Telephone is an instrument that sends and receives voice and data messages in the form of electrical, optical, or radio signals. It is one of our most valuable means of communication. In just a few seconds, you can telephone a person across the street or on another continent. Alexander Graham Bell, a Scottish-born teacher of the deaf, patented the telephone in 1876. The word telephone comes from two Greek words meaning far and sound.
A telephone enables people to talk with one another at distances beyond the range of the human voice. Modern smartphones can send and receive not only voice messages but also written words, songs, drawings, photographs, and video. A smartphone is a cellular telephone that also works as a small computer.
Telephones are connected through a vast, complex communication network. The network includes large computers, tremendous lengths of copper wire and hair-thin glass fibers, cables buried in the ground and laid along the ocean floor, radio transmitters and receivers, and artificial satellites orbiting far above Earth.
Many telephones connect with the communication network by means of wires that run through the walls of buildings. Usually, a small clip connects a telephone to the wiring. Other phones, called wireless telephones or mobile telephones, are not wired to the network but rather are linked to it via radio signals.
How a telephone works
Telephones come in a wide variety of designs. For much of the 1900’s, many of the parts inside phones were mechanical. In contrast, most contemporary telephones are primarily electronic devices that can include cameras, touch screens, video recorders, and such software as internet browsers.
Types of telephones.
Phones with a traditional design consist of a base unit and a handset that is held near the ear and mouth during a call. The handset is connected to the base unit by a cord or by radio signals. When messages travel as radio signals between handset and base, the phone is called a cordless telephone.
The mouthpiece of the handset contains a microphone that picks up the user’s voice and converts it into outgoing electrical signals. The earpiece of the handset contains a speaker that converts incoming electrical signals into sound that the user can recognize.
Many phones vary from this traditional design. Sometimes, a headset takes the place of a handset, allowing users to talk on the phone without using their hands. A speakerphone also allows hands-free calls. It has a microphone that can pick up all voices in a room and a loudspeaker that can broadcast incoming sound throughout the room. Often, a desktop or laptop computer can be used as a telephone. The computer needs special software, a microphone, speakers, a device called a sound card to digitize the electrical signals, and an internet connection. Digitizing the signals involves translating them from their original form into tiny impulses that represent numbers. Some phones contain built-in computer hardware and software that allow them to connect directly to the internet using Wi-Fi (Wireless Fidelity), Bluetooth, Ethernet, and other interfaces that are standardized for use by almost any modern phone.
A common type of wireless telephone is the cellular telephone. Cellular telephones communicate with radio antennas arranged in small geographical areas called cells. Some wireless telephones are satellite telephones that communicate with artificial satellites instead of land-based antennas.
Most cell phones are handheld units small enough to be carried in a pocket or a purse. Many cell phones are equipped with extra communication or computer features. For example, most of them can store phone numbers, calendar events, or other data. In addition to internet access and a digital camera, the phones may also include such features as a digital music player, alarm clock, electronic games, and a receiver for Global Positioning System navigation (see Global Positioning System). Cellular phones with a variety of computer features are typically called smartphones. 
Parts of a telephone.
All telephones have three basic parts: a dialing mechanism, a microphone, and at least one speaker. Other common parts of modern phones include one or more printed circuit boards with various electronic chips, a display, radio equipment, and a battery or other power source. The battery is often a lithium-ion battery, which is rechargeable and lasts for many years. Usually, a plastic or metal housing surrounds the parts of a phone. For smartphones, an additional cover or protective case is often used.
The dialing mechanism
enables a caller to enter phone numbers. On most phones, the dialing mechanism is a set of numbered buttons or keys called a keypad or keyboard. On many phones, the keypad uses tone dialing. In tone dialing, each key generates a pair of accurately controlled tones when pressed. Computers in the phone network recognize the sequence of tones as the phone number and direct the call accordingly.
The microphone,
also called the transmitter, changes sound waves into electrical signals and sends them on their first step into a phone network. In most cases, the microphone is a small electret condenser microphone, also called an electret capacitor microphone. The microphone has two metallic plates set slightly apart. The plates are electrically charged and serve as a capacitor, a device that stores a charge. The flexible front plate—which typically consists of an electrically insulating foil backed by a metal coating—acts as a diaphragm (thin, vibrating disk). The back plate is fixed and faces the foil side of the diaphragm. Sound waves make the diaphragm vibrate, causing variations in the capacitor’s electric current. These variations are an electric “copy” of the sound.
The speaker,
also called the receiver, collects electrical signals coming from a phone network and changes them into sound waves. A speaker is like a microphone in reverse. A typical telephone speaker consists of a wire coil called a voice coil, a permanent magnet, and a diaphragm. Electrical pulses pass through the voice coil, creating varying magnetic forces around the coil. These forces interact with the forces of the permanent magnet, causing the coil to vibrate rapidly. The diaphragm, which is attached to the coil, vibrates with it. The diaphragm vibrations produce sound waves that duplicate the voice of the caller on the other end of the line.
The printed circuit board
contains the “brains” of a modern electronic phone. The circuit board contains several tiny chips that control various functions of the phone. For example, one chip may generate a sound or vibration to alert a person that he or she has an incoming call. This chip has replaced the small bell that served the same function in early phones. Some chips may help the phone interact with the wire or radio antenna that connects the phone to a network. Others may help process the electrical signals into a form that can be sent over a network. Still others supply power to the circuit board or help recharge the phone battery.
An important chip called a microprocessor receives inputs from the dialing mechanism and sends outputs to the phone’s display. In a cell phone, the microprocessor also communicates through special radio channels with control centers in a cell network. The control centers tell the microprocessor how to send and receive calls through the network. In addition, the microprocessor coordinates the rest of the functions on a circuit board.
Memory chips on the circuit board store instructions and data that are used by the phone’s microprocessor. These chips also store inputs from phone users, such as a directory of phone numbers, voice-mail messages, text documents, or digital photographs. Memory chips in a modern phone can store a large amount of digital data. The capacity of the memory chip is often specified in gigabits. A gigabit is one billion data bits.
The display
is usually a liquid crystal display (LCD) screen. It may perform only one or two simple functions, such as displaying a clock, or an incoming caller’s phone number or name. On more advanced phones, the display may also be used for such functions as viewing a phone directory, playing electronic games, using a calculator, or reading and writing text messages.
The radio equipment.
Wireless phones have radio transmitters, receivers, and antennas. An antenna may take different forms, depending on the type of phone and the distance the radio signals need to travel. For example, the antenna may be a small device or a short length of wire inside the phone, a short stub or long rod on a handset, or a satellite antenna. The transmitter and receiver circuitry may be mounted on the phone’s circuit board. In a cordless phone, both the handset and the base contain radio equipment.
The power source.
Phones that have a traditional copper wire connection to a phone network usually receive their power over the phone line from the central office of the phone company. In most cellular phones and cordless phone handsets, the power source is a small internal battery. Some phones have a cord that is plugged into a regular wall socket. Phones that have a modern fiber-optic-cable link from a home or building to a phone network are linked at the building to a device called an optical network terminal. Because electricity cannot travel over an optical fiber, the optical network terminal is connected to the home or building’s electrical service, with a back-up battery also installed.
How a telephone call travels
A caller can connect to a telephone network in a number of ways. The traditional way involves using a phone connected by wires to the worldwide Public Switched Telephone Network (PSTN). A wire or fiber-optic connection to the PSTN is often called a landline.
The PSTN relies on a technology called circuit switching. A circuit-switched network requires a circuit (channel) to be opened between two callers before they can talk to each other. The phone signals flow in sequence over this circuit. The circuit is dedicated to that one call and cannot be used by other callers until the call ends. Circuit switching has been the basic technology used to transmit phone calls since the late 1800’s.
Today, calls can also be made using a phone connected to the internet, rather than the PSTN. The internet relies on a technology called packet switching. In a packet-switched network, phone calls are divided into packets of data that are sent individually over many channels. The packets are reassembled when they arrive at their destination. Transmitting calls over the internet or a similar packet-switched network is called Voice over Internet Protocol (VoIP). In many homes and offices, VoIP has replaced phone calls made over the PSTN.
In practice, most traditional long-distance calls already rely partly on packet switching. Even if the phones on both ends of a call have a traditional PSTN connection, phone companies often will route the call through parts of their networks that rely on packet switching.
In addition, people can also make calls with a wireless phone that sends and receives calls as radio signals. Most wireless phones rely on circuit switching, which means the signals travel continuously along single, dedicated radio channels. However, more advanced wireless devices can use packet switching to transmit and receive large amounts of data, including VoIP calls.
Traditional phone calls.
On a traditional phone network, a caller first listens for a dial tone—that is, a sound indicating that the phone has a connection to a central office. The central office is a facility of a local phone company, also known as a local exchange carrier. Then, the caller dials a phone number, causing electrical signals to travel from the phone to a switch in the central office. The switch uses the phone number as an “address” to determine where to route the call. At one time, human operators switched phone calls manually by plugging electric cords into a switchboard. Today, electronic switches—actually computers—route calls.
If the call is for someone connected to the same central office, the switch simply creates a loop between the two phones. If the call is for someone farther away, the switch routes the call to another local switch or to a long-distance switch. The call may pass through several switches of various local, national, and international carriers before reaching the central office of the local carrier that serves the phone being called. A switch in that office routes electrical signals to that phone, causing it to ring. When that phone is answered, a connection is made between the two phones. All the routing and switching occurs in seconds. Loading the player...
Telephone call
Once the connection is established, the electrical signals that make up the message travel between the two phones. Older traditional phone signals might begin and end their journey as analog signals transported over copper wires. Analog signals are continuously varying signals that are exact reproductions of the sound. However, for most of the journey, the signals travel as digital signals. Digital signals are in binary code—the same code that computers use. Binary code consists of sequences of two digits, 0 and 1. Phone signals are digitized by being divided into thousands of tiny impulses that can each be represented by a string of 0’s and 1’s. Other techniques of coding are in wide use. But, initially, all digital signals are represented as 0’s and 1’s.
Analog phone signals may travel all the way to the central office switch before they are digitized. Alternatively, a concentrator may digitize the signals before they reach the central office. As the signals move through each switch in a network, the digital sequences are duplicated. This duplication, known as repeating, maintains the strength and accuracy of the signals over long distances.
Most digital signals travel through the network over fiber-optic cables. These cables consist of bundles of hair-thin glass fibers that carry digital signals as impulses of light. A strand of optical fiber can carry thousands of times as much information as a pair of copper wires. Signals from millions of phones may travel through a single fiber-optic cable at a time. The cables may be buried in the ground or laid on the ocean floor. The glass strands are shielded with metal coverings to protect the cables. These metal “shields” also provide a means of sending electrical power to repeater amplifiers used in undersea cables.
The digital signals may also be transmitted on short-wavelength radio waves called microwaves. The network uses a series of relay stations to direct microwaves over vast distances. A dish antenna at a relay station receives a signal, and another dish antenna retransmits the signal to the next station. To direct the signals across oceans, the network uses communications satellites.
Cellular phone calls.
Companies that provide cellular phone service maintain one or more cellular networks. In each network, a city or other geographical region is divided into cells. Each cell has three or more antennas, pointing in different directions known as sectors. Most of these antennas are mounted on steel towers or on buildings. Cables connect the antenna to a radio receiver and transmitter at the base of the tower. This radio equipment site is called a base transceiver station, or just a base station. A large city may have hundreds of cells and base stations. There are several hundred thousand base stations throughout the United States. Loading the player...
Cellular telephone
In a typical cellular network, a piece of equipment called a base station controller (BSC) manages a small group of base stations. A mobile telephone switching office (MTSO), also known as a mobile switching center (MSC), then manages one or more BSC’s. A BSC helps perform some of the more basic tasks of an MTSO. In some networks, BSC’s may not be used.
During an outgoing call, a cell phone sends radio signals to the antenna in the cell where the phone is being used. The base receiver picks up the signals, and the base transmitter routes them to the BSC that is linked to the base station. The BSC then routes the signals to its MTSO. The MTSO switches the signals to another base station (usually via a BSC), or to another MTSO, or to an office that is part of the wire-based PSTN. Similarly, an MTSO ensures that the signals for an incoming call are routed to the correct base station. The base transmitter sends the call to a phone in the cell. The base stations, BSC’s, and MTSO may be connected by ground-based lines or by microwaves.
MTSO’s also play other roles. For example, they coordinate the handoff or handover of calls as a phone moves from one cell to another. An MTSO also keeps track of the location of phones within its network so that calls can be routed properly. If a phone within the network is not linked to that company’s cellular service, the MTSO verifies that the phone subscribes to another service. The MTSO relays information about the usage of the phone to the other service provider. When a phone leaves its home network and enters the network of another provider, the phone is said to be roaming.
A cellular company is assigned hundreds of radio frequencies for transmitting phone signals within a given region in a network. Frequency refers to the number of times an electromagnetic wave, such as a radio wave, vibrates per second. Each cell uses a portion of these radio frequencies. The company can use the same frequencies in different cells throughout the network, as long as the same frequencies are not used in two cells that border each other. If the same frequencies were used in adjacent cells, signals from different phone calls would interfere with one another. Because frequencies can be reused across networks, large numbers of people can make calls at the same time.
During calls, signals travel on one or more frequencies within an available bandwidth (range of frequencies). The frequencies make up the radio channels over which the calls take place. Most of a company’s assigned frequencies are used to transmit phone calls and other data. However, some of the frequencies are used for control channels. Cellular phones communicate with an MTSO over a control channel. For example, the MTSO uses a control channel to tell a phone which frequencies it should use to receive an incoming call. When the phone moves into another cell during a call, the MTSO uses a control channel to notify the phone to change frequencies. Even when a cellular telephone is not engaged in a call, the phone actively communicates with nearby towers.
If cellular phone signals are transmitted as analog signals, each call requires two channels dedicated only to the one call. One caller’s voice travels on one channel, and the other caller’s voice travels on the other channel. However, most cellular signals are transmitted as digital signals. Digital signals can be divided or manipulated so that they travel along channels in different ways. As a result, three or more digital cellular channels can occupy the same bandwidth that would be required for a single analog channel. Digital signals also enable a feature called voice activation. During a telephone call, there are pauses in which neither person is speaking. These instances of quiet time can be used for the transmission of other digital signals without being noticed by the people on the call.
In order for cellular and internet technologies to work together worldwide, technical information about the design, manufacturing process, and installation of telephones and networks is shared in documents called standards. For modern cellular telephones and networks, an international technical group called the Third Generation Partnership Project (3GPP) has defined the standards known as Long Term Evolution–Advanced. These standards include 3G LTE (Third Generation Long Term Evolution), 4G LTE, and 5G LTE. Earlier standards of the 1970’s and 1980’s, 1G and 2G, made the change from analog technology to digital technology. The more recent standards—3G, 4G, and 5G—have continued the development of telephony, with extraordinary increases in data speeds, video processing, and digital storage for smartphones and the worldwide cellular networks that make such phones possible.
VoIP phone calls.
Making phone calls over the internet or a similar network typically requires a broadband connection. The term broadband refers to the high-speed transmission of data. Broadband services include cable modem service and digital subscriber line (DSL) service. A cable modem is a device that links a computer to a network via cable television lines. DSL is a technology that increases the data-carrying capacity of traditional copper phone lines. Broadband data service is also provided over fiber-optic lines, via cellular networks, and through the air using satellites or other advanced wireless technologies.
VoIP calls are typically made in one of three ways. One way is by plugging a normal phone into an analog telephone adapter (ATA). The ATA changes analog signals into digital signals. When a phone number is dialed, the ATA digitizes the tones from the keypad and sends them to a call processor maintained by a VoIP company. The call processor is a device that maps (translates) a phone number into an Internet Protocol (IP) address. An IP address is a number that identifies a specific device connected to the internet. Mapping is done using a computer program called a soft switch. The soft switch connects the two ends of a call.
A caller can also use a special VoIP phone that has a direct connection to a networking device called a router. Many VoIP phones have a handset and keypad like a traditional phone. But all the computer equipment and programs needed for VoIP are contained within the phone. A Wi-Fi phone is a type of wireless VoIP phone. Wi-Fi is a common wireless packet-switched networking technology. A Wi-Fi device sends data through the air to a base station or router in the network. Many cities have citywide Wi-Fi networks.
A third way to make VoIP calls is by using a desktop or laptop computer. Modern computers have the necessary VoIP software, a microphone, speakers, a sound “card,” and two-way video capability. Zoom software is one of several software applications that extend the VoIP concept to online meetings, which include two-way sound and video for up to hundreds of participants at a time.
A VoIP call sent out over the internet travels in much the same way that a web page or an email message travels. The sending device splits the call up into packets of digital data. Information on each packet indicates the destination of the packet and how it should be reassembled once it arrives. The sending device transmits individual packets to one or more routers. Each packet travels from router to router until it arrives at its destination. After all the packets arrive, the receiving device reassembles them.
Telephone services
Telephone makers and telephone service providers offer a variety of services to callers. Besides cellular services, these services include operator, business, and residential services.
Operator services
use human operators or computers that imitate the human voice to provide various kinds of assistance. For example, in many countries, a person who needs help to complete a call can dial 0 to reach an operator at a local phone company. A service called directory assistance provides callers with the phone numbers of parties they wish to call, and can connect calls as well. Many countries have short numbers that can be dialed to reach emergency police, fire, or ambulance service. In the United States and Canada, the standard emergency number is 911. Common emergency numbers elsewhere include 112 and 999.
Business services.
Most businesses have more than one phone. A business may set up its phone system in various ways. In one arrangement, provided by the local phone company, each phone has its own number. One name for this service is Centrex service. In another arrangement, known as a private branch exchange (PBX), several lines owned by the phone company are connected to a switching system owned by the business. In this system, the business has one phone number, and each phone has a separate extension number. Employees can call one another merely by dialing the proper extension. A Centrex or PBX system may use either traditional telephone lines or a business version of VoIP.
Private line service, or dedicated service, is designed for businesses that have branch offices with which they communicate frequently. The phone company sets up a line or group of lines that run only between those offices. Private line service eliminates the need to send each of these calls over a public telephone network. Private lines may be equipped to handle large amounts of computer data or fax (facsimile) transmissions.
In many businesses, a system called voice mail answers incoming calls. A voice recording stored on a computer chip gives callers instructions to help them reach the desired party. If that party is not available, the caller can leave a message that the system records.
Another common business service is toll-free service, also called Freephone service or Freecall service. A subscriber to the service is issued a special number and pays the charges for all calls received by that number. Many companies that sell goods or services by mail or by telephone use toll-free service. In the United States and Canada, the service is commonly called 800 service, because the first three digits of toll-free numbers were all originally 800. Today, many toll-free numbers in the United States and Canada begin with 888, 877, or 866.
Residential services.
Many home telephone users have access to a variety of services. For example, the phone company can provide voice-mail service similar to that used by businesses. Call waiting lets a person put one call on hold to speak with another caller. Call forwarding automatically sends all calls to a designated phone number. Call blocking automatically rejects calls from phones whose numbers are designated by the subscriber. Similarly, subscribers can set up a digital “contacts” directory and only receive calls from that directory. A service called automatic caller identification, or caller I.D., enables a person to see the caller’s phone number or name before answering. Automatic callback service notifies a caller when a busy number he or she has been dialing becomes available.
Other services.
Many companies sell phone cards or calling cards that can be used to pay for long-distance, international, or cellular calls. The cards usually resemble credit cards. Many pay phones can read a phone card electronically and automatically deduct the cost of the call. Alternatively, the caller may have to first dial an access number to use the card.
Other telephone services supply information or advice, or enable callers to participate in informal polls or to enter contests. Often, a caller must dial a special number to access such services.
The telephone industry
For many years, telephone companies offered landline voice communication as their primary service. Today, the telecommunications industry includes voice, data, and video transmission over both wire-based and wireless networks. The transmission occurs over the PSTN, the internet, and private networks. A single company may offer several types of services. For example, a number of companies that once specialized in distributing cable television programs now also offer high-speed internet access and telephone service. Similarly, companies that once specialized in landline phone service are beginning to offer television programs as well. Some companies specialize in VoIP service.
In the United States,
hundreds of companies provide traditional local telephone service. Some have only a few hundred lines, and others have millions. Two firms provide the majority of local service: AT&T Inc., and Verizon Communications Inc. For cellular services in the United States, AT&T, Verizon, and T-Mobile/Sprint are the major carriers.
A few hundred U.S. companies offer traditional long-distance service. Some own all of their telephone lines and switches. Others—mostly the smaller companies—buy service from large firms and resell it to their customers.
Another type of U.S. telephone company is the competitive local exchange carrier. It provides telephone services in competition with established local telephone companies, most often to businesses.
In other countries.
For many years, the government provided telephone service in most countries. But since the 1980’s, many countries have sold part ownership—or in some cases, a whole telephone company—to private citizens. As in the United States, most of the world’s largest telephone companies offer a variety of telecommunication services, including local and long-distance landline, wireless, and internet services.
The wealthiest areas of the world have modern, extensive telecommunication systems. In these areas, both wire-based and wireless phone networks link almost all regions with one another and with other continents. These areas also have widespread access to the internet.
In other areas, telecommunication systems are less advanced. Traditional phone equipment and networks are often concentrated in the cities and larger towns. However, many of these less-developed areas are experiencing large growth in cellular phone usage, with cellular access to the internet. It is often easier and cheaper to develop cellular networks than wire-based networks, especially in sparsely populated regions.
History
Bell’s invention.
Alexander Graham Bell, a Scotsman who came to the United States in 1871, invented the telephone. Bell was a teacher of the deaf in Boston. At night, he experimented with a harmonic telegraph, a device for sending several telegraph messages at once over one wire. Bell developed the idea of the telephone in 1874 but continued experiments with the harmonic telegraph.
On June 2, 1875, one of the metal reeds of the harmonic telegraph stuck. Bell’s assistant, Thomas A. Watson, plucked the reed to loosen it. Bell, who was in another room, heard the sound in his receiver. He realized that the vibrations of the reed had caused variations of electric current. In turn, the electric current had reproduced the same variations in the receiver he was using.
On March 10, 1876, Bell finally succeeded in speaking words over a telephone. He was about to test a new transmitter. In another room, Watson waited for the test message. Suddenly, Bell spilled some acid from a battery on his clothes. He cried out, “Mr. Watson, come here. I want you!” Watson heard every word clearly and rushed into the room. In June 1876, Bell exhibited his telephone at the Centennial Exposition in Philadelphia, Pennsylvania.
Early telephones.
In August 1876, Bell received the first one-way long-distance call. This call came over an 8-mile (13-kilometer) telegraph line between Brantford and Paris, both in Ontario, Canada. In October 1876, Bell and Watson held the first two-way long-distance telephone conversation. They spoke between Boston and Cambridgeport, a part of Cambridge, Massachusetts, a distance of about 2 miles (3 kilometers). In 1877, Charles Williams, an electrical workshop owner, installed the first line intended exclusively for telephone use. It extended 3 miles (5 kilometers) between Williams’s home in Somerville, Massachusetts, and his shop in Boston.
The first telephones used no switchboards. A pair of iron wires connected each pair of phones. As more telephones came into use, each was connected to all the others. Over 1,000 connections were required to link only 50 phones. Switchboards solved this problem by bringing together the wires from all phones in an area. The first switchboard began operating in 1877 in Boston.
Telephone services soon began operating in other parts of the world. Service began in Australia in 1878 and in the United Kingdom in 1879.
Almon B. Strowger, an American inventor, patented an automatic switching system in 1891. The first commercial switchboard based on his patent opened in La Porte, Indiana, in 1892. The caller pressed buttons to get the number, then turned a crank to ring the phone.
In 1891, the first international telephone connection was established, between London, England, and Paris, France. In 1892, phone service began between New York City, New York, and Chicago, Illinois. In 1896, the first dial telephones began operating in Milwaukee, Wisconsin.
The Bell System.
Bell, Watson, Gardiner G. Hubbard, and Thomas Sanders formed the Bell Telephone Company in 1877. Hubbard was Bell’s father-in-law, and Sanders was the father of one of Bell’s pupils. They had helped pay for Bell’s experiments. The Western Union Telegraph Company also entered the telephone business in 1877. Western Union used transmitters developed by Thomas A. Edison, the great American inventor. Elisha Gray, another American inventor, developed Western Union’s receivers. The Bell company met the competition by using the improved transmitters of Emile Berliner, a German immigrant, and Francis J. Blake, an American.
In 1878, the Bell company sued Western Union to protect Bell’s patents. Western Union claimed that Gray, not Bell, had invented the telephone. On the same day Bell had applied for his first patent, Feb. 14, 1876, Gray had notified the U.S. Patent Office that he was working on a device to transmit speech. However, Bell submitted his application before Gray gave his notification. Bell’s patent was issued on March 7, 1876. In 1879, Western Union recognized Bell’s patents and sold its telephone business to the Bell company. This case was the first of about 600 lawsuits over Bell’s patents. The Supreme Court of the United States upheld Bell’s patents in 1888.
In 1878, the first telephone exchange (central office) opened in New Haven, Connecticut. It had 21 customers. Exchanges soon opened throughout the United States and Canada.
In 1878, two companies were formed as successors to the Bell Telephone Company: the New England Telephone Company and a new Bell Telephone Company. The New England Telephone Company licensed telephone service in New England, and the Bell Telephone Company licensed phone service in the rest of the United States. In 1879, the two companies combined to form the National Bell Telephone Company. The American Bell Telephone Company was founded as the successor to National Bell in 1880. In 1885, the American Telephone and Telegraph Company (AT&T) was established to operate the long-distance network. AT&T took over American Bell in 1899 and became the parent company of the Bell System.
Improvements in telephone technology.
Transcontinental phone service began between New York City and San Francisco, California, in 1915. Transatlantic radiotelephone service between New York City and London began in 1927. The first long-distance coaxial cable linked New York City and Philadelphia in 1936. See Coaxial cable.
Undersea telephone cables between North America and Europe began operating in 1956. A cable joined the U.S. mainland to Hawaii in 1957. A cable from Japan was joined to this cable in 1964, connecting Japan to the U.S. mainland. The first commercial communications satellite, Early Bird, was launched in 1965.
In 1970, international direct distance dialing (DDD) began operating between New York City and London. DDD enables people to make direct long-distance calls without the help of an operator.
In 1980, a fiber-optic system for transmitting local calls was installed in Atlanta, Georgia. A fiber-optic system between New York City and Washington, D.C., began operating in 1983. Fiber-optic cables began carrying messages across the Atlantic Ocean in 1988 and across the Pacific Ocean in 1989.
In the late 1970’s and early 1980’s, many countries started developing cellular systems. The world’s first commercial cellular system went into operation in Japan in 1979. The first commercial cellular system in the United States went into operation in 1983. By the late 1980’s, cellular service had gained popularity throughout much of the world.
In the early 2000’s, broadband internet service began to become widely available in Australia, Canada, Japan, South Korea, the United States, and most countries in Europe. In the United States, Verizon Communications was the first company to launch a major fiber-to-the-premises (FTTP) effort. With FTTP, broadband services are provided on fiber-optic cables that lead directly to people’s homes.
Competition in the U.S. telephone industry.
In the early 1900’s, AT&T began buying small telephone companies. In 1913, the attorney general of the United States warned AT&T that some of its planned purchases could violate antitrust laws designed to protect competition. AT&T promised not to buy any more competing telephone companies and to allow all local phone companies to connect to its long-distance network.
The Federal Communications Commission (FCC) ruled in 1968 that telephone users could buy their own telephones and other equipment to connect to the telephone network. Previously, AT&T and its local companies had leased all phone equipment to users. In 1969, the FCC cleared the way for MCI Telecommunications to offer long-distance service. MCI thus became the first long-distance carrier to compete with AT&T.
In 1974, the U.S. government filed a lawsuit against AT&T, charging it with anticompetitive practices. The case was settled in 1982, and AT&T agreed to give up its local telephone companies on Jan. 1, 1984. The local companies were grouped into seven regional holding companies (RHC’s), each of which provided local service in a particular U.S. region. The seven RHC’s, also known as the “Baby Bells,” were (1) NYNEX, (2) Bell Atlantic, (3) BellSouth, (4) Ameritech, (5) Southwestern Bell, (6) U S West, and (7) Pacific Telesis. The settlement allowed AT&T to keep its equipment-manufacturing plants, its long-distance business, and its research facilities.
The Telecommunications Act of 1996 loosened many restrictions that had limited competition in the U.S. telephone industry. It allowed local phone companies, long-distance companies, and cable-television companies to enter one another’s businesses. The act also allowed the RHC’s to compete in local markets outside their own regions. Starting in the mid-1990’s, many phone companies and other communications firms merged to form large national or international corporations. Most of the RHC’s became parts of large telecommunications corporations through mergers, often with other RHC’s.
Today, most personal phones are cellular, even for home use. The three major carriers for telephone services are AT&T, Verizon, and T-Mobile/Sprint.
