Saturday, January 14, 2006
History of Pagers
A pager is a dedicated RF (radio frequency) device that allows the pager user to receive messages broadcast on a specific frequency over a special network of radio base stations.
The first pager-like system was used in 1921 by the Detroit Police Department. The first time the term " pager " was used was in 1959, it referred to a Motorola radio communications product, a small radio receiver that delivered a radio message individually to those carrying the pager device. The first pager, as we are familiar with them today, was Motorola's Pageboy I, introduced in 1974. The pager had no display and could not store messages, but it was portable and notified the wearer that a pager message had been sent.
By 1980, there were 3.2 million pager users worldwide. Pagers had a limited range, and were used in on-site situations, e.g. medical workers within a hospital.
By 1990, wide-area paging had been invented and over 22 million pagers were in use. By 1994, there were over 61 million pagers in use and pagers became popular for personal use.
The first pager-like system was used in 1921 by the Detroit Police Department. The first time the term " pager " was used was in 1959, it referred to a Motorola radio communications product, a small radio receiver that delivered a radio message individually to those carrying the pager device. The first pager, as we are familiar with them today, was Motorola's Pageboy I, introduced in 1974. The pager had no display and could not store messages, but it was portable and notified the wearer that a pager message had been sent.
By 1980, there were 3.2 million pager users worldwide. Pagers had a limited range, and were used in on-site situations, e.g. medical workers within a hospital.
By 1990, wide-area paging had been invented and over 22 million pagers were in use. By 1994, there were over 61 million pagers in use and pagers became popular for personal use.
Telephone History
I. Introduction
"...an inspired black-haired Scotsman of twenty eight, on the eve of marriage, vibrant and alive to new ideas." Alexander Graham Bell: The Life and Times of the Man Who Invented the Telephone On March 10, 1876, in Boston, Massachusetts, Alexander Graham Bell invented the telephone. Thomas Watson fashioned the device itself; a crude thing made of a wooden stand, a funnel, a cup of acid, and some copper wire. But these simple parts and the equally simple first telephone call -- "Mr. Watson, come here, I want you!" -- belie a complicated past. Bell filed his application just hours before his competitor, Elisha Gray, filed notice to soon patent a telephone himself. What's more, though neither man had actually built a working telephone, Bell made his telephone operate three weeks later using ideas outlined in Gray's Notice of Invention, methods Bell did not propose in his own patent.
Intrigue aside for now, the story of the telephone is the story of invention itself. Bell developed new and original ideas but did so by building on older ideas and developments. Bell succeeded specifically because he understood acoustics, the study of sound, and something about electricity. Other inventors knew electricity well but little of acoustics. The telephone is a shared accomplishment among many pioneers, therefore, although the credit and rewards were not shared equally. That, too, is often the story of invention.
Telephone comes from the Greek word tele, meaning from afar, and phone, meaning voice or voiced sound. Generally, a telephone is any device which conveys sound over a distance. A string telephone, a megaphone, or a speaking tube might be considered telephonic instruments but for our purposes they are not telephones. These transmit sound mechanically and not electrically. How's that? Speech is sound in motion. Talking produces acoustic pressure. Speaking into the can of a string telephone, for example, makes the line vibrate, causing sound waves to travel from one end of the stretched line to the other. A telephone by comparison, reproduces sound by electrical means. What the Victorians called "talking by lightning."
A standard dictionary defines the telephone as "an apparatus for reproducing sound, especially that of the voice, at a great distance, by means of electricity; consisting of transmitting and receiving instruments connected by a line or wire which conveys the electric current." Electricity operates the telephone and it carries your voice. With that important point established, let's look at telephone history.
Modern telephones use electret microphones for transmitters and piezoelectric transducers for receivers but the principle described is the same. Sound waves picked up by an electret microphone causes "a thin, metal-coated plastic diaphragm to vibrate, producing variations in an electric field across a tiny air gap between the diaphragm and an electrode."[B] A piezoelectric transducer uses material, which converts the mechanical stress of a sound wave upon it into a varying electrical signal.
Telephone history begins, perhaps, at the start of human history. Man has always wanted to communicate from afar. People have used smoke signals, mirrors, jungle drums, carrier pigeons and semaphores to get a message from one point to another. But a phone was something new. Some say Francis Bacon predicted the telephone in 1627; however, his book New Utopia only described a long speaking tube. A real telephone could not be invented until the electrical age began. And even then it didn't seem desirable. The electrical principles needed to build a telephone were known in 1831 but it wasn't until 1854 that Bourseul suggested transmitting speech electrically. And it wasn't until 22 years later in 1876 that the idea became a reality. While Da Vinci predicted flight and Jules Verne envisioned space travel, people did not lie awake through the centuries dreaming of making a call. Who in the fifteenth century could have imagined a pay phone on the street corner or a fax machine on their desk? Telephone development did not proceed in an organized line like powered flight, with one inventor after another working to realize a common goal, rather, it was a series of often disconnected events, mostly electrical, some accidental, that made the telephone possible. I'll cover just a few.
II. Early Telephone Development
In 1729 English chemist Stephen Gray transmitted electricity over a wire. He sent charges nearly 300 feet over brass wire and moistened thread. An electrostatic generator powered his experiments, one charge at a time. A few years later, Dutchman Pieter van Musschenbroek and German Ewald Georg von Kleist in 1746 independently developed the Leyden jar, a sort of battery or condenser for storing static electricity. Named for its Holland city of invention, the jar was a glass bottle lined inside and out with tin or lead. The glass sandwiched between the metal sheets stored electricity; a strong charge could be kept for a few days and transported. Over the years these jars were used in countless experiments, lectures, and demonstrations.
In 1753 an anonymous writer, possibly physician Charles Morrison, suggested in The Scot's Magazine that electricity might transmit messages. He thought up a scheme using separate wires to represent each letter. An electrostatic generator, he posited, could electrify each line in turn, attracting a bit of paper by static charge on the other end. By noting which paper letters were attracted one might spell out a message. Needing wires by the dozen, signals got transmitted a mile or two. People labored with telegraphs like this for many decades. Experiments continued slowly until 1800. Many inventors worked alone, misunderstood earlier discoveries, or spent time producing results already achieved. Poor equipment didn't help either. Balky electrostatic generators produced static electricity by friction, often by spinning leather against glass. And while static electricity could make hair stand on end or throw sparks, it couldn't provide the energy to do truly useful things. Inventors and industry needed a reliable and continuous current.
In 1800 Alessandro Volta produced the first battery. A major development, Volta's battery provided sustained low powered electric current at high cost. Chemically based, as all batteries are, the battery improved quickly and became the electrical source for further experimenting. But while batteries got more reliable, they still couldn't produce the power needed to work machinery, light cities, or provide heat. And although batteries would work telegraph and telephone systems, and still do, transmitting speech required understanding two related elements, namely, electricity and magnetism.
In 1820 Danish physicist Christian Oersted demonstrated electromagnetism, the critical idea needed to develop electrical power and to communicate. In a famous experiment at his University of Copenhagen classroom, Oersted pushed a compass under a live electric wire. This caused its needle to turn from pointing north, as if acted on by a larger magnet. Oersted discovered that an electric current creates a magnetic field. But could a magnetic field create electricity? If so, a new source of power beckoned. And the principle of electromagnetism, if fully understood and applied, promised a new era of communication.
In 1821 Michael Faraday reversed Oersted's experiment. He got a weak current to flow in a wire revolving around a permanent magnet. In other words, a magnetic field caused or induced an electric current to flow in a nearby wire. In so doing, Faraday had built the world's first electric generator. Mechanical energy could now be converted to electrical energy. Is that clear? This is a very important point.
The simple act of moving ones' hand caused current to move, mechanical energy into electrical energy. Although many years away, a dynamo powered turbine would let the power of flowing water or burning coal produce electricity. Got a river or a dam?
The water spins the turbines, which turns the generators, which produce electricity. The more water you have the more generators you can add and the more electricity you can produce, mechanical energy into electrical energy.
(By comparison, a motor turns electrical energy into mechanical energy. Thanks to A. Almoian for pointing out this key difference.)
Faraday worked through different electrical problems in the next ten years, eventually publishing his results on induction in 1831. By that year many people were producing electrical dynamos. But electromagnetism still needed understanding. Someone had to show how to use it for communicating.
In 1830 the great American scientist Professor Joseph Henry transmitted the first practical electrical signal. A short time before Henry had invented the first efficient electromagnet. He also concluded similar thoughts about induction before Faraday but he didn't publish them first. Henry's place in electrical history however, has always been secure, in particular for showing that electromagnetism could do more than create current or pick up heavy weights -- it could communicate.
In a stunning demonstration in his Albany Academy classroom, Henry created the forerunner of the telegraph. In the demonstration, Henry first built an electromagnet by winding an iron bar with several feet of wire. A pivot mounted steel bar sat next to the magnet. A bell, in turn, stood next to the bar. From the electromagnet Henry strung a mile of wire around the inside of the classroom. He completed the circuit by connecting the ends of the wires at a battery. Guess what happened? The steel bar swung toward the magnet, of course, striking the bell at the same time. Breaking the connection released the bar and it was free to strike again. And while Henry did not pursue electrical signaling, he did help someone who did. And that man was Samuel Finley Breese Morse.
From the December, 1963 American Heritage magazine, "a sketch of Henry's primitive telegraph, a dozen years before Morse, reveals the essential components: an electromagnet activated by a distant battery, and a pivoted iron bar that moves to ring a bell."
In 1837 Samuel Morse invented the first workable telegraph, applied for its patent in 1838, and was finally granted it in 1848. Joseph Henry helped Morse build a telegraph relay or repeater that allowed long distance operation. The telegraph later helped unite the country and eventually the world. Not a professional inventor, Morse was nevertheless captivated by electrical experiments. In 1832 he heard of Faraday's recently published work on inductance, and was given an electromagnet at the same time to ponder over. An idea came to him and Morse quickly worked out details for his telegraph. As depicted below, his system used a key (a switch) to make or break the electrical circuit, a battery to produce power, a single line joining one telegraph station to another and an electromagnetic receiver or sounder that upon being turned on and off, produced a clicking noise. He completed the package by devising the Morse code system of dots and dashes. A quick key tap broke the circuit momentarily, transmitting a short pulse to a distant sounder, interpreted by an operator as a dot. A lengthier break produced a dash. Telegraphy became big business as it replaced messengers, the Pony Express, clipper ships and every other slow paced means of communicating. The fact that service was limited to Western Union offices or large firms seemed hardly a problem. After all, communicating over long distances instantly was otherwise impossible. Yet as the telegraph was perfected, man's thoughts turned to speech over a wire.
In 1854 Charles Bourseul wrote about transmitting speech electrically in a well-circulated article. In that important paper, the Belgian-born French inventor and engineer described a flexible disk that would make and break an electrical connection to reproduce sound. Bourseul never built an instrument or pursued his ideas further.
In 1861 Johann Phillip Reis completed the first non-working telephone. Tantalizingly close to reproducing speech, Reis's instrument conveyed certain sounds, poorly, but no more than that. A German physicist and schoolteacher, Reis's ingenuity was unquestioned. His transmitter and receiver used a cork, a knitting needle, a sausage skin, and a piece of platinum to transmit bits of music and certain other sounds. But intelligible speech could not be reproduced. The problem was simple, minute, and at the same time monumental. His telephone relied on its transmitter's diaphragm making and breaking contact with the electrical circuit, just as Bourseul suggested, and just as the telegraph worked. This approach, however, was completely wrong. Reproducing speech practically relies on the transmitter making continuous contact with the electrical circuit. A transmitter varies the electrical current depending on how much acoustic pressure it gets. It must be in continuous contact, even though people pause and stop while talking. Turning the current off and on could not begin to duplicate speech since speech, once flowing, is itself a fluctuating wave of continuous character. Reis's instrument, in fact, worked only when sounds were so soft that the contact connecting the transmitter to the circuit remained unbroken. Speech may have traveled first over a Reis telephone however, it would have been done accidentally and against every principle he thought would make it work. And although accidental discovery is the stuff of invention, Reis did not realize his mistake, did not develop his instrument further, nor ever claim to have invented the telephone.
The definitive book in English on Reis is: Thompson, Silvanus P. Phillip Reis: Inventor of The Telephone. E.&F.N. Spon. London. 1883
In the early 1870s the world still did not have a working telephone. Inventors focused on telegraph improvements since these had a waiting market. A good, patentable idea might make an inventor millions. Developing a telephone, on the other hand, had no immediate market, if one at all. Elisha Gray, Alexander Graham Bell, as well as many others, were instead trying to develop a multiplexing telegraph a device to send several messages over one wire at once. Such an instrument would greatly increase traffic without the telegraph company having to build more lines. As it turned out, for both men, the desire to invent one thing turned into a race to invent something altogether different. And that is truly the story of invention.
lll. "Major Telephone Breakthrough"
The principle of the telephone was uncovered in 1874, but it was the unique combination of electricity and voice that led to Bell's actual invention of the telephone in 1876. Convincing Bell's partners, Gardiner Greene Hubbard, a prominent lawyer from Boston, and Thomas Sanders, a leather merchant with capital from Salem, about the potential for voice transmittal was not an easy task, and they often threatened to pull Bell's funding. Nonetheless, agreement was finally reached and the trio received US Patent No. 174,465, issued on March 3, 1876 for "Improvements in Telegraphy," which is now considered to be the most valuable patent ever issued. Bell considered his invention's greatest advantage over every other form of electrical apparatus to be the fact that it could be used by anyone, as "all other telegraphic machines produce signals which require to be translated by experts, and such instruments are therefore extremely limited in their application, but the telephone actually speaks, and for this reason it can be utilized for nearly every purpose for which speech is employed" (from an address Bell made in 1878, as cited in Young, 1991, p. 6).
Bell was nearly beaten to the patent office by Elisha Gray, who had independently developed a very similar invention. Gray arrived just hours after Bell at the Patent Office, filing a "caveat," a confidential report of an invention that was not yet perfected. Western Electric, cofounded by Gray, became one of the Bell System's major competitors. Western Union was another major competitor, already having established itself as a communications provider with the telegraph system.
Another famous inventor, Thomas Edison, took advantage of Bell's failure to secure a patent in Britain for the Bell receiver, and received a patent for a new receiver, the "electro-motograph," which required continuous cranking -- else the conversation would end. However, by 1880, the Bell transmitter and the Edison receiver were combined and used throughout Britain.
The first permanent outdoor telephone wire, strung in 1877, covered a distance of three miles. Bell could be credited with the anticipation of fiber optics - he worked on a "photophone," which could actually transmit sound for a short distance over a beam of light. Commercial telephone service began in the United States in 1877. The workable exchange, developed in 1878, enabled calls to be switched among any number of subscribers rather than requiring direct lines. Exchanges were handled manually, first by boys, then by the now- famous women operators in their bustles.
In 1879, telephone subscribers began to be designated by numbers rather than names -- as a result of an epidemic of measles. A Lowell, Massachusetts doctor, concerned about the inability of replacement exchange operators to put calls through because they would not be familiar with the names associated with all the jacks on the switchboards, suggested the alpha-numeric system of identifying customers by a two- letter and five-digit system.
The dial phone was invented in the 1880s by Almond Brown Stroger, who was a Kansas City, MO undertaker and was convinced that the Bell Telephone operator was sending calls for his funeral home to the operator's brother-in-law... Stroger invented the dial telephone and installed automatic exchanges in the US and Europe. In 1924, the Bell Telephone System decided that using operators was NOT the way to go, and they licensed Stroger's technology. The step by step switch used to receive the dial pulses is/was called a Stroger Switch, after its inventor.
Because of the largely monopolistic power of the American Bell Company, profits were held high, reaching levels of $1 million in revenue while paying out $600,000 in dividends in 1882. Competition remained a major threat, as the Bell, Western Union, and Western Electric systems were incompatible and not connected. As many as three or more independent telephone companies battled in a given area for customers.
Problems with the telephone occurred when other applications of electricity flourished, particularly trolley cars and street lamps. Natural electricity also interfered with the system, as lightning wreaked havoc on the lines. Long-distance service was established and grew in the 1880s using metallic circuits. The common-battery system, developed by Hammond V. Hayes in 1888, permitted a central battery to supply all telephones on an exchange with power, rather than relying upon each unit's own troublesome battery. The first automatic dialing system was patented in 1891 by a Kansas City undertaker who believed that crooked operators were sending his business elsewhere -- with his main objective being to eliminate the operators. The first coin telephone was installed in Hartford, Connecticut in 1900. Party lines were soon developed to lower the cost of the telephone for individual families, especially those in rural locations.
A young inventor, Dr. Lee De Forest, began work in 1906 on applying what was known as an "audion," a three-element vacuum tube, which could amplify radio waves. He recognized the potential for installing audions or repeaters on telephone lines to amplify the sound waves at mid-points along the wires. The Bell System bought the rights to De Forest's patents in 1913. Long-distance telephone service was constructed on the New York to San Francisco circuit using loading coils and repeaters.
American Telephone and Telegraph (AT&T) took control of Western Union telegraph Company in a "hostile takeover," in 1911, having purchased the Western Union stocks through a subsidiary. The two eventually merged, sharing financial data and telephone lines. In 1918, ten million Bell System telephones were in service.
Theodore Vail, president of the Bell System from 1885 to 1887 and 1907 to 1919, faced the challenge of making a large private corporation adopt a policy of subordinating the maximization of profit to the provision of service to its customers (Brooke, 1976). The political and business environment in the United States following the First World War was strongly "anti-monopolistic." Yet, advantages to single- company service or limiting service in a given area to few competitors had its advantages.
Under Vail's leadership, automatic switching of large numbers of calls was made possible in 1921, using "phantom circuits," which allowed three telephone conversations to be conducted on two pairs of wires. The "French" phone, with the transmitter and receiver in a single handset, was developed by the Bell System around 1904, but was not released on a widespread basis because it cost more than the desk sets. They ultimately became available to subscribers in 1927. The first transatlantic service, from New York to London, became operational in 1927, and was transmitted by radio waves. Research in electronic telephone exchanges began in 1936 in Bell Labs, and was ultimately perfected in the 1960s with its Electronic Switching System (ESS).
Bell benefited greatly from US defense spending during World War II in its laboratories. War-time experiments, innovations, and inventions brought Bell to the forefront of telecommunications in the post-war era. The first commercial mobile telephone service was put in service in 1946, linking moving vehicles to telephone networks by radio. The same year brought transmission via coaxial cables, resulting in a major improvement in service as they were less likely to be interrupted by other electrical interference. Microwave radio transmission was used for long-distance telephony in 1947. The transistor, a key to modern electronics, was invented at Bell Labs in 1947. A team consisting of William Schockley, Walter Brattain, and John Bardeen demonstrated the "transistor effect," using a germanium crystal that they had set up in contact with two wires two-thousandths of an inch apart.
Changes were underway in the 1950s. Consumers initially objected to all-numeral telephone numbers (All Number Calling, or ANC) that were introduced in the latter half of the decade. Consumer demand for telephones had outstripped the ability of the telephone system to supply all of the required numbers, which were restricted by the alpha-numeric combinations in place for decades. The laying of transatlantic telephone cables began in 1955. Care was taken to ensure that the submarine repeaters would be of the highest quality, guaranteed to last at least twenty years before replacement would be required.
Telstar, the world's first international communications satellite, was rocketed into orbit on July 10, 1962, with a collaboration between NASA and the Bell System. Satellites in geosynchronous orbit are used mostly for long-distance service. Videophones, developed in the mid-1960s, were becoming more affordable and practical with the combination of devices that eased the transmission and reception of both audio and video signals over telephone lines.
Fiber optic cables (or "fiber optics"), developed in the early 1980s, offered the potential to carry greater volumes of calls than satellite or microwave links. Electrical telephone signals are fed into tiny semiconductor lasers, which produce pulses of light in response to incoming signals and are bounced down the inside of extremely thin glass fibers. Today's cellular mobile telephones rely upon a series of "cells," each with its own central radio transmitter and receiver. Each cellular telephone unit also has its own central transmitter-receiver, permitting it to receive seamless transmission as they enter and exit from a cell.
The impact of the telephone has been described as both positive and negative. On the negative side, wars are waged more easily, the scope of human conflict has been extended along telephone lines, the multi-generational household has been broken-up as living alone is no longer an experiment in isolation, and the time-space continuum seems to be compressed faster than previously thought possible (Brooks, 1976). On the other hand, the invention of the telephone has resulted in the rapid and diffuse dissemination of technical and scientific information, saved lives through links to emergency services, made possible the modern city through telephonic connections, increased the speed and ease with which information changes place, and accelerated the rate of scientific and technological change and growth in industry (Brooks, 1976).
It is curious in contrast to now consider the musings of Herbert Casson (1910, p. 299), who ended his book with a question, "Who could have foreseen what the telephone bells have done to ring out the old ways and to ring in the new; to ring out delay and isolation and to ring in the efficiency and friendliness of a truly united people?" The future combination of various means of telecommunications, with the personal computer and recent inventions such as the facsimile machine, could never have been foreseen yet they hold the potential for vast changes in the global environment for society, business and industry, and governments.
References American Telephone and Telegraph (AT&T). (1979). Events in telecommunications history. New York: Author. Brooks, J. (1976). Telephone: the first hundred years. Telephone: the first hundred years. New York: Harper & Row. Casson, H. (1910). The history of the telephone. Chicago: A. C. McClurg. Compton's Interactive Encyclopedia. (1994). The Telephone, software version 2.00 VW for CD-ROM. New York: Compton's New Media. Du Moncel, T. (1974). The telephone, the microphone, and the phonograph. New York: Arno Press. Reprinted from the 1879 edition printed by Harper, New York. Fischer, C. (1992). America calling: a social history of the telephone to 1940. Berkeley, CA: University of California Press. Young, P. (1991). Person to person: the international impact of the telephone. Cambridge: Granta Editions.
A History of the Telephone
1860 Philipp Reis develops a "telephon." 1874 Alexander Graham Bell discovered the principle of the telephone. 1876 US Patent No. 174,465, issued on March 3 for "Improvements in Telegraphy." 1876 Elisha Gray applies for a similar patent hours after Bell. 1877 Thomas Edison receives a patent in Britain for the "electro-motograph." First permanent outdoor telephone wire strung. Commercial telephone service began in the United States. 1878 The workable exchange enabled calls to be switched among any number of subscribers rather than requiring direct lines. Exchanges were handled manually, first by boys, then by the now-famous women operators in their bustles. 1879 Telephone subscribers began to be designated by numbers rather than names. 1880s Long distance service was established and grew using metallic circuits. 1888 The common battery system, developed by Hammond V. Hayes, permitted a central battery to supply all telephones on an exchange. 1891 The first automatic dial system was patented by a Kansas City undertaker. 1900 The first coin telephone was installed in Hartford, Connecticut. 1906 Dr. Lee De Forest, began work 1906 on applying what was known as an "audion," a three element vacuum tube, which could amplify radio waves, to telephony. 1911 American Telephone and Telegraph (AT&T) took control of Western Union Telegraph Company. 1913 The Bell System bought the rights to De Forest's patentsm\, which were used for long distance telephone service. First long-distance wire link was on the New York to San Francisco circuit using loading coils and repeaters. 1918 Ten million Bell System telephones were in service. 1921 Automatic switching of large numbers of calls was made possible using "phantom circuits," which allowed three telephone conversations to be conducted on two pairs of wires. 1927 The "French" phone, with the transmitter and receiver in a single handset, was developed by the Bell System was released on a widespread basis. 1927 Transatlantic service from New York to London became operational, transmitted by radio waves. 1936 Research on electronic telephone exchanges began in Bell Labs and was ultimately perfected in the 1960s with AT&T's Electronic Switching System (ESS). 1946 First commercial mobile telephone service put into service in 1946, linking moving vehicles to the telephone network by radio. 1946 Transmission via coaxial cables was accomplished. 1947 Microwave radio transmission was used for long-distance telephony. 1947 The transistor, a key to modern electronics, was invented at Bell Labs by a team consisting of William Schockley, Walter Brattain, and John Bardeen. 1955 The laying of transatlantic telephone cables began. 1958 All Number Calling (ANC) instituted to handle consumer demands for individual telephone numbers. 1962 Telstar, the world's first international communications satellite, was rocketed into orbit on July 10 with the collaboration between NASA and the Bell System. 1960s Videophones became more affordable and practical. 1980 s Fiber optic(s) technology developed
"...an inspired black-haired Scotsman of twenty eight, on the eve of marriage, vibrant and alive to new ideas." Alexander Graham Bell: The Life and Times of the Man Who Invented the Telephone On March 10, 1876, in Boston, Massachusetts, Alexander Graham Bell invented the telephone. Thomas Watson fashioned the device itself; a crude thing made of a wooden stand, a funnel, a cup of acid, and some copper wire. But these simple parts and the equally simple first telephone call -- "Mr. Watson, come here, I want you!" -- belie a complicated past. Bell filed his application just hours before his competitor, Elisha Gray, filed notice to soon patent a telephone himself. What's more, though neither man had actually built a working telephone, Bell made his telephone operate three weeks later using ideas outlined in Gray's Notice of Invention, methods Bell did not propose in his own patent.
Intrigue aside for now, the story of the telephone is the story of invention itself. Bell developed new and original ideas but did so by building on older ideas and developments. Bell succeeded specifically because he understood acoustics, the study of sound, and something about electricity. Other inventors knew electricity well but little of acoustics. The telephone is a shared accomplishment among many pioneers, therefore, although the credit and rewards were not shared equally. That, too, is often the story of invention.
Telephone comes from the Greek word tele, meaning from afar, and phone, meaning voice or voiced sound. Generally, a telephone is any device which conveys sound over a distance. A string telephone, a megaphone, or a speaking tube might be considered telephonic instruments but for our purposes they are not telephones. These transmit sound mechanically and not electrically. How's that? Speech is sound in motion. Talking produces acoustic pressure. Speaking into the can of a string telephone, for example, makes the line vibrate, causing sound waves to travel from one end of the stretched line to the other. A telephone by comparison, reproduces sound by electrical means. What the Victorians called "talking by lightning."
A standard dictionary defines the telephone as "an apparatus for reproducing sound, especially that of the voice, at a great distance, by means of electricity; consisting of transmitting and receiving instruments connected by a line or wire which conveys the electric current." Electricity operates the telephone and it carries your voice. With that important point established, let's look at telephone history.
Modern telephones use electret microphones for transmitters and piezoelectric transducers for receivers but the principle described is the same. Sound waves picked up by an electret microphone causes "a thin, metal-coated plastic diaphragm to vibrate, producing variations in an electric field across a tiny air gap between the diaphragm and an electrode."[B] A piezoelectric transducer uses material, which converts the mechanical stress of a sound wave upon it into a varying electrical signal.
Telephone history begins, perhaps, at the start of human history. Man has always wanted to communicate from afar. People have used smoke signals, mirrors, jungle drums, carrier pigeons and semaphores to get a message from one point to another. But a phone was something new. Some say Francis Bacon predicted the telephone in 1627; however, his book New Utopia only described a long speaking tube. A real telephone could not be invented until the electrical age began. And even then it didn't seem desirable. The electrical principles needed to build a telephone were known in 1831 but it wasn't until 1854 that Bourseul suggested transmitting speech electrically. And it wasn't until 22 years later in 1876 that the idea became a reality. While Da Vinci predicted flight and Jules Verne envisioned space travel, people did not lie awake through the centuries dreaming of making a call. Who in the fifteenth century could have imagined a pay phone on the street corner or a fax machine on their desk? Telephone development did not proceed in an organized line like powered flight, with one inventor after another working to realize a common goal, rather, it was a series of often disconnected events, mostly electrical, some accidental, that made the telephone possible. I'll cover just a few.
II. Early Telephone Development
In 1729 English chemist Stephen Gray transmitted electricity over a wire. He sent charges nearly 300 feet over brass wire and moistened thread. An electrostatic generator powered his experiments, one charge at a time. A few years later, Dutchman Pieter van Musschenbroek and German Ewald Georg von Kleist in 1746 independently developed the Leyden jar, a sort of battery or condenser for storing static electricity. Named for its Holland city of invention, the jar was a glass bottle lined inside and out with tin or lead. The glass sandwiched between the metal sheets stored electricity; a strong charge could be kept for a few days and transported. Over the years these jars were used in countless experiments, lectures, and demonstrations.
In 1753 an anonymous writer, possibly physician Charles Morrison, suggested in The Scot's Magazine that electricity might transmit messages. He thought up a scheme using separate wires to represent each letter. An electrostatic generator, he posited, could electrify each line in turn, attracting a bit of paper by static charge on the other end. By noting which paper letters were attracted one might spell out a message. Needing wires by the dozen, signals got transmitted a mile or two. People labored with telegraphs like this for many decades. Experiments continued slowly until 1800. Many inventors worked alone, misunderstood earlier discoveries, or spent time producing results already achieved. Poor equipment didn't help either. Balky electrostatic generators produced static electricity by friction, often by spinning leather against glass. And while static electricity could make hair stand on end or throw sparks, it couldn't provide the energy to do truly useful things. Inventors and industry needed a reliable and continuous current.
In 1800 Alessandro Volta produced the first battery. A major development, Volta's battery provided sustained low powered electric current at high cost. Chemically based, as all batteries are, the battery improved quickly and became the electrical source for further experimenting. But while batteries got more reliable, they still couldn't produce the power needed to work machinery, light cities, or provide heat. And although batteries would work telegraph and telephone systems, and still do, transmitting speech required understanding two related elements, namely, electricity and magnetism.
In 1820 Danish physicist Christian Oersted demonstrated electromagnetism, the critical idea needed to develop electrical power and to communicate. In a famous experiment at his University of Copenhagen classroom, Oersted pushed a compass under a live electric wire. This caused its needle to turn from pointing north, as if acted on by a larger magnet. Oersted discovered that an electric current creates a magnetic field. But could a magnetic field create electricity? If so, a new source of power beckoned. And the principle of electromagnetism, if fully understood and applied, promised a new era of communication.
In 1821 Michael Faraday reversed Oersted's experiment. He got a weak current to flow in a wire revolving around a permanent magnet. In other words, a magnetic field caused or induced an electric current to flow in a nearby wire. In so doing, Faraday had built the world's first electric generator. Mechanical energy could now be converted to electrical energy. Is that clear? This is a very important point.
The simple act of moving ones' hand caused current to move, mechanical energy into electrical energy. Although many years away, a dynamo powered turbine would let the power of flowing water or burning coal produce electricity. Got a river or a dam?
The water spins the turbines, which turns the generators, which produce electricity. The more water you have the more generators you can add and the more electricity you can produce, mechanical energy into electrical energy.
(By comparison, a motor turns electrical energy into mechanical energy. Thanks to A. Almoian for pointing out this key difference.)
Faraday worked through different electrical problems in the next ten years, eventually publishing his results on induction in 1831. By that year many people were producing electrical dynamos. But electromagnetism still needed understanding. Someone had to show how to use it for communicating.
In 1830 the great American scientist Professor Joseph Henry transmitted the first practical electrical signal. A short time before Henry had invented the first efficient electromagnet. He also concluded similar thoughts about induction before Faraday but he didn't publish them first. Henry's place in electrical history however, has always been secure, in particular for showing that electromagnetism could do more than create current or pick up heavy weights -- it could communicate.
In a stunning demonstration in his Albany Academy classroom, Henry created the forerunner of the telegraph. In the demonstration, Henry first built an electromagnet by winding an iron bar with several feet of wire. A pivot mounted steel bar sat next to the magnet. A bell, in turn, stood next to the bar. From the electromagnet Henry strung a mile of wire around the inside of the classroom. He completed the circuit by connecting the ends of the wires at a battery. Guess what happened? The steel bar swung toward the magnet, of course, striking the bell at the same time. Breaking the connection released the bar and it was free to strike again. And while Henry did not pursue electrical signaling, he did help someone who did. And that man was Samuel Finley Breese Morse.
From the December, 1963 American Heritage magazine, "a sketch of Henry's primitive telegraph, a dozen years before Morse, reveals the essential components: an electromagnet activated by a distant battery, and a pivoted iron bar that moves to ring a bell."
In 1837 Samuel Morse invented the first workable telegraph, applied for its patent in 1838, and was finally granted it in 1848. Joseph Henry helped Morse build a telegraph relay or repeater that allowed long distance operation. The telegraph later helped unite the country and eventually the world. Not a professional inventor, Morse was nevertheless captivated by electrical experiments. In 1832 he heard of Faraday's recently published work on inductance, and was given an electromagnet at the same time to ponder over. An idea came to him and Morse quickly worked out details for his telegraph. As depicted below, his system used a key (a switch) to make or break the electrical circuit, a battery to produce power, a single line joining one telegraph station to another and an electromagnetic receiver or sounder that upon being turned on and off, produced a clicking noise. He completed the package by devising the Morse code system of dots and dashes. A quick key tap broke the circuit momentarily, transmitting a short pulse to a distant sounder, interpreted by an operator as a dot. A lengthier break produced a dash. Telegraphy became big business as it replaced messengers, the Pony Express, clipper ships and every other slow paced means of communicating. The fact that service was limited to Western Union offices or large firms seemed hardly a problem. After all, communicating over long distances instantly was otherwise impossible. Yet as the telegraph was perfected, man's thoughts turned to speech over a wire.
In 1854 Charles Bourseul wrote about transmitting speech electrically in a well-circulated article. In that important paper, the Belgian-born French inventor and engineer described a flexible disk that would make and break an electrical connection to reproduce sound. Bourseul never built an instrument or pursued his ideas further.
In 1861 Johann Phillip Reis completed the first non-working telephone. Tantalizingly close to reproducing speech, Reis's instrument conveyed certain sounds, poorly, but no more than that. A German physicist and schoolteacher, Reis's ingenuity was unquestioned. His transmitter and receiver used a cork, a knitting needle, a sausage skin, and a piece of platinum to transmit bits of music and certain other sounds. But intelligible speech could not be reproduced. The problem was simple, minute, and at the same time monumental. His telephone relied on its transmitter's diaphragm making and breaking contact with the electrical circuit, just as Bourseul suggested, and just as the telegraph worked. This approach, however, was completely wrong. Reproducing speech practically relies on the transmitter making continuous contact with the electrical circuit. A transmitter varies the electrical current depending on how much acoustic pressure it gets. It must be in continuous contact, even though people pause and stop while talking. Turning the current off and on could not begin to duplicate speech since speech, once flowing, is itself a fluctuating wave of continuous character. Reis's instrument, in fact, worked only when sounds were so soft that the contact connecting the transmitter to the circuit remained unbroken. Speech may have traveled first over a Reis telephone however, it would have been done accidentally and against every principle he thought would make it work. And although accidental discovery is the stuff of invention, Reis did not realize his mistake, did not develop his instrument further, nor ever claim to have invented the telephone.
The definitive book in English on Reis is: Thompson, Silvanus P. Phillip Reis: Inventor of The Telephone. E.&F.N. Spon. London. 1883
In the early 1870s the world still did not have a working telephone. Inventors focused on telegraph improvements since these had a waiting market. A good, patentable idea might make an inventor millions. Developing a telephone, on the other hand, had no immediate market, if one at all. Elisha Gray, Alexander Graham Bell, as well as many others, were instead trying to develop a multiplexing telegraph a device to send several messages over one wire at once. Such an instrument would greatly increase traffic without the telegraph company having to build more lines. As it turned out, for both men, the desire to invent one thing turned into a race to invent something altogether different. And that is truly the story of invention.
lll. "Major Telephone Breakthrough"
The principle of the telephone was uncovered in 1874, but it was the unique combination of electricity and voice that led to Bell's actual invention of the telephone in 1876. Convincing Bell's partners, Gardiner Greene Hubbard, a prominent lawyer from Boston, and Thomas Sanders, a leather merchant with capital from Salem, about the potential for voice transmittal was not an easy task, and they often threatened to pull Bell's funding. Nonetheless, agreement was finally reached and the trio received US Patent No. 174,465, issued on March 3, 1876 for "Improvements in Telegraphy," which is now considered to be the most valuable patent ever issued. Bell considered his invention's greatest advantage over every other form of electrical apparatus to be the fact that it could be used by anyone, as "all other telegraphic machines produce signals which require to be translated by experts, and such instruments are therefore extremely limited in their application, but the telephone actually speaks, and for this reason it can be utilized for nearly every purpose for which speech is employed" (from an address Bell made in 1878, as cited in Young, 1991, p. 6).
Bell was nearly beaten to the patent office by Elisha Gray, who had independently developed a very similar invention. Gray arrived just hours after Bell at the Patent Office, filing a "caveat," a confidential report of an invention that was not yet perfected. Western Electric, cofounded by Gray, became one of the Bell System's major competitors. Western Union was another major competitor, already having established itself as a communications provider with the telegraph system.
Another famous inventor, Thomas Edison, took advantage of Bell's failure to secure a patent in Britain for the Bell receiver, and received a patent for a new receiver, the "electro-motograph," which required continuous cranking -- else the conversation would end. However, by 1880, the Bell transmitter and the Edison receiver were combined and used throughout Britain.
The first permanent outdoor telephone wire, strung in 1877, covered a distance of three miles. Bell could be credited with the anticipation of fiber optics - he worked on a "photophone," which could actually transmit sound for a short distance over a beam of light. Commercial telephone service began in the United States in 1877. The workable exchange, developed in 1878, enabled calls to be switched among any number of subscribers rather than requiring direct lines. Exchanges were handled manually, first by boys, then by the now- famous women operators in their bustles.
In 1879, telephone subscribers began to be designated by numbers rather than names -- as a result of an epidemic of measles. A Lowell, Massachusetts doctor, concerned about the inability of replacement exchange operators to put calls through because they would not be familiar with the names associated with all the jacks on the switchboards, suggested the alpha-numeric system of identifying customers by a two- letter and five-digit system.
The dial phone was invented in the 1880s by Almond Brown Stroger, who was a Kansas City, MO undertaker and was convinced that the Bell Telephone operator was sending calls for his funeral home to the operator's brother-in-law... Stroger invented the dial telephone and installed automatic exchanges in the US and Europe. In 1924, the Bell Telephone System decided that using operators was NOT the way to go, and they licensed Stroger's technology. The step by step switch used to receive the dial pulses is/was called a Stroger Switch, after its inventor.
Because of the largely monopolistic power of the American Bell Company, profits were held high, reaching levels of $1 million in revenue while paying out $600,000 in dividends in 1882. Competition remained a major threat, as the Bell, Western Union, and Western Electric systems were incompatible and not connected. As many as three or more independent telephone companies battled in a given area for customers.
Problems with the telephone occurred when other applications of electricity flourished, particularly trolley cars and street lamps. Natural electricity also interfered with the system, as lightning wreaked havoc on the lines. Long-distance service was established and grew in the 1880s using metallic circuits. The common-battery system, developed by Hammond V. Hayes in 1888, permitted a central battery to supply all telephones on an exchange with power, rather than relying upon each unit's own troublesome battery. The first automatic dialing system was patented in 1891 by a Kansas City undertaker who believed that crooked operators were sending his business elsewhere -- with his main objective being to eliminate the operators. The first coin telephone was installed in Hartford, Connecticut in 1900. Party lines were soon developed to lower the cost of the telephone for individual families, especially those in rural locations.
A young inventor, Dr. Lee De Forest, began work in 1906 on applying what was known as an "audion," a three-element vacuum tube, which could amplify radio waves. He recognized the potential for installing audions or repeaters on telephone lines to amplify the sound waves at mid-points along the wires. The Bell System bought the rights to De Forest's patents in 1913. Long-distance telephone service was constructed on the New York to San Francisco circuit using loading coils and repeaters.
American Telephone and Telegraph (AT&T) took control of Western Union telegraph Company in a "hostile takeover," in 1911, having purchased the Western Union stocks through a subsidiary. The two eventually merged, sharing financial data and telephone lines. In 1918, ten million Bell System telephones were in service.
Theodore Vail, president of the Bell System from 1885 to 1887 and 1907 to 1919, faced the challenge of making a large private corporation adopt a policy of subordinating the maximization of profit to the provision of service to its customers (Brooke, 1976). The political and business environment in the United States following the First World War was strongly "anti-monopolistic." Yet, advantages to single- company service or limiting service in a given area to few competitors had its advantages.
Under Vail's leadership, automatic switching of large numbers of calls was made possible in 1921, using "phantom circuits," which allowed three telephone conversations to be conducted on two pairs of wires. The "French" phone, with the transmitter and receiver in a single handset, was developed by the Bell System around 1904, but was not released on a widespread basis because it cost more than the desk sets. They ultimately became available to subscribers in 1927. The first transatlantic service, from New York to London, became operational in 1927, and was transmitted by radio waves. Research in electronic telephone exchanges began in 1936 in Bell Labs, and was ultimately perfected in the 1960s with its Electronic Switching System (ESS).
Bell benefited greatly from US defense spending during World War II in its laboratories. War-time experiments, innovations, and inventions brought Bell to the forefront of telecommunications in the post-war era. The first commercial mobile telephone service was put in service in 1946, linking moving vehicles to telephone networks by radio. The same year brought transmission via coaxial cables, resulting in a major improvement in service as they were less likely to be interrupted by other electrical interference. Microwave radio transmission was used for long-distance telephony in 1947. The transistor, a key to modern electronics, was invented at Bell Labs in 1947. A team consisting of William Schockley, Walter Brattain, and John Bardeen demonstrated the "transistor effect," using a germanium crystal that they had set up in contact with two wires two-thousandths of an inch apart.
Changes were underway in the 1950s. Consumers initially objected to all-numeral telephone numbers (All Number Calling, or ANC) that were introduced in the latter half of the decade. Consumer demand for telephones had outstripped the ability of the telephone system to supply all of the required numbers, which were restricted by the alpha-numeric combinations in place for decades. The laying of transatlantic telephone cables began in 1955. Care was taken to ensure that the submarine repeaters would be of the highest quality, guaranteed to last at least twenty years before replacement would be required.
Telstar, the world's first international communications satellite, was rocketed into orbit on July 10, 1962, with a collaboration between NASA and the Bell System. Satellites in geosynchronous orbit are used mostly for long-distance service. Videophones, developed in the mid-1960s, were becoming more affordable and practical with the combination of devices that eased the transmission and reception of both audio and video signals over telephone lines.
Fiber optic cables (or "fiber optics"), developed in the early 1980s, offered the potential to carry greater volumes of calls than satellite or microwave links. Electrical telephone signals are fed into tiny semiconductor lasers, which produce pulses of light in response to incoming signals and are bounced down the inside of extremely thin glass fibers. Today's cellular mobile telephones rely upon a series of "cells," each with its own central radio transmitter and receiver. Each cellular telephone unit also has its own central transmitter-receiver, permitting it to receive seamless transmission as they enter and exit from a cell.
The impact of the telephone has been described as both positive and negative. On the negative side, wars are waged more easily, the scope of human conflict has been extended along telephone lines, the multi-generational household has been broken-up as living alone is no longer an experiment in isolation, and the time-space continuum seems to be compressed faster than previously thought possible (Brooks, 1976). On the other hand, the invention of the telephone has resulted in the rapid and diffuse dissemination of technical and scientific information, saved lives through links to emergency services, made possible the modern city through telephonic connections, increased the speed and ease with which information changes place, and accelerated the rate of scientific and technological change and growth in industry (Brooks, 1976).
It is curious in contrast to now consider the musings of Herbert Casson (1910, p. 299), who ended his book with a question, "Who could have foreseen what the telephone bells have done to ring out the old ways and to ring in the new; to ring out delay and isolation and to ring in the efficiency and friendliness of a truly united people?" The future combination of various means of telecommunications, with the personal computer and recent inventions such as the facsimile machine, could never have been foreseen yet they hold the potential for vast changes in the global environment for society, business and industry, and governments.
References American Telephone and Telegraph (AT&T). (1979). Events in telecommunications history. New York: Author. Brooks, J. (1976). Telephone: the first hundred years. Telephone: the first hundred years. New York: Harper & Row. Casson, H. (1910). The history of the telephone. Chicago: A. C. McClurg. Compton's Interactive Encyclopedia. (1994). The Telephone, software version 2.00 VW for CD-ROM. New York: Compton's New Media. Du Moncel, T. (1974). The telephone, the microphone, and the phonograph. New York: Arno Press. Reprinted from the 1879 edition printed by Harper, New York. Fischer, C. (1992). America calling: a social history of the telephone to 1940. Berkeley, CA: University of California Press. Young, P. (1991). Person to person: the international impact of the telephone. Cambridge: Granta Editions.
A History of the Telephone
1860 Philipp Reis develops a "telephon." 1874 Alexander Graham Bell discovered the principle of the telephone. 1876 US Patent No. 174,465, issued on March 3 for "Improvements in Telegraphy." 1876 Elisha Gray applies for a similar patent hours after Bell. 1877 Thomas Edison receives a patent in Britain for the "electro-motograph." First permanent outdoor telephone wire strung. Commercial telephone service began in the United States. 1878 The workable exchange enabled calls to be switched among any number of subscribers rather than requiring direct lines. Exchanges were handled manually, first by boys, then by the now-famous women operators in their bustles. 1879 Telephone subscribers began to be designated by numbers rather than names. 1880s Long distance service was established and grew using metallic circuits. 1888 The common battery system, developed by Hammond V. Hayes, permitted a central battery to supply all telephones on an exchange. 1891 The first automatic dial system was patented by a Kansas City undertaker. 1900 The first coin telephone was installed in Hartford, Connecticut. 1906 Dr. Lee De Forest, began work 1906 on applying what was known as an "audion," a three element vacuum tube, which could amplify radio waves, to telephony. 1911 American Telephone and Telegraph (AT&T) took control of Western Union Telegraph Company. 1913 The Bell System bought the rights to De Forest's patentsm\, which were used for long distance telephone service. First long-distance wire link was on the New York to San Francisco circuit using loading coils and repeaters. 1918 Ten million Bell System telephones were in service. 1921 Automatic switching of large numbers of calls was made possible using "phantom circuits," which allowed three telephone conversations to be conducted on two pairs of wires. 1927 The "French" phone, with the transmitter and receiver in a single handset, was developed by the Bell System was released on a widespread basis. 1927 Transatlantic service from New York to London became operational, transmitted by radio waves. 1936 Research on electronic telephone exchanges began in Bell Labs and was ultimately perfected in the 1960s with AT&T's Electronic Switching System (ESS). 1946 First commercial mobile telephone service put into service in 1946, linking moving vehicles to the telephone network by radio. 1946 Transmission via coaxial cables was accomplished. 1947 Microwave radio transmission was used for long-distance telephony. 1947 The transistor, a key to modern electronics, was invented at Bell Labs by a team consisting of William Schockley, Walter Brattain, and John Bardeen. 1955 The laying of transatlantic telephone cables began. 1958 All Number Calling (ANC) instituted to handle consumer demands for individual telephone numbers. 1962 Telstar, the world's first international communications satellite, was rocketed into orbit on July 10 with the collaboration between NASA and the Bell System. 1960s Videophones became more affordable and practical. 1980 s Fiber optic(s) technology developed
Cordless Phone History
It all started around 1980. The cordless phones were primitive by today's standards. These cordless phones were given a frequency of 27 MHz. By this standard, FCC range was good but the sound quality was not. These cordless phones had a lot of noise and static. The FCC allowed ten channels. If you were within distance of someone using the same frequency you could share conversations or have a 3 way conversation at no additional charge from MA Bell. The cordless phone came with 1 of the 10 channels. If you had this problem you took the cordless phone back to the retailer and exchanged for another frequency. So, cordless phones would hunt for their base when portable. They may find their neighbor’s base. If you were using your neighbor’s cordless phone base you could make long distance calls and have it charged to the neighbor’s bill. That was fun!!Around 1986 the FCC stepped in and changed the cordless phone frequency to 47-49 MHz. This was a higher frequency which meant less noise. They also cut down the power to decrease range. This was an attempt to slow down the 3 way conversation problem and the long distance dialing problem. Cordless phone manufacturers were making huge strides in technology introducing security cords and cordless phones that actually could change channels. This was a big help but cordless phones just didn’t have any range. Customers would be able to talk as long as they were in the same room and standing or sitting still. It’s now 1990. The FCC allows a new cordless phone frequency of 900 MHz. These cordless phones were much clearer and had better distance than ever before. They also gave their cordless phones 100 channels to choose from which meant less crowding. The cordless phones work great but sold for $499.99. Retailers thought if they could sell them for less than $200 then they would sell.Around 1994 different choices in 900 MHz cordless phones would be developed. Previously, cordless phones had been analog meaning the transmission was sent and received in a regular voice format. The engineers found out that they could send out a digital signal (X and O’s) transforming them back to analog when received by this cordless phone. This increased clarity and it also made it impossible for radio scanners to pick up this frequency for listening to other’s conversations.1995 was a good year for cordless phones. DSS (Digital Spread Spectrum) was a whole new way of sending the cordless phone signal from the base to the handset. It spread the cordless phone signal 360 degrees so there were no dead spots and distance went up to half a mile. It was digital so your signal was secure. Cordless phones were expensive, and you had limited choices. The cordless phone of choice was Uniden 910 at $359.99. It was an awesome cordless phone at a great price. Of course there was a price to pay for this power. If this cordless phone was a car, the government would have slapped a gas guzzling tax on it! This cordless phone drained batteries like a Ferrari through gas. As technology progressed battery life got better and prices came down. I think they call it capitalism. Around this time, Caller ID was sweeping the nation, and this was a big boost for cordless phones. Now you could have the cordless phone next to your chair and see who was calling before you answered it. As additional features were added, prices dropped even further and more people bought cordless phones. Consumers were no longer satisfied with only one cordless phone in the home any longer. Now they wanted two or three or all the phones to be cordless. This created a new set of problems. If there was ever a power failure you wouldn’t have any working phones. All of the sudden, one phone line wasn’t enough. Because of the evolving of the Internet and teenagers, Americans decided that they needed two phone lines in the household. Manufactures starting selling two line cordless phones. Now you could buy a two line cordless phone with Caller ID and DSS. Life was good! However, this created a new problem. DSS is a bully phone. If you were on the DSS and someone else (example: your teenager) was on a regular 900 MHZ cordless digital or analog phone, the DSS cordless phone would walk over the other phone, meaning it would cause static or lessen the transmission of the non DSS cordless phone.In 1998 came another huge cordless phone advancement. The FCC saw how many cordless phones were being used and and gave the American public an expanded new cordless phone frequency. The frequency increased to 2.4 GHZ. It was so much higher, so you have better clarity, and in some cordless phone models you picked up better distance. Cordless phones had now reached their goal of true corded quality in a cordless phone. You could walk around the block with no noise and maximum security.In the year 2000 you can buy a DSS cordless phone for under $100. That’s amazing!! Technology in cordless phones has come a long way in the past 20 years!
Mobile Phone History
Digital wireless and cellular roots go back to the1940s when commercial mobile telephony began. Compared to today's furious pace of development, it may seem odd that wireless didn't come along sooner. There are many reasons for that. Technology, disinterest, and to some extent regulation limited early United States radio-telephone development. As the vacuum tube and the transistor made possible the early telephone network, the wireless revolution began only after low cost microprocessors and digital switching became available. And while the Bell System built the finest landline telephone system in the world, they never seemed truly committed to mobile telephony. Their wireless engineers were brilliant and keen but the System itself held them back. Federal regulations also hindered many projects but in Europe, where state run telephone companies controlled their own telecom development, although, admittedly, without competition, wireless came no sooner, and in most cases, later. Starting in 1921 in the United States mobile radios began operating at 2 MHz, just above the present A.M. radio broadcast band. [Young] These were chiefly experimental police department radios, with practical systems not implemented until the 1940s. [FCC] Police and emergency services drove mobile radio pioneering, with little thought given to private telephone use.
In 1934 the United States Congress created the Federal Communications Commission. In addition to regulating landline interstate telephone business, they also began managing the radio spectrum. It decided who would get what frequencies. It gave priority to emergency services, government agencies, utility companies, and services it thought helped the most people. Radio users like a taxi service or a tow truck dispatch company required little spectrum to conduct their business. Radio telephone used large frequency allocations to serve a few people. The FCC designated no radio-telephone channels until after World War II.
On June 17, 1946 in Saint Louis, Missouri, AT&T and Southwestern Bell introduced the first American commercial mobile radio-telephone service. Mobiles used newly issued vehicle radio-telephone licenses granted to Southwestern Bell by the FCC. They operated on six channels in the 150 MHz band with a 60 kHz channel spacing. [Peterson] Bad cross channel interference, something like cross talk in a landline phone, soon forced Bell to use only three channels. In a rare exception to Bell System practice, subscribers could buy their own radio sets and not AT&T's equipment. Installed high above Southwestern Bell's headquarters at 1010 Pine Street, a centrally located antenna transmitting 250 watts paged mobiles and provided radio-telephone traffic on the downlink. Operation was straightforward, as the following describes:
How Mobile Telephone Calls Are Handled
Telephone customer (1) dials 'Long Distance' and asks to be connected with the mobile services operator, to whom he gives the telephone number of the vehicle he wants to call. The operator sends out a signal from the radio control terminal (2) which causes a lamp to light and a bell to ring in the mobile unit (3). Occupant answers his telephone, his voice traveling by radio to the nearest receiver (4) and thence by telephone wire.
To place a call from a vehicle, the occupant merely lifts his telephone and presses a 'talk' button. This sends out a radio signal which is picked up by the nearest receiver and transmitted to the operator.[BLR1]
(The above accompanies a Bell Laboratories Record illustration, from the 1946 article first describing the system. It's a 346k download.)
The 20 watt mobile sets did not transmit back to the central tower but to one of five receivers placed across the city.[BLR2] Once a mobile went off hook all five receivers opened. The Mobile Telephone Service or MTS system combined signals from one or more receivers into a unified signal, amplifying it and sending it on to the toll switchboard. This allowed roaming from one city neighborhood to another. Can't visualize how this worked? Imagine someone walking through a house with several telephones off hook. A party on the other end of the line would hear the person moving from one room to another, as each telephone gathered a part of the sound.
One party talked at a time with MTS. You pushed a handset button to talk, then released the button to listen. (This eliminated echo problems which took years to solve before natural, full duplex communications were possible.) Mobile telephone service was not simplex operation as many writers describe, but half duplex operation. Simplex uses only one frequency to both transmit and receive. In MTS the base station frequency and mobile frequency were offset by five kHz. Privacy is one reason to do this; eavesdroppers could hear only one side of a conversation. Like a citizen's band radio, a caller searched manually for an unused frequency before placing a call. But since there were so few channels this wasn't much of a problem. This does point out radio-telephones' greatest problem of the time: too few channels.
This system presaged many cellular developments, indeed, Bell Laboratories' D.H. Ring articulated the cellular concept one year later in an unpublished paper. Young states all the elements were known then: a network of small geographical areas called cells, a low powered transmitter in each, the cell traffic controlled by a central switch, frequencies reused by different cells and so on. Young states that from 1947 Bell teams "had faith that the means for administering and connecting to many small cells would evolve by the time they were needed." [Young] While recognizing the Laboratories' prescience, more mobile telephones were always needed. In every city where mobile telephone service was introduced waiting lists developed, growing every year. By 1976 only 545 customers in New York City had Bell System mobiles, with 3,700 customers on the waiting list. Around the country 44,000 Bell subscribers had AT&T mobiles but 20,000 people sat on five to ten year waiting lists. [Gibson] Despite this incredible demand it took cellular 37 years to go commercial from the mobile phone's introduction. But the FCC's regulatory foot dragging slowed cellular as well. Until the 1980s they never made enough channels available; as late as 1978 the Bell System, the Independents, and the non-wireline carriers divided just 54 channels nationwide. [O'Brien] That compares to the 666 channels the first AMPS systems needed to work.
In mobile telephony a channel is a pair of frequencies. One frequency to transmit on and one to receive. It makes up a circuit or a complete communication path. Sounds simple enough to accommodate. Yet the radio spectrum is extremely crowded. In the late 1940s little space existed at the lower frequencies most equipment used. Inefficient radios contributed to the crowding, using 60 kHz to send an signal that can now be done with 10kHz or less. But what could you do with just six channels, no matter what the technology? Users by the scores vied for an open frequency. You had, in effect, a wireless party line, with perhaps forty subscribers fighting to place calls on each channel. Most mobile telephone systems couldn't accommodate more than 250 people. There were other problems.
Radio waves at lower frequencies travel great distances, sometimes hundreds of miles when they skip across the atmosphere. High powered transmitters gave mobiles a wide operating range but added to the dilemma. Telephone companies couldn't reuse their precious channels in nearby cities, lest they interfere with their own systems. They needed at least seventy five miles between systems before they could use them again. While better frequency reuse techniques might have helped, something doubtful with the technology of the times, the FCC held the key to opening more channels for wireless.
In 1947 AT&T began operating a "highway service", a radio-telephone offering that provided service between New York and Boston. It operated in the 35 to 44MHz band and caused interference from to time with other distant services. Even AT&T thought the system unsuccessful.
In that same year the Bell System asked the FCC for more frequencies. The FCC allocated a few more channels in 1949, but gave half to other companies wanting to sell mobile telephone service.
Berresford says "these radio common carriers or RCCs, were the first FCC-created competition for the Bell System" He elaborates on the radio common carriers, a group of market driven businessmen who pushed mobile telephony in the early years further and faster than the Bell System:
The telephone companies and the RCCs evolved differently in the early mobile telephone business. The telephone companies were primarily interested in providing ordinary, 'basic' telephone service to the masses and, therefore, gave scant attention to mobile services throughout the 1950s and 1960s. The RCCs were generally small entrepreneurs that were involved in several related businesses-- telephone answering services, private radio systems for taxicab and delivery companies, maritime and air-to-ground services, and 'beeper' paging services. As a class, the RCCs were more sales-oriented than the telephone companies and won many more customers; a few became rich in the paging business. The RCCs were also highly independent of each other; aside from sales, their specialty was litigation, often tying telephone companies (and each other) up in regulatory proceedings for years.
As proof of their competitiveness, the RCCs serviced 80,000 mobile units by 1978, twice as many as Bell. This growth built on a strong start, the introduction of automatic dialing in 1948. On March 1, 1948 the first fully automatic radiotelephone service began operating in Richmond, Indiana, eliminating the operator to place most calls. [McDonald] The Richmond Radiotelephone Company bested the Bell System by 16 years. AT&T didn't provide automated dialing for most mobiles until 1964, lagging behind automatic switching for wireless as they had done with landline telephony. (As an aside, the Bell System did not retire their last cord switchboard until 1978.) Most systems, though, RCCs included, still operated manually until the 1960s. Interestingly, some claim the Swedish Telecommunications Administration's S. Lauhrén designed the world's first automatic mobile telephone system, with a Stockholm trial starting in 1951.
I've found no literature to support a claim they were the first, before the 1948 Richmond Telephone Company service. For completeness, I should mention the following.
Anders Lindeberg of the Swedish Museum of Science and Technology does point out the link I provide in the preceding paragraph is "a summary from an article in the yearbook "Daedalus" (1991) for the Swedish Museum of Science and Technology.
The Swedish original article is much more extensive than the summary." He adds that "The Mobile Phone Book" by John Meurling and Richard Jeans, ISBN 0-9524031-02 published by Communications Week International, London in 1994 does briefly describe the "MTL" from 1951.
Speaking of Sweden, let's go to Europe to read about a typical radio-telephone unit, something similar to American installations:
It was in the mid-1950's that the first phone-equipped cars took to the road. This was in Stockholm - home of Ericsson's corporate headquarters - and the first users were a doctor-on-call and a bank-on-wheels. The apparatus consisted of receiver, transmitter and logic unit mounted in the boot of the car, with the dial and handset fixed to a board hanging over the back of the front seat. It was like driving around with a complete telephone station in the car. With all the functions of an ordinary telephone, the telephone was powered by the car battery. Rumor has it that the equipment devoured so much power that you were only able to make two calls - the second one to ask the garage to send a breakdown truck to tow away you, your car and your flat battery. . . These first car phones were just too heavy and cumbersome - and too expensive to use - for more than a handful of subscribers. It was not until the mid-1960's that new equipment using transistors were brought onto the market. Weighing a lot less and drawing not nearly so much power, mobile phones now left plenty of room in the boot - but you still needed a car to be able to move them around.
In 1956 the Bell System began providing manual radio-telephone service at 450 MHz, a new frequency band assigned to overcrowding. AT&T did not automate this service until 1969. In 1958 the innovative Richmond Radiotelephone Company improved their automatic dialing system. They added new features to it, including direct mobile to mobile communications.
Other independent telephone companies and the Radio Common Carriers made similar advances to mobile-telephony throughout the 1950s and 1960s. If this subject interests you, The Independent Radio Engineer Transactions on Vehicle Communications, later renamed the IEEE Transactions on Vehicle Communications, is the publication to read during those years.
In that same year the Bell System petitioned the FCC to grant 75 MHz worth of spectrum to radio-telephones in the 800 MHz band. The FCC had not yet allowed any channels below 500MHz, where there was not enough continuous spectrum to develop an efficient radio system. Despite the Bell System's forward thinking, the FCC sat on this proposal for ten years and only considered it in 1968 when requests for more frequencies became so backlogged that they could not ignore them.
In 1964 the Bell System introduced Improved Mobile Telephone Service or IMTS, a replacement to the badly aging Mobile Telephone System. It worked in full-duplex so people didn't have to press a button to talk. Talk went back and forth just like a regular telephone. It finally permitted direct dialing, automatic channel selection and reduced bandwidth to 25-30 kHz.
Before leaving conventional radio telephony I should mention fraud. As telephone folks were well acquainted with landline toll fraud, begun in earnest in the late 1960s, so they were aware of wireless fraud. Here's a summary from a 1985 article in Personal Communications Technology Magazine: "The earliest form of mobile telephony, unsquelched manual Mobile Telephone Service (MTS), was vulnerable to interception and eavesdropping. To place a call, the user listened for a free channel. When he found one, he would key his microphone to for service: 'Operator, this is Mobile 1234; may I please have 555-7890.' The operator knew to submit a billing ticket for account number 1234 to pay for the call. So did anybody else listening to the channel--hence the potential for spoofing and fraud.
Squelched channel MTS hid the problem only slightly because users ordinarily didn't overhear channels being used by other parties. Fraud was still easy for those who turned off the squelch long enough to overhear account numbers.
Direct-dial mobile telephone services such as Improved Mobile Telephone Service (IMTS) obscured the problem a bit more because subscriber identification was made automatically rather than by spoken exchange between caller and operator. Each time a user originated a call, the mobile telephone transmitted its identification number to the serving base station using some form of Audio Frequency Shift Keying (AFSK), which was not so easy for eavesdroppers to understand.
Committing fraud under IMTS required modification of the mobile--restrapping of jumpers in the radio unit, or operating magic keyboard combinations in later units--to reprogram the unit to transmit an unauthorized identification number. Some mobile control heads even had convenient thumb wheel switches installed on them to facilitate easy and frequent ANI (Automatic Number Identification) changes."
In 1934 the United States Congress created the Federal Communications Commission. In addition to regulating landline interstate telephone business, they also began managing the radio spectrum. It decided who would get what frequencies. It gave priority to emergency services, government agencies, utility companies, and services it thought helped the most people. Radio users like a taxi service or a tow truck dispatch company required little spectrum to conduct their business. Radio telephone used large frequency allocations to serve a few people. The FCC designated no radio-telephone channels until after World War II.
On June 17, 1946 in Saint Louis, Missouri, AT&T and Southwestern Bell introduced the first American commercial mobile radio-telephone service. Mobiles used newly issued vehicle radio-telephone licenses granted to Southwestern Bell by the FCC. They operated on six channels in the 150 MHz band with a 60 kHz channel spacing. [Peterson] Bad cross channel interference, something like cross talk in a landline phone, soon forced Bell to use only three channels. In a rare exception to Bell System practice, subscribers could buy their own radio sets and not AT&T's equipment. Installed high above Southwestern Bell's headquarters at 1010 Pine Street, a centrally located antenna transmitting 250 watts paged mobiles and provided radio-telephone traffic on the downlink. Operation was straightforward, as the following describes:
How Mobile Telephone Calls Are Handled
Telephone customer (1) dials 'Long Distance' and asks to be connected with the mobile services operator, to whom he gives the telephone number of the vehicle he wants to call. The operator sends out a signal from the radio control terminal (2) which causes a lamp to light and a bell to ring in the mobile unit (3). Occupant answers his telephone, his voice traveling by radio to the nearest receiver (4) and thence by telephone wire.
To place a call from a vehicle, the occupant merely lifts his telephone and presses a 'talk' button. This sends out a radio signal which is picked up by the nearest receiver and transmitted to the operator.[BLR1]
(The above accompanies a Bell Laboratories Record illustration, from the 1946 article first describing the system. It's a 346k download.)
The 20 watt mobile sets did not transmit back to the central tower but to one of five receivers placed across the city.[BLR2] Once a mobile went off hook all five receivers opened. The Mobile Telephone Service or MTS system combined signals from one or more receivers into a unified signal, amplifying it and sending it on to the toll switchboard. This allowed roaming from one city neighborhood to another. Can't visualize how this worked? Imagine someone walking through a house with several telephones off hook. A party on the other end of the line would hear the person moving from one room to another, as each telephone gathered a part of the sound.
One party talked at a time with MTS. You pushed a handset button to talk, then released the button to listen. (This eliminated echo problems which took years to solve before natural, full duplex communications were possible.) Mobile telephone service was not simplex operation as many writers describe, but half duplex operation. Simplex uses only one frequency to both transmit and receive. In MTS the base station frequency and mobile frequency were offset by five kHz. Privacy is one reason to do this; eavesdroppers could hear only one side of a conversation. Like a citizen's band radio, a caller searched manually for an unused frequency before placing a call. But since there were so few channels this wasn't much of a problem. This does point out radio-telephones' greatest problem of the time: too few channels.
This system presaged many cellular developments, indeed, Bell Laboratories' D.H. Ring articulated the cellular concept one year later in an unpublished paper. Young states all the elements were known then: a network of small geographical areas called cells, a low powered transmitter in each, the cell traffic controlled by a central switch, frequencies reused by different cells and so on. Young states that from 1947 Bell teams "had faith that the means for administering and connecting to many small cells would evolve by the time they were needed." [Young] While recognizing the Laboratories' prescience, more mobile telephones were always needed. In every city where mobile telephone service was introduced waiting lists developed, growing every year. By 1976 only 545 customers in New York City had Bell System mobiles, with 3,700 customers on the waiting list. Around the country 44,000 Bell subscribers had AT&T mobiles but 20,000 people sat on five to ten year waiting lists. [Gibson] Despite this incredible demand it took cellular 37 years to go commercial from the mobile phone's introduction. But the FCC's regulatory foot dragging slowed cellular as well. Until the 1980s they never made enough channels available; as late as 1978 the Bell System, the Independents, and the non-wireline carriers divided just 54 channels nationwide. [O'Brien] That compares to the 666 channels the first AMPS systems needed to work.
In mobile telephony a channel is a pair of frequencies. One frequency to transmit on and one to receive. It makes up a circuit or a complete communication path. Sounds simple enough to accommodate. Yet the radio spectrum is extremely crowded. In the late 1940s little space existed at the lower frequencies most equipment used. Inefficient radios contributed to the crowding, using 60 kHz to send an signal that can now be done with 10kHz or less. But what could you do with just six channels, no matter what the technology? Users by the scores vied for an open frequency. You had, in effect, a wireless party line, with perhaps forty subscribers fighting to place calls on each channel. Most mobile telephone systems couldn't accommodate more than 250 people. There were other problems.
Radio waves at lower frequencies travel great distances, sometimes hundreds of miles when they skip across the atmosphere. High powered transmitters gave mobiles a wide operating range but added to the dilemma. Telephone companies couldn't reuse their precious channels in nearby cities, lest they interfere with their own systems. They needed at least seventy five miles between systems before they could use them again. While better frequency reuse techniques might have helped, something doubtful with the technology of the times, the FCC held the key to opening more channels for wireless.
In 1947 AT&T began operating a "highway service", a radio-telephone offering that provided service between New York and Boston. It operated in the 35 to 44MHz band and caused interference from to time with other distant services. Even AT&T thought the system unsuccessful.
In that same year the Bell System asked the FCC for more frequencies. The FCC allocated a few more channels in 1949, but gave half to other companies wanting to sell mobile telephone service.
Berresford says "these radio common carriers or RCCs, were the first FCC-created competition for the Bell System" He elaborates on the radio common carriers, a group of market driven businessmen who pushed mobile telephony in the early years further and faster than the Bell System:
The telephone companies and the RCCs evolved differently in the early mobile telephone business. The telephone companies were primarily interested in providing ordinary, 'basic' telephone service to the masses and, therefore, gave scant attention to mobile services throughout the 1950s and 1960s. The RCCs were generally small entrepreneurs that were involved in several related businesses-- telephone answering services, private radio systems for taxicab and delivery companies, maritime and air-to-ground services, and 'beeper' paging services. As a class, the RCCs were more sales-oriented than the telephone companies and won many more customers; a few became rich in the paging business. The RCCs were also highly independent of each other; aside from sales, their specialty was litigation, often tying telephone companies (and each other) up in regulatory proceedings for years.
As proof of their competitiveness, the RCCs serviced 80,000 mobile units by 1978, twice as many as Bell. This growth built on a strong start, the introduction of automatic dialing in 1948. On March 1, 1948 the first fully automatic radiotelephone service began operating in Richmond, Indiana, eliminating the operator to place most calls. [McDonald] The Richmond Radiotelephone Company bested the Bell System by 16 years. AT&T didn't provide automated dialing for most mobiles until 1964, lagging behind automatic switching for wireless as they had done with landline telephony. (As an aside, the Bell System did not retire their last cord switchboard until 1978.) Most systems, though, RCCs included, still operated manually until the 1960s. Interestingly, some claim the Swedish Telecommunications Administration's S. Lauhrén designed the world's first automatic mobile telephone system, with a Stockholm trial starting in 1951.
I've found no literature to support a claim they were the first, before the 1948 Richmond Telephone Company service. For completeness, I should mention the following.
Anders Lindeberg of the Swedish Museum of Science and Technology does point out the link I provide in the preceding paragraph is "a summary from an article in the yearbook "Daedalus" (1991) for the Swedish Museum of Science and Technology.
The Swedish original article is much more extensive than the summary." He adds that "The Mobile Phone Book" by John Meurling and Richard Jeans, ISBN 0-9524031-02 published by Communications Week International, London in 1994 does briefly describe the "MTL" from 1951.
Speaking of Sweden, let's go to Europe to read about a typical radio-telephone unit, something similar to American installations:
It was in the mid-1950's that the first phone-equipped cars took to the road. This was in Stockholm - home of Ericsson's corporate headquarters - and the first users were a doctor-on-call and a bank-on-wheels. The apparatus consisted of receiver, transmitter and logic unit mounted in the boot of the car, with the dial and handset fixed to a board hanging over the back of the front seat. It was like driving around with a complete telephone station in the car. With all the functions of an ordinary telephone, the telephone was powered by the car battery. Rumor has it that the equipment devoured so much power that you were only able to make two calls - the second one to ask the garage to send a breakdown truck to tow away you, your car and your flat battery. . . These first car phones were just too heavy and cumbersome - and too expensive to use - for more than a handful of subscribers. It was not until the mid-1960's that new equipment using transistors were brought onto the market. Weighing a lot less and drawing not nearly so much power, mobile phones now left plenty of room in the boot - but you still needed a car to be able to move them around.
In 1956 the Bell System began providing manual radio-telephone service at 450 MHz, a new frequency band assigned to overcrowding. AT&T did not automate this service until 1969. In 1958 the innovative Richmond Radiotelephone Company improved their automatic dialing system. They added new features to it, including direct mobile to mobile communications.
Other independent telephone companies and the Radio Common Carriers made similar advances to mobile-telephony throughout the 1950s and 1960s. If this subject interests you, The Independent Radio Engineer Transactions on Vehicle Communications, later renamed the IEEE Transactions on Vehicle Communications, is the publication to read during those years.
In that same year the Bell System petitioned the FCC to grant 75 MHz worth of spectrum to radio-telephones in the 800 MHz band. The FCC had not yet allowed any channels below 500MHz, where there was not enough continuous spectrum to develop an efficient radio system. Despite the Bell System's forward thinking, the FCC sat on this proposal for ten years and only considered it in 1968 when requests for more frequencies became so backlogged that they could not ignore them.
In 1964 the Bell System introduced Improved Mobile Telephone Service or IMTS, a replacement to the badly aging Mobile Telephone System. It worked in full-duplex so people didn't have to press a button to talk. Talk went back and forth just like a regular telephone. It finally permitted direct dialing, automatic channel selection and reduced bandwidth to 25-30 kHz.
Before leaving conventional radio telephony I should mention fraud. As telephone folks were well acquainted with landline toll fraud, begun in earnest in the late 1960s, so they were aware of wireless fraud. Here's a summary from a 1985 article in Personal Communications Technology Magazine: "The earliest form of mobile telephony, unsquelched manual Mobile Telephone Service (MTS), was vulnerable to interception and eavesdropping. To place a call, the user listened for a free channel. When he found one, he would key his microphone to for service: 'Operator, this is Mobile 1234; may I please have 555-7890.' The operator knew to submit a billing ticket for account number 1234 to pay for the call. So did anybody else listening to the channel--hence the potential for spoofing and fraud.
Squelched channel MTS hid the problem only slightly because users ordinarily didn't overhear channels being used by other parties. Fraud was still easy for those who turned off the squelch long enough to overhear account numbers.
Direct-dial mobile telephone services such as Improved Mobile Telephone Service (IMTS) obscured the problem a bit more because subscriber identification was made automatically rather than by spoken exchange between caller and operator. Each time a user originated a call, the mobile telephone transmitted its identification number to the serving base station using some form of Audio Frequency Shift Keying (AFSK), which was not so easy for eavesdroppers to understand.
Committing fraud under IMTS required modification of the mobile--restrapping of jumpers in the radio unit, or operating magic keyboard combinations in later units--to reprogram the unit to transmit an unauthorized identification number. Some mobile control heads even had convenient thumb wheel switches installed on them to facilitate easy and frequent ANI (Automatic Number Identification) changes."
History of Cellular Phones
The basic concept of cellular phones began in 1947 when researchers looked at crude mobile (car) phones and realized that by using small cells (range of service area) with frequency reuse could increase the traffic capacity of mobile phones substantially, however, the technology to do it was nonexistent.
Anything to do with broadcasting and sending a radio or television message out over the airwaves comes under a Federal Communications Commission (FCC) regulation that a cellular phone is actually a type of two-way radio. In 1947, AT&T proposed that the FCC allocate a large number of radio spectrum frequencies so that wide-spread mobile phone service could become feasible and AT&T would have a incentive to research the new technology. We can partially blame the FCC for the gap between the concept of cellular phone service and it's availability to the public. Because of the FCC decision to limit the cellular phone frequencies in 1947, only twenty three cellular phone conversations could occur simultaneously in the same service area - not a market incentive for research.
The FCC reconsidered it's position in 1968, and stated "if the technology to build a better mobile phone service works, we will increase the cellular phone frequencies allocation, freeing the airwaves for more mobile phones." AT&T - Bell Labs proposed a cellular phone system to the FCC of many small, low-powered broadcast towers, each covering a 'cell' a few miles in radius, collectively covering a larger area. Each tower would use only a few of the total frequencies allocated to the cellular phone system, and as cars moved across the area their cellular phone calls would be passed from tower to tower.
By 1977, AT&T Bell Labs constructed and operated a prototype cellular phone system. A year later, public trials of the new cellular phone system were started in Chicago, IL with over 2000 trial cellular phone customers. In 1979, the first commercial cellular phone system began operation in Tokyo. In 1981, Motorola and American Radio phone started a second U.S. cellular radio-phone system test in the Washington/Baltimore area. By 1982, the slow moving FCC finally authorized commercial cellular phone service for the USA. A year later, the first American commercial for analog cellular phone service or AMPS (Advanced Mobile Phone Service) was offered in Chicago, IL by Ameritech. Despite the incredible demand, it took cellular phone service 37 years to become commercially available in the United States.
Consumer demand quickly outstripped the cellular phone system's 1982 standards, by 1987, cellular phone subscribers exceeded one million, and the airways were crowded. Three ways of improving services existed:
one - increase cellular phone frequencies allocation
two - split existing cellular phone cells
three - improve the cellular phone technology
The FCC did not want to handout any more bandwidth and building/splitting cells would have been expensive and add bulk to the cellular phone network. To stimulate the growth of new cellular phone technology, the FCC declared in 1987 that cellular phone licensees may employ alternative cellular phone technologies in the 800 MHz band. The cellular phone industry began to research new transmission technology as an alternative.
Anything to do with broadcasting and sending a radio or television message out over the airwaves comes under a Federal Communications Commission (FCC) regulation that a cellular phone is actually a type of two-way radio. In 1947, AT&T proposed that the FCC allocate a large number of radio spectrum frequencies so that wide-spread mobile phone service could become feasible and AT&T would have a incentive to research the new technology. We can partially blame the FCC for the gap between the concept of cellular phone service and it's availability to the public. Because of the FCC decision to limit the cellular phone frequencies in 1947, only twenty three cellular phone conversations could occur simultaneously in the same service area - not a market incentive for research.
The FCC reconsidered it's position in 1968, and stated "if the technology to build a better mobile phone service works, we will increase the cellular phone frequencies allocation, freeing the airwaves for more mobile phones." AT&T - Bell Labs proposed a cellular phone system to the FCC of many small, low-powered broadcast towers, each covering a 'cell' a few miles in radius, collectively covering a larger area. Each tower would use only a few of the total frequencies allocated to the cellular phone system, and as cars moved across the area their cellular phone calls would be passed from tower to tower.
By 1977, AT&T Bell Labs constructed and operated a prototype cellular phone system. A year later, public trials of the new cellular phone system were started in Chicago, IL with over 2000 trial cellular phone customers. In 1979, the first commercial cellular phone system began operation in Tokyo. In 1981, Motorola and American Radio phone started a second U.S. cellular radio-phone system test in the Washington/Baltimore area. By 1982, the slow moving FCC finally authorized commercial cellular phone service for the USA. A year later, the first American commercial for analog cellular phone service or AMPS (Advanced Mobile Phone Service) was offered in Chicago, IL by Ameritech. Despite the incredible demand, it took cellular phone service 37 years to become commercially available in the United States.
Consumer demand quickly outstripped the cellular phone system's 1982 standards, by 1987, cellular phone subscribers exceeded one million, and the airways were crowded. Three ways of improving services existed:
one - increase cellular phone frequencies allocation
two - split existing cellular phone cells
three - improve the cellular phone technology
The FCC did not want to handout any more bandwidth and building/splitting cells would have been expensive and add bulk to the cellular phone network. To stimulate the growth of new cellular phone technology, the FCC declared in 1987 that cellular phone licensees may employ alternative cellular phone technologies in the 800 MHz band. The cellular phone industry began to research new transmission technology as an alternative.
History of GSM
During the early 1980s, analog cellular telephone systems were experiencing rapid growth in Europe, particularly in Scandinavia and the United Kingdom, but also in France and Germany. Each country developed its own system, which was incompatible with everyone else's in equipment and operation. This was an undesirable situation, because not only was the mobile equipment limited to operation within national boundaries, which in a unified Europe were increasingly unimportant, but there was also a very limited market for each type of equipment, so economies of scale and the subsequent savings could not be realized.
The Europeans realized this early on, and in 1982 the Conference of European Posts and Telegraphs (CEPT) formed a study group called the Groupe Spécial Mobile (GSM) to study and develop a pan-European public land mobile system. The proposed system had to meet certain criteria:
Good subjective speech quality
Low terminal and service cost
Support for international roaming
Ability to support handheld terminals
Support for range of new services and facilities
Spectral efficiency
ISDN compatibility
In 1989, GSM responsibility was transferred to the European Telecommunication Standards Institute (ETSI), and phase I of the GSM specifications were published in 1990. Commercial service was started in mid-1991, and by 1993 there were 36 GSM networks in 22 countries . Although standardized in Europe, GSM is not only a European standard. Over 200 GSM networks (including DCS1800 and PCS1900) are operational in 110 countries around the world. In the beginning of 1994, there were 1.3 million subscribers worldwide , which had grown to more than 55 million by October 1997. With North America making a delayed entry into the GSM field with a derivative of GSM called PCS1900, GSM systems exist on every continent, and the acronym GSM now aptly stands for Global System for Mobile communications.
The developers of GSM chose an unproven (at the time) digital system, as opposed to the then-standard analog cellular systems like AMPS in the United States and TACS in the United Kingdom. They had faith that advancements in compression algorithms and digital signal processors would allow the fulfillment of the original criteria and the continual improvement of the system in terms of quality and cost. The over 8000 pages of GSM recommendations try to allow flexibility and competitive innovation among suppliers, but provide enough standardization to guarantee proper interworking between the components of the system. This is done by providing functional and interface descriptions for each of the functional entities defined in the system
The Europeans realized this early on, and in 1982 the Conference of European Posts and Telegraphs (CEPT) formed a study group called the Groupe Spécial Mobile (GSM) to study and develop a pan-European public land mobile system. The proposed system had to meet certain criteria:
Good subjective speech quality
Low terminal and service cost
Support for international roaming
Ability to support handheld terminals
Support for range of new services and facilities
Spectral efficiency
ISDN compatibility
In 1989, GSM responsibility was transferred to the European Telecommunication Standards Institute (ETSI), and phase I of the GSM specifications were published in 1990. Commercial service was started in mid-1991, and by 1993 there were 36 GSM networks in 22 countries . Although standardized in Europe, GSM is not only a European standard. Over 200 GSM networks (including DCS1800 and PCS1900) are operational in 110 countries around the world. In the beginning of 1994, there were 1.3 million subscribers worldwide , which had grown to more than 55 million by October 1997. With North America making a delayed entry into the GSM field with a derivative of GSM called PCS1900, GSM systems exist on every continent, and the acronym GSM now aptly stands for Global System for Mobile communications.
The developers of GSM chose an unproven (at the time) digital system, as opposed to the then-standard analog cellular systems like AMPS in the United States and TACS in the United Kingdom. They had faith that advancements in compression algorithms and digital signal processors would allow the fulfillment of the original criteria and the continual improvement of the system in terms of quality and cost. The over 8000 pages of GSM recommendations try to allow flexibility and competitive innovation among suppliers, but provide enough standardization to guarantee proper interworking between the components of the system. This is done by providing functional and interface descriptions for each of the functional entities defined in the system
