Communication

C

Postal Services

Different societies have also devised systems for transporting messages from place to place and from person to person. The earliest were courier-type services; messengers carried memorized or written messages from one person to another, and returned with the reply. The Persian and Roman empires and some Asian societies sent couriers regularly along planned routes to retrieve reliable and timely information about trade and military affairs from distant areas.

In Europe, similar systems were established by commercial concerns and merchants who needed to exchange information about trade routes and goods. The ruling aristocracy used trusted messengers to carry confidential or sensitive information from capital to capital or kingdom to kingdom, but they were typically soldiers or servants. Over time, these arrangements evolved into government-operated systems for any citizen or subject to post messages to any other, financed by charging users a tax or fee for postage (verified by postage stamps).

In the United States, the postal service was established by the government in 1789, and the postmaster general's office was created to supervise the mail service. The first postmaster general of the United States was Samuel Osgood. In the late 19th century, as the United States expanded its territory west beyond reliable roads or rail lines, the U.S. Post Office started the Pony Express, reviving courier-style services in the new territories. Pony Express riders carried sacks of mail through rugged and remote territory, relaying their loads from one rider to the next. The Pony Express quickly became renowned for its speed of delivery.

Over time, the U.S. Post Office took advantage of new transportation systems. Huge volumes of mail were sent across the country on trains, and the Post Office started its own postal security force to prevent the mail from being stolen in railroad holdups. They were also the first postal service to hire pilots to fly mail to distant or rural locations within the United States and overseas. By the 1930s every small town and rural route had carrier service; in many places, deliveries were made twice a day. As demand for postal services grew, the U.S. Post Office developed systems for coding and sorting the mail more quickly, notably the neighborhood ZIP Code system in the 1960s.

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The U.S. Post Office became a private operation in the 1970s under the supervision of the U.S. federal government, and was renamed the U.S. Postal Service (USPS). Today the USPS is self-supporting, and is exploring a number of new technologies that will allow it to offer better service at lower cost, including electronic document delivery services and new electronic sorting systems.

D

Telegraphy

The first truly electronic medium was the telegraph, which sent and received electrical signals over long-distance wires. The first practical commercial systems were developed by the physicist Sir Charles Wheatstone and the inventor Sir William F. Cooke in Great Britain, and by the artist and inventor Samuel F. B. Morse in the United States. Morse demonstrated the first telegraph system in New York in 1837. But regular telegraph service, relaying Morse code (system of code using on and off signals), was not established until 1844. Telegraphers would translate the letters of the alphabet into Morse code, tapping on an electrical switch, or key. The telegrapher at the other end of the line would decode the tapping as it came in, write down the message, and send it to the recipient by messenger.

Telegraph systems were immediately useful for businesses that needed to transmit messages quickly over long distances, such as newspapers and railroads. A telegraph room installed in the United States Capitol in 1844 was the center of a sensation when news of the nomination of James K. Polk as the Democratic presidential candidate was conveyed by telegraph between the convention in Baltimore, Maryland, and the Capitol Building in Washington, D.C. In cities, thousands of telegraph lines suspended on poles webbed the streets by the latter half of the 1800s. Telegraph cable was first laid under the Atlantic Ocean in 1858, and regular transatlantic telegraph service began in 1866.

The telegraph made it possible for many companies to conduct their business globally for the first time. Because price changes could be communicated almost instantaneously, the telegraph also prompted the reorganization of American commodities markets. Prices became uniform from city to city, and futures (agreements to buy a commodity at a fixed price on a fixed date in the future) markets were established. In addition, standard time zones across the United States were established so that railroads could set regular and consistent schedules as trains moved across the country, enabling the railroads to check on schedules, passengers, and freight via telegraph.

Telegraph technology became more sophisticated, especially after its competitor, the telephone, was introduced in the 1890s. Telegraph systems evolved into telex systems, in which machines eliminated the need for coding and decoding the messages. Users could type in a message, and the identical message would appear at the recipient's end, carried over telegraph and telephone lines (and eventually satellite systems) to telex machines anywhere in the world. In remote areas where long-distance telephone service was unavailable or impractical, telex machines were widely used (much like an early version of electronic mail). Telegraph and telephone lines were also used to transmit pictures via an early version of facsimile called telefacsimile or Wirephoto service; newspapers used Wirephoto to transmit photographs as early as the 1930s.

E

Telephone

Early devices capable of transmitting sound vibrations and even human speech appeared in the 1850s and 1860s. The first person to patent and effectively commercialize an electric telephone was Scottish-born American inventor Alexander Graham Bell. His patent, granted in 1876, was titled Improvement in Telegraphy, and contained the design of a device that would transmit the human voice over wires instead of electrical clicks or other signals, like the telegraph. Originally, Bell thought that the telephone would be used to transmit musical concerts, lectures, or sermons. The American inventor Elisha Gray filed an intent to patent at the same time, but after many court battles, Bell was given the rights to the invention. Another court case, on behalf of Italian-American inventor Antonio Meucci, was headed for the Supreme Court of the United States when Meucci died and the case was abandoned.

Bell and his financial backers established the Bell Telephone Company. In an extraordinary business move, Bell decided to lease telephones rather than sell them. His next step would be to build the connecting networks and sell services on those networks to customers. Bell began by leasing pairs of telephones that would connect two locations, such as a businessman's home and office, or between two partners' offices. However, the real appeal of telephone service emerged with the opening of the first telephone exchange—a switchboard connecting any member of a group of subscribers to any other member—in 1878.

The Bell Telephone Company established as many exchanges as possible, especially high-quality voice lines for wealthy city customers. Some customers resisted using the telephone at first because it did not leave a written record of transactions or orders; however, others saw this feature as an advantage. By 1894 roughly 260,000 Bell telephones were in use in the United States, about one for every 250 people.

After Bell's patents expired in 1893 and 1894, other companies began manufacturing telephones, wiring new networks, and installing exchanges. The new exchanges connected people in rural communities and residential households. Some were rural cooperatives owned and operated by the customers. The American Telephone and Telegraph Company (AT&T), which bought the Bell Telephone Company in 1900, developed switching systems to connect calls between exchanges, and eventually began experimenting with long-distance connections.

Between the 1880s and the 1980s the telephone system in the United States had an enormous effect on the quality of life and work. In rural communities, telephone service meant an end to the isolation and loneliness experienced by many farm and ranch families. Families whose members moved away to school or new jobs could stay in contact with each other over the phone. For ill or disabled people, the telephone became an indispensable link to the outside world. Telephone service also enabled immediate contact with emergency services, such as the police, fire department, or emergency medical services. By the 1960s the telephone was considered so essential that telephone companies provided basic services at reduced rates to elderly and disabled people.

The telephone network has also provided the electronic network for new computer-based systems like the Internet (a worldwide interconnection of computers and computer networks), facsimile transmissions (copies sent electronically by fax machines through telephone lines), and the World Wide Web (library of resources stored on computers and accessed through the Internet). The memory and data-processing power of individual computers can be linked together and data transmitted over telephone lines, even internationally via satellite, by connecting computers to the telephone network through telephone-like devices called modems (modulator-demodulators). The telephone network itself now relies extensively on computer-based switches and exchanges that have made all kinds of new telephone-related services possible, such as call waiting, call forwarding, call return, voice-mail services, and caller ID. The relationship today between computers and the telephone system is inseparable.

F

Radio

The telegraph and telephone were systems for distance communication that sent electrical signals through wires. The earliest system for sending electrical signals through the air via electromagnetic waves was called wireless, and later radio. Radio technology was based on the discoveries of James Clerk Maxwell. In 1864 he proposed a theory that electromagnetic signals did not need wires to be transmitted, but could be carried on electromagnetic waves. He demonstrated that light, electricity, and heat are all part of a band of radiant energy we now call the radio or electromagnetic spectrum (see Electromagnetic Radiation).

The Italian electrical engineer Guglielmo Marconi was the first person to invent a true wireless radio. In 1895 he built a system that could send and receive a signal at a distance of close to 3 km (close to 2 mi). He moved to England, and by 1899 the British Marconi Company had sent signals across the English Channel. In 1901 Marconi received the Morse code signal for the letter S sent across the Atlantic Ocean to Canada.

Marconi's radio system used a spark-gap technology that could transmit only simple on-off signals—so radio signaling used an on-off system like Morse code. This type of radio technology is called radiotelegraphy. Wireless was especially valuable for ships in distress, so that other ships could be dispatched to save their passengers and crews in times of emergency.

In 1901 the Canadian-born American physicist Reginald Fessenden patented an alternator that would use continuous waves instead of on-off spark-gap signals. This system could also send signals much farther and with much less background noise, so it could carry the sound of the human voice. This new approach to radio was called radiotelephony. On Christmas Eve and New Year's Eve in 1906, Fessenden produced the first radio broadcasts from Brant Rock, Massachusetts, which were picked up as far away as New York and by ships in the Atlantic. Another American, Lee De Forest, is best known for his invention of the triode vacuum tube, called the Audion, which amplified radio signals so that musical concerts, dramatic performances, and speeches could be heard clearly over the radio.

Radio technology improved rapidly throughout the 20th century. The first breakthrough was the invention of the cat's-whisker receiver, or crystal set, which used a silicon crystal and a small metal wire to detect radio waves clearly. Later improvements were made in the valves, or tubes, such as De Forest's Audion, which amplified the signal once it was received. Radio transmissions initially used amplitude modulation (AM) to superimpose audio signals onto radio waves. The invention of frequency modulation (FM) radio provided much more sensitive and clear radio transmission and reception. Tuners became more sensitive, and more broadcast signals were sent over the air at different frequencies. In the 1950s and 1960s radio manufacturers began replacing the bulky and heat-generating vacuum tubes in radios with transistors, and radios became smaller.

In the United States, the first regularly scheduled public broadcasts were made in 1920 from station KDKA in Pittsburgh, Pennsylvania. Other stations were soon established across the country, and companies like the Radio Corporation of America (RCA) and Westinghouse, which owned many stations, formed radio networks that would produce and share programming. Radio programming soon filled the airwaves. Competitors using the same frequencies jammed each other's signals.

Eventually the radio industry asked the federal government to intervene in their disputes over frequencies and signal power. The Federal Radio Commission (FRC) was created in 1927 and was given the task of allocating frequencies to different users. However, the FRC was a somewhat ineffective body until the Communications Act of 1934, when it was renamed the Federal Communications Commission (FCC) and given a budget and a staff. FCC rulings had the power of law, and the agency was responsible for issuing licenses to radio broadcasters for particular bandwidths, frequencies, and signal powers. License holders had to demonstrate that they operated their radio stations “in the public interest, convenience, and necessity” (see Radio and Television Broadcasting).

Most large cities and many small towns have a number of local radio stations, on both the AM and the FM frequencies. Other radio frequencies are used for other purposes, especially television. Certain frequencies are used to relay wireless telephone calls across small defined geographic areas called “cells” (see Cellular Radio). In the United States, some frequencies are dedicated to citizens-band (CB) radio, which long-distance truck drivers use to check on road conditions, report problems, or just to chat. Special frequencies are devoted to emergency use, such as police, fire, or emergency medical dispatching, or to aviation radio. An important part of the radio spectrum is shortwave, which can carry radio signals around the world. International shortwave broadcasts are very popular.

G

Television

Just as inventors had sought ways to transmit sound using electromagnetic waves, they worked to develop similar methods for transmitting pictures. By the first decade of the 20th century, the basic ideas of television technology were understood, although it took several more decades to work out the necessary improvements in existing technology.

Two pioneers independently created the first workable television systems—American inventor Philo T. Farnsworth and Russian-born American engineer Vladimir K. Zworykin. Farnsworth used an electronic camera he called an image dissector to transmit a picture of a dollar sign in 1927. He patented aspects of his system, and developed his television further in the 1930s, but lost his financial backing when World War II (1939-1945) began.

In 1923 Zworykin first demonstrated an electronic television camera he called the iconoscope. At the time, he was working for Westinghouse Electronic Corporation, but Zworykin moved to RCA when David Sarnoff, vice president of RCA, became interested in his invention. Sarnoff supported the development of the iconoscope when RCA obtained the rights to Westinghouse's radio research projects in 1930.

In 1932 RCA was transmitting 120-line pictures, and by 1935 had a 343-line image. The first television sets were offered for sale in the United States in 1938, although they had been available in England for two years before that. Standards for television broadcasting and television receivers were put in place by the FCC in 1939; in 1941 the commission accepted industry recommendations for television technology standards that are still in place today. RCA started the first regularly scheduled television programming on July 1, 1941, in New York City.

World War II put television technology on “hold.” After the war, however, technical improvements and American prosperity created a great demand for radio and television systems. At the end of the war, only six television stations were broadcasting in the United States (in New York City; Washington, D.C.; Chicago, Illinois; Philadelphia, Pennsylvania; Schenectady, New York; and Los Angeles, California), and for only a few hours each day. By 1948, 34 stations were broadcasting television signals in 21 major cities, and about 1 million television sets had been sold. By the end of the 1950s television was on the air almost everywhere in the country. The FCC set aside channels for public or educational television to ensure quality programming and to reach remote communities. Three national television networks emerged—NBC, then owned by RCA; CBS; and ABC.

Since the 1950s many improvements have been made in television technology, particularly the introduction of color television in the 1960s. Image reception has become clearer, and screens have become larger. Most televisions can now receive stereo sound. The widespread growth of cable television since the 1960s has introduced many new channels and types of programming into American homes. And today direct-broadcast-satellite (DBS) services allow individual households to receive hundreds of channels carried by satellites directly into their homes.

There is no doubt that television has been one of the most important communication technologies in history. Televisions are switched on an average of seven hours a day in American households. Debates continue about the medium's effects on children, culture, education, politics, and community life. Critics say that television feeds a constant stream of simplified ideas and sensationalistic images, that it has a negative effect on political campaigns and voting patterns, that it destroys local cultures in favor of a bland national culture, and that it has encouraged the growth of an uncritical and passive audience. Defenders say that television provides a great deal of high-quality educational and cultural programming, and that it is the major source of national and international news and information for most U.S. citizens. Television can be a very effective teaching tool in the classroom and at home. And, as the Canadian writer Marshall McLuhan pointed out, perhaps nothing has been more responsible for creating the global village—the sense that we can see and hear events anywhere in the world as they happen, and so can feel more connected to other places.

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