Communications Technologies
History of Communications Technologies, 1952-2002
Communications Before 1952
The inauguration of commercial telegraph service (by William Cooke and Charles Wheatstone in England in 1839 and by Samuel Morse in the United States in 1844) was the first major technical undertaking using electricity. From a technical standpoint, the most important attribute of the telegraph was its instantaneous operation across vast distances; it was the first technology to sever the transmission of information from the physical movement of goods or people. From a social and cultural perspective, the rapid spread of the telegraph network throughout the globe showed that rapid and dependable communication was indispensable to modern life. The subsequent history of communications has continued these two trends: on the one hand, engineers have worked to make communications more rapid, reliable, and affordable; on the other hand, communications networks have become a necessary and vital infrastructure of modern society.
By the early 1850s overland telegraph lines spanned much of Europe, North America, and the Middle East. At this time electricians in England and the United States began to consider ways to connect the continents by means of submarine cables. In 1851 England was permanently connected to continental Europe by means of a cable laid between Dover and Calais, France. The Atlantic cable was a joint Anglo-American project. After failed attempts to lay a cable in August 1857 and the spring of 1858, a working cable operated for about a month in the summer of 1858. Its failure, due to high voltages used in the signaling equipment, was not unusual. By 1861 entrepreneurs and governments alike had laid some 18,000 km of cable around the world, of which only 5,000 km actually worked. The American Civil War delayed a new attempt until 1865, but in 1866 the Anglo-American Telegraph Company permanently spanned the Atlantic Ocean with the successful laying of two cables. By the turn of the century cables connected every continent except Antarctica and spanned every major body of water.
Submarine telegraphy was the premier engineering project of the 1850s and 1860s, and it led to many fundamental advances in shipbuilding, cable construction and laying techniques, and even oceanography. It also revolutionized electrical engineering and placed it on a firm scientific footing. From a communications engineering standpoint, the major difficulty with submarine telegraphy was the attenuation and dispersion of signals passing through long cables. Dispersion due to the intrinsic capacitance of the cable especially limited the speed of long cables to just a few words a minute. William Thompson (later Lord Kelvin) was the first electrician to study systematically this phenomenon. In a paper published in 1854 Thompson borrowed Fourier's equations governing heat transfer to model the transmission of electrical signals through a long submarine cable. To do so, he decoupled the signal (the telegraphic pulse) from the medium (the cable), an insight which allowed him to optimize the dimensions of the cable conductor and insulation and to devise telegraphic sending and receiving equipment to shape and detect the pulses. In the same way Claude Shannon's work on information theory would be nearly a hundred years later, Thompson's decoupling of signal from medium was a conceptual revolution: it was the theoretical basis for much subsequent work in communications and signal processing.
The next major advance in communications, the telephone, was a direct outgrowth of electricians' efforts to increase the message-handling capacity of telegraph lines. Thanks to the work of Joseph Stearns and Thomas Edison, by the mid-1870s reliable systems existed for the simultaneous transmission of two and four telegraphic signals on a single wire. At this time several electricians began to investigate harmonic telegraphy, or the use of several different tones to transmit many discrete telegraph signals on a single line simultaneously. Alexander Graham Bell and Elisha Gray of the United States both realized that, if a telegraph line could convey several musical tones, it could also transmit human speech. In early 1876 Bell had the good fortune to file his patent just a few hours before Gray filed a caveat for his. The telephone quickly caught on for local service, and by 1880 the Bell Company had leased nearly 100,000 instruments.
The two major technical problems of early telephony were switching and long-distance transmission. At first, human operators, usually women, connected calls manually. However, this was slow and labor-intensive. In 1889 Almon B. Strowger, a Kansas City undertaker, patented an automatic dialing system. Strowger's system was quite successful, and was first installed in 1892. It continued to be used in many American and European cities as late as the middle of the 1970s.
The second major technical problem, long-distance transmission, was a much more daunting issue requiring several decades of research and development. Long-distance telephony posed a problem similar to that of submarine telegraphy: attenuation and dispersion degraded signals rapidly with distance. A copper wire pair could transmit intelligible speech for about 100 miles, but beyond this distance line losses and distortion due to the intrinsic capacitance of the line rendered speech unintelligible. Thus, successful long-distance telephony required two major engineering advances: inductive loading (to counteract line capacitance) and amplification. In 1900 George Campbell of AT&T and Michael Pupin of Columbia University filed patents describing a method of inductively loading a telephone line. Since the patent situation was unclear, AT&T bought Pupin's patent for an immediate cash payment of $185,000 plus another $15,000 per year during the seventeen-year life of the patent. The advantages of periodic loading were quite significant. Because it substantially reduced dispersion, it made possible the operation of a 4,300 km line from New York to Denver in 1911.
However, this represented the limit through which an unamplified telephone signal could travel. Greater distances awaited the development of electronic amplifiers. Around the turn of the century the British scientist Ambrose Fleming devised an electronic "valve," or diode vacuum tube, which proved useful as a radio detector. Lee de Forest of the United States placed a third electrode between the cathode and anode, and this device, the triode, became the fundamental building block of both amplifiers and oscillators. Within a few years electronic amplifiers had become reliable enough to enter telephone service, and in 1915 AT&T built a transcontinental telephone line between New York and San Francisco.
While technical advances such as inductive loading and electronic amplification were important, perhaps the greatest lasting significance of long-distance telephony was that it led to a permanent and sustained research and development effort at AT&T. Throughout much of the twentieth century, AT&T's Bell Laboratories ushered in many fundamental advances in electrical engineering and the physical sciences, including negative feedback, active filters, control theory, carrier transmission systems, semiconductor electronics, information theory, and even radio astronomy. Thus, the inauguration of fundamental corporate research and development may be the most important legacy of long-distance telephony.
The development of electronics after the turn of the century made possible another advance in communications engineering: radio. Radio had its origins in the work of the celebrated British physicist James Clerk Maxwell during the 1860s. Maxwell's equations remained just an elegant mathematical formulation until 1888, when the young German physicist Heinrich Hertz demonstrated the generation and detection of electromagnetic radiation in the laboratory. During the early 1890s, scientists in several countries experimented on electromagnetic waves. One of these researchers was a young Irish-Italian named Guglielmo Marconi. Marconi introduced his wireless signaling apparatus in 1896, and within a few years he could transmit over distances of several hundred miles. In December 1901 Marconi spanned the Atlantic, receiving in Newfoundland signals transmitted from England.
Early radio equipment depended on cumbersome transmission and reception techniques. It was difficult to tune precisely transmitters and receivers, and the presence of many transmitters generated a great deal of troublesome interference. However, in 1908 Lee de Forest patented a three-element vacuum tube, or triode, which made possible more precise transmission and reception of radio signals. Edwin Howard Armstrong, perhaps the greatest electrical engineer of the early twentieth century, used de Forest's triode to develop oscillator circuits which enabled the transmission of a continuous carrier wave at a sharply defined frequency and amplifier circuits which increased both the selectivity and sensitivity of receivers.
Until the rise of broadcasting after 1920 the major application of radio was for wireless telegraphy. At the beginning of the 20th Century, three maritime disasters, and the varying effectiveness of rescue operations coordinated by radio proved its worth. In January 1909, radio distress calls from the White Star liner Republic, which had been holed by a collision in fog with the passenger liner Florida, allowed the Baltic to rescue all 1,650 people aboard in a brilliant display of seamanship. In April 1912 the new luxury liner Titanic struck an iceberg and sank; of the 2200 passengers and crew, only about 700 were rescued. Many more lives would have been saved had nearby ships maintained a round-the-clock radio watch. In October 1913 another passenger liner, the Volturno, caught fire in the mid-Atlantic. Her distress call brought ten ships to the scene, and all passengers and crew were saved. The use of wireless equipment during the First World War was a further demonstration of the utility of the new technology.
A new -- and quite popular -- use of radio came about a few years after these maritime disasters. In 1916 Frank Conrad, an amateur radio enthusiast and Westinghouse engineer, began regular broadcasts of music from his Pittsburgh home. Other amateurs in the area were able to tune in his "wireless concerts." Westinghouse realized that there existed a vast potential market for broadcasting and on 2 November, 1920 the company established the first commercial radio station KDKA. By 1923 more than 500 stations were on the air, and by 1929 there were over 4 million radio receivers in use in the United States. In 1933 Edwin Armstrong invented frequency modulation, a transmission technique which greatly reduced fading and static. By 1940 Armstrong had set up an FM broadcast network in the northeastern United States, using the 42-50 MHz band.
World War II brought another advance in electronics technology which would eventually be applied to communications: radar. The British physicist Sir Robert Watson-Watt introduced the first practical radar system in 1935, and by 1939 the British military established the "Chain Home" network of radar stations to detect air and sea aggressors. In the same year two British scientists, Henry Boot and John T. Randall, developed a significant advance in radar technology, the resonant-cavity magnetron. The magnetron was capable of generating high-frequency radio pulses with large amounts of power, thus permitting the development of microwave radar. In September 1940 the British military decided to share its radar technology with the United States. The Americans moved quickly and opened the Radiation Laboratory at MIT under the leadership of Lee DuBridge. Radar proved crucial to the Allied war effort, and by 1943 the Allies were using radars for early warning, battle management, airborne search, night interception, bombing, and anti-aircraft gun aiming. Wartime radar work yielded important peacetime dividends, especially in the fields of television, FM radio, and VHF and microwave communications. Radar itself made all-weather air and sea travel routine. And today most kitchens in the developed world boast a cavity magnetron, usually used for warming up leftovers.
1952-1965
As the story of radar suggests, the war and the immediate post-war period led to many far-reaching advances in electronics and communications. The year 1948 was noteworthy for two major developments, the invention of the transistor by Bardeen, Brattain and Shockley around the beginning of the year, and the publication of Claude Shannon's seminal paper "A Mathematical Theory of Communication." It is noteworthy that all four researchers worked at Bell Laboratories. These two advances laid the foundations for subsequent developments, including undersea cables for telephony, communications satellites, and the beginnings of digital and data communications.
In 1956 the Bell System and the British Post Office inaugurated service on a transatlantic telephone cable, TAT-1. By this time, submarine telegraph cables had been in operation for more than a hundred years and the telephone for eighty years. However, before the installation of TAT-1, the dispersion and attenuation in long cables made the transmission of intelligible speech unworkable. In the early 1930s Bell began a long-range program of research and development to develop a reliable transatlantic cable, and by 1942 the company had a plan for a 12-channel system with repeaters at 50-mile intervals. America's entry into World War Two shelved this effort.
In 1952 Bell and the British Post Office began negotiations for a telephone cable connecting the US and UK. The partners successfully installed the cable and terminal equipment in 1955 and 1956, and TAT-1, capable of transmitting 36 4-kHz-spaced channels, entered service on September 26, 1956. TAT-1 was taken out of service in 1979, having exceeded its 20-year design life. Other cables followed by the end of the 1950s, including TAT-2 between France and Newfoundland and cables linking Alaska to Washington state and Hawaii to California.
Between 1956 and the early 1960s telephone engineers working on submarine cables confronted two major sets of technological problems: minimizing bandwidth and moving to solid-state circuitry. Because the message-handling capacity of the first cables was limited to a few dozen circuits, engineers sought to maximize that capacity by minimizing the bandwidth occupied by each telephone conversation. Bell engineers adopted two methods. The first was to change the channel spacing from 4 kHz to 3 kHz. The 4 kHz spacing used on TAT-1 was adopted because 4-kHz spacing had always been used in the land plant; this permitted the use of inexpensive filtering and modulation techniques. To reduce the bandwidth per conversation Bell designed a multiplex for 3-kHz channels with more complicated circuitry. Although the terminal equipment was more expensive, it was very cost effective when compared with the cost of laying another cable. Most undersea systems installed after 1959 used 3 kHz spacing.
A second method to minimize bandwidth was Time Assignment Speech Interpolation (TASI). TASI was an electronic circuit multiplier used to expand the transmission capacity of telephone lines. It depends on the fact that in a normal conversation the average speaker talks less than 40% of the time. By using fast switches and good speech detectors, the system permits voice circuits to time share a smaller number of channels. TASI equipment was expensive but it was very cost-effective for undersea use. The first TASI system was installed in 1959.
In this period Bell engineers also worked to develop solid-state circuitry for use on long telephone cables. TAT-1 had used a long-life pentode tube for its amplifier, but soon after its installation Bell researchers worked on transistor characterization and the development of amplifier circuits for a new wideband system. Transistor-based systems were installed after 1963.
The next major development in long-distance communications in this period was satellites. Developments in microwave circuitry during and after World War II, particularly waveguides and cavity resonators capable of operation up to 100 GHz, made satellite communications possible. The United States and Soviet space programs began in the mid-1950s, and the Soviets placed the first artificial satellite, Sputnik, in orbit in October 1957. An American satellite, Explorer I, followed Sputnik into orbit four months later. By the late 1950s, then, the two major ingredients of satellite communications, microwave transmission and reception and launch capability, were known quantities. In this period John Pierce (a future IEEE Medal of Honor winner) wrote several articles discussing how a satellite communications system might work. Pierce was a key part of the AT&T team which placed the first communications satellites, Echo I and Telstar, in orbit. In 1960 the world's first communications satellite, Echo I, was launched into a medium altitude orbit. In August of that year engineers successfully communicated across the United States and across the Atlantic Ocean by reflecting signals off Echo I. While Echo I demonstrated that satellite communications was possible, the major drawback of passive satellites was that they required high transmission power to overcome path losses. Indeed, only one part in 1018 of the 10 kW of transmitted power was returned to the receiving antenna. As a result, communications engineers began work on active satellites which could receive and retransmit signals.
The year 1962 was a milestone in the development of satellite communications, and witnessed both the launching of Telstar I and the passage of the Communications Satellite Act. Telstar I, launched on 10 July 10 1962, was the world's first active communications satellite. Unanticipated radiation damage from the Van Allen radiation belt caused it to operate for only a few weeks. However, Telstar 2, made more radiation resistant, was launched on 7 May 1963 carrying telephone channels and one television channel. The Telstar project was an experimental venture and not a commercial system, but it demonstrated the utility and workability of satellite communications. Also in 1962 the United States government recognized the growing importance of satellite communications and passed the Communications Satellite Act. This Act led to establishment of the Communications Satellite Corporation (Comsat), a quasi-public corporation in which both the major communications carriers and the U.S. government were represented. In 1964 Intelsat, an international organization to promote and coordinate the development of satellite communications, came into existence with 100 countries represented.
This period also saw the beginnings of data communication. Modern electronic computing arose as an outgrowth of high-speed calculating projects during World War II. Although computing applications quickly moved into the business world by the early 1950s, the first steps toward communication between computers was defense-related. In 1949 the United States Air Force sponsored development of a computerized electronic defense network called SAGE (Semi-Automatic Ground Environment). SAGE, constructed between 1950 and 1956, coordinated radar stations and direct air defenses to intercept incoming bombers; it consisted of 23 "direction centers" each capable of tracking 400 aircraft. Although the SAGE computers did not communicate directly with each other, the communications technology to connect them was innovative and established a technical base for computer communications for years to come. For example, the first large successful commercial computer network, the SABRE airlines reservation system built by IBM for American Airlines in 1964, owed a great deal to SAGE. The SABRE project also involved many engineers who had worked previously on SAGE. The system used modems to transmit data signals over ordinary analog telephone channels at speeds of about 1200bps. Encrypted military vocoder systems used this same method of interconnection. The increasing importance of sending data via modems on telephone circuits led to a long series of improvements in modem technology and in telephone networks.
In the early 1960s, a shift in thinking about data communications occurred. Two researchers independently realized that traditional circuit switching methods were too cumbersome for use in digital communications. Paul Baran, a young engineer at the Rand Corporation, began thinking about how to build a communications network which could survive a nuclear first strike. In 1960 Baran described a technique he called "distributed communication" in which each communication node would be connected to several other communication nodes. Switching was thus distributed throughout the network, giving it a high degree of survivability. To move data through this network Baran proposed message blocks, which digitized the information to be sent, broke it into chunks of 1024 bits, and provided a header containing routing information. A message would then be reconstructed at the receiving node. Baran described his proposed system in great detail in the summer of 1964 in an eleven-volume Rand publication entitled "On Distributed Communications." In 1965, Donald Watts Davies in Britain independently developed a similar data communication concept to Baran's and developed a more detailed design for a high-speed computer network including interface computers and communication protocols. Davies also coined the terms "packet" and "packet switching" to describe the data blocks and message-handling protocol. Both Baran and Davies thus independently conceived of packet switching as the best means to transfer data in a computer network. A few years later their ideas were incorporated into the ARPANET by Lawrence G. Roberts.
1965-1972
This period saw fundamental advances in three important areas of communications technology: computer networking, satellite communications, and lasers and optical fibers. These years also witnessed the initial steps toward the breakup of the Bell telephone monopoly, a regulatory and public-policy event which was to have long-term and fundamental consequences for communications technologies and their uses.
During the late 1960s and early 1970s the first computer networks to use packet switching came into existence. The United States Department of Defense's Advanced Research Projects Agency (ARPA) was the most important institutional force in driving this research. In 1962, with the formation of its Information Processing Techniques Office (IPTO), ARPA became a major funder of computer science research and was the driving force behind several advances in computing technology, including computer graphics, artificial intelligence, time-sharing, and networking. At the beginning of 1966 ARPA embarked on a program to connect computing sites at universities across the country. In early 1967 Lawrence Roberts, a computer scientist who had conducted networking research at MIT, took over management of the ARPANET project.
At the beginning, its planners envisioned that ARPANET would use message switching techniques to connect the several computers in the network. Packet switching was adopted after the inaugural Symposium on Operating System Principles (SOSP) in Gatlinburg, TN, in 1967. There, a member of Donald Davies' team, Roger Scantlebury, presented their work on "A Digital Communication Network for Computers Giving Rapid Response at remote Terminals" and referenced the work of Paul Baran. Roberts decided to adopt the new technique for the ARPANET. Many of the early pioneers of the ARPANET recalled that packet switching met with a great deal of resistance and skepticism from communications engineers. Roberts, for instance, recalled that telephone engineers "reacted with considerable anger and hostility, usually saying I did not know what I was talking about."
Paul Baran on acceptance of packet switching:
"The fundamental hurdle in acceptance was whether the listener had digital experience or knew only analog transmission techniques. The older telephone engineers had problems with the concept of packet switching. On one of my several trips to AT&T Headquarters at 195 Broadway in New York City I tried to explain packet switching to a senior telephone company executive. In mid sentence he interrupted me, "Wait a minute, son. Are you trying to tell me that you open the switch before the signal is transmitted all the way across the country?" I said, "Yes sir, that's right." The old analog engineer looked stunned. He looked at his colleagues in the room while his eyeballs rolled up sending a signal of his utter disbelief. He paused for a while, and then said, "Son, here's how a telephone works'." And then he went on with a patronizing explanation of how a carbon button telephone worked. It was a conceptual impasse."
A major technical difficulty with packet switching was that errors crept into data transmission at speeds above 2400 bits per second. To counteract this problem, in 1965 Robert W. Lucky of Bell Labs developed an adaptively equalized modem which adjusted its shaping of the phase and amplitude of the pulses in response to changing line conditions. Adaptive equalization made possible data rates of 14,400 bits per second and higher at acceptably low error rates.
The NPL Data Communications Network, designed by Donald Davies at the National Physical Laboratory in the United Kingdom, established the first single node packet switch in 1969.
The basic infrastructure of the ARPANET consisted of time-sharing host computers, packet-switching interface message processors (IMPs), and 56 kilobits-per-second telephone lines leased from AT&T. The major development task was to build the IMPs. In early 1969 Roberts awarded this contract to the firm of Bolt Beranek and Newman Corporation (BBN), a small consulting firm specializing in acoustics and computing systems. The BBN team working on the Interface Message Processors (IMPs), including Frank Heart, Robert Kahn, Severo Omstein, William Crowther, and David Walden developed significant aspects of the network's internal operation, including the routing algorithm, flow control, software design, and network control. In September 1969 engineers from BBN and Leonard Kleinrock's research group installed the first IMP at UCLA. By the end of the year BBN successfully installed and linked four initial nodes at UCLA, SRI, UC Santa Barbara, and University of Utah. Although the ARPANET was able to transmit test messages between the four sites, two more years of work lay ahead before the network could provide usable communications between the sites.
In hindsight the development of the ARPANET was perhaps the most significant advance in communications in this period. During the 1960s and early 1970s, however, satellite communications received much more public attention. While only a handful of electrical engineers and computer scientists were conscious of the ARPANET and its significance, most of the American public was aware of the latest advances in the country's space program, including communications satellites.
In 1964, by international agreement among the space agencies and telecommunications agencies of more than 100 countries, INTELSAT was formed as an international body to design, develop, and maintain the operation of a global commercial communications satellite system. One of INTELSAT's first major decisions was to use geosynchronous satellites instead of low-orbit satellites. In April 1965 the agency launched INTELSAT I (Early Bird), which provided 240 circuits between the United States and Europe. INTELSAT II and III soon followed Early Bird into geosynchronous orbit. Although Early Bird's planned operational life was only 18 months, it lasted four years with perfect reliability. In the seven years following Early Bird's deployment, INTELSAT launched and deployed four generations of satellites, each with increasing capabilities. Capacity increased from 240 telephone circuits in INTELSAT I through 1200 circuits in INTELSAT III, to 6000 circuits in INTELSAT IV. The first INTELSAT IV was launched on 25 January 1970 and it brought the INTELSAT system to full maturity. One problem with satellite communications was controlling the echo caused by the 550msec round-trip delay. The echo problem was solved by the use of echo cancelers, nonetheless, the delay remains an impairment in dialogue over circuits. After much debate, the ITU settled on standards which allowed only one satellite link in a connection.
A third technological development of far-reaching importance -- optical fiber -- came about in the mid and late 1960s. During 1959 and 1960 researchers developed the laser, a device capable of generating coherent, collimated, and monochromatic beams of light. At first the laser remained a laboratory research tool, but engineers realized that it had great potential for transmitting enormous amounts of information. Because lasers operated at the extremely high optical frequencies, they were capable theoretically of great bandwidths and data rates. However, exploiting the laser's potential as a communications device required the development of a low-loss, guided, and well-controlled optical transmission medium. A breakthrough occurred in 1966 when K. C. Kao and G. A. Hockham proposed a clad glass fiber as a suitable waveguide. They predicted that a loss of 20 dB/km should be attainable, a remarkable prediction given that the fibers of the time had losses on the order of 1000 dB/km. By 1968 researchers had prepared bulk silica samples with losses as low as 5 dB/km. In 1970 F. P. Kapron, D. B. Keck, and R. D. Maurer of Corning Glass Works reported the development of a fiber with a loss of 20 dB/km. That same year I. Hayashi and others at Bell Labs demonstrated successful transmission at this attenuation figure using a semiconductor laser. Although actual installation in the field would not occur until the mid-1970s, these and other researchers had demonstrated the feasibility of using semiconductor lasers and optical fibers for communications.
A fourth very important technology change began during this period: the evolution of communications networks from analog to digital technology, in transmission and in switching both. Digital methods appeared first in local trunking (T1 Carrier), then in local and toll switching systems (DMS 10, 4ESS, 5ESS, etc.), and finally in microwave radio and fiber optics long distance transmission systems.
Alongside these three significant technical advances in computer networking, satellite communications, and optical fibers , this era witnessed the beginning of a far-reaching development in telecommunications policy: the end of the Bell System telephone monopoly in the United States. Since 1913 AT&T had been a monopoly subject to strong federal supervision. It had focused on providing reliable, universal basic telephone service, but many critics charged that it was slow in adopting advances in fields like microwave transmission and data communications. Backed by Federal Communications Commission (FCC) regulations, AT&T did not allow users to attach devices to connect their telephones to two-way radios or computers and it did its best to block competition into the long-distance telephone market.
The first sign of change came in 1968 when the FCC ruled in favor of the Carter Electronics Corporation, whose Carterfone allowed customers to connect a radiotelephone to the telephone network. This decision opened up the terminal-equipment market to competition. A year later, the FCC granted Microwave Communications, Inc. (later MCI) permission to sell long-distance service over its own microwave phone links, and then connect into the AT&T network. To the consternation of AT&T, this allowed MCI to skim the most profitable segment of the telephone business. Thus, by the early 1970s, AT&T faced competition in two markets which it had previously held captive: terminal equipment and long-distance service. The potential of these new technologies had begun the process of unraveling the Bell System's telephone monopoly.
1972-1984
This era saw continued advances in communications technology, especially in computer networking and optical transmission. This period also brought about the introduction of intelligence into the public switched telephone network, beyond that which was required to complete a call to a dialed termination. The basic concept was to interrupt the processing of a call for accessing a database which contained information on how that call should be completed. The first use came in routing 800 calls, but many other applications followed. Common channel signaling via data channels and data switches was the underlying technology. This common signaling network was separate from the network conveying the communications message per se. Also, during these years the federal government began, and saw through to completion, anti-trust proceedings against AT&T in 1984 the Bell System's monopoly which had been sanctioned for more than seventy years, came to a close.
Between 1972 and 1983 ARPANET underwent two significant transformations: it became a network of networks, or an internet, and it began to realize its commercial potential. At the end of 1971 ARPANET entered service with fifteen sites connected to the network. At this point, ARPANET incorporated and embodied many significant advances in computer networking techniques, hardware, and software; however, usage remained low. Though a great technical achievement, it could hardly be considered successful if nobody used it. In 1972 Robert Kahn and Lawrence Roberts decided to demonstrate the ARPANET's capabilities at the first IEEE International Conference on Computer Communications (ICCC), held in October in Washington, DC. This demonstration made a powerful impression on the thousand or so attendees. The Washington demonstration marked the point at which telephone engineers, steeped in a culture of circuit switching, began to accept packet switching as a workable communications methodology. The ICCC demonstration also marked a turning point in the use of the system. Traffic on the ARPANET jumped 67% during the month of the conference and maintained high growth rates afterward. As more and more users entered the ARPANET they began to reshape it toward their own purposes. Although ARPANET's architects envisioned it as a system to facilitate resource sharing like remote file access and time-sharing, it soon became apparent that its most popular use was electronic mail.
The enthusiastic response among communications specialists and the large increase in traffic on the network encouraged some ARPANET contractors to leave BBN and to start the first commercial packet switching company. In 1972 they started Packet Communications, Inc., to market an ARPANET-like service. BBN also launched its own networking subsidiary, Telenet Communictions Corporation, and Lawrence Roberts left ARPA to become its president. Telenet was the first network to reach the marketplace, and it began service in seven U.S. cities in August 1975.
In addition to limited commercialization of network services, over the course of the next decade the ARPANET, a single network that connected a few dozen sites, would be transformed into the Internet, a system of many interconnected networks capable of almost indefinite expansion. The Internet would far surpass the ARPANET in size and influence and would introduce a new set of techniques to computer networking. However, like electronic mail, the development of the Internet was not part of ARPA's initial networking plans.
The transformation of the ARPANET into the Internet owed a great deal to the work of ARPA researchers Robert Kahn and Vinton Cerf. The Internet architecture which they proposed gained widespread acceptance because it was decentralized and flexible enough to accommodate a range of uses and users. After Lawrence Roberts left ARPA to head Telenet, (BBN's commercial spinoff of the ARPANET), Robert Kahn, a prominent BBN researcher, joined IPTO as program manager. The major challenge which Kahn and Cerf faced was the design of a communications protocol which was flexible enough to permit interconnection with a wide variety of computers.
In June 1973 Cerf organized a seminar at Stanford University to address the design of a protocol for internetworking. They drew on the experience of the ARPANET research community, the International Network Working Group and researchers at Xerox PARC (they credit Bob Metcalfe, Roger Scantlebury, David Walden, Hubert Zimmerman, Donald Davies, Louis Pouzin and Steve Crocker). Cerf and Kahn published their proposal for the Transmission Control Program (TCP) in 1974 and the initial version of TCP was specified later that year by Cerf, Yogen Dalal and Carl Sunshine. BBN developed a version of TCP for its TENEX operating system by November 1975, and also in that year successfully connected its in-house research network to the ARPANET. Stanford University and University College London (UCL) also implemented TCP in 1975. In November, the Stanford, UCL and BBN groups set up an experimental TCP connection between their sites. BBN also began installing experimental gateways to test TCP over satellite links in 1976 and 1977. These early efforts not only proved out the basic concept of TCP, but also revealed flaws and deficiencies which pointed the way to further improvement.
By late 1977 the various networks and test sites were ready to try out the improved TCP. Experimenters sent packets from a van on a California freeway through packet radio to an ARPANET gateway, to a satellite networking gateway on the east coast, by satellite to Europe, and finally back through the ARPANET to the van in California. This demonstration confirmed the feasibility of the Internet scheme and showed how connections between radio, telephone, and satellite networks could be used for networking.
Following discussions with Bob Metclafe and Yogen Dalal at Xerox PARC about improving the flexibility of the communication protocol, in January 1978, Vint Cerf, Jon Postel, and Danny Cohen split TCP into two components: a host-to-host Transmission Control Protocol within networks (TCP) and an internetwork protocol (IP). The pair of protocols became known as TCP/IP. IP would pass individual packets between machines (for instance, from host to packet switch, or between packet switches), while TCP would be responsible for ordering these packets and providing reliable connections between hosts. Over the next five years ARPANET architects refined TCP/IP and in March 1981 they decided to replace the existing Network Control Program with TCP/IP on all ARPANET hosts. By June 1983 every host was running TCP/IP.
After converting the ARPANET to TCP/IP, ARPA took two more steps to set the stage for the later development of a large-scale civilian Internet. One step was to separate the ARPANET's military users and academic researchers, who had been coexisting somewhat uneasily since the Defense Communications Agency had taken over the network in 1975. This separation, which hived off a military network called MILNET, occurred in April 1983. The second step was to commercialize Internet technology, particularly the TCP/IP protocol. All the major computer companies took advantage of this opportunity, and by 1990 TCP/IP was available for virtually every computer on the United States market. This ensured that TCP/IP would become the de facto networking standard.
Between 1972 and 1983 ARPANET underwent a number of significant transformations: the entire network switched to TCP/IP, the military users left for their own network, and the ARPANET became part of a larger system -- the Internet. The field of computer networking underwent a conceptual transformation: instead of thinking about how to connect individual computers together, network builders also had to consider how different networks could interact with each other. By 1984 the fledgling Internet connected over 100 universities and research facilities in the United States and Europe.
Just as the ARPANET and early Internet demonstrated the feasibility of large-scale computer networking, several significant projects in the mid and late 1970s proved the value of optical fibers for communications. In 1975 AT&T Bell Laboratories installed an experimental optical fiber trunk system in Atlanta, GA, using a 650 m 144-fiber cable in a loop configuration. The fibers could be interconnected to simulate longer transmission lengths. Bell Labs engineers carried out a full range of system experiments at a data rate of nearly 45 Mb/s and obtained unrepeatered spacings up to 11 km with an error rate less than 10-9 and negligible crosstalk. Thus the Atlanta experiment established the practicability of all aspects of optical fiber trunk transmission, including the performance of the fiber itself, its installation, splicing, transmitters and receivers, electronics, optical jacks and jumpers, and overall system performance.
The success of the 1975 Atlanta experiment led to the installation of a similar system in the spring of 1977 in Chicago's Loop. In September 1980, a second system entered service in the Atlanta-Smyrna region of Georgia, US. AT&T also installed major long-haul routes, including a 776-mile route from Moseley, VA to Cambridge, MA and a 500-mile route from Los Angeles to San Francisco. By the end of 1982 more than 150,000 km of cabled fibers had been installed in the Bell System, and a year later that figure had risen to more than 300,000 km of cabled fibers capable of data rates of 45 or 90 Mb/s. Finally, in 1982 and 1983 AT&T Bell Labs began testing of undersea light wave systems, a research and development program which would culminate in a transatlantic fiber cable, TAT-8, in 1988.
Japan's Nippon Telephone & Telegraph (NTT) also aggressively pursued optical fiber technology in this period. In 1978 NTT conducted a major field test involving 168 subscribers using fibers to bring broadband services to homes, including a very broad range of video services such as two-way video. NTT placed an 80-km trunk route into service in 1983, capable of carrying 400 Mb/s. After the successful installation of this system NTT announced plans for more than 60 such installations totalling nearly 100,000 km of fiber.
Alongside of these major developments in the fields of computer networking and optical fibers, a major shakeup in the American telecommunications industry began: the beginning of the breakup of the Bell System. In 1974 the Department of Justice filed an antitrust suit against AT&T. Federal regulators wanted to force AT&T to allow interconnects to its system, competition in the long-distance market, and the purchase of telephone equipment on the open market instead of from its subsidiary Western Electric. After ten years, hundreds of millions of dollars, and millions of pages of documents, AT&T and the Justice Department came to an agreement: the Justice Department allowed AT&T to keep Western Electric, but directed it to divest itself of all the local operating companies.
On 1 January 1984 AT&T exited the local telephone business, spinning off seven regional Bell operating companies (RBOCs). AT&T kept its long-distance operations, Western Electric, and Bell Labs,and it began to move into non-regulated businesses such as computing. A research and systems engineering organization, later known as Bellcore, was established by the divestiture agreement. It provided technical support to the newly-formed regional telephone companies on a shared ownership basis. In its original form, Bellcore was a major force in the communications industry, doing applied research and developing network plans and generic requirements for the elements required to build and operate those networks. Bellcore has since been acquired by SAIC, and now provides its services to a wide spectrum of clients beyond the original seven regional companies. Deregulation spurred competition and lowered prices in the long-distance market, but created some confusion among consumers. Before the breakup, 80% of the public said that they were satisfied with their telephone service; in 1985 64% of Americans thought divestiture was a bad idea and many called for the reunification of AT&T. Deregulation also eroded the preeminent position of Bell Labs as a leading research center in basic engineering and science. Under the AT&T monopoly, Bell Labs depended on a protected source of operating revenue and its researchers enjoyed a great degree of independence. This environment helped Bell Labs researchers to win 7 Nobel Prizes since the 1920s, more than any other organization in the world, and to undertake far-reaching work in many areas of electrical engineering and basic science. Thus, while the breakup of AT&T offered the telecommunications consumer more choices and lower costs, it also eroded an important component of the nation's research infrastructure.
1985-2002
Two major trends have shaped the telecommunications landscape since the mid-1980s, both having profound influence on technology, the marketplace, and society. In computing, the convergence of personal computers and networking has made the Internet a ubiquitous and permanent infrastructure; many users regard the Internet as an information and communications utility which is nearly as important as telephone and electricity service. In telephony, the explosive growth in wireless has given the consumer much more flexibility and convenience. For many users, cell phones have replaced the wired home telephone as their primary communications device.
At the beginning of the 1980s the Internet comprised only a small set of networks at universities or defense research establishments. Over the course of the 1980s and 1990s the Internet grew enormously in the number of networks, computers, and users connected. By the mid-1990s, many people had begun to experience firsthand the potential the Internet offered for information, social interaction, entertainment, and self-expression.
One of the most striking aspects of the Internet during the 1980s was its explosive growth. At the end of 1985 about 2000 computers had access to the Internet; by the end of 1987 that figure had risen to 30,000; by the end of 1989, the Internet linked 160,000 computers. This expansion was a largely unplanned and decentralized phenomenon, made possible by the modularity of the Internet's operating architecture designed by Kahn and Cerf.
During the same time that the Internet dramatically expanded, personal computers (PCs) began to make their presence felt in the consumer and business markets. Although they had entered the hobbyist market in the late 1970s, personal computers did not find widespread application until the early 1980s. However, the growth of personal computing paralleled the growth of the Internet. In 1983, for instance, some 3.5 million personal computers were sold and Time magazine named the personal computer "Man of the Year."
During the early 1980s several companies, such as CompuServe, America Online, and Prodigy, introduced commercial online services for the home PC user. Subscribers accessed these services by means of a modem and software supplied by the service provider. At first these online services did not provide connection to the (as yet restricted) Internet, but did provide users with information services, chat rooms, and online shopping. These online services helped to introduce large numbers of users to the practice of retrieving information and communicating with others by means of their home computers. In 1985 Stewart Brand set up the WELL (Whole Earth 'Lectronic Link) as an alternative to the commercial systems. The WELL soon became known as a gathering place for advocates of counterculture ideas and free speech. By the late 1980s, therefore, several million computer users could exchange mail and news over these networks. Though these systems were not parts of the Internet, they established links to it fairly soon.
In 1991 the National Science Foundation issued a plan to foster the commercialization of the Internet. Under this plan, Internet service would be taken over by competitive Internet Service Providers (ISPs) who would operate their own backbones. ISP subscribers would connect their computers or local-area networks to one of these backbones, and the ISPs would allow for intercommunication among their systems. On 30 April, 1995 the US government formally terminated its control over the Internet's infrastructure. Privatization opened up the Internet to a much larger segment of the American public. Commercial online services could now offer Internet connections, and the computer industry rushed into the Internet market.
A necessary precondition to large-scale public participation in the Internet was the development of network applications, particularly search engines. Without an easy-to-use search engine, an Internet user had no way to locate desired information or to transfer files easily. In the early 1990s the University of Minnesota introduced its gopher system, which helped users to organize and to locate information. But the most significant advance in this area was the World Wide Web, developed by Tim Berners-Lee of the European high-energy physics establishment CERN. In December 1990 the first version of the Web software began operating within CERN, and CERN began distributing its Web software over the Internet to other high-energy physics sites. Among them was the National Center for Supercomputing Applications (NCSA) at the University of Illinois.
In 1993 an NCSA team led by Marc Andreessen developed an improved Web browser called Mosaic, the first system to include color images as part of the Web page. When NCSA officially released Mosaic to the public in November 1993, over 40,000 users downloaded copies in the first month; by the following spring more than a million copies were in use. In 1994 Andreessen and his team left NCSA to develop a commercial version of Mosaic called Netscape. The Web and browsers like Netscape completed the Internet's transformation from a research tool to a popular medium.
The growing popularity of wireless telephony, more commonly known as "cell phones," paralleled the explosion of the Internet. A series of papers in Bell Labs Technical Journal in 1979 outlined the basic principles of cellular telephony, but sustained development and market penetration occurred only after the mid-1980s. From their start in the early 1980s, cell phone usage boomed: the industry grew exponentially from 25,000 subscribers in the United States in 1984 to 1 million in 1987, to 4 million in 1990, 9 million in 1992, and more than 50 million in 1999. Similar growth occurred in many other countries; in Hong Kong, for example, more than half the adult population operated cell phones by the end of 1991.
Communications in the 21st Century
The expansion in communications technologies and markets since the founding of the IRE's Professional Group on Communications Systems in 1952 has been dramatic indeed. In 1952 the two most common communications devices in American homes were the telephone and the radio. Today, most Americans communicate with each other over wireless telephones and obtain their information through the Internet. The dramatic development of communications in the past half-century, and particularly the exponential growth of cell phones and the Internet in the past decade, points out two guideposts for the future. From a technological standpoint, the communications infrastructure of the 21st century will continue to rely on a mix of wired and wireless systems. Communications engineers will confront and solve a set of technical challenges to provide adequate bandwidth and data rates for the ever-growing numbers of subscribers; customers will continue to demand new services which will require more bandwidth and higher speed. In the social realm, the Internet and wireless telephony have jointly demonstrated that communication is both a basic human need and an indispensable part of modern society. As it begins its second half-century, the members of the IEEE Communications Society are well poised to meet the technical and social challenges of communicating in the 21st century.
Timeline of Key Communications Technology Events
Pre-1900
| Year | Event |
| 1837 | Cooke and Wheatstone obtain a patent on telegraph. Morse publicly demonstrates his telegraph. |
| 1844 | Morse's first telegraph line between Washington and Baltimore opens in May. |
| 1865 | Maxwell mathematically predicts the propagation of electromagnetic waves through space. |
| 1866 | Uninterrupted transatlantic communications are established with the successful laying of the first telegraph cable on 27 July. |
| 1876 | Alexander Graham Bell and Elisha Gray independently invent the telephone. Bell awarded priority. |
| 1884 | AIEE formed with Norvin Green, president of Western Union, as first President. |
| 1887 | Heinrich Hertz shows that electromagnetic waves exist. |
1900s
| Year | Event |
| 1901 | Guglielmo Marconi sends first transatlantic wireless signals, 12 December. |
| 1902 | Poulsen-Arc Radio Transmitter invented. |
| 1903 | AIEE Committee on Telegraphy and Telephony formed. |
| 1904 | John Ambrose Fleming invents the two-element "Fleming Valve". |
| 1905 | Marconi patents his directive horizontal antenna. |
| 1906 | Dr. Lee de Forest reads a paper before an AIEE meeting on the Audion, first of the vacuum tubes that would make long distance radiotelephony possible. |
| 1906 | Reginald Fessenden broadcasts Christmas Carols on Christmas Eve from Brant Rock, MA |
| 1907 | The world's first transatlantic commercial wireless services is established by Marconi with stations at Clifden, Ireland and Glace Bay, Nova Scotia. |
| 1909 | Marconi shares the Nobel Prize in Physics, with Karl Ferdinand Braun for their work in the development of wireless telegraphy. |
1910s
| Year | Event |
| 1910 | The first commercial radios are sold by Lee de Forest's Radio Telephone Company. |
| 1911 | Using loading coils properly spaced in the line, the transmission distance for telephone reaches from New York to Denver. |
| 1912 | IRE is founded. (13 May) |
| 1912 | Major Edwin H. Armstrong invents the feedback regenerator. |
| 1912 | The Titanic sinks, it is equipped with a Marconi wireless set, sending out distress signals. |
| 1913 | Armstrong patents his version of the valve generator. |
| 1914 | The last pole of the transcontinental telephone line is placed in Wendover, Utah, on the Nevada-Utah state line. |
| 1915 | Direct telephone communications opened for service at 4pm, EST. Alexander Graham Bell, in NY, greets his former assistant, Thomas Watson, in San Francisco, by repeating the first words ever spoken over a telephone, "Mr. Watson, come here I want you". Mr. Watson would reply that it would take him a week to get there. |
| 1918 | Edwin Armstrong develops a receiving circuit - the superheterodyne. |
| 1919 | Radio Corporation of America (RCA) is formed |
1920s
| Year | Event |
| 1920 | Westinghouse Radio Station KDKA is established (2 November) |
| 1921 | First radio broadcast of a sporting event (Dempsey/Carpentier Heavyweight Championship Prize Fight, 2 July) |
| 1922 | Alexander Graham Bell dies at his summer home in Beinn Breagh, near Baddeck, Cape Breton Island, Nova Scotia (2 August). Telephone service is suspended for one minute (6:25pm-6:26pm) on the entire telephone system in the United States and Canada during the funeral service (4 August) |
| 1922 | British Broadcasting Corporation (BBC) is formed. (It would receive it's Royal Charter in 1927). |
| 1923 | Meetings at New York and Chicago of the American Institute of Electrical Engineers (AIEE) are linked by long distance lines connected to loudspeakers so that both meetings could follow the same program (14 February). |
| 1924 | Directive short wave antenna is developed by Professor Hidetsugu Yagi and his assistant, Shintaro Uda. |
| 1925 | The Combined Line and Recording (CLR) method of handling toll calls over long distances (100 miles or more) is introduced experimentally by Bell Systems. It reduces the handling of toll calls from 13 minutes (in 1920) to 7 minutes. |
| 1926 | The first public test of radiotelephone service from New York to London. |
| 1927 | First public demonstration of long distance transmission of television. |
| 1927 | Formal opening of telephone service between the US and Mexico, and also, Mexico- London, via New York. |
| 1928 | A joint meeting of the AIEE and the British IEE is held over radiotelephone channels, with the respective groups assembled in New York and London. |
| 1929 | 29 October, the Great Depression |
1930s
| Year | Event |
| 1931 | AT&T inaugurates the Teletypewriter Exchange Service (TWX) 21 November |
| 1933 | Edwin Armstrong demonstrates frequency modulation (FM) to David Sarnoff. |
| 1934 | The Federal Communications Commission (FCC) is established. |
| 1935 | The first around-the-world telephone conversation takes place. (25 April) |
| 1935 | Western Union's "Telefax" begins operating. Telefax sent telegrams, manuscripts, line drawings, maps and page proofs for magazines. |
| 1936 | Invention of coaxial cable is announced at a joint meeting of the American Physical Society and the IRE (30 April). |
| 1937 | Seven-hour radio broadcast of the coronation of King George VI and Queen Elizabeth of England. |
| 1938 | The power of radio is demonstrated by Orsen Wells with the broadcast of "War of the Worlds". This causes telephone traffic to peak in nearly all cities and on long distance lines. |
| 1939 | The Golden Gate Exposition (San Francisco) and New York Worlds Fair are opened. These exhibit the newest technologies, including the Voder (synthesized speech) and television. |
| 1939 | FM is used by Bell Laboratories in a radio altimeter that uses signal reflections from the surface of the earth. |
1940s
| Year | Event |
| 1940 | FM Police Radio Communications begin in Hartford, CT |
| 1941 | The Japanese attack on Pearl Harbor affects the telephone system of the United States by causing tremendous traffic peaks in all cities, and an increase from 100 to 400 percent in long distance telephoning - which already is at a record high of 3 million messages. (The United States would again experience this phenomenon in 2001, during the 11 September attacks.) |
| 1941 | Radar successfully detects the attack on Pearl Harbor, but the warnings are ignored. |
| 1942 | The first section of telephone line is completed along the Alcan Highway, from Edmonton, Alberta, to Dawson Creek, British Columbia. The Alcan Highway begins at Dawson Creek. |
| 1943 | Construction of a telephone line from Calcutta, India to Kunming, China, along Stilwell Road, begins at Ledo, Assam. |
| 1944 | A telephone submarine cable is laid across the English Channel. |
| 1945 | Western Union installs the first commercial radio beam system. |
| 1946 | Mobile telephone service is placed into commercial use in St. Louis, Missouri. |
| 1946 | The beam traveling-wave tube is announced by Bell Telephone Laboratories. This tube is an important amplifier for broadband communication. |
| 1947 | Invention of the point contact transistor by Brattain and Bardeen at Bell Labs in Murray Hill, NJ. (23 December) |
| 1947 | Demonstration of mobile telephone equipment from a United Airlines plane to ground stations. |
| 1948 | Invention of the junction transistor. |
| 1949 | The volume of telephone calls reaches 180 million a day! |
1950s
| Year | Event |
| 1952 | IRE Professional Group on Communications Systems is formed. |
| 1953 | John Pierce proposes deep space communication. |
| 1954 | US Air Force's SAGE system sets precedent for computer communications, including use of modems. |
| 1955 | Recorded announcements of disconnected and changed numbers begin to be used in some small dial offices. |
| 1956 | The Bell System and the British Post Office inaugurates service on a transatlantic telephone cable, TAT-1. |
| 1956 | The 1956 Nobel Prize in Physics is awarded to the inventors of the transistor: Dr. Walter H. Brattain, Dr. John Bardeen and Dr. William Shockley. |
| 1957 | Soviet Union launches Sputnik, humanity's first artificial satellite, on 5 October. |
| 1958 | Jack S. Kilby and Robert Noyce independently invent an Integrated Circuit. |
1960s
| Year | Event |
| 1960 | ECHO I communications satellite is launched on 12 August. Provides first satellite television broadcast of 1962. |
| 1960 | Laser is invented. |
| 1961 | Leonard Kleinrock of MIT publishes "Information Flow in Large Communication Nets", applying queuing theory to message switching networks. |
| 1962 | United States Congress passes the Communications Satellite Act. |
| 1962 | T1 carrier is put into commercial service. |
| 1962 | The first transatlantic transmission of a TV signal via the TELSTAR satellite. (11 July) |
| 1962 | EES™ Electronic Switching Systems is introduced. |
| 1963 | AIEE and IRE merge to form IEEE (1 January) |
| 1963 | NASA announces that the new Syncom II communications satellite has been used successfully to transmit voices live between the U.S. and Africa. At the time of the conversations, Syncom II hovers 22,000 miles over Brazil. The satellite is the first successful synchronous satellite. This mean that the satellite's revolution matches the daily revolution of the earth about its axis, so that the satellite seems to remain "stationary" over the same earth location |
| 1963 | A telephone hotline connects Soviet and American leaders (30 August) |
| 1963 | Touchtone phones are introduced to replace the rotary dial phones. |
| 1963 | BBN develops the first modem. |
| 1964 | Based on work carried out thorugh the early 1960s, Paul Baran of RAND publishes "On Distributed Communications Networks," outlining the operations of distributed networks using message blocks for communication with the goal of surviving node outages. |
| 1964 | An improved stock ticker tape machine (designed, developed and manufactured by Teletype Corporation) is placed into service at the New York Stock Exchange. The ticker, which transmits stock prices to brokerage houses nearly twice as fast as the previous system, has a capacity of ten million shares a day without incurring delays. (22 June) |
| 1964 | IEEE Group on Communication Technology is formed. (1 July.) |
| 1965 | Donald Davies conceives of packet switching for data communication. The following year, he designs a high-speed computer network with interface computers. The year after, his team propose a communication protocol for the network. |
| 1965 | K. C. Kao and G. A. Hackham publish an influential paper on fiber optics. |
| 1965 | The first commercial communications satellite, Early Bird, later named Intelsat 1, is launched into orbit from Cape Kennedy. The 85-pound satellite is a synchronous satellite, matching the earth's rotation to hover over the same spot all the time. (6 April) |
| 1965 | The Soviet Union launches its first communications satellite and carried out transmissions of television programs. The satellite is named "Molniya 1", which translates to "Lightning 1". (23 April) |
| 1965 | Northeastern United States experiences it's first great Blackout (9 November) |
| 1966 | Thomas Marill and Lawrence G. Roberts of MIT publish "Towards a Cooperative Network of Time-Shared Computers", which discusses some of the problems in forming a network of computers. |
| 1966 | Worldwide direct telephone dialing has its first public demonstration, a call from Philadelphia to Geneva, Switzerland. (15 June) |
| 1967 | Dolby introduces its noise reduction. |
| 1967 | Bell Laboratories announces a new solid-state source of high frequency radio waves. The "LSA diodes" emitted millimeter waves, a part of the radio frequency range that could carry about nine times more telephone calls than all lower frequencies combined. An LSA diode and its power supply is about as large as a deck of cards. (15 February) |
| 1967 | An experimental cordless extension telephone is introduced by Bell Laboratories (30 June) |
| 1968 | Bell System adopts the use of "911" as a nationwide emergency telephone number (12 January) |
| 1968 | Huntington, Indiana became the first U.S. city served by the Bell System to receive the new universal emergency telephone number "911". (1 March) |
| 1969 | The NPL Data Communications network in the United Kingdom establishes the first single node packet switch. ARPANET begins 4-node operation (UCLA, Stanford Research Institute (SRI), UC Santa Barbara and University of Utah. |
| 1969 | Video and Audio are transmitted back from the first Moon landing (20 July) |
| 1969 | UNIX Operating System is developed. |
1970s
| Year | Event |
| 1970 | Corning Glass demonstrate highly transparent fibers, and Bell Laboratories demonstrates semiconductor lasers that could operate at room temperature; these demonstrations help establish the feasibility of fiber-optic communications |
| 1971 | The Intelsat IV communications satellite goes into commercial operation. Initially it has 830 circuits in service and linked ground stations in 15 countries. |
| 1971 | The DUV (Data Under Voice) is introduced. It permits signals to "hitch-hike" on existing microwave radio systems by using the lower end of the frequency band not normally used for voice. |
| 1971 | Ray Tomlinson writes the first email program. The @ sign is used for the first time in an email address. |
| 1972 | IEEE Communications Society is established on 1 January. |
| 1972 | Jon Postel writes the specifications for Telnet. |
| 1972 | IEEE Proceedings publishes its first issue on computer communications. Guest Editors are Paul Green and Robert Lucky. |
| 1972 | A demonstration of the ARPANET at the 1972 IEEE International Conference on Computer Communications. |
| 1973 | Robert Metcalfe invents Ethernet at Xerox PARC. Ethernet uses a cable rather than a radio channel as the transmission medium. |
| 1973 | The "Touch-a-matic" telephone is introduced. It can automatically dial a call anywhere in the U.S. at the touch of a single button. Its solid-state memory allows dialing up to 32 pre-coded telephone numbers. |
| 1973 | Construction of a new, high-capacity coaxial cable system, called L5, is completed between Pittsburgh and St. Louis. It has the capacity of carrying 108,000 simultaneous telephone conversations, three times the capacity of any previous system. |
| 1973 | File Transfer Protocol (FTP) is introduced. |
| 1974 | Vinton Cerf and Robert Kahn publish "A Protocol for Packet Network Interconnection", in IEEE Communications Magazine, which outlines design of a Transmission Control Program (TCP). The term "Internet" is used for the first time. |
| 1974 | Western Union launches Westar, the nation's first domestic communications satellite. |
| 1974 | New York Telephone inaugurated Dial-A-Joke, an addition to the recorded announcement field. During the first month of operation, more than 100,000 calls a day are made to the number. |
| 1975 | Bolt, Beranek and Newman (BBN) opens Telenet, the first public packet data service. |
| 1975 | Viking is launched. Lands on Mars in 1976 and sends back data to Earth. |
| 1975 | Transmission testing begins on the T4M, highest-capacity, short-haul digital transmission system in the U.S. The new system, linking Newark, NJ to New York City, transmits 274 million "bits" of information per second over a single coaxial tube. |
| 1976 | Centennial of the Telephone |
| 1976 | IEEE establishes the Alexander Graham Bell Medal to commemorate of the centennial of the telephone's invention and to provide recognition for outstanding contributions in telecommunications. Amos Joel, William Keister and Raymond Ketchledge are the first recipients. |
| 1976 | COMSTAR is launched and begins commercial service. It is in permanent orbit over the Galapagos Islands. |
| 1977 | Voyager spacecraft is launched. Sends back signals from Jupiter (1979-1980), Saturn (1981), Uranus (1986) and Neptune (1989). |
| 1977 | Bell Laboratories announces the development of the MAC-8, a microprocessor suited for a wide range of telecommunications applications. |
| 1978 | TAT-1, the world's first transoceanic telephone cable was retired (27 November) |
| 1978 | TCP split into TCP and IP |
| 1979 | A 62,000-mile microwave telecommunications system is completed within Saudi Arabia. |
| 1979 | Emoticons are suggested :-) |
1980s
| Year | Event |
| 1980 | First use of the "900" number. |
| 1981 | First cellular mobile telephone service is offered, in Saudi Arabia and Scandinavia. |
| 1981 | A new telephone service, DIAL-IT® allowed a caller to listen to the voice communications between the Space Shuttle Columbia and the ground command center. |
| 1981 | BITNET is introduced (Because Its There NETwork) |
| 1982 | 256K DRAM (Dynamic Random Access Memory) is introduced. |
| 1982 | The first full-color two-way video teleconferencing service is offered. |
| 1982 | The development of TFM (Time Frequency Multiplexing) |
| 1983 | The Cleaved Coupled-Cavity (C3) laser was introduced. The single frequency tunable laser emitted a light so pure that over a billion bits of information per second could be sent through a glass fiber. (April) |
| 1983 | The first commercial cellular phone system is introduced in Chicago. (13 October) |
| 1983 | Desktop workstations are introduced. |
| 1984 | IEEE Centennial |
| 1984 | Breakup of AT&T.(1 January) |
| 1985 | Local area signaling service is introduced. The service is used to trace nuisance calls, transfer calls, and provide other advanced calling services. (20 May) |
| 1985 | AT&T and NASA space shuttle Discover launch its second Telstar 3 satellite. 1 Sept. |
| 1985 | Domain Name Service (DNS) is introduced. DNS is used mostly to translate between domain names and IP addresses, and to control Internet email delivery. |
| 1985 | AT&T Bell Laboratories combine 10 laser beams on a single optical fiber demonstrating the capability of lightwave systems to carry 20 billion bits per second (equal to 300,000 telephone calls.) |
| 1985 | Whole Earth 'Lectronic Link (WELL) is started. |
| 1985 | Symbolics.com is assigned on 15 March to become the first registered domain. Other firsts: cmu.edu, purdue.edu, rice.edu, berkeley.edu, ucla.edu, rutgers.edu, bbn.com (24 April); mit.edu (23 May); think.com (24 May); css.gov (June); mitre.org, .uk (July) |
| 1986 | TAT-3 transatlantic cable is retired (1 Sept.) |
| 1987 | An Integrated Services Digital Network (ISDN) is deployed, capable of handling voice, data and video. (16 December) |
| 1987 | The first Freenet comes on-line 16 July in Cleveland, OH. |
| 1987 | Superconductivity is discovered - the transmission of electricity without resistance through low temperature material. |
| 1987 | TDD (telecommunications device for the deaf) is initiated. |
| 1987 | UUNet is founded by Rick Adams. |
| 1988 | A self replicating program, a worm, invaded hundreds to thousands of computers, making them unusable. (3 November) |
1990s
| Year | Event |
| 1990 | Timothy Berners-Lee at CERN develops World Wide Web (December) |
| 1990 | ARPANET is retired (28 February) |
| 1992 | A new Internet protocol, the Hypertext Transfer Protocol (HTTP), was introduced to improve the efficiency of document retrieval (July) |
| 1992 | The Internet Society (ISOC) is formed. |
| 1993 | Mosaic, which is one of the first web browsers is released. |
| 1994 | Yahoo goes on-line. |
| 1994 | The World Wide Web Consortium (W3C) is created. |
| 1995 | CDMA (Code Division Multiple Access) is introduced. |
2000s
| Year | Event |
| 2000 | 3G Standard is finalized. |
| 2002 | IEEE Communications Society celebrates it's 50th Anniversary |
