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Magazine for the Science & Technology Innovation Center in Middletown, NJ • Premier Edition

Honoring the Past, Creating the Future

Innovation is in ourDNA Letter from Our Contents page 12 our Editor Features

2 The History of AT&T 94 Data Transmssion — Welcome to our Science & Technology Innovation Center of Middletown, New Jersey magazine premier edition. The new Innovation Center is a place 12 The 100 Cellular Phones of inspiration and learning from the history of AT&T and significant inventions that our company has created over the past 142+ years that contribute to 13 Bell 104 Project AirGig™ the advancement of humanity. Over my years at AT&T, I have spoken to many The Project Our Contributors people who never knew that AT&T had a history of innovation in so many 16 109 areas beyond the creation of the by . Coax Cable 24 Throughout the years, AT&T has been a key player in local and long-distance 30 Fiber Optics in the AT&T Network voice , motion pictures, computers, the cable industry, , and Science & Technology . AT&T has served the nation’s needs and par- 34 and ticipated in many technology partnerships in every industry throughout the globe. The breadth of technology and innovation goes on and on, but a 44 Picturephone Irwin Gerszberg few of the innovations you might see at our new Innovation Center include: Innovation ground-to-air radio telephony, motion picture sound, the Telstar satellite, Theseus Honoring the Past, Creating the Future AVP Advanced Technology Research 48 telephone switching, the facsimile machine, military radar systems, the AT&T Science & Technology transistor, undersea cable, fiber communications, Picturephone via T1’s, coin 50 A Short History of UNIX™ EDITOR-IN-CHIEF Innovation Center phones, touch-tone dialing, AMPS cellular phones, UNIX™ and language Irwin Gerszberg programming. 55 Museum and Map [email protected] MANAGING EDITORS

Pam Bogdan, Don Barnickel As a forward-thinking technology company, AT&T is continually re-inventing 58 Transmission Evolution itself. Innovation has been alive in our corporate DNA for the past 142+ years. ARCHIVISTS Sheldon Hochheiser, Melissa Wasson, While this magazine is a tribute to the great people that give us such a rich 64 Millimeter Waveguide William Coughlin history and future, it is my hope to inspire every person visiting the Innova- Undersea Transmission tion Center and reading this magazine to become a part of AT&T’s legacy of 68 ART DIRECTOR innovation. With the opening of our new Center, it will be the first time people John MacNeill 76 The Evolution of Switching will see many of the artifacts on permanent display to inspire the current and PHOTOGRAPHER all future generations of AT&T employees. 86 Telephone Booth Michael Mills

ILLUSTRATOR Finally, I would like to thank our leadership and the many individuals who 90 Sharing the Conversation Jacqueline Bogdan made the Center and this magazine possible: our partners in this project, Hank Kafka, Scott Mair, Marachel Knight, Sihem Ben Saad, Middletown I2I; the AT&T Archivists — Sheldon Hochheiser, Bill Caughlin and Melissa Wasson; from Corporate Real Estate Jeff Onori and Chuck Ott; for help with Cen- ter media Barbara Laing and Dave Mahar; and the many volunteer authors, editors and other contributors who shared their spare time to produce the articles in this magazine.

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AT&TAT&T SCIENCE SCIENCE & & TECHNOLOGY TECHNOLOGY INNOVATION | 1 The History

A Company Grounded in Innovation of AT&T

By Sheldon Hochheiser

Welcome to this exploration of Morse code, but what he called an applied for and received a second AT&T’s long history of innovation. “undulating current,” a continuous patent for a practical telephone. AT&T was founded with an innova- electrical wave analogous in form tion — Alexander Graham Bell’s in- to the sound wave. By June 1875, he Bell, however, was not interested vention of the telephone in 1876, and had proven his idea by transmitting in business, so he left the commer- we have been innovating ever since speech sounds (but not intelligible cialization of his invention and the in the interests of using technology speech) down an electrical wire. This company founded to exploit it, the — — to bring led Bell to file a patent application first Bell Telephone Company, in the people together. on February 14, 1876. The patent, hands of his chief financial backer #174765, was issued on March 7. and now father-in-law Gardiner The Birth of the Hubbard. Bell and his wife left for Telephone England on a long honeymoon. He Bell was born in Edinburgh, Scot- “Mr. Watson, come was 31, and never had to work for a land in 1847. By the early 1870s, he here; I want you!” living again. was living in Boston and working as a teacher of the deaf, a profes- The Telephone in the sion he learned from his father. Like Three days later on March 10, using 19th Century many young men with a technical a newly designed instrument, the Hubbard raised the to com- bent, he turned to the cutting-edge liquid , Bell succeeded mercialize the telephone primarily technology of the day, the electri- in transmitting the first intelligible by what we would call franchising — cal telegraph, as an area where he speech ever sent via electricity: “Mr. he licensed people in various cities could his fortune by invention. Watson, come here; I want you!” to operate telephone businesses Along with a few others, he thought Thomas Watson, Bell’s assistant, under Bell’s patents. The first such of making the telegraph transmit heard it down the hall on his reed franchisee, George Coy of New speech rather than Morse code, receiver. Watson wrote this and Haven, CT, invented the telephone but unlike the others he combined several subsequent sentences down switchboard, and with it opened the his newly acquired knowledge of in his notebook, which is one of the world’s first in electricity with an understanding of treasures of the AT&T Archives and New Haven on January 28, 1878. The Alexander Graham Bell (1876) speech and hearing. In the summer History Center. It is so fragile that telephone caught on; by 1881 there Photo courtesy AT&T Archives and History Center of 1874, he had a key intellectual a replica is on display at the AT&T were telephone exchanges licensed breakthrough—what was needed Science and Technology Innova- in almost every place in the United was not the digital on-and-off of tion Center. The following year, Bell States with over 10,000 residents. By

2 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 3 Theodore Vail (1915) then the parent company had been American Bell and became the par- can Bell, and later as the founding Photo courtesy AT&T Archives and History Center reorganized as the American Bell ent company of what soon began president of AT&T when it was the Telephone Company, and Hubbard to be referred to collectively as the long-distance subsidiary. Vail was a and the other initial owners had lost . Over the years, AT&T visionary, a firm believer in systems control of the business to a group acquired a controlling interest, and and networks. He fought the inde- of Bostonians. American then complete ownership of most of pendents by many means, including coils, placed according to a theory Bell and its franchisees continued its licensees, which it combined into the nation’s first public image adver- developed independently in 1899 to grow. In 1882, American Bell a smaller number of companies. tising campaign. He used the slogan by George Campbell at AT&T and acquired a majority interest in the “One Policy, One System, Universal Michael Pupin at Columbia Universi- Western Electric Company, a leading This followed the 1894 expiration Service” to convince the American ty reduced attenuation, permitting manufacturer of electrical equip- of Bell’s second patent at which people and government that the circuits of up to around 2,000 miles, ment. It became the sole supplier of time it became legal for others to would best be served such as one AT&T opened between telephone equipment to American open telephone exchanges. Within by having a single national telephone and Denver in 1911. What Bell and its licensees. Engineers a decade, over 6,000 independent system under AT&T control. He was needed was a way to amplify employed by Western Electric, such telephone companies had gone argued that the telephone, by the the signal. So, Carty hired a bright as Charles Scribner, made numerous into business across the United nature of its technology, was a nat- young physicist, Dr. Harold Arnold, in inventions to improve the telephone States, but while Bell’s market share ural where competition 1910 to work in the Western Electric system from multiple switchboards dropped from 100 percent to 50 was inherently inefficient. Govern- Engineering Department on an elec- to underground cables. percent, its number of subscribers ment regulation was the appropriate trical . In late 1912, indepen- increased by 700 percent as the tele- alternative. dent inventor brought And after the success of an 1884 phone became democratized. his invention, the audion, the first long-distance line connecting New He succeeded, but with limits, when three-element to York and Boston, American Bell Theodore Vail—One AT&T Vice President Nathan Kings- AT&T. It would do a small amount of formed a subsidiary in 1885, the New Policy, One System, bury negotiated an agreement with amplification but would break down, York-based American Telephone Universal Service the U.S. Justice Department in 1913. giving off a blue glow, at any attempt and Telegraph Company, to build In 1907, Theodore Vail became Presi- In the agreement, regulation was to do a practical amount. Arnold ex- and operate a network of interstate dent of AT&T. He had previously been accepted as substitute for compe- amined the tube and quickly figured long-distance lines connecting the a senior manager of the business tition. AT&T agreed to divest the it out. The blue glow was caused local companies. AT&T reached its between 1878 and 1887, serving first controlling interest it had acquired in by residual gasses interacting with initial goal, connecting the nation’s as the general manager of Ameri- Telegraph Company, electrons. If he just increased the two largest cities, New York and vacuum in the tube, it would work , in October 1892. Alexander as an amplifier. AT&T bought the Graham Bell made the ceremoni- to bring the non-competing inde- AT&T operated the Bell System as a patent rights from de Forest, and by al call from New York to open the pendents into the system by inter- regulated, government sanctioned mid-1913 had successfully tested Ar- service. The line used an extremely connecting them to AT&T’s long-dis- national monopoly. And in doing so, nold’s high-vacuum tube thick copper wire to reduce the rate tance network, and not to acquire with dedication and a strong service on existing lines. Now it became a at which resistance weakened the any independents without govern- ethos, it by all accounts provided the construction project. One team built signal so the call could travel the ment consent. This agreement also people of the United States with the west from Denver, the other east distance. Still, 1000 miles seemed served as the core of the settlement best telephone system in the world. from Sacramento.The two crews the approximate limit for a call made of an antitrust suit brought by the met and completed the line on June with thick copper wires. government earlier that year. The To Vail, one of the several mean- 17, 1914 at Wendover, Utah. The line agreement, and Vail’s organization ings of universal service was that all opened for commercial service with In an 1899 corporate reorganization, of the business, provided the philos- should be connected in great fanfare on January 25, 1915. American Telephone and Telegraph ophy, strategy and structure under a single national network. In 1908, he Arnold’s vacuum tubes were adapted acquired the assets of its parent which the U.S. telephone system, made completing a transcontinental to many other applications where both the dominant Bell System and telephone line AT&T’s top technical electrical amplification was needed.

Advertising Brochure (1892) the approximately 20 percent of the priority. Yet, as his Chief Engineer Photo courtesy AT&T Archives population served by independents, John J. Carty knew, the technology Arnold’s success had one other and History Center would operate into the 1980s. So, to do this did not exist. Signals weak- consequence — it convinced Vail and for much of the twentieth century, en as they go down wires. Loading his successors that bringing research

4 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 5 Dr. , a brilliant young solid-state theoretical physicist to lead the project. Two more sol- Completion of the First Transcontinental Line (1914) id-state physicists, theoretician Dr. Photo courtesy AT&T Archives and History Center John Barden, and experimentalist Dr. Walter Brattain soon followed. With the coming of World War II, normal Labs work gave way to projects for the war effort. The physicists re- sumed their prewar work as the war wound down. In December 1947, Bar- deen and Brattain succeeded in am- plifying an electrical signal with their invention, the point-contact tran- sistor. There is a replica of this first transistor on display in the exhibit. In 1948, the project moved from research to development, where a team under Jack Morton spent three years turning a handmade laborato- ry device into something that could be produced in commercial quan- tities. The first applications for the transistor were for the U.S. military. and development in-house was a ries. By the mid-1920s, under AT&T With Bell Telephone Laboratories Commercial applications by others, good business strategy. And this led President Walter Gifford, universal leading the way, AT&T was truly an such as hearing aids and radios, fol- to the Western Electric Engineer- service had come to be understood innovative company. The absence lowed over the next few years, as did ing Department being elevated in as meaning that AT&T and the of competition gave the the first applications within the Bell 1925 to a separate subsidiary — the government’s agreed goal was that luxury of taking a long view. The System. But AT&T never lost sight of famous Bell Telephone Laborato- eventually everyone would have a story of the transistor, the basis of the original goal, and in 1965, twenty telephone. This guided AT&T’s mis- all modern electronics, is a good nine years after Kelly decided to un- sion into the 1970s. example of how this worked out for dertake solid-state physics research, The First Transistor (1947) Photo courtesy AT&T Archives and History Center AT&T, the nation and the world. It be- AT&T installed the first solid-state Bell Telephone Laboratories’ First Head- The Bell System gan in 1936 with Dr. Mervin Kelly, Vice electronic telephone , the #1 quarters, 463 West St., New York (1927) Photo courtesy AT&T Archives Under the leadership of Gifford and President for Research. Kelly was ESS, in a local office in Succasunna, and History Center Bell Telephone Laboratories’ found- thinking about the millions of mov- New Jersey. ing president, Dr. Frank Jewett, Bell ing electromechanical relays in the 21–24 such companies, depend- universal service had essentially Labs became the premier industrial thousands of automatic telephone The Bell System developed a stable ing on the year, which collectively been achieved. research laboratory in the United in the Bell System, and the decentralized organizational struc- provided service in the continental States. It undertook far ranging and many vacuum tubes amplifiers in the ture that served the nation well. At United States. With the exception of Despite the success of AT&T and often basic research. The ultimate long-distance network. The relays the top were the AT&T General De- the Depression years of the 1930s, the Bell System in providing ev- goal was improving the telecom- required extensive maintenance, and partments, which provided overall the percentage of households with er-improving telephone service in munications system of the United eventually wore out; the vacuum coordination, and ran the system. telephone service steadily rose, the United States, the company’s States, but many innovations had tubes were fragile, gave off heat, and Below that, AT&T Long Lines provid- reaching 40 percent in 1930, 62 per- monopoly status was a cause for far broader applications. Through eventually burned out and needed to ed interstate long distance service, cent in 1950, and 90 percent in 1969. periodic federal government inquiry the articles in this magazine, and the be replaced. Kelly thought that a re- Western Electric manufacturing Innovations such as the several and action. In general, displays in the exhibit, you can learn search program in the emerging field and supply, and Bell Labs research generations of automatic switching were against American political about some of these innova- of solid-state physics, if successful, and development. But what most played a major role in this expan- philosophy and could violate the tions and their applications. might lead to solid-state replace- people knew were their local Bell sion. Both AT&T and the country at law. The Federal Communications ments for both. So, in 1937, he hired Operating Companies. There were large saw 90 percent as a sign that Commission (FCC), as required by

6 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 7 the statute that created it in 1934, task, but it was done well and on undertook a massive multi-year January 1, 1984, the Bell System was investigation of AT&T. In 1949, the no more. Corpo- Justice Department filed an antitrust ration (SBC) was the smallest of the suit primarily seeking the divesti- seven regional holding companies, ture of Western Electric. The suit but the one that would figure most was settled out of court in 1956 on prominently in subsequent AT&T terms widely perceived as favorable history. SBC provided local service in to AT&T. AT&T agreed to restrict its Arkansas, Kansas, Missouri, Okla- business to those things related homa and Texas. Among the assets to the national telephone system, that passed to the Baby Bells was and government projects. (AT&T, cellular telephone service, which had including Bell Labs, undertook many just gotten started with the launch government projects during the of the first commercial system in Cold War.) AT&T also agreed to freely Chicago, in October 1983. license its patents for uses outside of telecommunications. The Modern Era Fiber-Optic Strand, Bell Labs (1976) Over the next few years, long dis- Photo courtesy AT&T Archives and History Center The Fall of the tance became fiercely competitive Bell System as multiple companies competed for It was the third antitrust suit, filed in customers. Prices began a continu- as potential competitor for the tele- major obstacles to their attempts to 1974, that transformed telecommu- ous decline, but the transition to fi- communications services business. grow their businesses. After several nications in the United States. The ber optics as the dominant transmis- In 1995, AT&T announced that it was years of effort, Congress responded nature of telecommunications had sion medium caused costs to decline spinning off its manufacturing busi- by enacting the Telecommunications changed in many ways since 1956. even more quickly. With substantially ness into a separate company, which Act of 1996, which President Clinton Mainframe computers had become lower prices, call volume explod- took the name Technologies. signed on February 8. The Act super- a major feature of the American ed. The business remained very Since research and development seded the MFJ, and provided a new economy, and an increasing portion profitable for AT&T, as did AT&T’s served both the equipment and set of guidelines for the industry. It of telephone traffic was actually business of providing computer data rather than conver- communications services to large sations. Many predicted a future corporations. AT&T gained entry The substantial part of the community that Vice President Using a Cell Phone (1984) convergence of computing and to the growing wireless business in Photo courtesy AT&T Archives and History Center supported services stayed with AT&T, and communications. The rise of micro- 1994 by purchasing McCaw Cellu- wave technology for long-dis- lar Communications, which it soon continued its share of the Bell Labs heritage tance transmission, beginning in the renamed AT&T Wireless. Throughout as AT&T Labs. 1940s, provided for the first time an long distance, manufacturing, and ing subsidiaries. Seven independent the 1990s, data traffic grew even economically feasible alternative to research and development. Regional Bell Operating Companies faster than voice, especially after the physical wires and cables, one that (RBOCs), informally known as “Baby introduction of the public services businesses, it too split. The set up series of requirements which as MCI proved in the 1970s, made AT&T CEO Charles Brown accepted Bells,” would inherit the 22 phone in mid-decade. In 2000, the volume majority of the Bell Labs community if met would allow the long-distance it possible to create an alternative these terms to end the prospect companies and retain the local of data transmitted on the AT&T supported the equipment business, companies and the local telephone long-distance network to AT&T’s. of years of uncertainty. AT&T and monopolies. AT&T would keep the network finally exceeded the volume and therefore went to Lucent, as did companies to enter each other’s AT&T sought a negotiated settle- the Justice Department announced long-distance business, manufac- of voice. the famous Bell Laboratories name. businesses. It removed other restric- ment as the case was actively being the agreement on January 8, 1982. turing (i.e., Western Electric) and Bell The substantial part of the commu- tions on RBOC activities. tried in court. The concept offered in Federal judge Harold Greene ap- Labs. The RBOCs were barred from In the 1990s, AT&T came to realize nity that supported services stayed 1981 by the Justice Department was proved the agreement after the long distance and manufacturing, that without the local companies, with AT&T, and continued its share of Edward Whitacre, the CEO of SBC, simple: separate those parts of the incorporation of a variety of changes and would require a waiver from there were few synergies between the Bell Labs heritage as AT&T Labs. realized, even before the bill was AT&T-owned Bell System where the he required. The agreement took the the court to enter other businesses. its communications and manufac- passed, that there would now be natural monopoly argument was still legal form of a Modification of Final AT&T was barred from the local tele- turing businesses. The RBOCs in- Throughout these years, the RBOCs no MFJ-related obstacles to one valid, namely local telephone service, Judgement (MFJ). AT&T would divest phone business. Breaking up the Bell creasingly saw AT&T not so much as found that the restrictions placed Baby Bell’s acquisition of another. from those parts where it was not; all 22 of its local telephone operat- System was an enormously complex a preferred equipment supplier, but on their activities by the MFJ raised Whitacre acted quickly and on April

8 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 9 laid out in the law to lease lines from the RBOCs. As AT&T’s profits plum- meted, it responded with a variety of cost-cutting measures, including spinning off AT&T Wireless as a sep- arate company in 2001. Cingular, the SBC-BellSouth joint venture, in turn acquired AT&T Wireless in 2004.

By this time, it had become apparent to many observers that AT&T’s most likely future was acquisition by an- other healthier company. On January 31, 2005, SBC CEO Ed Whitacre and AT&T CEO David Dorman announced a definitive agreement for the two companies to merge, though it was clear that SBC would be acquiring AT&T. The transaction closed on No- vember 18, 2005 once the companies had obtained all necessary regulato- ry approvals. SBC promptly changed its name to AT&T Inc. AT&T was a much better known and established brand. Besides the brand, the other major assets the new AT&T acquired

Ed Whitacre speaking at the birth of was a large enterprise telecommu- the new AT&T Inc. (2005) nications business serving corporate Photo courtesy AT&T Archives and History Center and government customers, the premier global communications network, and a major R&D operation 1, 1996 announced an agreement cations Act’s requirements to offer in AT&T Labs. to acquire Group, the long-distance service when the FCC RBOC serving California and Nevada. approved its application for New Whitacre was not finished using Two years later, SBC reached agree- York. The next June, SBC became acquisitions to build his company. In ment to acquire Ameritech Corpo- the second RBOC to obtain such 2006, AT&T acquired RBOC BellSouth, “You Will” was an AT&T ration, the Baby Bell serving Illinois, approval, for the state of Texas. Over and with it complete ownership of Indiana, Michigan, Ohio and Wiscon- the next several years, the RBOCs Cingular Wireless. AT&T soon re- advertising campaign sin. This deal closed in 1999. And then received these approvals across the branded Cingular as AT&T. Whitacre in 2000, in order to provide a national country, and then aggressively and over the course of a decade had from 1993–1994 that footprint to compete in the rapidly successfully marketed combined merged four of the seven Baby Bells, growing cellular telephone business, local and long-distance packages to legacy AT&T, and a national cellu- presented a future to SBC combined its cellular business their customers. AT&T’s consumer lar carrier. With this achievement, with that of fellow RBOC BellSouth long-distance business went into Whitacre retired in 2007. Randall be brought to you Corporation in a joint venture, Cingu- rapid decline. Its attempts to counter Stephenson succeeded him as AT&T lar Wireless. by offering its own combined pack- CEO, a position he continues to hold by AT&T. ages were not successful, in large as this article is being written. In late December 1999, Bell Atlan- part because it did not have its own tic Corporation became the first lines into people’s homes, and had RBOC to satisfy the Telecommuni- to rely on contentious procedures

10 | AT&T SCIENCE & TECHNOLOGY INNOVATION particular the field-effect device patented by Julius Edgar Before the Transistor: Lilienfeld, existed by the 1920s, it was not until the mid The Vacuum Tube part of the twentieth century that practical The precursor to the transistor was the vacuum tube, were developed. which was originally used for demodulation of radio sig- nals and for rectification of current. These tubes took the The Transistor The first functional transistor was produced in 1947 at form of large glass bulbs containing two or more elec- AT&T’s Bell Laboratories in Murray Hill, New Jersey by theo- trodes, an anode, a cathode, and a control grid surrounded The Invention that Started the Digital Age retical physicist , and experimental physicist by a vacuum. Energizing the cathodes allowed electrons to Walter Brattain, working under department head William flow through the tube. Shockley. Prior to this, Shockley had been working at Bell Labs for ten years on creating a transistor. In three years’ Vacuum tubes took communications and general elec- time, Bardeen and Brattain completed the “point-contact” tronic technology very far, for instance allowing World transistor, which was followed by Shockley’s own bipolar War II code-breaking computers to operate, but they soon Replica of First Transistor Prototype on Display at the junction transistor (BJT). The BJT ultimately replaced the became impractical. Although smaller and smaller ones Science & Technology point-contact model because of its superior performance. were made, vacuum tubes are fragile, gave off heat, and Innovation Center Photo by Michael Mills In 1956, the world honored their achievement, as they could burn out, necessitating replacement. The practical were awarded the for discovering transistor developed at Bell Laboratories solved all of the transistor effect. This effect is comparable to the way these problems. that valves on a faucet control the flow of water.

By Daniel Gruspier

Each morning my alarm clock wakes me up by turning on the radio. I switch it off and get dressed after checking the weather on my . As I drive to work, I stream music from my phone through my car’s speakers. Later when I get home, I raise the thermostat a few degrees to make the house warmer. None of these things would be possible without the transistor, the tiny devices that give us digital logic. Digital logic is the root of the modern digi- tal age, and it is the only way of life that I have ever known. John Bardeen, William Shockley The transistor is the primary functional component of all and Walter Brattain (1947) modern electronics. At its simplest, it allows the flow of Photo courtesy AT&T Archives and History Center electricity between two point as controlled or switched by the supply of energy into another point. All modern elec- tronics depend upon transistors. Although prototypes, in

12 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 13 and incorporated into electronic devices. The number of The number of transistors in transistors in constant use now exceeds the number of Quick Look constant use now exceeds the cells in the human body of every person in the state of California. And each of these are expanding our digital number of cells in the human world. The initial device created by Bardeen, Brattain and body of every person in the Shockley shifted the course of humanity by launching the state of California. modern digital age.

References The Transistor Watkins, Thayer, The History of the Transistor, San Jose State Univer- The first practical transistor was, perhaps, 4 by 4 cm in sity, n.d. size. Even this first prototype (a replica of which is on Riordan, Michael et. al., The Invention of the Transistor, Stanford display at the Science & Technology Innovation Center University, 1999. in Middletown, NJ) achieved significant scale reduction Nave, R., Transistors, Georgia State University, n.d. in size, power consumption and heat generation. Today’s transistors are microscopic and consolidated into inte- Foundations of the : the Transistor, AT&T Tech Chan- nel, May 2012. grated circuits. More complicated electronics, such as and laptops contain the equivalent of billions A Modern Aladdin’s Lamp, AT&T Tech Channel, December 2011. of individual standalone transistors. Other simpler devices, How Many Transistors Have Ever Shipped? Jim Handy, such as hair dryers, need a way to manage the “on” and https://www.forbes.com/sites/jimhandy/2014/05/26/how-ma- ny-transistors-have-ever-shipped/#2ebb40c04425 “off” switch and their electronics contain at least a few transistors. Every year, billions upon billions are produced

Megabit Chip with Pen Point for Comparison (1985) Photo courtesy AT&T Archives and History Center

Inventors: , , and Calvin Fuller (1954) Photo courtesy AT&T Archives and History Center Bell Solar Cell

In 1954, researchers designed the first practical solar cell, a solid-state device capable of converting sunlight into electricity at a useful efficiency of six percent. The unit on display at the Science and Technology Innovation Center in Middletown, NJ, Solar Battery: Comprised of 8 Solar Cells is an early solar battery containing eight individual Photo by Michael Mills cells. AT&T later used solar cells to provide power for its 1962 Telstar satellite.

14 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 15 Launching Satellite Communications:

The Telstar Project By Leon Lubranski On July 10, 1962, a Thor-Delta rocket was launched from Society. In it he proposed the use of orbiting satellites for Cape Canaveral, Florida and successfully inserted the first the purpose of delivering transoceanic communications. active , AT&T’s Telstar, into orbit These satellites would effectively play the role of micro- around the earth. By day’s end the satellite had proven wave towers in space. However, 1955 was pre-Sputnik and that it could successfully relay both voice and television the United States didn’t have a rocket capable of orbit- signals. In doing so it demonstrated that it could achieve ing a satellite. Nevertheless, Dr. Pierce and his colleagues one of its prime objectives. AT&T received numerous lau- decided to start research and development on technology datory messages. For example: that could potentially play a role in a satellite communica- tions system. “Congratulations on your Telstar accomplishment. It was one of the truly great technical accomplishments of all time.” AT&T’s entry into satellite “Our congratulations to you and your associates on communications came about the magnificent Telstar success. The conception of completely by chance. the satellite communication system and its perfect execution on the first shot certainly makes the whole world well aware of your fine capabilities and capacity for such an enormous undertaking.” AT&T’s entry into satellite communications came about completely by chance. At a technical meeting, W. H. Pick- “Warmest congratulations on your distinguished ering of JPL (Jet Propulsion Laboratories) described to Dr. achievement. It promises world consequences far Pierce and Rudy Kompfner, his colleague, an experiment beyond the boundaries of science and technology.” they were planning for NASA (National Aeronautics and Space Administration). A 100-foot sphere of metallized The Meeting of Great Minds plastic would be placed in a circular orbit around The relatively short but very difficult and challenging jour- the earth. Its purpose was to measure the density of the ney from idea to concept to realization began in 1955. Dr. upper atmosphere. Pierce and Kompfner recognized that John R. Pierce, Research Director for Bell Laboratories (BL), would reflect radio waves, i.e., behave as a published a highly technical article entitled, “Orbital Radio passive system. A proposal was written for JPL, which led Relays”, in Jet Propulsion, a journal of the American Rocket to a joint experiment involving Bell Laboratories, NASA, and JPL. BL decided to deploy the infrastructure – receiver and transmitter – for the experiment in Holmdel, NJ. The receiving system consisted of a horn-reflector and the associated radio signal amplification equipment. Echo I was launched in August of 1960. During one of its Telstar Satellite Being Placed atop a Rocket (1962) Photo courtesy AT&T Archives and History Center

16 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 17 Diagram Depicting Telstar Interior and External Features (1962) Photo courtesy AT&T Archives and History Center

Project Echo — Horn Antenna Holmdel, NJ (1960) sonnel, numbering about 500, were recruited from almost Photo courtesy AT&T Archives and History Center every part of BL. The first system proposal was issued on August 30, 1960, less than three weeks after Echo had been launched. It called for the orbiting of an active com- munications satellite system, called Telstar, by mid-1962. The success of Echo created some excitement about the potential of communications satellites. There was a reali- zation by NASA, the Department of Defense, communica- tions carriers, and satellite hardware manufacturers that the time of satellite based communications had arrived. tion of the satellite and had to pay NASA $3 million for all AT&T decided that its satellite development program costs associated with the rocket, the launch and ground should lead to a fully operational commercial system. It support. NASA also got worldwide rights to any patents envisioned the deployment of 50 satellites that would that AT&T might develop from the satellite, and it could support worldwide delivery of voice, data, and television license these patents royalty-free to any third party. communications. These systems could replace undersea transmission cables. Subsea technology, at the time, was very expensive to deploy and offered a relatively small number of communications channels. Capacity could not keep up with demands, especially for TV broadcasts.

Productization of an AT&T Satellite and a New Industry On October 21, 1960, AT&T Long Lines requested approv- al from the FCC for the deployment of an experimental space communications system. Authorization was granted on January 27, 1961. However, just as Telstar development was gathering momentum, NASA told BL on November 4, 1960 that they were planning four launches of com- munication satellites (known as Relay) of their own, and they expected BL to bid. Basically, BL had no choice since NASA had the launch vehicles. The NASA RFP (Request for Proposal) was issued on January 4, 1961 and In May the passes JPL transmitted a message from President Eisen- This type of system receives a radio signal and amplifies contract was awarded to RCA. AT&T’s proposal was ranked hower via Echo which was successfully received in Holm- it before beaming it back to earth. He made the proposal fourth primarily due to the fact that it had no prior experi- del. Numerous experiments proved that it was practical partly because he realized that AT&T already possessed ence in satellite construction. Shortly afterwards, NASA in- to use man-made satellites to reflect two-way telephone “most of the tools to do the job.” BL had developed a num- dicated that it was willing to discuss the launch of Telstar. conversations. The lessons learned from the Echo exper- ber of new electronic devices, many of which had direct After six months of negotiations NASA agreed to supply iment would have direct applications to active satellite application to satellite technology. AT&T with a three-stage Thor-Delta rocket. AT&T had to technology. cover all costs related to the development and construc- As early as May 1960, even before the launch of Echo, R.W. From Proposal to Proof-of-Concept Kompfer wrote Leonard Jaffe, NASA’s Director of Commu- In August 1959, Leroy C. Tillotson, head of BL’s Radio Sys- nications Systems, describing research toward an active Telstar 1 Launched from tems Research Department proposed that AT&T should satellite already under way in BL. It became apparent that Cape Canaveral (1962) Photo courtesy AT&T Archives build and launch an experimental active satellite. a major AT&T project was materializing. Development per- and History Center

18 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 19 Telstar Electronic Thermo Vacuum Chamber Test Component Housing (1962) to Determine Thermal Effects Photo courtesy AT&T of Sunlight (1962) Archives and History Center Photo courtesy AT&T Archives and History Center

The Telstar Satellite services. NASA was very concerned about the impact of Telstar’s exterior consisted of 72 flat facets, a double row radiation on satellite components. The surface of Telstar of antennas around its equator – one row for receiving was equipped with sensors to measure this phenomenon. and another for transmitting. Sixty of the facets were used for solar cells (power source) and others were uti- The success of the project would hinge on the use of lized to support radiation measurements, tracking, and numerous BL inventions, capabilities, processes and skills, the determination of satellite orientation. The teleme- including: try, command, and antenna was located at the top. The structure of Telstar consisted of a magnesium a. Maser microwave amplifiers (very low , frame that was covered by aluminum panels. The satel- required to maintain usability of a signal) lite’s various electronic circuits contained more than 1000 b. Travelling-wave-tube amplifiers (amplifies transistors and numerous other components. A critical very faint signals) function was provided by a single electron tube – a travel- c. Transistors ing-wave tube – used for communications amplification. d. Solar cells (provides power to the satellite) All electronic components were housed inside a 20-inch Telstar engineers developed a number of techniques that e. Microwave technology (used extensively by diameter aluminum canister.The canister was filled with would be useful in building future satellites. They found AT&T for its long distance network) a liquid foam that when hardened served to protect the a way to mount 3600 solar cells on the outside so that f. Design and construction of horn-reflector equipment from damage and vibration. It was hermeti- they could provide about 15 watts of power. The cells were antennas (supported the Echo experiment) cally sealed before its installation in the satellite. Thirty coated with a layer of artificial sapphire to protect them g. Design and construction of high reliability watts of power would be required to support a fully oper- against the effects of radiation and impacts of microme- electronic systems for undersea cable applications ational (meaning all functions powered up) system. Only teorites. The Telstar Project was extraordinarily demanding con- h. Frequency feedback circuits half of this requirement could be met by solar cells. The sidering its 21-month interval. During this period, BL had (invented in 1930, a tuning device that keeps out rest would be provided by 19 batteries which would be to design and produce a complicated satellite, design and background noise) recharged during those periods of the orbit that weren’t construct a large high performance earth station in the i. Experience with the Echo project used for communications experiments. US, and reach agreement with European carriers for con- j. The use of polyurethane foam to form a firm The first phone call via Telstar struction of similar facilities in a number of countries. The structure highly immune to the effects of shock The satellite consisted of three primary systems. The occurred at 7:30 pm EDT. It was key objectives for the project were: and vibration. The technique was developed communications system supported 600 one-way voice between F. R. Kappel, Chairman previously by BL in missile-guidance work for the channels or one TV channel. The very faint signals received • Prove that a broadband communications satellite could military. from the earth stations were amplified by a factor of 10 of the Board of AT&T, and Lyndon transmit telephone messages, data, and television billion by the combination of transistors and the traveling Baines Johnson. across the Atlantic Another key success factor was the Bell Labs environ- wave tube. The amplified signal was then transmitted to • Test, under the stresses of an actual launch and the ment which encouraged the exploration of new areas of its destination. The telemetry system was responsible for hazards of space, some of the electronic equipment that research and supported collaboration across different collecting 115 different measurements related to satellite had been developed for satellite communications departments with a minimum level of formality. performance factors such as critical temperatures, pres- The satellite was assembled at Western Electric’s Hill- • Measure the radiation that a satellite would encounter The design of the satellite was driven by the objectives sure, solar cell power output, and data from the radiation side, NJ shop. This facility’s clean rooms had been used in space (Telstar’s orbit passed through the Van Allen discussed above. The Delta-Thor launch vehicle imposed damage experiments. These would then be transmitted to to assemble submarine cable . Processes were belts, a region of energetic charged particles which were restrictions on satellite size, weight, and orbital parame- Earth every minute. The command system provided the already in place to support high standards for electronic captured by the Earth’s magnetic field) ters. The weight was limited to a maximum of 170 pounds means for power management. Commands would be is- system assembly. This included strict inspection require- • Find the best ways to track a moving satellite accurately and it was determined that a sphere with a 34.5 inch diam- sued by the earth station to turn on or off various satellite ments and detailed record keeping. The Bell System eter was the best geometry. This meant that microwave systems. The communications system, which consumed had considerable experience in designing equipment for Within BL the project was viewed as the “Telstar Exper- functions that would normally require hundreds of square 50% of the satellite’s peak power, was only turned on reliability. This included procedures that addressed the iment” since many of functions went beyond proving feet of floor space would have to be compressed to fit when needed for testing purposes. testing and selection of system components for undersea that a satellite could effectively support communications into a very small volume. cables. The vast majority of components used for Tel-

20 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 21 Television Image of American Flag Waving in Front of the Andover Radome (1962) pass. Bell Labs had long term relationships with carriers management concluded that Telstar was going to be a Photo courtesy AT&T Archives in France, England, and Germany. They readily agreed to “one-shot experiment” and that AT&T should focus on and History Center deploy (at their own expense) ground stations to support reaping the public relations benefits. This was the first TV image sent to space and back. the project. The success of the Telstar Project was critical to proving Success in the feasibility and value of broadband communications Telstar I was successfully launched from Cape Canaveral via active repeater satellites. To date, approximately 2000 star were off-the-shelf and were designed to operate in on the morning of July 10, 1962. A number of communi- civilian and military communications satellites have been a controlled environment. There was insufficient time to cations transmissions were scheduled for late in the day. launched. AT&T BL demonstrated how a complex idea design custom components and to execute lengthy tests The first phone call via Telstar occurred at 7:30 pm EDT. It could be turned into reality through ingenuity, scientific to assess their reliability. Widely fluctuating temperatures, was between F. R. Kappel, Chairman of the Board of AT&T, research, engineering, collaboration, intelligent manage- such as those occurring in orbit, could seriously limit their and Lyndon Baines Johnson. Afterwards, the first television ment, and of course, will power. The Telstar Project is just performance and even shorten their life. A decision was transmission via Telstar was initiated. Viewers saw a picture one example of how AT&T Bell Laboratories innovation has made to implement a thermal control mechanism that of the American flag waving in front of the Andover ra- proven to be beneficial for AT&T and the world resulting in would insure a near room temperature environment for dome. That was followed by a question-and-answer period transformative and historical changes to societies, com- the batteries and electronic components for a satellite The Ground Station between a Washington and AT&T executives in merce, and global relations. functioning in outer space. The satellite weight limitation The design and construction of the earth-based support Andover that was relayed “live” via Telstar. At 7:47 pm the meant that the number of redundant components had to infrastructure was in many ways just as complex and French reported that they were also seeing the broadcast. References be kept to a minimum. Once completed the satellite was challenging as the satellite itself. The site for this facility subjected to a series of tests meant to simulate the vibra- was a 1000-acre piece of land in Andover, Maine. The major Hundreds of additional tests were conducted during the Solomon, Louis, (1962). Telstar, Communications Breakthrough by Sat- ellite, McGraw-Hill tions and shock of launch and the environment of space. elements of the ground station included: next few months. They covered TV broadcasts (color and black and white), voice, data, and facsimiles. Satellite te- Foster, R. M. (1963). Satellite Communications Physics, Editor AT&T Document, Project Telstar, FCC Annual Report, June 1, 1962 and • A horn-reflector antenna and associated amplifiers lemetry revealed that thermal and electrical performance June 30, 1963 • Various acquisition and tracking antennas aligned extremely well with design targets. However, in Blackmore, R. W., Design and Construction of the Horn Antenna, Bell • Computer systems used for orbital predictions mid-November 1962, Telstar starting to experience prob- Laboratories Record, April 1963 • Highly sensitive receivers lems with its command system. As a result, all communica- Anderson, R. E. D., Meszaros, G. W., Ciccolella, D. F., The Satellite Power • Powerful tions related tests had to be halted. BL initiated an effort to System, Bell Laboratories Record, April 1963 • Equipment associated with the sending and receiving determine the origins of the failure. They concluded that it Haury, P. T., Thermal Design of the Electronics Canister, Bell Laborato- of command and telemetry signals was due to the impact of excessive radiation exposure that ries Record, April 1963 • A massive radome (161-feet high) designed to cover exceeded the design target by a factor of 100. This level West, J. W., Space Hardware Aspects of the Satellite, Bell Laboratories the horn-reflector antenna structure and prevent of radiation may have been a direct result of the Starfish Record, April 1963 damage and physical that would impact Prime high-altitude nuclear bomb test that occurred on Lewis, P. J., Archives of Business: Telstar; The Night the Satellite Flew, antenna performance due to weather conditions the day before the Telstar launch. A fix was implemented New York Times, July 5, 1987 and Telstar began to function normally during the begin- Zimmerman, R., (Fall 2000). Telstar, Invention & Technology AT&T anticipated that the site could support additional ning of January 1963. The command system failed again

antennas if needed for a network of satellites. and on February 21, 1963, Telstar ceased to function. Chapman, R. C., Critchlow, H. M., Command and Control Systems, The Bell System Technical Journal, July 1963

The power of the broadband communications signal AT&T’s plans for deploying a network of communications Mayo, J. S., Mann, H., Witt F. J, Peck D. S., Gummel, H. K., and Brown, W. radiated from the satellite is about 2.25 watts. The Ando- satellites was never realized. The political environment L., The Command System Malfunction of the Telstar Satellite, The Bell System Technical Journal, July 1963 ver horn antenna was modeled after the one in Holmdel had changed in late 1961. The Department of Justice took that supported Echo. However, it was considerably larger the position that a space communications system was Hrycak, P., Koontz, D. E., Maggs, C., Stafford, J.W., Unger, B. A., Witten- berg, A. M., The Spacecraft Structure and Thermal Design Consider- since it had to capture very weak transmissions – about a too important to be turned over to any group that might ations, The Bell System Technical Journal, July 1963 billionth of a watt – from a satellite that could be situated be dominated by any one company, particularly AT&T. R.H. Shennum, R. H., and Haury, P. T., A General Description of the approximately 3500 miles above Earth. A maser (micro- The Communications Satellite Act was signed into law on Telstar Spacecraft, The Bell System Technical Journal, July 1963 Andover, Maine, wave amplifier) was employed to amplify this signal with- August 31, 1962. It placed all American satellite commu- Telstar Earth Station (1962) Shennum, R. H., and Reid, E. J., The Design and Construction of the Photo courtesy AT&T out introducing any perceptible noise which could make nications under control of a federally managed, privately Electronics Package, The Bell System Technical Journal, July 1963 Archives and History Center the signal unusable. A critical function of the Andover owned corporate monopoly, COMSAT. In hindsight, the Peck, D. S., and Wooley, M. C., Component Design, Construction and facility was the rapid acquisition and accurate tracking of RCA win of the NASA communications satellite bid in May Evaluation for Satellites, The Bell System Technical Journal, July 1963 the satellite. This was important since Telstar was “visible” of 1961 may have been the turning point for AT&T’s vision AT&T Document, Transcript of Interview with A. C. Dickieson, E. F. to the site for approximately 20 minutes of each orbital of a privately owned global satellite system. Telstar project O’Neill, H. P. Kelly, I Welber, and R. H. Shennum, 4/10/70

22 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 23 in Long Distance Transmission

By Doug Olsen

Most of us are familiar with Cable obvious. Coaxial cable had its com- Bell Labs Innovation in that could carry an enormous signal cations grew, it became obvious to • Electronics at terminals could be TV and the coaxial copper cable or mercial origins in AT&T’s Bell Labs Transmission as compared to the exist- the engineers that the existing low upgraded along existing cable “coax” in use in millions of homes and AT&T’s network. The initial appli- In the 1920s, while the decade ing open wire and cables frequency analog carrier systems routes, allowing for future-proof- across the United States today. How- cations of coaxial cable systems were “roared” and time and technology in use at that time. The transmission would be unable to fulfill the need. ing the deployment ever, AT&T’s role in the development in long distance telephony, early long advanced, ambitious innovators signals were contained between the Espenschied and Affel’s coaxial of the coaxial cable, as well as the distance television transmission, and grappled with a fresh set of commu- outer surface of the central core, cable system was able to handle the • Simultaneous High Capacity Voice, history of the cables’ use in AT&T’s transmission of a technology ahead nications challenges. Novel experi- and the inner surface of the tube. increasing capacity demands. These Television, and Data Transmission long distance network may not be as of its time — the Picturephone.™ ments and increased pressures on The system also included terminal systems would eventually carry the transmission capacity of the long equipment at each end 13,200 voice circuits per channel. Key The era’s analog carrier systems distance open-wire communications of the line along with repeaters at advantages of coaxial based trans- included terminal multiplexer equip- networks pushed researchers to regular intervals designed to boost mission systems are listed below: ment and line and repeater equip- develop a transmission medium that the signal along the line. ment. Espenschied and Affel’s coaxial could meet the growing bandwidth • Less channel noise and elimination cable is the transmission medium and capacity demands of the 20th Why Coaxial Cable? of crosstalk interference century. In 1928, British inventor C. During the early 20th century the S. Franklin patented a coaxial cable method Bell System engineers em- • Higher frequencies vs. open wire for limited use as an antenna feeder. ployed to increase long haul circuit and copper cable carrier systems A year later, Lloyd Espenschied and capacity was accomplished with ana- Herman Affel of Bell Labs (AT&T’s log carrier systems (C, J, and K) on R&D subsidiary) enhanced earlier open wire and copper cable. These models to develop the first modern systems were limited to transmis- high capacity coaxial cable trans- sion bandwidths in the KHz range mission system, which was patent- (4-12 voice circuits per channel) and ed in 1931 (U.S. Patent 1,835,031). were subject to external electro- Espenschied and Affel’s cable was magnetic interference. As capacity comprised of a central conducting needs in long distance communi- wire centered in a conducting tube

Coaxial Cable (1936) Photo by Michael Mills Lloyd Espenschied and Herman Affel (c. 1949) Photo courtesy AT&T Archives and History Center

24 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 25 30” for the remainder. As mentioned system deployed in the AT&T long repaired. The system required solid previously, this cable was capable distance network. These systems state repeaters which were placed Terminal Multiplexing Terminal Multiplexing of transmitting a television signal were typically used in high traffic at varying intervals based on the Apparatus Apparatus in addition to the voice channels. In routes terminating in large metro- repeater function employed. Basic May of 1941 an 800 mile circuit was politan areas. The L-5 system was repeaters were spaced at 1 mile Lines and Repeaters created by connecting the four 200 eventually capable of transmitting intervals, regulating repeaters were mile conductors in series; this was 108,000 two way voice calls over spaced at 7 miles max intervals, and the longest successful test of televi- 20 coaxial tubes (0.375" in diameter equalizing repeaters were spaced at sion transmission over coaxial cable each tube) with 10 transmit tubes 38 miles max intervals. at the time. and 10 receive tubes in a cable providing the two way communica- Interestingly, these systems were AT&T’s L-5 Coaxial tion. The system had a spare pair of also designed for future trunks to System coaxial cables in case one of the 10 carry AT&T’s Picturephone™ service, Diagram of Coaxial System In 1970 an L-5 Coaxial Cable Carrier pairs failed. Upon failure, the built the late 1960’s precursor to today’s Drawing courtesy AT&T Archives system was trialed by AT&T between in line protection switching system video calling applications such as and History Center Cedarbrook NJ and Netcong NJ and would switch the traffic to the spare Skype™ and Facetime.™ Diagram from 1934 Bell System Technical Journal Systems for Wide-Band Transmission Over Coaxial was expected to carry 90,000 voice pair until the failed pair could be Lines. calls and 420 Picturephone™ calls, or 30 color TV programs, or high-speed data. Full blown deployments of the L-5 Coaxial System began in 1972. Sample Length of 20 Coaxial Cable with Bob Robertson in Baltimore, Maryland which creates the “line” component portion of AT&T’s long distance AT&T’s L-1 Coaxial The diagram depicts the Western (1964) of the system. Single Sideband voice communication for over 50 System Electric L-5 Coaxial Cable Carrier Photo courtesy AT&T Archives and History Center Modulation (SSB) was the signal years. These systems were typically In 1941, AT&T deployed the first processing used to maximize the deployed over long distance spans commercial field application of a bandwidth per transmitted signal ranging from 250–4,000 miles. Coaxi- L-1 Coaxial System, consisting of on the line. The terminal equipment al system design changed drastically two hundred miles of coaxial cable used Frequency Division Multiplexing over 34 years to handle ever increas- between Stevens Point, Wisconsin, (FDM) which allows many channels ing long-distance call volumes. The and Minneapolis, Minnesota. The to share a wide bandwidth whereby number of conductors per cable in- L-1 was capable of each channel is assigned a portion of creased from 4 to 22, while the voice transmitting 480 simultaneous the frequency spectrum. The photo circuit carrying capacity improved voice conversations and one 4 MHz shows a cross section of a 20 tube from 600 circuits to 13,200 circuits, a Television signal over this span. The coaxial cable. 2200% increase per tube. The voice system used 4 coaxial tubes in a circuits per system similarly saw a single cable sheath comprised of a The following sections provide a vast improvement with voice cir- working pair (TX, RX) and a backup deeper understanding of a sampling cuits increasing from L1 at 600 voice pair in case of failure. The overall of the historical milestones list- circuits per system to L5E at 132,000 route was approximately 200 miles ed above. The focus will be on the voice circuits per system. In addition end to end, broken into four 50 mile evolution of the L-Carrier system, to cable and multiplexing improve- segments. At the end points in Ste- an integral component in AT&T’s ments, repeater technology also vens Point and Minneapolis, terminal long distance core for almost half a took advantage of another Bell Labs modulators transformed the carrier century. innovation, the transistor. Invent- circuits to voice circuits and vice ed in 1947 by innovators Shockley, versa. The end terminal also included L-Carrier Systems Brattain, and Bardeen, the transistor power supply equipment, testing Evolution supplanted the vacuum tube, in- and alarm equipment, amplifiers and AT&T deployed L-Carrier systems creasing the performance, scale, and regulating equipment. The cable manufactured by Western Electric reliability of repeater equipment. was attached to aerial pole lines for from 1941 through the 1970s. These part of the route, and buried under- coaxial systems carried a significant ground at an average depth of about

26 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 27 Undersea Coaxial Cable 2,240 miles with a range of depth George C. McConnaughey in NY, Brit- The TAT-1 undersea coaxial system TAT-1 from a few fathoms on the conti- ish Postmaster General Charles Hill was in service for a total of 22 years In 1956, a joint U.S.-British-Canadian nental shelves to a maximum depth in , and Minister of Transport and was retired from service in 1978. Historical Milestones of effort led to the application of coax- of 2,300 fathoms. TAT-1 was one of George Carlyle Marler in Ottawa. The Coaxial Cable Systems ial technology for the first transat- a number of SB undersea carrier ceremony was viewed and heard by Future of Coaxial Cable lantic telephone cable, TAT-1 (Trans- systems deployed from 1956-1960 thousands that gathered at the Bell The advent of fiber optic transmis- • 1929 Broadband coaxial cable invented by Lloyd Espenschied and Her- atlantic No. 1). TAT-1 was designed to which used (2) 0.62" diameter coaxial Systems headquarters building. On its sion systems in the late 1970s and man Affel. connect London to NY and London cables run in parallel. The system first full day of operation TAT-1 com- early 1980s rendered copper coaxial • 1929 Proof of concept coaxial line near Phoenixville, PA (2) 2600 foot to Montreal, the key interexchange was able to carry 36 working voice pleted 588 US-UK calls. This capped cable transmission systems obsolete coaxial sections tested. points to reach further into North circuits along with maintenance a unique collaboration between the for all long haul carrier service. Coax- • 1936 First Field Trial coaxial system, New York to Philadelphia, capable of America and Europe. The London–NY circuits. engineering and management teams ial cable continues to be used today carrying 240 conversations or a single television channel. circuit was 4,078 miles and the Lon- on both sides of the Atlantic. Each predominantly for intra-building don-Montreal circuit was 4,157 miles. In September of 1957 the TAT-1 cable contributing their unique talents and CATV transmission, and in the “coax” • 1936 First Bell System coaxial cable for TV use in NYC. A 1.5 mile span The deep sea submarine coaxial opened at 11:00AM EST with a three expertise to the project, ensuring part of hybrid fiber-coax systems from NBC studio to the transmitter on the State Building. connection from Clarenville, New- way call between AT&T Board Chair- its success for the mutual benefit of in MSO networks. The “coax” is the • 1937 Experimental transmission of motion pictures over the NY-Philly foundland to Oban, Scotland was man Cleo F. Craig and FCC Chairman North America and Europe. distribution plant in the last mile into coaxial system. the CATV subscriber’s home. Howev- er, the field of use for coaxial cable • 1941 First U.S. commercial L-1 coaxial cable installation, Minneapolis, MN will continue to diminish over time as to Stevens Point, WI. fiber optics moves closer to the end • 1947 World Series baseball games were televised through coaxial cable, user’s equipment and fiber to the NY-Philly-Baltimore-DC home services, such as AT&T Fiber,™ • 1947 Transistor invented by Shockley, Brattain, and Bardeen all affiliated penetrate more homes. In addition, with Bell Labs. WIFI, 4G-LTE cellular, and eventually 5G cellular will provide high speed • 1950 First undersea coaxial system, Florida to Cuba. substitutes for coaxial cable es- • 1956 First transatlantic telephone cable opens, Newfoundland-Scotland. pecially in the last mile and home TAT-1 Coaxial. network. The future of coaxial cable, the transmission medium that car- • 1964 First transpacific telephone cable opens, California-Hawaii-Japan, ried long distance communications TPC-1 and HAW-1 for thousands of miles over land and • 1970 L-5 Coaxial Cable Carrier system trialed between Cedarbrook NJ and undersea for over half a century, is Netcong NJ expected to carry 90,000 voice calls and 420 Picturephone™ tenuous at best. calls, or 30 color TV programs, or high-speed data.

• 1983 Last Coaxial Undersea transatlantic telephone cable opens, New Jersey-England, TAT-7

References

Bell Labs RECORD July-August 1976/page Members of the Technical Staff Bell Tele- http://ethw.org/Telephone_Transmission#- 214 phone Laboratories. 1982 Fifth Edition. Coaxial_Cable Transmission Systems for Communications. L. Espenschied and M. E. Strieby. 1934. Kelly Education and Training Center. 1992. Systems for Wide-Band Transmission over L5 Coaxial Carrier Transmission System Undersea Optical Communications OC5200 Coaxial Lines. Bell System Technical Journal Forward. Bell System Technical Journal. Version 1 Transtlantic TAT 1- Pulling the cable onto shore 13, 654-679. Volume 53 December 1974 (c. 1954) Photo courtesy AT&T Archives and History Center E.T. Mottram, R.J. Halsey, J.W. Emling and R. C.H. Elmendorf, R.D. Ehrbar, R.H. Klie, and A.J. G. Griffith. October 1956. Transatlantic Tele- Grossman. 1953. L3 Coaxial System. phone Cable System- Planning and Overall Bell System Technical Journal. July 1953 Photo Title Here Performance. 781-832. Photo courtesy AT&T Archives and History Center AT&T Archives. 1992. Events in Telecommu- Bell Labs RECORD January 1942 pages nications History 127-132

28 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 29 made by drawing (i.e. pulling while heating) a glass rod, called a preform, to a diameter slightly thicker than a human hair (125 micrometers).

The basic structure of a standard Fiber Optics single-mode fiber (SSMF) consists of a high purity glass core of ~10um di- Jacket ameter that guides light, and a clad- ding comprised of glass of a slightly in the AT&T different chemical composition and Structure and Light Propagation having 125um (0.125mm) diameter. Coating Illustration by Jacqueline For mechanical and chemical protec- Bogdan tion, the optical fiber has a polymer Cladding Network coating applied in two or more Core different layers and may also have a PVC jacket for additional protection. By Kathy Tse Optical Fiber Light is guided in the core of an Domestic fiber deployments and Cable Systems division, and was the multi-mode fiber had to optical fiber by a phenomenon the advancements of fiber systems multi-mode fiber. This limited be overcome to keep the called total internal reflection. Total Transmitter technology have uniquely enabled the distance and bit rate that pulses from spreading. The internal reflection occurs when a Receiver the high bandwidth required today could be reached, due to the next generation of fiber ca- light beam traveling in one medium Electrical to drive our need for video and large core diameter that allows mul- ble, using single mode fiber, hits the interface with a medium of Light ray trapped in the Output Signal beyond. Earlier coaxial cable system tiple modes of the light to be prop- was first introduced into the lower refractive index at a sufficient- core of the fiber and radio technology had extremely agated. Multi-mode fiber is still used network in early 1985. This ly large angle, such that the light is limited bandwidth, and the advent today for applications inside fiber was fabricated by AT&T refracted back into the first medium, Electrical Input Signal of fiber optic cabling opened up buildings, due to the low cost in Atlanta, Georgia thus “trapping” the light beam. This new possibilities, with AT&T leading for short reach connectivity phenomenon guides light in the fi- the way. and the enablement of lower An optical fiber is a thin, flex- ber. Using this single mode fiber and cost optics. ible strand of silica glass that an FT Series G system developed Starting in 1977, ATT used the first can guide light over distances by the Network Systems division, out a larger fiber footprint across Light is guided fiber optic cable in a commercial In order to support the longer of up to several thousands of AT&T’s first single mode fiber system the US map. Through the first use of communications system for local distances required for coast- kilometers. Optical fibers are was deployed between Wayne and WDM ( Division Multi- in the core service in central Chicago (the loop). to-coast transmission, the Harrisburg, Pennsylvania carrying a plexing), AT&T was able to increase of an optical Other local installations followed. modal present in 417 Mb/s signal with single channel the capacity on a fiber up to 1.7 Gb/s AT&T’s first long distance commer- repeaters spaced every 50 km. There through multiple carriers spread fiber by a cial fiber optic installation, between was skepticism about the ability across the fiber spectrum. phenomenon New York and Washington opened of the fiber systems to operate at called total in February 1983. The fiber AT&T that rate with the same quality as The fiber deployed in the 1980s and deployed was from their Network the deployed radio systems, early 1990s served AT&T well, but internal but after a month without the quality of the deployed fiber was reflection. a single error it was clear surpassed by new fiber that was be- that the single mode ing produced using better processes Fiber-Optic Cable Photo by Michael Mills fiber systems were here and with a variety of compositions to stay. met different transmission needs advantages. When AT&T looked at Soon the race was on options to build a new fiber back- to put more bandwidth bone composed of the most mod- across the fiber and to build ern fiber, different options for the

30 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 31 AT&T Access Network Field Trial AT&T’s NexGen Fiber Backbone Connecting to Offer Multi-Gigabit Internet Speeds Major US Cities

Seattle AT&T will e field testing 10 gigait per second symmetrical passive optical networ technology Cleveland later this year. We call this (XS-N) and this new Chicago technology can deliver up to 10ps on the downlin Denver New York o a roadand connection. Salt Lake City San Francisco Herndon Kansas City Software-defined networks and Los Angeles XGS-PON are a natural step along Atlanta the evolutionary of PON Dallas technology... This is another way Key “ OC-768-capable DWDMs we’re enhancing our network Interoperability is key to our “Open Access” strategy. Houston Backbone Router and staying ahead of changing Its necessary or the Soware-efined Networ (SN) Miami consumer and business needs. and Networ unction irtualization(N).

Eddy Barker, Asst. Vice President of Access Architecture and” Design, AT&T

best way to accomplish this build with partners sharing the cost. The us to get the best optical distance, were looked at, including outsourc- NexGen Fiber Network construc- reducing the need for costly elec- ing our entire backbone to a com- tion started in the late 1990s, with trical regeneration, and provides AT&T’s goal is to support the merging of all services on petitor, buying already deployed a major buildout to all the critical for multiple diverse paths between a single networ, including wireless inrastructure. cities. This massive effort used a cities. As the fiber has evolved, so AT&Ts vision is to put XS-N in the cloud using hut spacing that was optimized to have the systems, with the modern soware. pen hardware and soware designs speed Today AT&T has the long distance fiber systems that systems allowing 96 channels with innovation. This innovative application can save time were available, overcoming many of 100Gb/s of data per wavelength, needed to manage, deliver, monitor, trouleshoot and a great fiber the issues of the early fiber builds and distances of thousands of provide care services to customers. network, the that had long distances between kilometers between regeneration ustomers are reuiring aster internet speeds of our amplifiers limiting the total distance points. Digital signal processing has possible before electrical signal avoided the need for coils of dis- ecause o andwidth-heavy applications lie virtual and augmented reality and artificial intelligence. competitors. regeneration. persion-compensating fiber at each XS-N helps networs handle the andwidth rom amplifier site by digitally “erasing” these cutting-edge technologies. Today AT&T has a great fiber net- chromatic dispersion at the wave- Learn more about GPON here fiber from a competitor, or build- work, the envy of our competitors. length termination. In 2017, AT&T ing our own fiber backbone with Between the Nexgen backbone that has demonstrated 400G wavelength partners. After a business analysis forms an express “highway” be- transmission on a deployed sys- the decision was made that AT&T tween large cities, and the regional tem, proving the fiber is ready as should have their own fiber back- fiber that terminates at hundreds the transmission systems support bone as a competitive advantage, of smaller cities, we blanket the US increasingly higher bandwidth into and that it would be built together with fiber cabling. This fiber allows the future.

32 | AT&T SCIENCE & TECHNOLOGY INNOVATION

© October 2017 AT&T Intellectual Property. All rights reserved. Vitaphone and Western Electric Recording Bringing Sound to Film

The Vitaphone and Western Electric By Zoe Goodman-Frost Recording System Photo by Michael Mills

The technology that successfully investment in the thriving ability. The reproduction of sound brought sound to motion pictures in industry and there were no busi- for background to silent movies the 1920’s was developed at AT&T’s ness drivers to risk this by investing would give a consistent quality to Bell Laboratories and its predeces- in movies in which the characters the musical accompaniment. The sor, the Western Electric Engineering spoke. Previous attempts were movie Don Juan (1926), the first film Department. AT&T initially had no found to have poor synchronization, made with Vitaphone technology by corporate goal to introduce sound inadequate sound volume, and had Warner Brothers, was essentially a to motion pictures – its goal was been described as expensive failures. silent movie with background score to improve the national telephone The movie industry was concerned, performed by the New York Philhar- network. Credit is given to AT&T however, in creating a more con- monic. Only one scene contained R&D executive E.B. Craft, who, in sistent movie-going experience. ground-breaking sound effects – a 1922, recognized that telephone and Movie-goers in the larger cities had sword fight included the clanging of transmission research and develop- the benefit of orchestras provid- sword against sword. ment provided all the piece-parts ing musical accompaniment, while (i.e., amplifiers, , mi- those in small towns often had a The movie industry was presented crophones, and electrical recording) single pianist, sometimes of dubious with two methods to record sound for the addition of sound to movies, – one in which sound is recorded on except for the means to synchronize a disc resembling a re- sound and picture in both record- cord which is played while a projec- ing and playback. By 1924, this was tor displays the film, and the second developed which completed the in which sound is recorded on the working system. film itself. The Vitaphone – from the Latin and Greek words for “living” Interestingly, the movie industry and “sound” – was the only sound- initially also had no interest in talking on-disc method which was commer- pictures. They had a tremendous cially successful. It was developed by Bell Telephone Laboratories and Western Electric.

Cover Western Electric The system was first embraced by Sound Systems brochure Warner Brothers and both feature (c. 1929) Photo courtesy AT&T Archives and short subjects were pro- and History Center duced at the Warner Brothers-First National Studios between 1926 and

34 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 35 Edward C. Wente of Bell Laboratories with a Condenser (1931) condenser microphone a key com- captured on either disc or film. Two to develop an electrical recording Photo courtesy AT&T Archives ponent for Western Electric sound teams at Bell Laboratories were process that involved and History Center and telephony systems. created in 1920 to pursue electrical and electrical disk cutting which did recording. Joseph P. Maxfield and not produce a good enough sound Making a Better Way to Henry C. Harrison were charged with quality. But by mid-1922, Maxfield’s Record Sound developing a - group produced an experimental low and good linear ampli- of the carbon microphone was too The researchers also needed to ing system, or more specifically, prototype system for electrical disc fication and made transcontinental uneven and was limited to a narrow record and reproduce sound electri- an electromagnetic version of the recording using Wente’s condenser telephone communication possible. range, and even well-engineered cally. There seemed to be two likely existing acoustic disc phonograph. microphone and Arnold’s amplifi- Telephone service was expanded carbon microphones produced a low paths to electrical recording. Either The second group, E.C. Wente, Irving ers. In the new system, a condenser from NY to San Francisco. Western level hissing or sizzling background the existing phonograph could be Crandall, and Donald MacKenzie, was microphone converted the musi- Electric engineers soon applied the sound from the vibration of the car- re-engineered or sound could be assigned to develop a sound-on-film cian’s sound energy into electrical amplifier to loudspeakers, making bon granules. translated into patterns recordable recording technique. energy, which was then amplified it possible for many people to hear on photographic film. Recording before being converted into me- simultaneously what only one could Using Arnold’s amplifier to augment would need to be done electrical- The of the era were chanical energy at the recording hear through a conventional tele- the extremely weak signals, Edward ly with both methods. The voice acoustic-mechanical devices that stylus. The stylus scratched a groove phone receiver. By 1922, Western Christopher “E.C.” Wente in 1916 or music to be recorded would be were limited and uneven in fre- Electric public address systems were turned a previously unusable device picked up by a microphone which quency response, and could not

widely used. known as an electrostatic trans- generated a small be coupled directly to telephone Stoller and Pfannenstiehl with 1931. Ultimately, however, the sound- mitter into the first flat frequency whose variations correspond to the lines. Prior to the Bell Laboratories Vitaphone Projector (1926) Photo courtesy AT&T on-film technique prevailed and is In addition to amplification, the response microphone or, as Wente sound waves. These would then be research, attempts had been made Archives and History Center the method used today. existing device to convert sound called it, the condenser microphone. energy into electrical signals needed This design also consisted of two Making a Better to be improved. Since the earliest conducting plates with one plate Microphone days of Bell’s telephone, the car- serving as a diaphragm. A volt- In 1911, the single most important bon microphone had been used. age was applied to the plates. The problem in the national telephone It consisted of two metal plates diaphragm vibrated when struck by network was the limited distance separated by granules of carbon. sound waves, changing the distance over which a telephone conversation The plate facing the speaker was between the two plates and there- could be transmitted. Long-distance very thin and flexible, and acted as fore changing its capacitance. This service had just been established be- a diaphragm. Sound waves striking allowed a change in current flow in tween New York and Denver, but this the diaphragm caused it to vibrate, the circuit connected to the micro- was the limit possible with then-cur- exerting varying pressure on the phone. [Specifically, when the plates rent technology. Bell and Western granules, which in turn changed are closer together, capacitance in- Electric research had been working the electrical resistance between creases and a charge current occurs. on technologies for long-distance the plates. Higher pressure lowered When the plates are further apart, telephone transmission to span the the resistance as the granules were capacitance decreases and a dis- US. A device was needed to ampli- pushed closer together. A direct cur- charge current occurs.] The amplifier fy the electric current that carried rent was passed between the plates circuit then amplified this low-level conversations. through the granules. The varying signal to a useable level. The con- resistance resulted in a modulation denser microphone connected to Lee de Forest, in 1906, developed of the current, creating a varying an amplifier was found to produce the audion tube, the first three-ele- electric current that reproduced strong signals capable of transcon- ment vacuum tube, which amplified the varying pressure of the sound tinental transmission. It was also electrical signals, and demonstrated wave. In telephony, this modulated found to have remarkable acoustic it to Western Electric in 1912. West- current was directly passed through performance. The larger frequency ern Electric purchased the rights in the telephone wires to the central range, lower harmonic distortion, 1913. The tube was then improved in office. However, the carbon micro- and the fact that it did not suffer 1913 by Harold D. Arnold, making it a phone was not well suited for sound from the background noise inherent practical amplifier. This amplifier had research. The frequency response in the carbon microphone, made the

36 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 37 perimental system not yet ready for pany existing film footage, the film moved from the inside of the disc to Vitaphone Photo courtesy AT&T Archives and History Center commercial use. In addition, initially was projected so that the conductor the outside. In addition, unlike the

This shows Western Electric engineer George Groves, in 1927, cutting an electrical master. Groves was the sound quality and fidelity of the could watch the recently completed prevailing speed of 78 revolutions assigned to Vitaphone and he was the recording engineer on The Singer and Don Juan. He later sound-on-disc system surpassed the film and synchronize the music with per minute for phonograph records, relocated to Hollywood and became one of the great sound engineers, winning 2 Oscars (Sayonara 1957, My Fair Lady 1964) and was nominated for 6 additional films (The 1930, The Nun’s Story 1959, track. the visual cues. In this way, it was the Vitaphone discs – typically 16 inches Sunrise at Campobello 1960, The Music Man 1962, The Great Race 1965, Who’s Afraid of Virginia Woolf 1966) projector, rather than the camera, in diameter – were played at 33-1/3 The company’s developments in am- that was in sync with the recording rpm to increase the playing time to plifiers, loudspeakers, microphones, machine. match the running time of a reel of and electrical recording had been film. undertaken as part of AT&T’s efforts The end product – the Vitaphone to improve the telephone network. – was not just the single piece of Except for the unusual disc size and In 1922-1923, Research Administra- sound-on-disc equipment, but speed, the physical record-making tor E. B. Craft proposed to apply the rather a system of interdependent process was the same one used by company’s developments towards a parts. A Vitaphone-equipped the- record companies to make records commercial system for sound mo- ater used special projectors, sound for home use. The recording lathe tion pictures. As he wrote to Western amplification, and speakers. The cut an audio-signal-modulated spiral Electric Vice President in charge of projectors operated the same way groove into the polished surface of a research Frank Jewett, “It seems ob- that a conventional motorized silent slab of wax-like material rotating on vious that we are in the best position projector would, but there was also a turntable. Since the wax was much of anyone to develop and manufac- an attached phonograph turntable. too soft to be played in the usual ture the best apparatus and systems When the film was threaded into the way, a specially supported and guid- for use in this field.” Management projector, the projectionist aligned ed pickup was used to play it back agreed. a start mark on the film with the immediately to detect any sound picture gate on the projector, and problems that might have gone Putting Sound and would at the same time place a unnoticed during the filming. If prob- Moving Pictures Together phonograph record on the turntable, lems were found, the scene could Two related problems remained aligning the phonograph needle with then be re-shot while everything – synchronized recording and an arrow on the record’s label. The was still in place. Even the lightest playback. Playback was the more projector motor would also drive the playback caused some damage to straightforward. The problem was phonograph turntable, and played the wax master, so it was customary solved by running both projector sound synchronized with the film to employ two recorders and simul- and turntable from a single motor passing the picture gate. The discs taneously record two waxes, one with a mechanical filter in place to themselves were slightly different to play and the other to be sent for in a spinning wax disk. While the Victor and Columbia, took licenses the fluctuations of the microphone screen out vibrations. Synchronized from typical phonograph discs. processing if that “take” of the scene existing acoustic device picked up from Western Electric and switched current, creating a photographic recording was more difficult, be- The needle on Vitaphone records was approved. At the processing only the sounds aimed directly at the to this new technology. record of these fluctuations, and cause it was necessary to keep the sound-collecting horn, the micro- therefore the voice or music. After recording equipment stationary to phone was sensitive to more distant At the same time, Wente’s team the film was developed, the film was prevent vibrations while allowing the sounds. This allowed an orchestra to had succeeded in developing a played back between a constant camera motion for filming. This was sit normally, but it also meant that prototype for translating electrical light source and a photoelectric cell. solved in studio design. The record- room acoustics became important. impulses from a microphone into The cell output corresponded to the ing machines were usually located Since the microphone and amplifier variable-density light patterns on patterns of exposure which was then in a separate building to completely had a broader frequency range and photographic film. They developed amplified. isolate them from sound stage floor less harmonic distortion, the record- the light valve, a light-emitting vac- vibrations and other background A section of showing the ing cut into the wax was dramatically uum tube with a shutter of metallic Wente was granted a patent on this noise. Synchronization was main- photographic recording. The arrow points to the sound track. better. Maxfield’s group went on to ribbon. In their design, the width of technology in 1923, and it was the tained by driving all the cameras and develop the system further for use the slit formed by the ribbon var- basis for Western Electric’s sound- recorders with synchronous electric Photo courtesy AT&T Archives and History Center in consumer phonographs. By 1925, ied with an applied electric current. on-film process. However, in the view motors powered from a common the phonograph was re-engineered. During film recording, the exposure of the AT&T engineers of the mid- source. When music and sound ef- The two major record companies, received by a moving film varied with 1920’s, optical recording was an ex- fects were being recorded to accom-

38 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 39 Western Electric—Sound Projector sound record is on the same film The New Movie Theater Systems for Theatres (1929) with the picture made synchroni- Experience Drawing courtesy AT&T Archives and History Center zation inherent. The sound record For both sound-on-disc and the later consisted of a band about 1/8 inch sound-on-film techniques, the ampli- wide, called the sound track, which fied current was then converted into plant, a metal mold was produced ran down one side of the film. Such a sound. The number and size of the with a ridge instead of a groove, film was called a sound film, and was speaker horns in the theater would and this was used to press discs. It otherwise similar to an ordinary film. depend on the room’s acoustic prop- is interesting to note that, because After leaving the projector head, the erties. Horns were placed behind the nies and several minor companies Warner Brothers announced it would Vitaphone — Don Juan Premiere (1926) Photo courtesy AT&T Archives of the desirability of an immediate sound film entered the reproducing screen so that a perfect illusion that expressed their complete lack of use “Vitaphone”, as the new technol- and History Center playback capability, later on even unit, where it passed over a sprock- the voice or music is coming from interest. In 1925, Warner Bros – then ogy was now called, to provide syn- studios using sound-on-film systems et that moved it along at constant the screen was obtained. a minor company – saw the Western chronized musical accompaniment used a wax disc “playback machine” speed. A narrow bright beam of Electric sound motion picture sys- for all its films. together with their film recorders. light from a high-intensity lamp was The microphone plus amplifier com- tem as a means to become a major Film was preferred for editing and focused on the sound track of the bined with the electromechanical player in the business. Don Juan Premiere electrical sound system – carrying final release, but disc could be played film through a system of lenses and disk cutting mechanism was the new in 1926 the recorded strains of the New York back immediately for the director to an aperture plate. The light passing Western Electric electrical recording The Vitaphone Corporation was set Vitaphone debuted with the opening Philharmonic – replaced accompani- see if the sound take was satisfacto- through the moving film would then system, commercialized as the “We- up as a joint venture to experiment of the silent movie Don Juan, star- ment by live musicians. The system ry. Without the disc recordings, pro- vary in intensity according to the strex” system. It was an integrated with the production and exhibition ring , at the Warner’s was a hit. duction crews needed to wait until variations recorded on the sound system for recording, reproducing, of sound motion pictures. War- Theater in on August the optical recording returned from track. This light fell on a photoelec- and filling a theater with synchro- ner Brothers provided the picture 6, 1926. The movie featured the first The following year (October 6, 1927), the film processing laboratory. tric cell, causing variations in an nized sound. By May of 1924, Western production skill and Western Electric synchronized musical soundtrack Warner Brothers released its second electric current passing through it; Electric was ready to demonstrate provided the sound skill. In 1926, with sound effects – no spoken Vitaphone feature, , The Other Innovation these variations corresponded to its system to the movie industry. Vitaphone Corporation was given dialogue – accompanied by several which included classical and popular Path – Sound on Film the light, and therefore to the sound exclusive license to produce sound short subjects featuring comedians music, as well as about 350 words In contrast, in the sound-on-film which was recorded. The current was When the Western Electric Sales pictures using the Western Electric and singers, and a greeting from of dialogue. Human voice was now method under development by then amplified. Department approached the motion system and to equip theaters with motion picture industry spokesman added to film. The film broke box-of- Wente’s team, the fact that the picture industry, the largest compa- Western Electric sound systems. Will Hays. As for the main feature, an fice records and established Warner

40 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 41 Cast of Don Juan (1926) Western Electric Sound Installation Drawing courtesy AT&T Archives in a Modern Theatre (c. 1926) and History Center Drawing courtesy AT&T Archives and History Center

was a sound version – music plus and directors vastly preferred sound sound effects only – of the silent film on film technology. Wings which was shown in around a dozen specially equipped theaters Vitaphone’s disadvantages ultimate- The film broke pete with Western Electric’s sound during 1927. RCA then changed the ly led to its retirement early in the systems. The first was , width of its variable-ar- sound era. All but Warner Brothers box-office records which later evolved into Movietone. ea sound track to that used by had settled on sound-on-film by and established The variable-density track was ERPI. This made it possible to show the end of 1929. It was simply easi- created by the audio modulating the films recorded by either technique er to work with and to edit. By 1931 Warner Brothers intensity of a recording lamp which through the same equipment. All the Warner Brothers-First National was as a major exposed the sound track, similar to projectionist had to do was change a also recording and editing optical player in the film the technique developed by Western single part. sound on film – primarily using RCA’s sound element recording systems the country were still showing silent Electric, but used an invention by Photophone rather than Western on a non-exclusive basis. In general, pictures. In 1937, ERPI left the motion industry. called the AEOlight. Ultimately, the sound-on-film tech- Electric’s – and then dubbing the motion picture producers elected to picture theater business. Wiring the of the Corpo- nique dominated the industry. The completed soundtrack to discs for license one or the other. In a few cas- nation’s theaters had been lucrative. ration acquired the AEOlight from sound-on-disc system was already use with the Vitaphone projection es where mergers had occurred, a AT&T remained active in providing Brothers as a major player in the film Theodore Case. Since the new Fox- known to have drawbacks. First, system. There were many theaters producer might be licensed for both. sound equipment to movie studios industry. Case Corporation had no amplifiers there were distribution problems. - that had invested in the earlier tech- For many years, it was customary to for another twenty years, leaving nor a to show taphone records containing the film’s nology and could not immediately brand a film with its sound system, thousands of films with the credit In 1927, Western Electric established its Movietone films, they acquired sound track had to be distributed afford to switch from their sound- as “RCA Sound Recording,” “Western line “Sound by Western Electric.” a subsidiary, Electrical Research a license to use Western Electric along with film prints, and shipping on-disc only equipment. To make Electric Recording,” or similar brands, Products Inc. (ERPI) to work with equipment. Bell Labs engineers the records required an infrastruc- new film titles backward-compatible often including the corporate logo Acknowledgements the motion picture industry to developed a layout for theaters that ture apart from the already-existing with Vitaphone equipped theaters, of the licensor. This branding for the The author wishes to thank Sheldon develop commercial sound film could play both sound-on-disc or film distribution system. Second, films produced with sound-on-film most part ended by about 1976, as Hochheiser, Melissa Wasson, and production, and also to work with sound-on-film, the latter with either there were synchronization prob- processes were released by Warner by that time nearly all optical sound William Caughlin for providing mate- theater owners to equip theaters the Fox-Case AEOlight or the Wente lems. If a record was improperly cued Brothers and the other Hollywood recording had been converted to a rial from the AT&T Archives used in to show sound films. Following this, light valve for variable-density sound up or if a record skipped, it would be studios simultaneously in Vitaphone stereo variable-area system. writing this article. The author also Vitaphone Corporation and Warner recording. By 1927, producer William out of sync with the picture and the versions as late as 1937. Warner thanks Don Barnickel for providing Bros became a nonexclusive licens- Fox introduced sound-on-film with projectionist would have to try to Brothers kept the “Vitaphone” name 1929 was the year that the talkies information for this article. ee of ERPI for sound motion picture the feature film Sunrise. manually acquire sync. If the wrong alive as the name of its short sub- conquered Hollywood and the silents recording technology. Later in 1927, record had been cued up there was jects division, The Vitaphone Cor- died. The transition to sound was References Warner Brothers moved production The second sound-on-film tech- no option but to pause the show for poration, most famous for releasing rewarding for the entire industry, from New York to the West Coast, nology to emerge was Photophone, a few minutes while swapping in the Leon Schlesinger’s and but most especially to the compa- Hochheiser, Sheldon, What Makes the Picture Talk: AT&T and the Development where it had constructed the first a “variable-area” sound-on-film correct disc and starting that reel (Leon Schlesinger nies that had taken the initial risks. of Sound Motion Picture Technology, IEEE studio designed for sound pictures. system developed by RCA and its again. If the film print became dam- Studios later became the Warner Warner Brothers used its profits Transactions on Eduction, Vol. 35, No. 4, November 1992. Bell Laboratories constructed a new part-owner between aged and was not precisely repaired, Brothers Cartoons Studio). from sound to acquire First National, building in New York exclusively for 1925 and 1927. This system used a the relationship between the record and along with Fox and RKO, joined Sound Projector Systems for Theatres – A Description of the Main Technical Features, sound picture development. fast-acting mirror galvanometer to and the print would be thrown off, For nearly half a century, motion Paramount and MGM as the leading Western Electric, Electrical Research Prod- create the variable-area film expo- also causing a loss of sync. Third, picture sound systems were li- companies in Hollywood. ucts Inc., Acoustic Dept. The Next Generation of sure, in which the modulated area there were editing problems. A censed, with two major licensors in Bell Laboratories and The Development of Technologies (width) corresponded to the wave- phonograph record can’t be edited North America – RCA and Western By January 1932, the job of wiring ex- Electrical Recording By this time, two sound-on-film form of the . The first directly, and this created a night- Electric (Northern Electric, in Cana- isting theaters for sound was com- technologies emerged to com- public screening with this system mare for the sound editor. Editors da) – which licensed their principal plete. Only 2% of isolated theaters in

42 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 43 A Service Decades Too Early Picturephone

By Elisabeth Patterson

Visitors to the 1964 World’s Fair were offered a wide choice of attractions. Some amused, some celebrated the past, and some presented futuristic technolo- gies and possibilities. One astonishing technology on display was a device like a small television set, 5x5 ½ inches, that offered a video display to accompany a phone conversation. This was the general public’s

first introduction to Picturephone. Bell Labs scientists Picturephone presented the system to the fair-going public, and Photo by Michael Mills Picturephone was surveyed human factors analysis to refine an offering they hoped to make public in the 1970’s. conceived in part as a humanizing Picturephone was conceived in part as a humanizing element to telephone service, improving commu- element to nications by adding sight to voice, for a more satis- telephone service fying exchange. Picturephone could also be used to transmit graphical material, like drawings and pho- tographs, as well as images of physical objects. Moreover, the equipment could be used for rudimentary remote communication with a computer, via Touch-Tone keypad, and display on the Picturephone screen.

Infrastructure Picturephone technology was designed to work with existing telecommunications infrastructure. Pic- turephone was supported at first by No.5 crossbar switching machines, with the expectation that the capability would be added to 1ESS switches over time,

44 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 45 volume control knob on the con- display unit yielded a satisfactory trol unit. The control unit allowed image. Sound was provided by a a speaker to mute his microphone, touch-tone speaker phone. Users Picturephone and monitor and disable the broad- could view the video display, monitor Birth to Death cast image. their own image, or turn the video of. • 1956 Bell Labs Video Telephone The control unit included capabilities Commercial History systems in development. Prototype to support document and image Picturephone was introduced in transmitted and received pictures transmission, to automatically focus Pittsburgh PA in July 1970, targeted over ordinary telephone wires. the camera unit to the correct angle towards large business custom- • 1957 Experiments produce a feasi- to a physical desktop. The resolution ers. Service was soon expanded to ble system, establishing standards offered was imperfect for typed Chicago. But Picturephone service for picture resolution, contrast and and printed text, but sufficient for never really developed a following of other features. sketches and photographs. In a par- enthusiastic early adopters, and the allel development, the same small number of installations remained • 1963 Experimental Picturephone monitor could be used to retrieve static. In 1973 AT&T eliminated the system: station set included the and display data, and even be the Picturephone offering. camera-receiver- unit, gateway to controlling a computer in and separate combination tele- a remote location. What Happened? phone set-video control unit. Picturephone at Bell System Exhibit, Picturephone technology offered NY World’s Fair (1964) • 1964 Public debut of Picturephone Photo courtesy AT&T Archives These requirements were embodied a human face to telephone con- and History Center service at the New York World’s in the Picturephone MOD II set. versations on a small black-and Fair. Selected individuals tried the white desk monitor. Picturephone system for ten minutes or so, and The Mod II set consisted of a picture never achieved wide success, for a shared their reactions with Bell Lab display unit, containing the cam- variety of reasons. The equipment Researchers. Limited Picturephone era, picture tube, and loudspeaker. was never widely deployed among service was established between Video was displayed on a 5x5 ½ inch customers, so its use never became New York, Chicago and Washing- broadening the geographic base for tion. (The single encoding protected tions. It had to be versatile enough black and white monitor. The display routine. The service was extremely ton DC. the service. The voice component the signal from degradation during to show objects and sketches, unit contained all the video circuits, expensive. Although so much at- of a Picturephone call was carried transmission.) It was expected that change the field of view for addition- camera and picture tubes, and the tention was paid to the ergonomics • 1965 Equipment and operational on the existing two-wire loops, as the projected T-2 digital carrier al persons in a single setting. And speaker. Presenting 30 frames per of the system, many people were changes improve Picturephone was typical for voice traffic. For the system would be used for the trans- naturally it had to offer the user the second with an odd-even line inter- uncomfortable to be “seen” on the capability. Experimental trials be- Picturephone signals, two additional mission of Picturephone signals. The option not to be seen. face to give 60 fields per second, the telephone. An enthusiastic customer gin at certain corporate locations, pairs were added, one pair for trans- T-2 system was understood to be a base never really coalesced around expanding to include three Bell mission in each direction. The voice single network that could transmit The Picturephone was designed with the video capability. Labs locations. The trial integrated pair was connected to the central all services. close attention to human factors, Picturephone service with normal office as usual, however the video to simulate as closely as possible Still, Picturephone represents as telephone service, and explored pairs were connected to a separate Video Telephone the free and natural communication early attempt to transmit image and further uses, such as an interface four-wire video switch, under the Equipment of face-to-face conversations. The data over the wired telephone net- to a computer. control of the existing switching The essential component of video integrated camera was situated to work. It was an ambitious attempt to • 1968 The Picturephone “see- equipment. telephony was the Picturephone control the eye contact angle, to expand telephone capability, and the while-you-talk” set incorporates itself. The equipment was designed replicate normal conversational facial technical ancestor of applications improvements and new features. The Picturephone picture signal was to meet stringent requirements in expressions in the video subject. and services that we now take for MOD II Picturephone set is created. transmitted as analog between cen- technology and human factor engi- Camera placement supported the granted in daily communication. • 1970 Picturephone service intro- tral offices within a distance of six neering. most natural, least distorted view of duced in Pittsburgh, but does not miles. Beyond six miles the picture, the subject, permitting natural move- find a wide market. voice and signaling information were The camera requirements included ment and the use of ambient light. encoded as a digital signal, which a great image that could stay sharp Western Electric • 1973 Picturephone is withdrawn Picturephone Ad (1969) remained encoded to within six automatically, and adapt to a variety In addition to the camera, the display Photo courtesy AT&T Archives from the market. miles of the central office destina- of subjects, backgrounds and condi- unit contained a speaker, with a and History Center

46 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 47 ing with a magnet underneath and complex mazes, but fundamentally, References whiskers made of copper wires. are not much different from Theseus All the moving, remembering, and from nearly 70 years ago. The true Mouse with Memory, Time, May 19, 1952, p59, learning is in fact housed under the legacy of Theseus, however, is not https://www.bell-labs.com/claude-shan- maze along with the 90 electrical faster and smaller autonomous mice, non/assets/images/automata/pages- from-shannon-bell-labs-reporter-1952-vol- telephone communication relays but the vastly improved learning 1-1-carousel-01.pdf whose logic and memory decide capabilities of modern AI systems, A Mind at Play, J. Soni and R. Goodman, how the mouse moves by way of enabled by unimaginably faster Simon & Schuster, 2017, p206 Theseus magnets and actuators. The circuits and power-efficient https://youtu.be/vPKkXibQXGA, Bell Labs hidden under the maze remember digital circuits than Shannon’s relays on Theseus A Mouse with Artificial the layout of the maze as the wood- and switches, and the availability of ‘The Idea Factory,’ by Jon Gertner, 2012 en mouse explores and calculates more or less curated and structured Intelligence where to explore next so as not to data through the expansion of the https://en.wikipedia.org/wiki/Micromouse go where it already learned was a Internet with which to teach new dead end. It is this learning, however AI systems to perform seemingly By Byoung-Jo Kim primitive at the time, places it at the impossible tasks. very beginning of the AI history as the first implementation of learning It has a simpler brain than a mi- capabilities envisioned only in theo- croscopic worm in the soil of your ries at the time. backyard, but the size of its brain is

that of a small reading desk. It does vivid the abili- Theseus’s direct descendant, mod- (1952) not eat, it does not tire, although it ty of a ma- ern-day maze-solving robots known Photo courtesy AT&T Archives and History Center constantly seeks its inedible metal chine to solve, as the Micromouse, are entirely con- “cheese.” Most importantly, it learns by trial and er- tained in the mouse body and fully from its experience. It is this ability ror, a problem, autonomous, while the maze is in to learn and change its behavior and remember fact just a maze, no circuits or relays that makes Theseus one of the very the solution.” underneath. They run much faster first ancestors of Siri or Alexa, the AI Shannon’s fame as the and smoothly, and solve much more Theseus (Artificial Intelligence) assistants in ‘father of information theory’ Photo by Michael Mills your smartphones and many other (the foundation of all digital commu- AI innovations of late. nication technologies) afforded him nearly unfettered freedom to pursue As the inventor and builder of The- whatever intellectual interest that cific tasks such as juggling, playing seus, Claude Shannon, surmised, it fancied him. This was even more so chess, riding a unicycle, and playing a is “a demonstration device to make for him than other research scien- flame-throwing trumpet. tists at the Bell Labs who already enjoyed substantial freedom that Theseus is perhaps the most well resulted in much of modern innova- known of his such inventions: a tions that we take for granted now. mouse with memory and the ability One of such pursuits was to build to learn. The mouse that moves in various robots that perform spe- the maze is a mere wooden carv-

Theseus’ Path through a Maze (1952) Photo courtesy AT&T Archives and History Center

48 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 49 A Short History of UNIX™ By Tony Hansen

hat do billions of cell phones have in common with Printout of UNIX™ Version 3 or 4 W Photo by Michael Mills billions of Internet of Things devices, millions of comput- ers sitting on desktops, and the largest supercomputers?

Go on, take a guess. (Hint: look at the title of this article.)

Got it yet? They all are using UNIX™ or a UNIX™ - like . Yes, the operating system running in the smart phone in your hands, microcomputers such as Raspberry Pis, the Apple Macs, and the Dennis Ritchie (left) and Ken Thompson working at a PDP-11 (1971) largest supercomputers in the world all Photo courtesy AT&T Archives share a common heritage with each other. and History Center

A New Operating System Is Created and Evolves Back in the late 1960s and early 1970s, a group of scientists from Bell Labora- by Dennis Ritchie and Ken Thompson. Its abstract says: It is hoped, however, the users of UNIX™ will find that tories created a new operating system the most important characteristics of the system are for the Digital Equipment Corporation’s UNIX™ is a general-purpose, multi-user, interactive its simplicity, elegance, and ease of use. PDP-7 computer that they had sitting operating system for the Digital Equipment Corpora- in their lab. Ken Thompson, Dennis Ritchie and others at tion PDP-11/40 and 11/45 computers. It offers a num- In addition to the basic operating system kernel, end users Bell Laboratories had been working on a multiple-user ber of features seldom found even in larger operating were also provided basic commands for compiling and timesharing project known as Multics, but the PDP-7 ran systems, including: (1) a hierarchical file system incor- linking executable programs, a rudimentary command The most important a single-user operating system (DECsys). After Bell Lab- porating demountable volumes; (2) compatible file, language interpreter (the Thompson shell), and a set of oratories pulled out of the Multics project, Ken decided device, and inter-process I/O; (3) the ability to initiate small general-purpose tools. All of this allowed end users characteristics of the to write a new operating system for the PDP-7, which he asynchronous processes; (4) system command lan- to write complex programs in a multitude of languages.[1] system are its simplicity, wrote in assembler in 1969. This operating system went guage selectable on a per-user basis; and (5) over 100 Another innovation supported in this early shell was the through several revisions and subsequently ported to a subsystems including a dozen languages. This paper notion of many small programs tied together in a com- elegance, and ease PDP-9, and then different versions of a PDP-11. During that discusses the nature and implementation of the file mand pipeline, whereby the output of one program could of use. time, Dennis Ritchie developed the language C (based on system and of the user command interface. be automatically passed as the input to another program. the B language that Ken had previously created). Brian Note, to most people the term UNIX™ covered not only Kernighan suggested the name UNIX™ as a pun on Multics, In their article they state a goal achieved through the the kernel code but also all of (or only) the tools that com- and the first public article was published in The Communi- widespread use of UNIX™ and its derivatives: monly came with a particular version. Thus, you had the cations of the ACM (Ritchie & Thompson, 1974) in July 1974 UNIX™ mail program, the UNIX™ shell, etc.

50 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 51 UNIX™ As a Commercial Product The UNIX™ kernel was ported to a number of other sys- It was about this time that variations of the UNIX Oper- tems during this time. Of particular note were the DEC ating System began spawning new versions and related VAX-11 series; the VAX-11/780 and later the VAX-11/750 software, both within Bell Laboratories and externally. were popular machines to run UNIX™ on both within Internally, the UNIX™ Support Group was created and the universities and Bell Laboratories. UNIX™/32V was a direct Programmer’s Workbench series was put together to sup- port of v7 to the 32-bit Vax architecture, done by a sepa- port a department of 1000 programmers, with a number rate organization within Bell Labs. The 3rd Berkeley Soft- of new tools added for document preparation and com- ware Distributions was based on UNIX™/32V. pilation/cross-compilation support. PWB/UNIX™ 1.0 was based on UNIX™ Version 6, and PWB/UNIX™ 2.0 was based Back within AT&T, UNIX™ System III built from PWB/UNIX™ on UNIX™ Version 7. Tools added to one system were 2.0 and UNIX™/32V; UNIX™ 4.0 and UNIX™ System V later quickly added to the other as well. came from that.

AT&T decided that UNIX™ might actually be a valuable The Research organization continued work on operating commodity, and UNIX™ Version 7 (announced in June 1979) system research, eventually creating UNIX™ versions 8, had a drastically different license. Commercial licenses to 9 and 10, and subsequently a derivative known as Plan 9. other companies were $20,000. Automatic permission to Some ideas from v8 and v9 eventually made it into other use it in a classroom was removed, so most universities UNIX™ flavors. stopped teaching courses based on the UNIX™ kernel Murray Hill, NJ (c. 1973) code. The Lions books also were no longer published, The Apple Mac OS X has its roots in BSD UNIX™, as does iOS. Photo courtesy AT&T Archives and History Center although multiple-generation Xerox copies were still sometimes studied “on the side.” (The Lions books were UNIX™ System Laboratories officially republished in 1996 by SCO.) The changes in the consent decree in the early 1980s al- lowed AT&T to officially sell copies of UNIX™ to individuals UCB continued teaching courses based on UNIX™, subse- and not just companies, and they decided to do so with quently creating the Berkeley Software Distribution (BSD) System V as the base. Other innovations include the I/O, file structure and Because of the 1956 Consent Decree, AT&T could not sell and bundling the UNIX™ kernel and tool set with additional file system. Other operating systems often supported a UNIX™. The UNIX™ Version 5 and 6 code was made available programs, many of which were extensions of the V6 or Around this time, AT&T became very protective over the variety of file types, such as fixed-length 80-character to various universities under an educational license for little V7 code. UCB students and staff started adding their own word UNIX™, making certain that everyone knew that card-image files or indexed access files; in UNIX™, all files more than the cost of the media and shipping; Version 6 innovations to the kernel, particularly in the areas of net- it should ALWAYS be used as an adjective for the words appear as a series of bytes. Special files might be associ- was also available with a commercial license for $20,000. working, compilers and visual interfaces. The 3rd and 4th Operating System and that the ™ symbol would always be ated with physical devices, such as a “punch paper tape” Although the source code was considered to be a “trade Berkeley Software Distributions gained significant popu- used with it. Nevertheless, most people continued to use device, /dev/ppt; the user reads from or writes bytes to it secret”, the early UNIX™ license did not forbid teaching larity outside of UCB. just “UNIX™” in everyday speech. Many people also spelled and the device file does the translation. classes on the code base. The University of Illinois was the it “Unix” instead of “UNIX™.” first to receive such a license, and the University of New As Thompson and Ritchie put it in their ACM article: South Wales and the University of California, Berkeley were The term “System V” itself became a branded term, so some of the many schools that taught classes on UNIX™. from System V came System V release 2, System V release The success of UNIX™ lies not so much in new inven- 3 and eventually System V release 4. tions but rather in the full exploitation of a carefully John Lions (UNSW) wrote a series of class notes that selected set of fertile ideas, and especially in showing annotated the entire Version 6 kernel source code. With In 1989, AT&T coalesced all of the UNIX™ development that they can be keys to the implementation of a small the blessing of Western Electric, the class notes (Lions, into a separate organization, UNIX™ System Laborato- yet powerful operating system. 1976) and the kernel code (Bell Laboratories, 1976) were ries, and eventually spun USL off into a separate compa- made available to UNIX™ licensees in March 1977; in 1978 By the time UNIX™ Version 5 came out, most of the they were published as books by Bell Laboratories. The operating system kernel was written in C with only some two books are each about a quarter inch thick. There are Advertisement for UNIX™ (1980) assembler. When UNIX™ Version 6 came out in May 1975, exactly 9,073 lines of C code, including comments, in the Photo courtesy AT&T Archives the operating system was completely written in C. This kernel book. (Original copies of these two volumes are and History Center drastically improved the portability of the code, and mov- rare and hard to come by.) Because of his work, Professor ing to new hardware platforms became much easier. Lions was later invited to join the Bell Labs technical staff in Murray Hill during a sabbatical.

52 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 53 Exploring the UNIX™ System by Stephen G. Kochan and Patrick H. Wood (1984) ECOMP & ONAP Photo courtesy AT&T Archives and History Center

As with UNIX™, Linux has gone through a number of fla- SDN and ECOMP: SDN allows us to move vors starting with the original Linux Kernel, then Debina to a software-centric network running and now the most recent being Unbuntu Linux. on a cloud environment. Think of our Standardizing UNIX™ and UNIX™-Like network as a giant computer and ECOMP Operating Systems is the brain, the operating system that There’s a saying that the wonderful thing about Standards manages it. is that there are so many to choose from. Many companies I SN stands or soware-defined networ. This wanted to make products that ran on UNIX™, but it was soware-centric cloud environment creates a difficult because of the numerous versions of UNIX™, IEEE, etter, more secure, aster, and more cost-effective X/Open, Unix International, Open Software Foundation, networ where resources and unctions are and were all various groups involved in or created to controlled dynamically. ny. Novell purchased USL in 1993, along with all rights to “standardize” on different aspects of UNIX™. Some were AT&T’s UNIX™ copyrights. Novell subsequently sold part formed to directly compete with others. I M stands or nhanced ontrol, rchestration, create the new pen Networ Automation latorm of its UNIX™ business to The Santa Cruz Operation (SCO), Management and olicy. M is the rain, (NA) roect at the inux oundation. AT&T is but maintained certain rights. The following twenty years IEEE created the Portable Operating System Interface the operating system that manages the networ. opening up not ust the soware code or third- have been a licensing mess, with suits and counter suits (POSIX), which formed the basis for most further stan- It helps us to automate networ unctions and party operators, developers and other groups, ut between SCO, Novell, and various other organizations that dardization. The Common Open Software Environment size the networ instantly to enale the est also inormation lie documentation and educational had licensed UNIX and created their own variations. formed another part. Novell assigned the UNIX™ trade- customer experience. videos. Maing two sample use cases (one on mark to X/Open in 1993. virtual security firewall and one on virtual dynamic I NA stands or pen Networ Automation Opensource Versions networs) that will e placed on a pulic cloud latorm and will allow end users to automate, Because UNIX™ was licensed software, and many people X/Open and OSF merged in 1996 to form The Open Group. or users to access. design, orchestrate, and manage services and were unwilling or unable to pay the licensing fees, open- It became THE certifying body for the UNIX™ trademark virtual unctions. source versions sprang up in the 1980s. Although they may and publishes the Single UNIX™ Specification technical Opening up ECOMP is a game-changer & not have direct code lineage to UNIX™ they are considered standard, based on POSIX and the earlier efforts. benefits the entire ecosystem. to be UNIX™ - like, leveraging all of the most important “Opening up ECOMP” means making it I pening up M is a game-changer. It sees characteristics of the system: simplicity, elegance, and Even though Linux is not derived from UNIX™ source code, available for others to use to create a common platorm or uilding ease of use that Ritchie and Thompson strove for in 1974. the Linux distributions generally aim for POSIX compli- I ur AT&T M soware code and the pen communications services within a soware ased These often used a name that ended with the letter X, as ance, so a high amount of compatibility has been main- rchestrator roect (N-) are merging to networ cloud. in Minix and Linux. The GNU project has both a kernel part tained between UNIX™ and Linux. and tool part, but the kernel part (Hurd) was never fin- I The initiative invites a gloal communications ished. The most popular UNIX™ - like distributions use the Enabling Software Anywhere ecosystem to explore, contriute to, test, integrate Linux kernel combined with the GNU toolset, plus many So there you have it. From many IoT devices to your and deploy the code. By providing a common, open other free software programs. smartphone, from your video game system to the Apple source, standards-ased platorm, it promotes a laptops and desktops, from the systems your web brows- gloal standard or these inds o technologies. FreeBSD was created from 4BSD by reimplementing er attaches to the largest weather-data-crunching super I veryone wins rom standards. or example, cars and from scratch the Berkeley Software Distributions kernel computers, the odds are extremely high that you are using planes are uilt ased on standards. With standards, portions whose code was derived from AT&T code. It is some embodiment of UNIX™ vision. we and others in the ecosystem can offer customers licensed under a rather permissive license, different from the est experience when interacting with each GPL. MacOS uses some FreeBSD code, as does the Play- Thank you, Ken and Dennis, for your wonderful legacy. other on any device, anytime, anywhere. Station 3 and 4, and the Nintendo Switch. See video or more on M or www.att.comecomp References and also more inormation aout inux here. The Android OS is based on a Linux kernel. Many computer systems, from the smallest Raspberry Pi micro-computer [1] Later versions of the shell (the Mashey shell, the Bourne shell, the C shell, the Korn shell, and the Bourne-Again shell) still use many of to large super computers, use a Linux+GNU distribution. the syntax elements first created in the Thompson shell.

54 | AT&T SCIENCE & TECHNOLOGY INNOVATION

© 2017 AT&T Intellectual Property. All rights reserved. Museum INNOVATION AT&T’s strong history of innovation is represented in this section of the Science & Technology Innovation Center. The Telstar satellite, a U.S. Navy radar dish, the Vitaphone , Shannon’s mouse, and Science & Technology the transistor, as well as a host of other innovations, are represented in this section of the Center. Innovation Center Middletown, New Jersey

INSTRUMENTS Main From the wall-mounted, hand-crank phone to the classic candlestick to the Trimline and smartphone, Enterance the Science & Technology Innovation Center has an expansive collection of end user devices. Although the phone booth in the Center proper is for display purposes only, a second working model will be located just outside the center so visitors can see what it was TRANSMISSION like to make a public call in quiet privacy.

SWITCHING

The switching section contains two manual INTRO switchboards from an earlier era when a local operator was necessary to connect a call. On the opposite end of the time scale, the 4ESS INNOVATION switch, AT&T’s largest, is represented by its control panel. Vitaphone Projector INSTRUMENTS

Radar Antenna

Telstar Satellite Telephone Booth TRANSMISSION SWITCHING The large wall photo in the Transmission section depicts the completion of the first transcontinental telephone line. The evolution of AT&T’s transmission is also represented by cable, undersea cable, microwave radio, fixed waveguide, and fiber artifacts, as the company sought to deploy longer lines at greater capacities.

Renderings by Blumlein Associates, Inc.

56 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 57 Enabling innovations of transmission Open Wire Lines media in the first 40 years on open The open wire type lines were the NY-Boston Line Open Wire (c. 1899) wire systems included first commercial telephone lines in- Photo courtesy AT&T Archives stalled for telephony use only. Initial and History Center • Hard Drawn Copper Wire applications used telegraph lines • 2 Wire Copper Line with a ground return which turned Transmission • Line Transposition out to be very noisy and made clear • Phantom Circuits communication difficult. Pole lines • Loading Coils (induction) on rooftops became overcrowded • Amplifiers (Repeaters) with lines in the late 1800s which drove engineers to work on under- Media Evolution We will explore each of the innova- ground cable solutions especially in tions and provide a summary of how cities where the growth of telephone Open Wire through Coaxial Cable and a Glimpse of the Future they enabled the growth of the Bell lines was exponential. Systems long distance transmission lines over the first 100 years. The telephone lines in the late 1800s were made of iron or steel No. 12 by Doug Olsen, Kathy Tse gauge and No. 14 gauge respective- ly. These lines would easily corrode The evolution of metallic wired[1] and rust which led to noisy connec- transmission media covers a period tions. In addition the relatively high of 100 years (1875 to 1975), begin- resistance of these materials led to ning with the first telephone calls increased attenuation. This attenu- over existing iron telegraph wire and ation was a major obstacle to long concluding with L-5 coaxial cable distance telephone transmission. systems. These first 100 years saw Innovators would need to solve the tremendous innovations in transmis- attenuation and noise problems sion media that expanded system associated with these early open capacity, improved voice quality, and wire lines. introduced new services. The eventual solution had two com- The innovation timeline leading up ponents. One was changing the wire to the first transcontinental tele- material to a lower resistance metal phone call was approximately 40 (copper), and second was adding a years, starting with the first one way second wire to the line instead of call transmitted a distance of eight using a ground return which was the miles over telegraph wire in 1876, state of the art to this point. through to the first transcontinental call over 2 wire circuit with amplifiers Two Wire Copper Circuit line between Boston and Providence. transmitted a distance of 3000 miles Thomas B. Doolittle implemented Doolittle’s hard drawn copper and from NYC to San Francisco in 1915. the first hard-drawn copper wire, Carty’s two wire circuit innovations it was strung at Ansonia Brass Co. were combined and by 1884 the first Open Wire in Ansonia, CT, in 1877, intended to long distance two-way conversation Photo courtesy AT&T Archives and History Center overcome the resistance inherent was completed between Boston in the iron and steel lines. During and NYC. The Boston–NYC line was the same period the conversion of a sponsored by the American Bell single wire line to a two-wire line was Telephone Company and 500 miles Cable (Non-Coax) first introduced into the commer- of copper wire were produced by the [1] This report does not include wireless Photo by Michael Mills transmission such as microwave radio cial network by future AT&T Chief Bridgeport Brass Company, resulting which was also in use during this time. Engineer John J. Carty in 1881 on a in a two wire #12 copper line that

58 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 59 Phantom Circuits — nental long distance line was the Carrier Systems Early Loading Coil Early Multiplexing vacuum tube amplifier[2]. The vac- With the attenuation problem solved Photo by Michael Mills As the long distance network ex- uum tube amplifier was developed by amplifiers, the long distance panded, so did the demand for long over a period of years starting in network continued to expand across distance calls. The problem with the 1906 when Dr. Lee de Forest invent- the country, along with the de- open wire lines was only a single ed the three element tube; how- mand for long distance calls. Carrier voice call could be transmitted over ever, it was nine years before the systems were invented to solve the the two wire circuit. As the cost of first transcontinental long distance capacity problem. adding additional circuits and space line from NYC to San Francisco was on the pole lines was at a premium, completed using both loading coils There were three types of analog more innovation was required. An and amplifiers. At a distance of over carrier systems deployed over a pe- early form of multiplexing, the phan- 3000 miles, this line took advantage riod of approximately 50 years from was able to carry a call over 250 tom circuit, allowed three telephone of the amplification made possible 1924 through 1975. Three types of miles from Boston to NYC. conversations to be carried simul- by the vacuum tube amplifier. Over transmission media were leveraged taneously over two pairs of wires. time, the NYC to San Francisco line for carrier systems, including open Line Transposition The uses the side was improved by adding additional wire pair, two cable pairs, and coaxial The two wire copper line reduced circuits, side circuit 1 and side circuit amplifiers. Eventually in 1920, all the cable. While there were many sig- the noise and attenuation associat- 2 as its four wire transmission media. loading coils were removed and 12 nificant technical innovations in this ed with the ground return lines; how- The combination of two wire copper coil. A loading coil is a magnet in a Phantom circuits did not really pro- improved amplifiers were added period the primary challenge that ever, crosstalk was still a problem on line and transposition lead to long toroidal shape that is inserted into vide the gain that the next promising which cut the line loss in half and in- Bell Systems engineers faced was these early lines. Between 1885 and distance transmission that reached a telephone circuit to increase its technology, vacuum tube amplifiers creased the propagation velocity by capacity growth, in particular growth 1904 a series of innovations were from NYC to Omaha NE, a distance . Loading coils in long haul would provide, and as a consequence a factor of 3.5. These additional am- on the busiest existing routes. made with a line balancing technique of over 1300 miles. However, the cost telephone transmission were placed had a short lifespan as compared to plifiers greatly improved the voice called transposition. Transposition and the quality of the service at these at intervals of approximately 8 miles other technologies. transmission quality. Vacuum tube cancelled out the crosstalk by trans- distances was subpar. Additional and reduced the attenuation of the amplifiers would also play an inte- [2] Amplifier and repeater are used inter- posing the position of the copper innovations would need to be dis- line by a factor of 2 over a non-load- Vacuum Tube Amplifiers gral role in the next breakthrough changeably in telephony parlance. conductors along the length of the covered if coast to coast telephone ed open wire line. The concept of The final innovation that would in long distance transmission, the [3] Type D carrier was two voice circuits per line at regular intervals. Three inno- service was going to be possible. loading coils was discovered by eventually enable the transconti- carrier system. channel for shorter haul of ~200 miles vators are credited with developing 1860s in England the method of transposition. John Loading Coils while studying undersea telegraph A. Barret patented transposition in The attenuation problem on long cables. The actual design for loading 1885, J.J. Carty developed the theo- distance lines was still not remedied; coils was developed around 1899, ry around transposition in 1891 and however, a significant improvement by George Campbell at AT&T and Audion and High Vacuum Tube finally in 1904 E.H Colpitts developed was introduced to the network Michael Pupin at Columbia University Amplifier (1913) Photo courtesy AT&T Archives modern transposition design. around 1900 by way of the loading independently. Pupin actually re- and History Center ceived two United States patents for loading coils in 1900. AT&T purchased the rights from Pupin and eventually deployed millions of loading coils in both its local and long distance networks.

Transposition Frame for Insulators Photo courtesy AT&T Archives and History Center

60 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 61 late 1970s and early 1980s rendered add or drop had ports used to meet the future needs of Cross-section of Coax Cable copper coaxial cable transmission that required a specific “color” of our customers for bandwidth when Photo by Michael Mills systems obsolete for all long haul light and were connected to a single and where they need it. It is also carrier service. direction. Even though the lasers being used for a coordinated Pack- could be tuned to any wavelength, as et/Optical layer that has improved As capacity needs A Glimpse of the Future soon as they were cabled to a port reliability and efficiency. in long distance Fiber optic transmission has evolved they were fixed in terms of the color from a single wavelength of 45 Mb/s and direction associated with that References communications on a fiber with regeneration ev- add/drop. By deploying C/D ROADMs, E. F. O’Neill, ed. 1985. A History of Engineer- grew, it became ery 80 miles, to 96 wavelengths of AT&T can now change both the color ing and Science in the Bell System: Trans- 100Gb/s that can go thousands of and direction of the wavelength mission Technology. Murray Hill: NJ, AT&T Bell Laboratories obvious to the miles without the need for electrical using software, allowing reconfig- regeneration. In addition, the ca- uration on the fly to a new path or M.D. Fagan, ed. 1975. A History of Engineer- engineers that the ing and Science in the Bell System: The existing low pability to switch individual wave- connection. This allows the applica- Early Years 1875-1925. Murray Hill, NJ: Bell lengths of light between fibers using tion of optical bandwidth on demand, Telephone Laboratories

frequency analog WSS (Wavelength Selective Switch) where wavelengths can be turned up AT&T Archives. 1992. Events in Telecommu- carrier systems devices the size of a paperback nov- or down as needed by the application nications History el allow for ROADMs (Reconfigurable and the equipment returned to the Bell System Technical Journal, 2: 2. April 1923 would be unable to Optical Add/Drop Multiplexers) that pool for future demands. pp 41-52. Practical Application of Carrier Telephone and Telegraph in the Bell Sys- fulfill the need. can route wavelengths in a tem. (Rose, Arthur F.) between many directions or drop AT&T has taken this a step further, Bell System Technical Journal, 18: 2. April the appropriate wavelengths needed by spearheading an effort called 1939 pp 338-362. Some Applications of for service. These advances have al- Open ROADM (details at Open- the Type “J” Carrier System. (Starbird, L.C.; Mathis, J.D.) lowed high bandwidth, low cost opti- ROADM.org). C-Carrier was the first widely de- open wire pair. The J-Carrier system interference. As capacity needs in cal connectivity between customers Members of the Technical Staff Bell Tele- ployed multiplexing system that operated in frequency above that long distance communications grew, or routers, but are still limited in the For Legacy ROADM systems there phone Laboratories. 1982 Fifth Edition. Transmission Systems for Communica- increased the capacity on open of C-Carrier and was superposed on it became obvious to the engineers need to manually set up the wave- was no interoperability at the optical tions. wire from one to four voice cir- the same copper conductors as the that the existing lengths requiring multiple truck rolls. layer, so a single vendor’s system cuits, and by 1950 there were 1.5 C-Carrier system. The figure below analog carrier systems would be In order to overcome this limitation, had to be used in a Metro or Long million voice-circuit miles installed shows phantom circuits, side circuits, unable to fulfill the need. The next two advances were required. The Haul area. Open ROADM defines on C-Carrier. J-Carrier was the C-Carrier, J-Carrier, and D-Carrier[3] innovation would be in 1928, when on/off ramps to the optical high- optical “pieces” such as a ROADM, next advance in open wire carrier all on the same physical pole line. British inventor C. S. Franklin pat- way needed to be flexible, allowing Amplifier and Transponder, and By deploying systems, J-Carrier was capable of ented a coaxial cable for limited use each wavelength to be connected defines interoperability between the C/D ROADMs, AT&T transmitting 12 voice circuits over an During the early 20th century, the as an antenna feeder. A year later, to any “color” in any direction using devices across different vendors. In method Bell System engineers Lloyd Espenschied and Herman Affel software. AT&T has been the leader addition, a set of common APIs are can now change employed to increase long haul of Bell Labs (AT&T’s R&D subsidiary) in deploying these C/D ROADMS defined, allowing interchangeability both the color and circuit capacity was accomplished enhanced earlier models to devel- (Colorless/Directionless), first in our between devices and connectivity with analog carrier systems (C, J, and op the first modern high capacity Ultra-long Haul Backbone and now across a flexible network regardless direction of the K) on open wire and copper cable coaxial cable transmission system, spreading into our regional and met- of deployed equipment. The final wavelength using discussed previously. These sys- which was patented in 1931 (U.S. ro nodes. In addition, we have led the advancement of Open ROADM is a tems were limited to transmission Patent 1,835,031). Espenschied and work to develop optical controllers set of Yang models that describe the software — this bandwidths in the KHz range (4–12 Affel’s coaxial cable system was able that can use SDN control to turn up, devices and hide their complexity, a allows the application voice circuits per channel) and were to handle the increasing capacity down and reroute the optical wave- network model that describes the of optical bandwidth subject to external electromagnetic demands. These systems would lengths on demand to serve our optical layer, and a service model eventually carry 13,200 voice circuits Common BackBone and customer that further abstracts the network on demand. per channel. However another inno- needs. to a multi-layer controller. vation was right around the corner

Phantom Circuit Patent Drawing that would ignite the revolution we Legacy ROADMs allow wavelengths Using SDN control and Open ROADM, Photo courtesy AT&T Archives and History Center are still in today. The advent of fiber to be expressed or add/dropped at AT&T is deploying a multi-vendor optic transmission systems in the a node, however the devices used to SDN controlled network that can be

62 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 63 Millimeter Waveguide

The Technology that Nearly Changed the World of Telecommunications by Thomas Willis III

Metal electromagnetic waveguides (hollow metal pipes tem at Bell Laboratories. The ultimate result of the joint of various cross-sectional shape) can carry different development program between Bell Laboratories, AT&T configurations of radio signals, known as modes, provided Long Lines and the Western Electric Engineering Research the frequency of operation is high enough. As long ago as Center was the WT4/WT4A millimeter waveguide system. the 1930s, George C. Southworth and other researchers By the mid-1970s use of millimeter waveguide systems for at Bell Laboratories were aware of the large theoretical usable bandwidth within the millimeter wave spectrum that could be carried by circular waveguide. The resistive (heat) losses of Transverse Electric (TE) modes in circular As long ago as the 1930s, waveguide actually decrease with frequency. Compared researchers were aware of to coaxial cable systems, where resistive losses increase with frequency and thereby limit their usable bandwidth, the large theoretical usable Millimeter Waveguide (1970s) circular waveguide transmission systems held the great bandwidth within the Photo by Michael Mills promise of extremely large capacities. The ever increasing traffic on the AT&T millimeter wave spectrum network led Bell Labs to a search for a higher capacity transmission medium. By the early History 1970s, the Labs had developed a prototype that could be carried by system using millimeter frequency radio In 1959 Bell Laboratories began an exploratory develop- waves transmitted inside highly polished circular waveguides. metal tubes, such as this one. Before the ment program on a system utilizing a 51 mm inner- di- system was commercially released, however, ameter circular waveguide. At that time the best device something better came along — fiber-optics. available to generate and amplify the millimeter wave sig- nals needed was the Travelling Wave Tube (TWT). However telecommunications was also being investigated in the the project was abandoned in 1962 due to TWT cost and United Kingdom, France, Italy, West Germany, Japan and reliability issues, along with the fact that the Bell System the U.S.S.R. did not yet need the capacity provided by the waveguide system. However in the mid-1960s solid-state devices such A WT4 system could provide just over 16.1 Gbps of as the IMPATT diode were developed that could also gen- throughput capacity in each direction (nearly 238,000 erate millimeter wave signals. By 1968 additional capacity voice circuits) transmitting signals in the millimeter wave growth in the long-haul network along with the availability spectrum from 38 GHz to 104.5 GHz down a 60 mm in- of solid-state millimeter wave devices, sparked renewed ner-diameter circular waveguide. Regenerators would be interest into developing a waveguide transmission sys- needed every 50 Km to 60 Km depending on the required

64 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 65 Millimeter Waveguides bends along the route of the Illustration by Jacqueline Bogdan in Cranbury, NJ had to manufacture the millimeter wave- keeping crew at the Holmdel Bell Labs facility. Although waveguide line. The waveguide guide for the FET to very exacting mechanical tolerances this seems an ignominious end to millimeter waveguide, line itself was made from two dif- and material properties. Regenerators, line equalizers, it should be remembered that new technologies often ferent types of circular waveguide High-loss channelizing networks and digital multiplexing equipment grow out of the ashes of those discarded. Much of the sections: 9 meter sections of inte- Dielectric all had to be designed, built, tested and along with 14 Km high speed digital multiplexing work done for the milli- rior dielectric coated waveguide of millimeter waveguide installed in the field. The FET meter waveguide project was re-used with fiber optics. and 4.4 meter sections of helical included all the elements of a complete operating sys- Furthermore low loss circular waveguide has been used by waveguide. The helical wave- tem such as protection switching, span terminating, fault the National Radio Astronomy Observatory at their Very guide had a tightly wound coil of locating, auxiliary communications and maintenance. Large Array facility located outside of Socorro, NM. Hence insulated copper wire bonded to the quintessential waveguide research that made the WT4 the inside surface of the wave- Special construction equipment was developed for system possible lives on there. Copper Wire guide. A helical waveguide section trenching and installing the waveguide. During the instal- was used in roughly one out of every lation process, first a 140 mm outer-diameter protective Steel Pipe References 50 sections while the rest were the simpler sheath steel pipe was deployed using techniques similar 1. “Hyper-Frequency Wave Guides---General Considerations and Ex- dielectric lined variety; so that about 1% of the to a conventional pipeline. Then the millimeter waveguide perimental Results”, G.C. Southworth; BSTJ Vol. 15 No. 2; pp. 284-309, length of the line consisted of the helical waveguide. sections were fusion welded together in the field at their April 1936

The purpose of the helical waveguide was to filter out end flanges and pushed into the outer sheath pipe at 2. “Hyper-Frequency Wave Guides---Mathematical Theory”, J.R. Car- undesired modes, which may be generated by mode con- selected insertion sites. Spring loaded roller supports were son, S.P. Meade, S.A. Schelkunoff; BSTJ Vol. 15 No. 2; pp. 310-333, April 1936 version, from propagating down the line. Furthermore, by 5µ Copper placed approximately every 50 cm around the waveguide Plating 180µ Low-loss Dielectric upgrading just the electronics in the regenerators and line to accommodate its insertion into the pipe. A special 3. “Waveguide as a Communications Medium”, S.E. Miller; BSTJ Vol. 33 No. 6; pp. 1209-1265, Nov. 1954 terminating equipment to the WT4A system, the mod- waveguide insertion machine that could apply up to 10,000 ulation could be changed from BPSK to QPSK thereby carry up to 124 radio channels grouped into seven sub- lbs of insertion force was used in this process. 4. “WT4 Millimeter Waveguide System”, BSTJ (Special Issue) Vol. 56 No. 10; Dec. 1977 doubling the capacity to over 32.3 Gbps. bands. Channels within the same subband were spaced at 500 MHz. Each channel occupied 475 MHz of spectrum and During the FET a maximum length of approximately 5. Engineering Operations in the Bell System, 1st Ed. I. Dorros Ed.; pg. 130-132, 340-342; 1977 These data rates were carried on a number of radio chan- carried a DS4 (274 Mbps) signal. In the WT4A system, using 2.4 Km of waveguide was inserted into a section of the nels over the millimeter waveguide. The WT4 system could QPSK modulation, each channel carried two DS4 signals. sheath pipe requiring about 2000 lbs of insertion force, 6. “Millimeter Waveguide Scores High in Field Test”, W.D. Warters; Bell The 62 channels in the upper three subbands above 75 although longer runs were theoretically possible. Once Laboratories Record; pg. 401-408; Nov. 1975 GHz carried traffic in one direction down the millimeter the waveguide was completely installed, the air inside it 7. History of Engineering and Science in the Bell System: Transmis- waveguide, while those in the lower four subbands below was evacuated and replaced with dry nitrogen. This was sion Technology (1925-1975), E.F.O’Neill Ed., pg. 623-647, 1985 ISBN 9780932764089 75 GHz were used for traffic in the other direction. Of the done to eliminate any attenuation that could be caused by 62 channels for each direction, two were reserved for moisture or oxygen absorption around 60 GHz. automatic protection and one as a manual patch channel. This left 59 working channels for each direction of trans- Microwave Good, Fiber Better mission in a fully equipped system. After the successful completion of the FET, managers at AT&T had planned to start deploying millimeter waveguide Field Evaluation Test across the nation for commercial services during the From 1974 to 1976 a Field Evaluation Test (FET) of the WT4 1980s. However this vision was never realized. By system was conducting in New Jersey from the AT&T Met- the late 1970s, another technology that promised Waveguide Steel Pip Sheath ropolitan Junction Station in Netcong to a test equipment even greater potential capacity with easier, lower Flange shelter 14 Km away in Long Valley. A great many engi- cost deployments loomed on the horizon. Fiber Spring Supported Rollers neering and operations challenges had to be overcome to optics would bring an end to millimeter wave- conduct this trial. The Western Electric Forsgate pilot plant guide at AT&T. In fact after the dissolution of the project, discarded sections of millimeter wave- guide were sawed down and reduced to garden stakes to support sapling trees by the grounds Waveguide Insertion Process (1974) Photo courtesy AT&T Archives and History Center

Components of WT4 Sheathed Waveguide Medium Photo courtesy AT&T Archives Circular Waveguide and History Center

66 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 67 Connecting the World —

Landing of the First Transatlantic Telephone Cable, (1955) Undersea Photo courtesy AT&T Archives and History Center Transmission

by Mike Neubelt, Ken Reichmann, Beatriz Ugrinovic

Over 150 year ago the world as we First transatlantic telegraph cable know it changed forever with the to successfully be laid was the 1858 laying of the first transatlantic tele- Atlantic cable. This feat was accom- graph cable, establishing a commu- plished by cable laying ships HMS nication link between Europe with Agamemnon and the USS Niagara. America for the very first time. Until While transmission quality began this time the only way messages to deteriorate immediately and it could be sent across the Atlantic was failed within a few weeks of being via mail carried by ships, taking up to laid it proved that it was possible 10 days to deliver. to build a telegraph link that con- nected Europe with America. Even The 1850’s ushered in several at- with a transmission rate of only a tempts to lay a telegraph cable few words per hour it proved to be a across the Atlantic, however these financial success, and more transat- first attempts were plagued by re- lantic cables were soon to follow. peated failures. Upon the successful laying of the cable a congratulatory message from Queen Victoria was received by the President of the United States, James Buchanan. This first official This first official exchange over the exchange over the newly laid trans- newly laid transatlantic telegraph cable led to atlantic telegraph cable led to a great celebration in New York City a great celebration in New York City including including a parade featuring a replica a parade featuring a replica of the ship of the ship that completed the final that completed the final leg of the cable leg of the cable laying operation Unfortunately, poor attention to the laying operation. engineering of the cable led to its early failure. However, many lessons were learned from this initial cable laying experience and future cable designs proved to be much more robust.

68 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 69 Manufacturing an Undersea Repeater, Several more attempts were made late 1940s by Bell Labs and Simplex, TAT-1 went into service in September Clark, NJ Plant (1962) Photo courtesy AT&T Archives and History Center to connect the continents and in and was first used commercially for of 1956 and operated for 22 years July, 1866 Europe and America were the 1950 Key West - Havana cable. without a single tube failure. The ca- once again connected and this time The cable demonstrated the viability ble was taken out of service in 1979, the cable did not fail. This new cable of a repeatered system design and exceeding its 20-year design life. could transmit up to eight words was designated the SA System. This per minute which represented a was a trial run for the design, and Based upon this success the SB great leap in speed from the first would form the foundation for new design was also used for the 1956 transatlantic cable laid less than cable designs to follow. Washington-Alaska telephone cable, seven years earlier. The cost to send and in 1957 for the California-Hawaii a message was $10 per word with a The SA cable design could carry 24 cable, HAW-1. 10 word minimum so needless to say voice channels but could carry voice most of the traffic was sent by large traffic in only one direction, hence The TAT-1 repeater was based upon to carry the Moscow–Washington companies. two cables had to be laid to support a flexible outer housing design with hotline between the American and bi-directional communication. articulated sections not much larger Soviet heads of state, although using First Bell System than the cable itself. This section a rather than voice calls Repeatered Cable – The two cables were 120 nautical was about 8 feet long while the as written communications were SA System Design miles long and had three repeat- overall length with the cable tails regarded as less likely to be misinter- Driven by the desire to transmit ers on each cable that were laid at measured approximately 70 feet preted. The link became operational voice, rather than messages using depths of 950 fathoms. long. on 13 July 1963, and was principally Morse Code, and with the advance motivated as a result of the Cu- in electronic technology during the The SA cable design was like that The flexible repeater, due to its inte- ban Missile Crisis where it took the 1930’s it became feasible to build an used on early telegraph cables, rior volume, had a limited bandwidth US nearly 12 hours to receive and undersea repeater using high reli- however polyethylene was used as which could support only 36 4-kHz decode the initial settlement mes- ability vacuum tubes. After 18 years the insulator instead of gutta-per- spaced voice channels and transmit sage that contained approx. 3,000 of reliability testing the technology cha, the gum of a tree native to the signals in just one direction. Bi-di- words. By the time the message was was ready to be used on a brand- Malay Peninsula and an ideal insula- rectional communication required decoded and interpreted, and an new repeatered coaxial cable design. tor for submarine cables. In addi- two cables, one for each direction answer had been prepared, another tion, an outer conductor was added of transmission. The length of each more aggressive message had been This type of repeatered coaxial cable to create a complete coaxial cable uni-directional cable on TAT-1 was received. system had been developed in the structure. 1950 nautical miles with 51 repeaters spaced every 37.5 nautical miles. TAT-3 – A second Based upon the success of the Flor- generation SD system ida – Cuba cable system a new cable Time-assignment speech interpola- design design was developed capable of tion (TASI) was used to upgrade the This new cable design was based Based upon the spanning the Atlantic Ocean and was TAT-1 cable in June 1960 and effec- upon a rigid repeater housing, success of the called the SB system. tively increased the cable’s capacity though much larger than the flexible Florida – Cuba to 72 voice channels. repeater used on TAT-1 it had space Based upon these new cable han- began on a new system design called for more electronics, thus enabling dling designs the C.S. Long Lines SF. cable system a TAT-1 – The First Over 8000 nautical miles of cable a much wider bandwidth system ca- would now be able to deploy the re- new cable design Transatlantic Coaxial based upon the SB cable design was pable of transmitting 138 3kHz voice peatered cable continuously, without In 1970 the TAT-5 cable based upon Repeatered Cable – SB deployed. channels in both directions simulta- having to stop the cable payout and the SF design was installed between was developed system design neously on a single cable. manually handling the repeater each the Green Hill, Rhode Island, USA capable of spanning In 1952 the British Post Office began Following the success of TAT-1 time a repeater was launched over and Conil, Spain. An extension from negotiations with AT&T for a transat- numerous improvements of repeat- This new rigid repeater design re- the stern of the ship. Spain to Italy was also built and was the Atlantic Ocean. lantic cable based on the SB System ered coaxial cable designs would quired the design of new shipboard called MAT-1. that would connect Oban, Scotland follow, culminating in TAT-7. handling equipment for the cable TAT-5 – SF system and Clarenville, Newfoundland and and repeaters as well as the design Following upon the success of im- While the SF design shared many of this cable was called TAT-1 (the first An example of the important role of a brand-new cable laying ship, the proved electronics used on the TAT-3 the characteristics of the SD design transatlantic telephone cable). TAT-1 played was when it was used C.S. Long Lines. system design, in 1963 development it did introduced a major technical

70 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 71 AT&T Cable Ship Long Lines, Launched in 1961 Photo courtesy AT&T Archives and History Center

TAT-8 – the first generation of fiber optic cables With the development of low loss optical fiber, it was now possible to replace the coaxial cable with a fiber TAT-8 Repeater optic cable, however a new repeat- Photo by Michael Mills er design was needed to support the optical transmission along the optical fiber. With this advanced de- sign, TAT-8 was initially able to carry mission rate of 280 Mbit/s on each NJ. Final repeater assembly occurred month after its installation, AT&T 40,000 voice circuits. By 1993 over of its two active pairs of optical fiber. at Bell Laboratories in Holmdel, NJ. learned that the cable had a “Shark 125 km of TAT-8 systems had been Presently, most long-haul systems As part of the rigor, the electronic Attraction Problem.” Since it was installed. It remained in use until operate near 1550 nm and at much circuitry was encased in a hardened an optical cable not a coaxial cable, retired in 2002. higher transmission rates. These housing, sealed and insulated to the electrical interference shield for wavelengths are located just past prevent penetration of seawater and When you visit the Science & Tech- visible light in the infrared region of corrosion. advancement with the use of germa- TAT-6 – SG system nology Innovation Center in Mid- the electromagnetic spectrum and nium transistors in place of vacuum The demand for the ability to carry dletown New Jersey, you will see an are invisible to the naked eye. The Some of the repeater features in- tubes. Future SF systems were up- yet more voice channels continued example of a TAT-8 repeater. Since copper cladding applied over the clude; integrated circuits as opposed graded to transistors. This new and early development began 1966 all transmission signals, even optical steel reinforcing strands for the fiber to discrete transistors, independent design was capable of transmitting on a higher bandwidth repeater de- transmission suffer loss, repeaters cable serves as the conductor to digital regeneration for each direc- 845 3kHz voice channels. TAT-5 was sign capable of carrying 4000 3kHz are installed periodically in order to power the repeater electronics. tion of transmission, and of course 3461 nautical miles long and used 361 voice channels. cover the span for both TAT-8 and all it is an optical fiber-based solution repeaters with a repeater spacing of undersea systems. These repeaters Given their location, the repeat- exploiting all the benefits of fiber. 12 nautical miles. MAT-1 was 990 nau- In 1976 the first system based upon receive digital light signals, re-time, ers needed to be manufactured to tical miles long with 93 repeaters. the SG design was installed between re-shape and regenerate them and perform flawlessly and reliably for Fine-tuning the Green Hill, Rhode Island and St. Hil- subsequently transmit them to the upwards of 20 years as the cost to First Generation of By 1983 over 17,000 nautical miles of laire, France. next repeater downstream. In the recover and repair them was nearly Undersea Fiber-Optic SF design cable had been installed. case of TAT-8, the repeaters would prohibitive. As a result, unprecedent- Cable Design be spaced every 40 km (24 miles) ed diligence, testing and inspection The first TAT-8 deployment was the over its entire length of 5066 km was required in order to insure the 72-mile prototype laid by AT&T in (3148 miles) and would lie on the operating life of the devices. As the Canary Islands in 1983 (between ocean floor at depths reaching 5,486 part of the quality control, many of Gran Canaria and Tenerife), in part- meters (17,998 feet or 3.4 miles). the critical electronic components, nership with the Compañía Telefóni- The repeater was based on an including the transmitters and ca Nacional de España (CTNE). A optical regenerator operating at a receivers were manufactured in the wavelength of 1310 nm with a trans- Western Electric facility in Read- ing, Pennsylvania under ultra-clean conditions. Further assembly, preci- Fish Bite Protected Deep Sea Fiber-Optic Cable sion tooling and extensive testing, Photo by Michael Mills New Link to Europe – TAT 5 Route Map Photo courtesy AT&T Archives including exposing the repeater to and History Center high pressures, was performed in the Western Electric facility in Clark,

72 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 73 to create “Jaws” to evaluate physi- the optic fiber to feed the repeaters,

AT&T SCARAB, Remote Controlled cally new cable designs and select regenerators, and branching unit. Cable Repair Submarine (1986) the most appropriate one. The new Photo courtesy AT&T Archives and History Center design included a “shark shield” that TAT-9 – the second Bell Labs Innovations for TAT-8 prevented the sharp teeth from generation of fiber reaching and damaging the fiber optic cables Optimized Fiber-Optic Cable: in two versions: Deep water with no and the power lines in the cable, al- This cable went into service in 1992 protection for fish bites and the special FBP (Fish Bite Protected) cable though it did not prevent the sharks and remained in use until 2004. It for the slopes where the sharks live. The glass fibers were manufac- from biting the cable. The new “FBP” was owned by a consortium of AT&T, tured by AT&T at its Norcross, Georgia facility and converted to un- (Fish Bite Protected) Cable was British Telecom and France Telecom dersea cable by Simplex Wire and Cable Company in Newington, New designed with a dual layer of helical and was initially able to carry 80,000 Hampshire. steel tape over the original cable voice circuits. It was a two fiber pair with an outer shell of polyethylene cable transmitting at 560 Mb/s per Terminal Equipment: Undersea cable system terminal equipment was wrapping. fiber pair. similar to the terminal equipment that was developed by AT&T Bell Labs for Optical terrestrial Transport Systems; with the added requirement Studies conducted by Bell Labs engi- Subsequent cables, TAT-10 and TAT- that it had to conform to the agreed International Digital Interworking neers concluded that the habitat of 11, shared a similar design and repre- Hierarchy, per ITU G.704, and it also had to provide the power feed to the power supply lines was consid- bites deep enough to puncture the shark species that “attack” the cable sented the last transatlantic cables the regenerators, repeaters, and branching unit to be installed under- ered unnecessary for this cable and cable allowing salt water to reach is at ocean depths between 1300 to based upon repeaters that had to water. therefore removed from the original and short-circuit the power lines 2600 m (~4300 to ~8500 feet); based perform an optical-electrical-optical design. After analyzing recovered serving the repeaters. on the Atlantic Ocean Floor Profile, regeneration of the optical signal Underwater Regenerators and Repeaters: Same as the Terminal pieces of the damaged sections of for TAT-8 this habitat is limited to a along the way. Equipment, the Regenerators and Repeaters to be used in TAT-8 were the cable, it was discovered that Using the recovered shark teeth, portion of the slopes between the similar to the ones used in terrestrial systems, but had to be designed the sharks that swam nearby were Bell Labs scientists teamed up with continental shelves and the deep TAT-12/13 – First and built with a special housing suitable for underwater conditions, and compelled to “attack” the cable with members of NYU School of Dentistry ocean floor. Only 130 Km (81 miles) transatlantic fiber optic using a power feed embedded in the Undersea Fiber-Optic Cable. of TAT-8[1] required the FBP cable with optical amplifier design, since the remaining cable By the 1990’s the erbium doped Branching Unit: An innovative undersea branching unit was devel- is either buried or installed in ul- optical amplifier had been developed oped to enable the TAT-8 System to serve three countries (US, UK, and tra-deep waters. and enabled a huge leap in transmis- France) with a single transatlantic crossing. This Branching Unit was sion rate along the optical fiber. Now deployed underwater on the continental shelf off the coast of Great There are many theories regarding the optical signals did not need to be Britain. the stimuli that cause the deep-wa- converted to an electrical signal at ter sharks to attack the undersea each repeater and regenerated. This Fiber-Optic cable; the most accepted meant transmission speeds were no one points to the strong electric longer limited by the speed of the fields around the cable – created by electronics inside the repeater. Connect (AEC) cable can carry 130 few words per hour now it is possible the power supply line running along wavelengths operating at 100Gb/s to stream live video on your phone TAT 14 and beyond per fiber pair for a current system with friends around the globe. News This first all-optical transmission capacity of 52 Tb/s. travels instantaneously, doctors can cable was able to transmit at 5 Gb/s interact with patients remotely, and on each of the two fiber pairs. TAT-14 The World Is a Much financial markets can react to global Ralph Rue and Mike Notarfrancesco Test Submarine Cable Against increased the capacity by carrying 16 Smaller Place news immediately just to name a Their Jaws (1989) optical wavelengths operating at 10 With the rapid advance in under- few ways instantaneous commu- Photo courtesy AT&T Archives and History Center Gb/s on each of four fiber pairs for sea cable transmission rates it has nication has affected the way we a total cable capacity of 640 Gb/s. dramatically changed the way we in- interact. We live in a very connected This is equivalent to 9,700,000 voice teract globally. These undersea sys- world and all of it due to the long circuits. tems were critical to the launch of history of pioneering research and

[1] The entire length of TAT-8 was about the global Internet and the commu- development of undersea communi- 5800 km (3600 miles); it lied on the ocean Today undersea cables have evolved nications between the Continents. cation systems. floor at depths reaching 5,486 meters (17,998 feet or 3.4 miles). dramatically and as of 2016 the AE Where once we could only transmit a

74 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 75 The Evolution of Switching

By Magda Nassar

The story of switching is the story of innovation in and had more than half of the world’s telephones. Shortly America. It illustrates that creative minds are always in after, Telephony service, with many advanced features, motion, and that necessity is the mother of Invention. became not only an affordable and reliable service in every Furthermore, good Inventions lead to the realization of household, but also an essential component of every suc- a vision through leveraging teamwork and cooperation cessful business. among those sharing the vision. Less than two years after Alexander Graham Bell received his first patent for the Telecommunication Networks telephone, the world’s first telephone exchange service To understand the role switching systems played in the became operational in New Haven, Connecticut. The telecommunications network, we must first start with a exchange provided service to only twenty subscribers basic explanation of a Network. In a broad sense, a Net- who had to first call the exchange operator, and then be work is a group of interconnected elements needed to manually connected to one of the other twenty subscrib- provide service to a large number of widely dispersed cus- ers using a central switchboard. Within a decade, switch- tomers. The two most basic network elements in a simple boards, with many innovations for automation and scale, telecommunication network are links and nodes. Graph- were operational in nearly every city in the United States. ically the links are the lines and the nodes are the points As late as the 1950s, the U.S. lead the technology evolution where the lines interconnect. Within AT&T’s network, the nodes could be Switching Offices, while the links are trans- mission facilities such as fiber cables. The primary function Telephony service, with many of a Switching office in a telecommunications network is to provide a central point that can economically connect advanced features, became not telephones or other devices amongst a wide array of only an affordable and reliable customers. This connectivity can vary across many differ- ent types of network elements depending on the type of service in every household, but service being provided. also an essential component of every successful business.

Bell Opening New York–Chicago Telephone Line (1892) Photo courtesy AT&T Archives and History Center

76 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 77 Manually Operated Switching Systems to reduce some of the manual operations and improve The first form of a switching system was a manually op- call set up time. These manual switch boards required the erated switch, where an operator was required for each operator to operate listening keys and ringing keys to call and completed the connection by plugging cords into answer the calling party and ring the called party. These jacks on switchboards. Initially, these systems could only innovations allowed the initiated call to be answered handle a limited number of end points. However, at the automatically by the operator inserting the cord into the time, this was a fascinating advancement in the capability subscriber’s switchboard jack. Subsequently, the ringing of personal communications. cord was plugged into the subscriber’s jack being called and the call completed “automatically”. The key point here Later these exchanges grew to support hundreds of sub- is that operators were still needed to connect the calling scribers and many staffed switchboard operators. Many party to called party, even though their level of manual advanced capabilities and tools began to emerge to sup- involvement was reduced to allow them to handle much port larger and larger numbers of subscribers. Each oper- larger volumes of calls. ator was provided access to a vertical bank of jacks, each of which was a local termination of a subscriber telephone Electromechanical Switches line. The operators would manually connect the calling As the demand for calls increased, the need for a faster and called party. When the caller initiating a call lifted their and more efficient method to meet the demand arose. telephone receiver, a signal lamp or a buzzer was activated This led to the invention of the next generation of switch- at the switchboard to signal the operator. The operator es. Until 1889 a human operator was needed to complete Rural Operator at Magneto Switchboard (c. 1940) then responded by inserting the answering cord into that a call. In 1891, Almon Strowger was granted a US Patent for Photo courtesy AT&T Archives subscriber’s designated jack and the operator would ask what would be the basis for the first practical automatic and History Center for the number that they wished to call. The operator telephone switch. In the , pulses generat- would then connect the two jacks as long as both parties ed at a subscriber’s telephone directly moved electromag- were on the same switchboard. netic contacts in a two-way motion in a stack of rotary contacts, thus selecting a , one digit at In the case of long distance call, or a connection to a a time, without operator intervention. His original device It is easy to illustrate the tremendous value locations and serve to interconnect end user subscriber on a different switchboard, the operator would was crude and impractical, but achieved the main purpose of centralized switching. First, start with telephone lines and establish communica- connect into a “ Trunk Circuit” that connected to another of eliminating the operator. a highly over simplified telecommunica- tion between subscribers. These Switching Operator sitting at another switchboard. In 1918, the aver- tion network In this first model there are Systems make it possible for subscribers age time to complete the connection for a long-distance no switching systems. Each telephone is to connect to each other across a variety call was 5 minutes. directly interconnected by transmission of locations (homes, businesses, or public links. For networks supporting millions of spaces) without the need for dedicated For Calls to be completed across the country, an interme- end users, who are geographically dispersed, direct connections between each of these diate operator and intermediate trunk between the differ- it is not hard to realize how extremely complex end points. ent operators were needed at all times. These calls could and prohibitively expensive this solution becomes. only be completed when the intermediate trunk lines were It is interesting to note that Telephones were invented available. Calls needed to be scheduled hours in advance This initial model can be significantly improved with the before switching systems. However the invention and to get the needed trunks between cities, this was still true introduction of a switching function in a central location introduction of Switching technology, along with its in 1976 for International calls as experienced by the author. to interconnect transmission paths to every endpoint. continued evolution provided the key elements that Starting in the 1920s, the next key wave of innovations in All end points are connected to the Switching made telephony a viable communications tool this operator based environment were the introduction of System, which in turn facilitates the connec- that was scalable, affordable, and widely used. the dialed number, listening keys, and ringing capabilities tivity between 2 or more end points in the This evolution has seen many remarkable network. It is easy to see how valuable a technologies including electromechanical, central switching point can become as the complete electronic, and most recently Strowger Switch numbers of end points grow. Programmed Software based Solutions. Patent Model (1890) Photo courtesy AT&T Archives Many of these innovations have interest- and History Center Switching Systems (often referred to as ing stories of their own that drove various Telephone Exchanges) are typically located needs and solutions and the basis for much at Service Provider centers or large enterprise of the technology still used today.

78 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 79 A commonly told story explained that Strowger, an under- The was a complex device equipped with tall combination with work they had done earlier. They reject- had many innovative features that gave it a more flexible taker in Kansas City, was driven to his invention by learning panels that were covered with 500 rows of terminals. Each ed the idea of simply replacing the selectors on the exist- and adaptable design than panel or Strowger switches. that the funeral of a friend was being handled by a com- panel had an electric motor to drive its selectors by elec- ing panel design, and instead they developed, beginning in petitor. Strowger was convinced that his friend’s family tromagnetically controlled clutches. The selector moved 1934, an entirely new switch for urban use. The units used to establish calls were not only separate had been led to another undertaker by an unscrupulous continuously rather than in steps, and the selectors estab- from those used for the actual call paths, as they had been telephone operator. Strowger and his backers formed lishing contact points could move a considerable distance. By combining these inventions from Western Electric by in the panel, but there were also common control units. a company, eventually known as the Separate frames were used for the several parts of the Reynold’s, and the Swedish Postal Telegraph and Tele- This meant that all selector frames were accessible to all Company, to develop the patent into a practical switch telephone-calling process. phone Administration by Betulander, the cross bar switch of the phones, and after a call they were released for use and eliminated the dependency on humans to direct and was invented. In this design there were small mechanical on other calls. These “markers” as they became known, complete a call. The Bell System’s initial plan was for semiautomatic oper- motions and none of the large sliding movements required were fast, thus reducing connection times. ation, where subscribers would still call operators, who in in the panel and Strowger switches. In a Strowger switch, the subscriber’s rotary telephone dial turn would enter the subscriber’s desired number. Howev- directly controlled the movement of the switch contacts er, the Bell System soon moved to fully automatic switch- The first two crossbar switches went into service in 1938 that established the circuit. The earliest switch could only ing, partly because of continued growth in the number of in New York City. The achieved its goal of Panel Switch at handle a very limited number of customers. However, the telephones that further complicated manual interoffice reducing costs for manufacturing and maintenance, and it Chicago ‘Franklin’ CO (1938) Photo courtesy AT&T Archives invention continued to be refined and eventually in- trunking, and partly because of changing labor conditions. and History Center creased the switch capacity to 10,000 telephones. But the direct control of the switch by the subscriber remained For the operation of smaller, non-urban exchanges, AT&T the key innovation. acquired a license in 1916 to manufacture Strowger step- by-step switches, and also reached an agreement to pur- The Strowger, or step-by-step switch as it also became chase such switches. The first step-by-step switch in the known, remained the most widespread switch in use until Bell System entered service in Norfolk, Virginia in 1919. the 1960s, and was particularly common in non-urban exchanges. The crossbar switch achieved AT&T’s Panel Switch The AT&T Bell System did not adapt the Step-by Step its goal of reducing costs for automatic switches because they needed a larger capac- manufacturing and maintenance, ity switch to serve large urban cities. Additionally, a large percentage of calls required routing between exchanges and it had many innovative within a city. The Strowger switches seemed to be slower features that gave it a more than AT&T’s improved manual switches. In addition, by this flexible and adaptable design time there were many subscribers connected to the man- ual exchanges and changes needed to be compatible with than panel or Strowger switches. this existing network.

In 1905 an AT&T engineer, Edward C. Molina, invented AT&T’s Crossbar Switch a design breakthrough that was better suited to meet Due to the high cost, complexity, and demanding mainte- urban needs. This invention introduced the concept of nance requirements, it became critical to work on alterna- indirect control. The pulses from the telephone dial would tive solutions to the complex panel switches. By the 1920’s, be translated into an electromechanical code. This code AT&T’s W.R. Mathies from the research and development allowed for a subscriber’s telephone to select from a division and other researchers had been working to pro- larger number of possible circuits, and for the separation duced a more cost effective design to solve the issues of of the circuits used to set up calls from those used for the the panel switch for urban use. It was not until 1930 when call itself. This in turn led to the development of the Panel Mathies visited Sweden and saw the crossbar selectors in Switch which was more suitable for large cities and large use in rural exchanges, that he decided to combine inno- volumes of interoffice calls. It was this technology that vations to create something even more effective was chosen by Western Electric for continued develop- ment in the United States. Convinced that the crossbar selectors could be adapted to large switches, Mathies had his group build on this idea in

80 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 81 Also significant, was that the crossbar was the first switch Thus, it proved easy for Bell Labs to adapt the crossbar where both the originating and terminating traffic were switch for use as the first automatic switch in the long combined on the same set of line switches. This made distance network. Previously all long-distance calls re- connections from telephones to the switches much quired one or more operators at manual long distance simpler, and also allowed the crossbar to be adapted, as switchboards. The first long distance crossbar switch, the it soon was, for use in tandem switches. Tandem switch- #4 crossbar, was installed in Philadelphia, Pennsylvania in es were used specifically to route calls between multiple 1943. Four additional #4 crossbars were installed in other urban exchanges. Crossbar tandems also allowed, for the metropolitan areas in the next five years. Thus the evolu- first time, automatic alternative routing when the direct tion to the long distance capabilities and communications route between exchanges was not available. Crossbar that we know today was underway. switches were wired to allow for the separation of the two directions of transmission. These highly innovative Electronic Switching System features made the switch very adaptable and provided for AT&T Bell Labs continued to improve the switching system easy modification for both applications as well as and new to meet a growing demand for telephone services. The peripheral additions and features. electronic switching, made possible with the invention of the transistor, used an electronic data processor, operat- ing under the direction of , and a high-speed switching network. The stored program con- trol had the software containing the logical steps involved First TSPS Operators, Morristown, NJ (1969) in making a telephone connection. Photo courtesy AT&T Archives and History Center

No. 4 ESS Installation, In electromechanical switching, changes to the operations Chicago, IL (1975 - 1976) or services required extensive circuit redesign and, fre- Photo courtesy AT&T Archives and History Center quently, labor-intensive rewiring in the field. In an elec- tronic switching system, new services can frequently be implemented by making changes to the stored program control. This makes it available to the customers sooner demand for new sophisticated business and residential after the software has been centrally developed and dis- services is high. tributed to the systems. The need for smaller local switches was met with the 2ESS. The processors used in a switching system are input/ It was oriented toward residential services rather than output driven and are designed for real time processing. business. The processor was smaller and less expensive. It They respond promptly to signal and data transmitted by was used in areas that were previously served with Step- customers and other switching systems. In addition, these by-Step switches. The Rural areas were served with 3ESS processors must be highly reliable and provide continuous switching equipment, yet a smaller and more economical operation 99.999 percent of the time (approximately 5 min- implementation than the 2ESS design. utes of allowable planned/unplanned downtime per year). No. 4 Electronic Switching System The first trial of electronic switching was in 1960 after 6 (4ESS) years of development. The trial proved the viability of the The next crucial step in the evolution of electronic switch- Stored Program Control concept. The first application ing was the introduction of the 4ESS. In 1976, the first was the 1ESS switch in 1965 in NJ. It was used in areas electronic toll switching system to operate a Digital Time with heavy business customers. The ease and flexibility of Division Switching network under Stored Program Control, the 1ESS made it a natural fit for city applications where the 4ESS system, was placed in service.

82 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 83 On January 17, 1976, the first 4ESS™ switch was placed into has passed the test of time, every major subsystem within service, culminating the single largest switch development the switch has gone through one or more technology effort ever undertaken in the Bell System, until that time. upgrades to offer new features and reduce costs. When it was introduced, the 4ESS switch was the largest high-capacity digital switch in existence. The 4ESS switch The Architecture of the 4E includes three main building played a pivotal role in enabling the emerging U.S. long blocks: The Switching Processor Platform, the Switching distance market to grow into today’s multibillion $ indus- Fabrics Platform, the Customer Interface Platform. try. The hallmark reliability and capacity of the 4ESS switch set the standard for digital switching. Although the classic The Switching Processor Platform provided the central digital switch architecture pioneered by the 4ESS switch intelligence of the system and overall call control, call sig- naling processing, operation, Administration and Mainte- nance support and Overall system integrity. The starting point of the processor evolution was the 1A Processor, a Key Dates in the Switching high-capacity, custom designed uniprocessor. The rising call traffic growth, new call features, and growing sophis- Technology Evolution: tication of end customer service/features created the need for a higher processing capacity and Intelligence • 1878 The first manual telephone exchange opens in the 4ESS Switch. To meet that need, the 1B processor in New Haven, Connecticut. was introduced to replace the 1A. The 1B processor more • 1889 Almon Strowger invents the first automatic than doubled the call handling capacity of the 4ESS switch telephone switch. while achieving the same extraordinary reliability objec- tives as the 1A. • 1891 Strowger receives US Patent 447918 for his invention. The Switch Fabric Platform is managed by commands • 1891 The Automatic Electric Co. is formed to from the Processor Platform. Real Time routing routines develop a practical Strowger system. were developed to optimize the call routing in real time to • 1896 The first prototype of a dial telephone sys- manage cost and increase call completion. The 4ESS first tem operates. implemented a Dynamic Non-Hierarchical Routing (DNHR) No. 5 ESS, Seneca, IL (1982) Photo courtesy AT&T Archives and then evolved to a more advanced Real Time Routing No. 5ESS Switching System (5ESS) • 1912 Gotthief A. Betulander invents the first all- and History Center (RTNR) scheme for optimal call completion. AT&T supplemented the 4ESS toll tandem switches with relay telephone switch. 5ESS switches featuring an advanced design, and are used • 1913 John Reynolds invents the crossbar selector. In a sheer physical size and cost, the switching fabric as edge switches in the network. The 5ESS was also a Dig- platform dominated the switch. Work continued upgrad- ital switching system. It was designed to replace smaller • 1921 AT&T introduces the panel switch, designed ing 4ESS Switch fabric in 1980’s and 1990’s. From a physical offices in rural, suburban and urban areas. for use in large cities. size perspective, generally a single deployed 4ESS switch Control and Administrative Maintenance; the Communica- • 1938 AT&T installs the first #1 crossbar switch in would take up at least an entire floor in a Central office. The 5ESS switch was deployed in 1982, initiating the global tions Module (CM) is the central time multiplex switch of New York City. The development of the expanded Time Slot Interchange presence of AT&T digital switching equipment around the the system; and the Switching Module (SM) which makes • 1943 AT&T introduces the #4 crossbar switch, offered the most significant innovation in the 4ESS switch world. It was destined to replace the Number 1 ESS and up most of the equipment in most exchanges. designed for long distance calls. fabric evolution. It provided a high speed transmission, 1AESS. The 5ESS was also used as a class 4 switch or as a higher capacity, and reduced cost, power, and floor space. hybrid class 4/5 switch in markets too small for the 4ESS. The SM performs multiplexing, analog and digital coding, • 1948 AT&T introduces the #5 crossbar switch, It also provided an integrated echo cancellers to eliminate The 5ESS 2000 version, introduced in 1990’s, increased the and other work to interface with external equipment. designed for suburban exchanges. a significant capital investment in associated transmission capacity of the switching module and provided more en- Each has a controller, a small computer with duplicated • 1951 Customer dialing of long distance calls begins equipment. hanced features. A major design goal of the 5ESS was the CPUs and memories, like most common equipment of the in the United States. use of equipment modularity to achieve an economically exchange, for redundancy. During a call the Customer Interface Platform enables the competitive system over wide range of line sizes. The • 1965 AT&T installs the first all-electronic telephone switching processor Platform to interact with the end cus- 5ESS switching equipment uses distributed processing The 4ESS and the 5ESS technology, along with their pre- switch. tomers using touchtone reception, announcements and and modular software and hardware to provide a flexible decessors, were transferred to the AT&T Network Systems • 1975 - 1976 AT&T installs the first 4ESS.™ speech recognition capabilities enabling more advanced architecture and simplify the addition of new features. The division upon the breakup of the Bell System. The division • 1982 AT&T installs the first 5ESS.™ service features. 5ESS switch has three main modules: The Administrative was divested by AT&T as Lucent Technologies, and after Module (AM) contains the central computers for Routing becoming Alcatel-Lucent, it was acquired by Nokia.

84 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 85 Mobile Calls Before the Cell Phone

First Los Angeles Pay Station (1899) Photo courtesy AT&T The Phone Booth Archives and History Center

By Samantha Lelah

From near ubiquitous deployment created in the late . It was op- a soundproof booth, double walls, in every town and city to an almost erated by a “post-pay” honor system curtains and even rugs were added non-existent phenomenon in the where the user would put in their to the interior. In the early 1900s, the United States, the telephone booth coins after they completed their telephone started to become less of has had a significant impact on phone call. At the Science and Tech- rarity so the booths were installed America’s ever-evolving culture. nology Museum in Middletown, N.J., in more constricted quarters. The Whether one considers this inven- we pick up the story of the phone hinged door became dangerous tion as a practical enabler to make booth in 1939 with a Western Elec- to unaware individuals who were a private call in a public place or tric #2 model. Built around 1939, the walking right in front of the booth. Like most simply as a now-famous icon in main material used for this phone Maurice Turner, who was an employ- pop culture, it is important to booth construction was wood. Inside ee of the New York Telephone Com- innovations its acknowledge this innovation and the booth is a three-slot rotary pay pany, patented his idea in 1910 of a story has various its evolution over time. phone where users could place a door that folded inside the booth. paths and key local call for a nickel. The folding door was supported on The Beginnings of the hinges so the user could easily pull moments of Phone Booth and the A Constant Evolution the door open and shut. Turner’s notoriety. and Spread of Phone invention lasted the test of time, as Like most innovations its story has Booths this innovation can be found on the various paths and key moments of The need for phone booths was few telephone booths that are still notoriety. Therefore, the telephone mainly for convenience reasons around today. booth that we know today has come when traveling away from home or a long way since 1878. In this year, work. In cities, where it seemed like There were other changes through- Thomas Doolittle, a notable inventor, they were situated in nearly every out the early to mid-1900s but what repurposed an old telegraph wire corner store, decorated with a sign is important to note about this part and stretched it from Bridgeport to that read “Telephone.” Sometimes of the telephone booth’s history is Black Rock, Connecticut — a dis- accompanied by a phone book that that household phone penetration tance of just over two miles. On each was secured by a chain, users would rate was increasing. Between 1910 end of the line, he placed a wooden be able to talk on the phone in com- and 1920, the rate was only 15% but booth where people could pay 15 plete privacy while encircled by the by the end of the 1920s, almost 40% cents (about $3.60 today) to make hectic city life. of all household in America had land- a phone call to the other town. The lines. Then, the rate declined to 30% telephone booth is a combination of As the years went on, there was during the Great Depression and two major functions: the payphone continued development and re- then increased after WWII to 50%. and a privacy space. William Gray is finement of the phone booth to However, telephone booths were responsible for the invention of the accommodate the public’s basic still a significant aspect in American first commercial payphone, which he need for them. To create more of culture. So much so that in October

86 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 87 and payphone’s demise goes to the All of my change I spent on you.” As Corey Kilgannon, “And Then There Were invention of the commercial cellu- you visit the Science & Technology Four: Phone Booths Saved on Upper West Indoor Telephone Booths in NYC (1940) Side Sidewalks,” The New York Times, Photo courtesy AT&T Archives lar system in 1983. With this mobile Innovation Center in Middletown, NJ February 10, 2016, https://www.nytimes. and History Center phone, people no longer needed to we hope that as you look at the tele- com/2016/02/11/nyregion/and-then-there- were-four-phone-booths-saved-on-upper- stop and find a booth because they phone booth you are transported west-side-sidewalks.html?_r=0 could now talk anywhere at any time. back to simpler times where society Renee Reizman, “What Killed the Pay wasn’t always on the go. Phone?” The Atlantic, February 2, 2017, The Telephone Booth’s The Nostalgic Imprint https://www.theatlantic.com/technology/ archive/2017/02/object-lesson-phone- Demise America’s culture was becoming References booth/515385/ The phone booths nowadays are enamored with mobile telecommu- “Superman,” video, 1:12, July 26, 2007, comprised of steel and glass; how- nications and the personal freedom Merrill Fabry, “Now you Know: Where was the First Public Telephone Booth?” Time, https://www.youtube.com/watch?v=VhC- ever, they have drastically dwindled of communications anywhere. One August 3, 2016, http://time.com/4425102/ m66QhW_Y public-telephone-booth-history/ in numbers. Currently, there are only by one, telephone booths were “Maroon 5-Payphone,” video, 4:39, May four spread out in the removed from the corners, stores Cullen Colton, “The Booth,” Western Electric 10, 2012, https://www.youtube.com/ watch?v=KRaWnd3LJfs area; a huge change from when they and hotels, only to remain as a faint Company, October 1949. were located on every street corner memory in society’s brain. With this in every major city. These four are demise, telephone booths became only preserved for historical curiosi- more of an icon and used in song ty reasons instead of practical ones. and films to invoke feelings of The gradual extinction stemmed nostalgia. Clark Kent relied on them from the increasing cost of mainte- as a place for a quick change into nance and stricter regulations of the Superman. However, in the 1978 actual telephone booth. In the 1960s, “Superman” there is an iconic scene new phone booths were no longer where Lois Lane is in trouble and the primary deployment method for Clark Kent needs to change. He finds . While the number of ful- a pay phone but it is only surrounded ly-enclosed telephone booths began by small glass panels. He looks it up to give way to these smaller enclo- and down briefly and runs to find of 1949, an article was published by effect,” so notes and other random sures, the number of payphones another dressing room. Additionally, the Western Electric Company that doodles could be easily erased. As continued to grow until 2001. By the in the film “Phone Booth,” released presented a new telephone booth for the floor, it was made out of late 1960s, the household phone in 2002, Stu Shepard is confined in designed by Bell Laboratories. 13,000 an impermeable, perbunan rubber penetration rate was almost 90% a — you guessed it — phone booth booths were being made for distri- that eliminated any possibility of of homes across America. Howev- in fear for his life. He is forced to stay bution that year and they would add fading. As for the payphone itself, er, the overall blame for the booth on the line or a sniper that is appar- to the 300,000 Bell System tele- the cost of a phone call increased to ently aimed right at him might kill phone booths already in operation a dime. However, if the user didn’t him. Booths even made it into songs around the country. The demand of have exact change, the phone had a in the 2000s when the lead singer of the product increased exponentially coin return (invented in 1908 by an Maroon 5, Adam Levine, released the because of “population growth and electrical engineer of Western Elec- song “Pay Phone.” Levine sings, “I’m the faster tempo of modern life.” tric). Later the booth portion was no at a pay phone trying to call home. Bell Laboratories’ new design called longer part of the full deployment of for major improvements in aesthetic pay phones. and practicality. The most note- worthy item that was added was a ventilator, which changed the air three to four times a minute so the space would be less polluted and Telephone Booth, Peoria, IL (1956) Public Telephone — Walk-up, more refreshing. The outer lining Photo courtesy AT&T Drive-up (c. 1959) Archives and History Center Photo courtesy AT&T on the inside of the booth was now Archives and History Center made of steel that had a “hammered

88 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 89 Woman Using Candlestick Phone All photos courtesy AT&T Archives and History Center Sharing the the need for a magneto and bat- teries in the individual telephone unit, allowing for a new, smaller and Conversation simplified design to the telephone set. Common battery systems were 142 Years of Talking on the Phone installed one exchange at a time, and for many years were not suitable by Elisabeth Patterson for the long circuits found in rural areas. A recent editorial by an author, Telephones are familiar and indis- Commercial telephones for the ear- an induction coil, and the bottom born in small-town Minnesota in pensable devices. But the familiar liest exchanges were available to the box two wet-cell batteries. The bat- 1942, casually mentions memories appearance has changed a lot over public by 1878. teries powered the talk circuit. of the use of a magneto phone and the years, and the changes represent It’s worth noting that a telephone is the need to turn the crank to sum- enormous advances in capability and By 1882 the Western Electric Com- only one element of the telephone mon an operator. Innovation and service to customers. pany introduced a telephone model network. The other components improvement were constant, though that remained in production for are transmission and switching, and implementation was spread out over Telephone infrastructure begins most of a decade, and in use well each of the elements affects all the time, depending on local needs and in parallel to , with the beyond that. This was a large wood- others. Advances in switching and local geography. attempt to adapt that infrastructure en wall set with three separate networking proceeded rapidly, if to the transmission of the human boxes attached to a backboard. The in the background for most users. Common battery systems also en- voice. In 1875 Alexander Graham Bell top box contained a ringer, a switch Changes in the network led to chang- abled the development and intro- filed a patent for an “Improvement hook on the left, and a magneto es in the telephone design as well. duction of desk sets. The Model 20 in Telegraphy” that could transmit with a crank to generate the current was introduced in 1904, and with box on the wall. This box, the “sub- the transmission network, the sounds, and by 1876 he had famously necessary to signal the telephone A key network change was the minor modifications remained the scriber set” or subset, later included telephone wiring in the subscriber’s transmitted a voice message to his operator. The middle box contained introduction of the common battery most widely used telephone model additional components for service home, and the telephone unit itself, assistant, Thomas Watson. variable-resistance transmitter and system. In this system, a low dc cur- for over 25 years. The phone itself improvement. which was rented from the compa- rent was sent down the transmission was a desktop unit, while the ringer ny at a monthly cost. This allowed wire from the telephone exchange and induction coil, collectively known It’s worth remembering that at this the phone system stringent control A Timeline of Telephone Instruments to all subscribers. That eliminated as the network, resided in a separate time, the Phone Company owned over service and device quality while

“Three Box” Telephone “Candlestick” Model 20 Model 302 Wall Telephone Trimline Nomad 4000 Cordless

1876 1882 1892 1904 1919 1937 1950 1956 1959 1965 1976 1985

Bell’s “Liquid Transmitter” Common Battery Set Dial Telephone Model 500 Princess Phone Mickey Mouse Phone

Timeline photos courtesy AT&T Archives and History Center and Michael Mills

90 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 91 500 Series Wall Phone (1957) Mother and Child with Photo courtesy AT&T Archives Princess Phone (1967) and History Center Photo courtesy AT&T Archives and History Center

reliability and ease of maintenance, ing a Model 500 in the home of their time period, considerable research and were not subject to consumer families and friends, with the typed continued in the transmission tech- fashion. Still, subscribers pressed for phone number including letters nology. certain stylistic changes, including for the exchange, well into the late the development of a combined 1970’s. Digital telephone transmission came handset. Western Electric engineers into use in the early sixties, support- experimented with combined hand- The phone was introduced in black ing data and improved voice com- sets as early as the 1890s, however, only. However, the plastic housing munication. Touch tone service was it wasn’t until the late 1920’s that a could be manufactured in almost any introduced in 1963, initially only in 2 combined handset was produced for color. Beginning in 1954, telephones towns in Pennsylvania. The availabil- use by Bell subscribers. But the initial were introduced and advertised ity spread one exchange at a time offering aged poorly and had perfor- in a range of colors for an added into the 1970s. Touch-tone service mance problems. monthly charge. Wall set versions, transmitted tones at a unique pair of particularly popular in kitchens, were frequencies for each key to indicate making advancements in telephone In 1937 Bell Laboratories produced a introduced in 1956. the digits of the number that the technology. completely new telephone design, subscriber wished to reach. These the Model 302. It was a complete For business customers, the tele- tones, working in conjunction with For instance, dial telephones were desk telephone, with all components phone set was enhanced to include new equipment added to existing tied to the introduction of automat- reduced in size and contained in the ability to accommodate multiple switches, could travel through the ic telephone switching. Automatic device. For the first time, the Labs phone lines, and pick up or hold calls, entire network rather than just as far switching required that the subscrib- engaged an industrial designer to using a series on buttons on the as the local switch, and thus had the er send signals to operate the switch explicitly consider the aesthetics phone set. potential for a variety of additional from his or her telephone, since a of a phone. The result was efficient, uses. Phone designs were modified human operator would no longer durable and popular, and remained in The 1958 Rogers and Hammerstein to include the Touch-tone keypad. routinely handle the call. The num- production into the 1950’s. musical “Flower Drum Song” features During all these innovations, the Bell bered telephone dial was created the song “I Enjoy Being a Girl,” with an System maintained a strict policy for this purpose. Each rotation of In 1951, the Bell System introduced a actress that she “talks on the of supporting compatibility with old the dial sent electrical pulses to the new standard telephone, the West- telephone for hours.” In 1959 AT&T equipment. A candlestick phone in switch to indicate the digits of the ern Electric 500, developed again at introduced a very different phone working order could be wired for a The production and sale of tele- “it’s little, it’s lovely, telephone number. The dial also in- Bell Labs. The case, again designed that played into that sensibility, to be phone jack, and plugged into the phones naturally became a compet- cluded letters, since early telephone for aesthetics, was more stream- marketed for its style. The Princess network, and that device would still itive and consumer-driven market. it lights.” exchanges were known by name lined and rounded in design. Num- phone featured a wide, low, oval provide phone service. Telephones were no longer designed as well as number. In 1919, the Bell bers and letters were place outside shape, and was marketed with the to work without fail for years, and System installed its first dial tele- the dial for easier readability and slogan, “it’s little, it’s lovely, it lights.” Until 1975, the Bell System had became more disposable. The degra- phones in Norfolk, Virginia, and then reduced wear. The feminine name and profile be- complete control over consumer dation in quality may have come as a undertook the enormous task of came very popular as an extension telephony, owning the telephones to consumers who took the converting its exchanges from man- Technically the handset contained phone for the bedroom. that were rented to consumers. In reliability of the standard equipment ual telephones and switches to dial an improved transmitter and re- 1975 the United States Supreme for granted. On the positive side, telephones and automatic switches, ceiver, supporting a stronger signal The last major design innovation Court ruled that subscribers could competition in telephone sets led one exchange at a time. Complete on the subscriber’s wire. The new from Bell Labs was the redesign of a own their telephone units. In some to innovations, such as the wide- implementation took decades. phone was also easier to maintain dial-in handset, the Trimline, intro- areas the Bell System opened Phone spread adoption of cordless phones. and repair, benefitting the company duced in 1965. The ringer, receiver Stores, and made a variety of prac- The change in the nature of service Telephony in the United States was and the subscribers. The phone was and dial were all reduced in size, a tical and whimsical designs available represented the end of an era in operated as a regulated monopo- extremely durable. The author and major engineering effort driven by for sale, for instance the Mickey telephony. ly. Telephones were designed for contemporaries may well recall hav- considerations of style. In the same Mouse phone.

92 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 93 A Brief History of Data Transmission over the Ground Environment”) computing sites where they were processed into a unified view of the airspace. The first generation of SAGE modems used vacuum tubes and Phone Network transmitted at 750 bits per second (bps). By the late 1950’s, vacuum tubes gave way to discrete transistors and trans- mission rates reached 1300 to 1600 bps. By Dave Hayward, Al Morton, Sal Talamo Commercial Data Applications Starting in World War II, the emergence of electronics Early Drivers of Modem Development Military applications covered much of the research and and computer systems led to the desire to share digi- As with many technologies, military applications drove development costs, and led to modems being manufac- tal information between locations. The ubiquity of the initial modem developments. Perhaps the first modern tured in large numbers. This pushed modems down the telephone network made it an obvious choice for mak- modem was used to transport voice, not computer data. technology cost curve and made them more attractive to ing these connections. However the copper wires of the During the second world war, a secure telephone was business customers. Some modems were developed for phone network were designed to carry the human voice, invented which prevented enemy agents from listening specific applications while others could be used for any not the “ones and zeros” used by digital devices. So de- to classified phone calls. This “SIGSALY” system, whose type of digital information. vices were needed to transform the binary digits (“bits”) development was led by AT&T Bell Labs, turned human into a more voice-like signal. This led to the invention of voice into digital bits which were encrypted before being Examples of modems for specialized commercial applica- the “modem” which uses the information bits to control fed to a modem and transported over the network. At the tions include: (“modulate”) a signal suitable for the telephone network receiving end, the signal was turned back to bits, unscram- at the source of the data, and turn that signal back into bled, and converted back to voice. A SIGSALY system • Evolving from telegraph-based systems, the teletype- bits (“demodulate”) at the destination. In true geek fash- ran over special connections, used 40 racks of electronic writer took text entered by a typewriter-like keyboard ion, engineers soon shortened the name of this device to equipment, weighed over 50 tons, and consumed about at one location and reprinted it out at another. Classic “modem.” 30 kW of power! Later versions of “secure (voice) terminal uses included news distribution, speeding sales orders units,” such as STU-III (1987) which used echo cancella- to manufacturing plants or warehouses, and hotel / air- tion based modems to provide high speed connections line reservation systems. Starting in the late 1950’s, AT&T over ordinary phone lines, were about the size of a phone developed a progression of modems such as models 28, answering machine, weighted a couple of pounds, and 101, 402 A/B/C/D for teletypewriters with transmission The copper wires of the phone plugged into ordinary electrical outlets. Digitizing voice for speeds of 300 bps. While most of these units worked network were designed to encryption / transmission is now the standard operation over “private line” connections, dial-up connections us- carry the human voice, not of ordinary cell phones. ing a special private switch were also supported. the “ones and zeros” used by In the early 1950’s, the need to defend against enemy digital devices. bombers and missiles led to creation of radar “warning lines” across Canada and the U.S. coast lines. Data from these radar installations were digitized and transmit- DEW Line, Canadian Arctic (1956) ted using modems to central “SAGE” (“Semi-Automatic Photo courtesy AT&T Archives and History Center

94 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 95 directions simultaneously; they also included a 110 bps subchannel which was used for testing and configuring Modem Terminology remote modems. These were AT&T’s first micropro- cessor-based modems which made extensive use of Simplex A transmission mode where data is sent in Error Rate The rate at which a demodulating mo- Private Line Private lines were hard-wired connec- integrated circuits. Later models running at 14,400 and only one direction. dem incorrectly identifies the received signal. Errors tions between (or among) fixed endpoints. They can 19,200 bps were introduced. can be caused by various kinds of electrical “noise.” be thought of as a pair of wires from one location to Half-Duplex A transmission mode where data is The most common error measure is the “bit error another. They are not sent through telephone voice Consumer Data Applications sent in both directions but only in one direction at a rate” which is calculated by dividing the number of switches which may add noise to the signal. It was The availability of reasonably priced personal computers time. bits received in error by the total number of bits possible to lease “conditioned” private lines which and the spread of the Internet led to the general public’s sent. When transmitted data are segmented into were guaranteed to meet specific transmission quality desire for data connections. In the late 1980’s many homes Full Duplex A transmission mode where data is sent groups of bits (blocks), the “block error rate” may standards. added a second standard phone line for internet access. in both directions simultaneously. better reflect the efficiency of the transmission. The Initially the only method of getting to the internet used block error rate is calculated by dividing the number Multipoint Connections made between one fixed end- relatively inexpensive but slow (300 to 1200 bps) modems. Bit Rate The number of bits per second that are of blocks containing errors (which requires the en- point (the “central site”) and more than one other fixed Advances in integrated circuit and manufacturing tech- being sent/received at a point in time. tire block to be retransmitted) by the total number endpoints (the “remotes”). Multipoint connections were nologies quickly lowered the cost and raised the speed of of blocks sent. often set up between a bank’s computer center and a dial-up connections. AT&T’s Dataphone II line of switched Baud Rate The number of times the modem signal number of remote branches. network modems included the 2224 (1988; 2400 bps), the changes per second. Each signal change is called a Dial Up Line A connection made over the standard 2248 (1988; 4800 bps) and the 2296 (1989; 9600 bps). These symbol. Depending on the modulation technique telephone network where the destination endpoint Signal-to-Noise Ratio The “SNR” is a measure of the modems used echo cancellation to provide high-speed being used, a symbol can represent one or more one is specified by the number dialed at the originat- quality of the connection. It is measured at the receiv- data transfer in both directions simultaneously. Addition- bits. For example, if a signal can take on one of four ing site. Modem signals made on dial up lines go ing (demodulating) modem. It is calculated by dividing al advances in modulation techniques, specialized signal states, each signal state (symbol) represents two through telephone switches which can add noise the energy level associated with the signal transmitted processing chips, and methods quickly bits (00, 01, 10, 11). The bit rate is equal to the symbol and other impairments which ca limit the bit rate. by the sending modem by the level of any other energy led to ever higher speeds: 14,400 bps (14.4 kbps) in 1991, rate multiplied by the number of bits per symbol. seen at the receiving modem. A higher SNR indicates a 28.8 kbps in 1994, 33.6 kbps in 1996, and 56 kbps in 1998. Point-to-Point Connections made between exactly better transmission path which results in a lower error Advances in integrated circuit technologies eventually led two endpoints. rate and a more efficient data transfer. to these modems becoming just a card inside a personal computer and, later, just a chip or two on the main com- puter board.

Fax Transmission and International • Starting in the early 1960’s, AT&T developed a series of 602A fax modem in 1963; that system took 6 minutes to Voiceband modems for general commercial applications Standards “Touch-Tone” transmitters and receivers. These were transfer one page over dial-up connections! The coming originated in the late 1950’s and advanced in speed and In the time before wide-spread e-mail, fax machines used for signaling between customer phones and a of inexpensive large scale integrated circuits enabled capabilities over the next 40 years. Some of the notable provided an efficient and timely alternative to overnight telephone switch as well as between switches within the faster page scanning, compression of images and faster models include: envelope shipping and the postal services. The name “fax” network. An expanded Touch-Tone product, with 16 keys modem speeds, all of which shortened page transmis- is the nickname for facsimile transmission, where text instead of the typical 12, was used for certain military sion times to a few 10’s of seconds by the mid-1980’s. • Developed in 1959, the Bell 101 modem ran at 110 bps – pages and some types of images are transmitted over and network control functions. about 10 characters a second. phone lines with sufficient fidelity to fulfill their purpose • In 1965 AT&T introduced the model 603 modem which • Introduced in 1961, the 201A/B transmitted at 2400 bps (a “reasonable facsimile” of the original). Court rulings was used to send electrocardiogram information over in one direction on private lines. that a signature received by fax remains legally binding dial-up connections from hospitals or doctor offices to • In 1962, the Bell 103A modem provided 300 bps over encouraged widespread adoption in the business sector, specialists. dial-up connections. and this aspect (combined with near immediate delivery) • The transmission of images (pictures or text) over • The invention of adaptive equalization in 1968 allowed is a key reason why fax transmission is a feature still found distances, today known as a fax (facsimile) began in the Bell 203A modem to operation at 4800 to 9600 bps in many devices. But how did we reach the point where all the mid-1800’s. Until the mid-1900’s fax machines were over private lines. the operations required to send a page work seamlessly large, expensive, and slow. AT&T introduced the model • By 1976, the Bell 212A modem provided 1200 bps simulta- between any two fax machines? The answer is Interna- neously in both directions over dial-up connections. tional Standards for facsimile transmission, first agreed in • In the late 1970’s, AT&T introduced a new line of “diag- the mid-1980’s. The standards included protocols for ma- Dataphone 608D Portable, Acoustic Coupled Modem (1966) nostic” private line modems named “Dataphone II.” The chine identification and capability negotiation, modem se- Photo by Michael Mills initial 3 models ran at 2400, 4800, and 9600 bps in both lection and control, and methods to select page scanning

96 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 97 The 5G Future for Business

Dataphone Facsimile (c. 1966) We expect 5G will offer businesses so much more than just faster speeds. 5G will unlock Photo courtesy AT&T Archives and History Center experiences of the future like Augmented Reality and Virtual Reality. Not only will 5G modernize businesses, it will disrupt entire industries.

We also expect 5G will help handle massive device connectivity in the Internet of Things (IoT). 5G’s ultra-reliability will help industries that use robotics, like healthcare and manufacturing. 5G’s ultra-low latency will be essential for real-time applications, like gaming and live maps for connected cars. More connection points in a smaller area – along with using small cells and unlicensed spectrum, will improve capacity – and offer abetter customer experience.

Ultra-Reliability Help first responders and telemedicine, Massive Device as well as industries using robotics like Connectivity healthcare and manufacturing Handle over 30 billion devices connected globally by 2030

resolution and perform , in addition to router, most desktop computers, notebook computers, the standards for data modems. tablets, as well as many printers, digital cameras, wireless headphones, and internet TV devices each have a wi-fi Ultra-Low Latency Better Capacity With world-wide fax adoption brought a series of im- modem. A typical smart phone may have a half-dozen mo- Support real-time applications used & Coverage for gaming and connected cars provements. The first wave of the so-called “Group 3” fax dem functions inside it — for wi-fi, Bluetooth, and several Provide a better customer machines was susceptible to modem transmission errors generations of cellular data standards such as GSM, EDGE, experience with more capacity which could cause a line of text to become un-readable. EV-DO, HSPA, and LTE. Wi-fi and Bluetooth only provide through more connection points in smaller areas. This fostered standards for page quality evaluation and connections within a location; connecting the home router various forms of transmission error-correction in en- to the Internet requires yet another device such as a hanced standards. Other enhancements included sup- “DOCSIS” modem for systems, an optical port for color images, page transmission times of just a modem for light wave “fiber optic” systems, or a digital few seconds, and printer-quality resolution, eventually subscriber line modem (“DSL”) for access over traditional reaching the point where fax machines were like remote copper phone lines. Even satellite TV receivers include a AT&T’s on-going 5G technical trials show real benefits are coming for businesses. printers. very high bit rate modem to demodulate the digitized video streams. „ In June 2017, AT&T launched a second millimeter Wave (mmWave) fixed wireless trial in Austin, TX. Modems Today ■ Customer trial locations in Austin are seeing speeds up to 1 Gbps and latency rates well under 10 milliseconds The standalone dial-up modem, which was ubiquitous But as modems have proliferated, they have also disap- at the radio link. at the start of the Internet era, has largely disappeared. peared from view. Advances in integrated circuits and Modems, however, are far from extinct; in fact the number signal processing techniques have allowed functions „ mmWave fixed wireless trials are also on-going in Indianapolis, IN and are expanding to include Waco, TX; of modems in active use today vastly exceeds that of even that once took multiple circuit boards (or even most of a Kalamazoo, MI; and South Bend, IN. 20 or 30 years ago. Consider the number of wi-fi enabled room!) are now implemented on just a small portion of an devices found in typical homes. In addition to a wireless electronic chip.

98 | AT&T SCIENCE & TECHNOLOGY INNOVATION

© December 2017 AT&T Intellectual Property. All rights reserved. Putting Together All the Pieces for

a New Idea Can Take Time Oki Model CS-1 1983

Cellular Phones Motorola Ultra Classic 1989 By Byoung-Jo “J” Kim AT&T Model 3045 “bag phone”

The “cell” in ‘cellphones’ or ‘cellular coverage area using many smaller 1994 networks’ reflects the shape of over- cells remains the foundation of mod- lapping areas of radio signal cover- ern cellular networks. In his memo, age provided by many radio signal Ring credits the origin of the hexag- In 1947, the same transmit/receive towers over a large onal layout to W.R. Young, describing year the transistor area, as in numerous biological cells it as the most efficient layout for was invented, covering the skin of a leaf. In 1947, covering a flat surface. This is in fact the same year the transistor was the same reason that this pattern is

Doug Ring’s cellular invented, Doug Ring’s cellular con- frequently found in nature, such as in Motorola StarTAC concept memo cept memo [1] was shared inside Bell skin cells, bee hives, and crystalline Labs. This was 32 years before the structures. Besides the grid layout, 1996 was shared inside cellular concept was described in the Ring describes frequency reuse and Bell Labs. special cellular issue of the January, call handoff among adjacent cells, 1979 Bell System Technical Journal where cellphones (mounted in cars Nokia 3360 [2] and 36 years before the first com- then imagined) would travel beyond mercial became op- the coverage of one cell. These 2000 erational in Chicago in October 1983. aspects are the three pillars of a The idea of providing a larger signal cellular network, being continually RIM Blackberry 6710 2002

Bell Labs Engineers Test Motorola RAZR Car Phone (1977) Photo courtesy AT&T Archives and History Center 2004 Apple iPhone 2007

Photos courtesy AT&T Archives and History Center and Michael Mills

100 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 101 Douglas Ring (1948) Photo courtesy AT&T Archives but took another 36 years to be and History Center realized. The successive introduction and expansion of cellular technology its integration into everyday life and business has driven the expansion of 1994, providing more portability than capabilities: SMS (Short Messaging a car-mounted system. Service), Internet access over limited data capabilities of 3G, smartphones The 2nd generation digital voice and their huge demand for data phones were much smaller and capacity to name a few. Each “next cheaper, mainly due to lower pow- generation” of wireless technology er consumption enabled by digital spurs the imagination of the users to transmission formats, such as the greater demand for mobile commu- low-cost Nokia 3360 Cellular Phone, nications. The latest 5th generation the ‘small-is-better’ Motorola is projected to explode with IoT StarTAC, and the most well-known usage which will move our world refined through the 5 generations “fashion phone” Motorola RAZR. The from communications anywhere of technological stages. 5G currently Motorola RAZR was a 3rd generation to communications anywhere with being developed by AT&T and many wideband cellphone. anything. other entities around the world. Given birth during the 3rd gener- References Since the cellular networks are only ation of cellular technology, the [1] Doug Ring, “ – Wide indirectly experienced by consumers iPhone transformed the whole Area Coverage,” Bell Laboratories Technical through their cellphones (and nowa- industry with the popularization of Memoranda, 1947 days through mostly smartphones), the smartphone, whose potential [2] V.H. MacDonald, “Advanced Mobile the phones mark more tangible was glimpsed earlier through the Phone Service: The Cellular Concept”, Bell System Technical Journal, Vol 58, No. 1, milestones in the public’s mind. Blackberry. January, 1979, pp. 15-41.

All first-generation cell phones were The concept for communications analog voice phones, most were anywhere first crystalized in 1947 car-mounted. Analog signals were in Ring’s internal memo — “Mobile used to carry the voice via FM type Telephony — Wide Area Coverage”, modulation. Starting with the 1st generation cellular networks, the control signals were already digital. Successive miniaturization leads to cellphones like the Motorola Ultra Classic” Cellular Phone, [ca. 1989] and AT&T 3045 Cellular “Bag” Phone,

Drawing from D.H. Ring’s 1947 paper about providing mobile telephone service Drawing courtesy AT&T Archives and History Center

102 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 103 Project AirGig™ The Promise of Broadband Everywhere by Paul Henry

Project AirGig™ is a transformative deployed. This means connected ex- technology that could one day de- periences become an everyday real- liver low-cost, multi-gigabit wireless ity — regardless of location. Almost Low-cost, Pole-mounted Installation for Project AirGig™ Illustration by John MacNeill Internet speeds using ordinary pow- unique among technological advanc- multi-gigabit The regenerator and inductive power supply are housed in an egg that snaps over the medium- wire. er lines. Now in the trial phase, the es, Project AirGig™ represents the wireless Internet The 5G wireless equipment is mounted on the top of the utility pole. hope is that this technology will be opportunity for a single infrastruc- easier to deploy than fiber, can oper- ture to serve two distinct, non-com- speeds using ate over license-free spectrum and, peting industries — telecommunica- ordinary power in conjunction with 4G-LTE and 5G tions and power utilities. It operates cellular services, expected to deliver over existing electric power lines, but lines. broadband connectivity to homes utilizes extremely high frequency and mobile or handheld wireless millimeter waves rather than con- devices wherever there are power ventional 60 Hz alternating current. lines — whether urban, rural or un- derserved parts of the world. Project AirGig™ delivers this last-mile access without any new fiber-to-the-home; it leverages the electric power grid, an infrastructure that’s already been

5G Wireless Drop to Neighborhood Inductive Power and mmWave Surface Wave Coupler

104 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 105 Walking or driving down the street, the user’s device connects automatically and wirelessly with nearby Project AirGig™ equipment

More than a decade ago, AT&T (mmWave) technology — a region a practical way. The challenges were The first experiments were a skunk- the attention of higher manage- Wireless Link to Mobile Unit and Wireless Drop to Residence Labs engineers had worked on of extremely high radio frequencies many. If a viable system was going works initiative involving just a hand- ment, especially Henry “Hank” Kafka, Illustration by John MacNeill experiments to deliver broadband (roughly 30 GHz and above), where to be built (if it was even possible!), ful of engineers — strictly off-the- an engineer himself, who secured over power lines (BPL). Back then, bandwidth, and therefore data every aspect of the technology — books. Their rudimentary apparatus the funding needed to support a broadband meant merely megabit traffic capacity, was plentiful and mmWave characterizations and transmitted data signals using plas- deeper look into this new technolo- speeds. The technology worked licensing requirements were mini- inductive power supplies, to name tic funnels from a local auto parts gy. Thus was Project AirGig™ born. well, but couldn’t keep up with Inter- mal. They were intrigued with the a few — would need to be created store covered with aluminum foil, Addressing myriad technical chal- net users’ demands for higher data possibility of uniting mmWave tech- from scratch. There were no engi- placed next to unenergized power lenges, the Project AirGig™ team rates. So engineers shifted their nology with power lines, which no neering guidelines, no handy how- cables. These tests produced unex- created a stream of innovations as focus from BPL to millimeter wave one up to that time had achieved in to manuals. pectedly positive results, and caught they staked out new territory. Since

106 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 107 a remote antenna some distance A key feature of Project AirGig™ is its support away. of the recognition by utility companies that Lastly, a key feature of Project they need to evolve toward the “smart grid.” AirGig™ is the collaboration with Our Contributors utility companies as they evolve toward the “smart grid.” The data it was expected that Project AirGig™ Wide scale deployment of 5G cellu- required by the power company would be widely deployed, cost con- lar technology — the key to ubiqui- for real-time management of its siderations were paramount. Devel- tous multi-gigabit wireless connec- power-line network can use Project oping a technology capable of high tivity — will require a dense network AirGig™ capability already in place Sheldon Hochheiser performance and reliability while of small cells, cells far smaller than on those same power lines. This Sheldon Hochheiser is AT&T Corporate Historian and manager of the AT&T also achieving low cost made the the familiar ‘macro-cells’ used on enables a wide variety of smart-grid Archives and History Center facility in Warren, New Jersey. Sheldon joined the engineering task especially daunt- today’s cellular deployments. This applications, such as support for AT&T Archives as a historian in 1988. He has been studying the history of AT&T ing. Particularly challenging was the ‘densification’ requires a cost-effec- utilities’ meter-reading, appliance and U.S. telecommunications ever since, and is the world’s leading expert on design of the signal regenerator, the tive approach to connecting these and usage-control systems, as well the company’s history. Sheldon holds a Ph.D. in History of Science from the device that attaches to the power small cells into the national broad- as detection and pinpointing the University of Wisconsin — Madison, and a B.A. in Chemistry-History from Reed line and boosts the signals as they band network. Project AirGig™, location of power-line disruptions, College. In addition to his years at AT&T, Sheldon has served on the faculties of travel on their way. The engineers which leverages the ubiquitous such as encroaching tree branches Rensselaer Polytechnic Institute, the University of Minnesota, and the Stevens devised a unique inductive coupler power-line grid, is ideally suited to or actual line breaks. Institute of Technology, and as a historian for the Rohm and Haas Company that could power the regenerator by this task. By reducing the need to and the IEEE. Sheldon is an active member of the Society for the History of extracting energy from the magnet- deploy new optical fiber, Project Air- In conjunction with power compa- Technology and the Business History Conference. ic fields created by the alternating Gig™ becomes even more economi- nies, AT&T is now conducting trials current in the power line itself. Other cally attractive. of Project AirGig™ to demonstrate noteworthy innovations included its high-speed capability and reli- Dan Gruspier inexpensive plastic antennas and To provide multi-gigabit 5G service ability under actual field conditions. Daniel Gruspier is a high school senior at the Academy of Allied Health and an overall packaging concept called in less-populated areas, where a Many lessons will be learned and the Science. He was an intern at AT&T Labs in Middletown during the an “egg” that allowed a complete dense array of small cells is neither details of the system that emerges 2017-2018 school year. regenerator to be packaged into a needed nor cost-justified, Project may well be substantially different small, footballshaped split plastic AirGig™ will employ a Radio Distrib- from the ones under trial. But of container. A unique hinged design uted Antenna System (RDAS), an one thing we can be confident: Proj- Leon Lubranski allowed it to be easily snapped over innovation that extends the reach ect AirGig,™ coupled with 5G cellular Leon Lubranski is a member of the Architecture and Design the power line, thereby reducing of the pole-mounted 5G cellular technology, has opened the door to Organization. His activities during his career with the Labs has included the installation costs to a minimum. To radio transceiver. Rather than rely- the possibility of broadband Inter- design of integrated circuit packaging, supporting the delivery of both domes- date, there are close to 300 patents ing solely on transmitting wireless net connectivity for nearly everyone tic and international communications services, and systems engineering for or filed patent applications related signals directly from the transceiver, served by an electric utility. Where wireless transport. Prior to joining AT&T he worked in the defense industry to Project AirGig.™ RDAS transports a replica of the this technology is deployed in the where he had responsibility for structural, vibration, and thermal analysis for signal over power lines and then future, if power is available. naval vessels and aircraft electronic systems. The connection from the utility reconstructs and radiates it from pole to the end users – the “drop” in telecommunications parlance — is To provide multi-gigabit 5G service in Doug Olsen achieved wirelessly using 4G-LTE Doug Olsen is an accomplished telecommunications professional with 30 years or 5G cellular technology. Whether less-populated areas, where a a dense array of engineering experience. His current role is Principal Member of Technical the user is “fixed” — at home or in of small cells is neither needed nor cost- staff in the AT&T Labs Middletown, NJ complex where he is a member of the the office — or mobile — walking or D2.0 Packet Optical Network team. Doug is one of the lead network design driving down the street, the user’s justified, Project AirGig™ will employ a Radio engineers for AT&T’s Layer 2 transport network called IPAG or IP Aggregation. device connects automatically and Distributed Antenna System (RDAS) Doug has his B.S. in Mechanical Engineering from Rutgers University, and his wirelessly with nearby Project Air- MBA in Finance from St. Johns University. Gig™ equipment.

108 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 109 Kathy Tse Tom Willis III Kathleen Tse has worked on a number of major photonic transformations in Thomas Willis graduated in 1987 with a Ph.D. in Electrical Engineering specializ- AT&T’s network. Her current role at includes developing strategy for next gen- ing in electromagnetics from the University of Michigan. His graduate studies eration photonic technologies including metro and long-haul technologies, and at Michigan were supported under an AT&T Ph.D. Fellowship. After graduation, she leads a small team of engineers across the country. Kathy received a PhD he came to work at AT&T Bell Laboratories in Holmdel, NJ. He currently works degree in Engineering from Brown University and a BSc From Cornell University. in the area of microwave wireless communications at AT&T Laboratories in She received AT&T’s Medal of Science and Technology for her work on AT&T’s Middletown, NJ. His most recent assignment has been on Project AirGig™. ULH backbone. Mike Neubelt Zoe Goodman-Frost Michael Neubelt received his B.S. degree in electrical engineering from the Zoe’s career at AT&T spans 32 years. During this time, some of the projects she University of Connecticut, Storrs, CT, USA. He is a Principal Member of Techni- has been involved in include the development of fiber optic based biosensors, cal Staff at AT&T Research & Development Labs, Middletown, NJ, USA where laser beam propagation through the atmosphere, technology analysis and cer- he works on the design, development and deployment of International DWDM tification for the AT&T Network, and Mobility Gateway architecture and design. networks. Prior to joining AT&T he spent 24 years working in aerospace re- After 9/11, she served on a team doing consulting work for the Department of search on fiber optic gyroscopes and in telecommunications research on ultra Defense and Homeland Security. She is currently working on Project AirGig™. long- haul transmission for undersea fiber optic networks. In his spare time, he Zoe has a doctorate in physics from Yale University, is married with a daughter, raises puppies for the Morristown Seeing Eye, coaches high school sailing and is and plays the cello. a scout leader in the Boy Scouts of America. He and his wife, Melanie, raised five children and reside in New Jersey. Elisabeth Patterson Elisabeth Patterson has worked in the Telecommunications industry since 1990, Ken Reichmann as a writer, instructional designer, project manager and instructor, including Kenneth (Ken) Reichmann holds a B.S. in physics and a M.S. in electrical engi- teaching overseas and training military instructors. Since 2011 she has support- neering. At present, he is a Principal Member of Technical Staff in the Access ed AT&T Cloud services, including CaaS and AIC. She holds a B.A. from Yale Uni- Architectures and Devices department at AT&T Labs, concentrating on broad- versity and a Masters in Technology Management from the Stevens Institute of band wireless technologies. Prior to this, he was an experimental researcher in Technology. She and her husband, George, live in Middletown NJ. the areas of optical communications for residential and business access, metro transport and cellular backhaul. Ken is the author of over 130 peer-reviewed Byoung-Jo “J” Kim publications and has 45 patents to his name. He has been a speaker, a technical Byoung-Jo “J” Kim (IEEE S’93 – M’98) received his B.S. from Seoul National sub-committee member and chair for major conferences University, Korea in ‘93, M.S. in ‘95 and Ph.D. from Stanford University in ‘97 all and remains a technical journal reviewer. Ken is a Senior Member of the IEEE. in Electrical Engineering. He had worked and consulted for several wireless start-up companies in the Silicon Valley before joining AT&T Labs-Research Beatriz Ugrinovic in ‘98. One major theme of his work is to combine the advancement of wire- Beatriz Ugrinovic is an LMTS at AT&T Labs, in the Wireless Network Architecture less systems research from Electrical Engineering and that of mobile systems and Design organization. She joined Bell Labs in 1986 as an MTS in the Network research from Computer Science. His recent interests cover 5G, LTE, radio Operations Systems Planning Group and became Director of the International propagation, multi-interface/domain mobility, security, radio resource instru- Network and Private Line Development District (2000 to 2014), responsible for mentation/management, next-generation cellular network architecture, and designing the architecture for AT&T’s Layer 1 Network for Asia-Pac and Latin related industry standards. He maintains both eternal hope and heightened America. Beatriz studied Electronics Engineering at the Universidad Mayor de skepticism towards bold claims of major breakthroughs in his and other fields San Andres, in La Paz, Bolivia, and obtained her MSc degree in Electrical Engi- of knowledge. neering from the University of Texas at Austin, in 1984.

Tony Hansen Magda Nassar Tony Hansen is a graduate of Stanford University and South Dakota State Magda joined Bell Labs in 1982 and continued her career in AT&T R&D until her University, in computer science/engineering, electrical engineering and mathe- retirement in 2017. As an Assistant VP, Magda was responsible for the design of matics. He is a software engineer, martial artist, author, maker, genealogist, avid the VoIP core network infrastructure and VOIP services. Most recently, Magda reader, and a student for life. He has about a dozen Raspberry Pis and micro led the VOIP Network infrastructure virtualization. Earlier in her career Magda controllers performing various tasks, multiple 3D printers, lots of power tools, led the planning of AT&T SS7 signaling and switching for Intelligent Services. and loves the smell of solder. He still prefers using the command line for many Magda Played a key role in the development of the AT&T Global Network Oper- things. ation Center. Magda holds a PhD and an MS in EE from Case Western Reserve University, Ohio. She received her B.S. in EE from Cairo University, Egypt.

110 | AT&T SCIENCE & TECHNOLOGY INNOVATION AT&T SCIENCE & TECHNOLOGY INNOVATION | 111 Samantha Lelah Samantha Lelah, a student from Rowan University, interned during the summer of 2017 at the Bedminster location under the Andre Fuetsch organization. She is interested in pursuing a career in communications and hopes to obtain some Golden Boy freelance article writing opportunities in the future as well. Samantha enjoys all types of research and especially liked exploring AT&T’s extensive past with Commissioned by AT&T President Theodore N. Vail in 1916 and originally called the technology “The Genius of Electricity,” its purpose in 1916 was to express the power of electricity and service to humanity worldwide. With three 12K Volt power lines in his right hand Dave Hayward and bolts in his left, he was second only to the Statue of . He was first Dave Hayward joined AT&T Bell Labs in June of 1978 and has worked in some located at AT&T’s headquarters at 195 in NYC. In 1930 he was renamed part of AT&T since then. His first project at the labs was developing software “The ” and now resides in our Dallas headquarters. for Dataphone II modems. Over the years he contributed to many products and services including phone systems for small businesses, secure voice tele- phones, high speed networking multiplexers, credit card processing networks, integrated voice/data access services, voice over IP networks, and integrated circuits for modems. Dave has bachelor’s and master’s degrees in electrical engineering from The Cooper Union and Rensselaer Polytechnic Institute, and holds several patents. He and his wife, Laura, live in Lincroft, NJ where they raised their four children.

Al Morton Al Morton is a Lead Member of Technical Staff at AT&T Labs, Middletown, New Jersey. He has been a chairman and recognized contributor in US and Interna- tional network performance standards committees for more than 25 years. He authored or co-authored more than 31 IETF RFCs, and is a committer on several Linux Foundation projects. He has worked at Bell Labs, the U.S. Army Satellite Communications Agency, and Computer Sciences Corporation. Al spends his spare time making and enjoying music with friends and family on the New Jersey Shore and Chicago, Illinois.

Sal Talamo Sal Talamo started his career with AT&T in June of 1985, initially performing certification for Dataphone II modems. He has contributed to numerous AT&T product and service offerings spanning modems, DSUs, high speed networking multiplexers, integrated voice/data access services, voice over IP networks, soft- ware defined networking and network function virtualization. He has led tech- nical planning teams and engineering and development for AT&T’s network. Sal completed his B.S. and M.S. degrees in Electrical Engineering from the NYU School of Engineering. He and his wife, Donna, live in Matawan, NJ with their two children.

Paul Henry Paul Henry, a Fellow of AT&T and IEEE, joined AT&T (Bell) Laboratories imme- diately after receiving his Ph.D. in physics from . He has published papers or patented inventions in several fields, including millime- ter-wave radio techniques, cosmology, wireless systems, optical communica- tions and data security, as well as serving as a Technical Editor of IEEE Commu- The Genius of Electricity (1966) Photo courtesy AT&T Archives and History Center nications Magazine and Guest Editor for the Journal of Lightwave Technology. Dr. Henry’s current research emphasis is on circuits and systems for broadband Internet connectivity to homes and businesses.

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