, the switch used selectors to connect calls, these mechanical arms moving up and down in large banks of contacts. When crossbar switching came on the scene in 1938, panel switches were removed where possible, although some remained working until the mid 1970s. Panel became the first defunct switch in the public switched telephone network. At this site were marvelous photos of the last functional panel switch: http://xy3.com/phone/vintage/panel%201.stm (external link). If you have the time, you might try entering the URL above into the Internet Archive Wayback Machine (external link) For a wonderful history of early electronic pioneering, click here for a must read interview with Ray Sears: http://www.ieee.org/organizations/history_center/oral_histories/transcripts/sears.html (external link) Part CIn 1925 Western Electric sold its overseas manufacturing plants to a small company with a big name and even bigger ideas: International Telephone and Telegraph. A controversial decision within the Bell System. AT&T sold factories in 11 countries, fearing a United States anti-trust lawsuit. Western kept a minority interest in one foreign company, Northern Electric, in Canada, until 1963.. AT&T would not return officially to the international market until 1977. [Kimberlin] "Western Electric never controlled Northern Electric (now Nortel) although they owned shares always in a minority position, the most they held was 43.57% in 1929, by 1962 they held .01% and by 1964 they were fully divested. The majority shareholder was the Bell Telephone Company of Canada." Thanks to Ken Lyons, Curator, Telecommunications Museum Telecommunications Museum,Maison des benevoles retraites, Nortel Retirees Club in Montreal, LaSalle, QC ITT's owners, the curious, conspiratorial Behn brothers, Sosthenes and Hernand, bought Western Electric International for 30 million dollars and renamed it International Standard Electric. Their purchase, backed by J.P. Morgan's bank, included Western's large British manufacturer, renamed Standard Telephones and Cable. The Behns agreed not to compete in America against Western Electric, and to be the export agent for AT&T products abroad. AT&T agreed in return not to compete internationally against the Behns. Now equipped with a large manufacturing arm, IT&T spread across the globe, buying and influencing telephone companies (and their governments) on nearly every continent. In January, 1927, commercial long distance radio-telephone service was introduced between the United States and Great Britain. AT&T and the British Postal Office got it on the air after four years of experimenting. They expanded it later to communicate with Canada, Australia, South Africa, Egypt and Kenya as well as ships at sea. This service had fourteen dedicated channels or frequencies eventually assigned to it. The overseas transmitter was at Rugby, England, and the United States transmitter was at Deal, New Jersey. (According to Bell Labs, but see Kimberlin's notes here.)[BLR] Nearly thirty years would pass before the first telephone cable was laid under the Atlantic, greatly expanding calling capacity. In the next year The Great Depression began, hitting independent telephone companies hard, including the manufacturer Automatic Electric. Click here for an excellent discussion (internal link) of British involvement with radio telephone, by Don Kimberlin, and a photograph of the main transmitting tube at Rugby, a ten foot tall, one ton valve. A photograph of AT&T's overseas radio-telephone switchboard Although telephones had been used in the White House for many years, the instrument did not reach the president's desk until the Hoover administration at the start of the Great Depression. "In 1929, when the Executive Offices were remodeled the historic one-position switchboard which had served for so many years was retired from service and a new two-position switchboard, especially built to meet the President's needs, was installed. The number of stations was materially increased in addition to many special circuits for the use of the President. It was at this time a telephone was installed on the President's desk for the first time." [Hoover Library] (Thanks to L. Nickel for researching this point) The United States Congress created the Federal Communications Commission in 1934 to regulate telephones, radio, and television. It was part of President Roosevelt's "New Deal" plan to bring America out of the Great Depression. Not content to merely follow congressional dictates, and unfortunately for wireless users, the agency first thought it should promote social change through what it did. To promote the greater good with radio, the F.C.C. gave priority to emergency services, broadcasters, government agencies, utility companies, and other groups it thought served the most people while using the least radio spectrum. This meant few channels for radio-telephones since a single wireless call uses the same bandwidth as an F.M. radio broadcast station; large frequency blocks to serve just a few people. Treating radio like a public utility, something like the railroads, it was thought a public agency could protect the public against monopoly practices and price gouging. But like many bureaucracies, at every opportunity the FCC tried to enlarge its role and power, eventually aligning itself with large communications companies and then actually working against the consumer. The worst examples were outside of telephony, helping the RCA corporation against F.M. broadcasting, ruining Edwin Armstrong in the process, and favoring RCA over Farnsworth, the first real developer of television, leaving him penniless as well. Along the way were maddening delays in approving technical advances and frequency allocations, something that continues to this day. Late in 1934 the FCC began investigating AT&T as well as every other telephone company. The FCC issued a 'Proposed Report' after four years, in which its commissioner excoriated AT&T for, among other things, unjustifiable prices on basic phone service. The commissioner also urged the government to regulate prices the Bell System paid Western Electric for equipment, indeed, even suggesting AT&T should let other companies bid on Western Electric work. The Bell System countered each point of the FCC's report in their 1938 Annual Report, however, it was clear the government was now closely looking at whether the Bell System's structure was good for America. At that time AT&T controlled 83 percent of United States telephones, 91 percent of telephone plant and 98 percent of long distance lines. Only the outbreak of World War II, two and a half months after the final report was issued in 1939, staved off close government scrutiny. In 1937 Alec Reeves of Britain invented modern digital transmission when he developed Pulse Code Modulation. I say modern because Morse code and its variants are also digital: organized on and off pulses of electrical energy that convey information. While PCM took decades to implement, the advent of digital working was a momentous event and deserves much consideration. David Robertson, a biographer of Reeves, goes so far as to claim Reeves as the father of modern telecommunications. "I think a fair argument can be sustained that the adoption of digital is the principal motor of change in the early 21st century. For sure, there'd have been no merger between AOL and Time Warner and other moves towards combining media with telecom companies had it not become possible to transmit information of all sorts in the same binary way. Whether all this is good news is, of course, another issue." For more information on Alec Reeves click here (internal link) For a website devoted to Reeves go here: http://www.AlecHarleyReeves.com (external link) In 1937 coaxial cable was installed between Toledo, Ohio and South Bend, Indiana. Long distance lines began moving underground, a big change from overhead lines carried on poles. In that same year the first commercial messages using carrier techniques were sent through the coax, based on transmission techniques invented by Lloyd Espenschied and Herman A. Affel. Multiplexing let toll circuits carry several calls over one cable simultaneously. It was so successful that by the mid 1950s seventy nine percent of Bell's inter city trunks were multiplexed. The technology eventually moved into the local network, improving to the point where it could carry 13,000 channels at once. For more information on Lloyd Espenchied's brilliant career, go here:
In 1938 retractile, spring, or spiral cords were introduced into the Bell System. A single cotton bundle containing the handset's four wires were fashioned into a spiral. This reduced the twisting and curling of conventional flat or braided cords. Spiral cords were popular immediately. AT&T's Events in Telecommunication History [ETH] reported that introduction began in April, with Western Electric providing 6,000 cords by November. Still, even with W.E. then producing 1,000 cords a week, the cords could not be kept in stock. In 1938 the Bell System introduced crossbar switching to the central office, a system as excellent as the panel switch was questionable. The first No. 1 crossbar was cut into service at the Troy Avenue central office in Brooklyn, New York on February 13th.This culminated a trial begun in October 1937. [ETH]A detail of a crossbar switch is shown on the right. Western Electric's models earned a worldwide reputation for ruggedness and flexibility. AT&T improved on work done by the brilliant Swedish engineer Gotthilf Ansgarius Betulander. They even sent a team to Sweden to look at his crossbar switch. Installed by the hundreds in medium to large cities, crossbar technology advanced in development and popularity until 1978, when over 28 million Bell system lines were connected to one. That compares to panel switching lines which peaked in 1958 at 3,838,000 and step by step lines peaking in 1973 at 24,440,000. Much telephone progress slowed as World War II began. But one major accomplishment was directly related to it. On May 1, 1943 the longest open wire communication line in the world began operating between Edmonton, Alberta and Fairbanks, Alaska. Built alongside the newly constructed Alaskan Highway, the line was 1500 miles long, used 95,000 poles and featured 23 manned repeater stations. Fearing its radio and submarine cable communications to Alaska might be intercepted by the Japanese, the United States built the line to provide a more secure communication link from Alaska to the United States. A little bit on radar development in World War II Back to crossbar. Note the watch-like complexity in the diagram. Current moving through the switch moved these electro-mechanical relays back and forth, depending on the dial pulses received. Despite its beauty, these switches were bulky, complicated and costly. The next invention we look at would in time sweep all manual and electro-mechanical switching away. 
------------------------------------------- Resources [BLR] "The Opening of Transatlantic Service on Shortwaves" 6 Bell Laboratories Record 1928: 405 [Hoover Library] Personal correspondence from the Hoover Library to L. Nickel (10/19/2000)" [ETH] Events in Telecommunication History, AT&T Archives Publication: Warren, New Jersey (8.92-2M), p53 [Kimberlin] "While AT&T purported to stay out of international markets, they always had an entity with several names like "Bell International" that functioned as sales offices to those who would inquire. No special modifications done, even for AC power. You take it the way we make it if you want it, was the slogan. To that extent, many of the overseas HF radio-telephone points we worked from ATT's Fort Lauderdale office had Western Electric HF radios and terminals that matched ours. There are many more stories like this . . ." Don Kimberlin (internal link to Don's page at this site).
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