15th C

Printing Press

Total Internal Refelection

Inverse Square Law

Diffraction

Interference

In 1850, J. L. Foucault (France) determined the speed of light in air using a rotating mirror. He obtained a value of 298,000 km.s^-1. He used the same method to measure the speed of light in stationary water and found that it was less than in air [5].

Pony Express

In 1860, the Pony Express was set up to carry messages from St Joseph, Missouri to Sacramento, California (over 3000 km). Using relays of messengers and changhing horses every 16 kilometres it took between 10 and 16 days to cover the distance. The Pony Express only lasted 18 months and was shut down once the transcontinental telegraph was finished in 1861 [9].

In 1866, the first successful transatlantic telegraph cable was laid between New York and London by The Great Eastern. This was the second attempt to bridge the Atlantic. The first attempt, in 1858, failed because the voltage was too high [25].

The first practical typewriter was designed by Christopher Sholes, Samuel Soule and Carlos Glidden and was put into production in 1874 by Remington, a firm of gunsmiths [26]. It embodied many of the ideas in Henry Mill's patent of 1714 and had a keyboard arranged in what has become known as the QWERTY pattern (from the first six letters in the top row). This pattern is still used in nearly all modern keyboards even though the original reason for doing so has long since vanished. The original purpose was to slow down the keystrokes so as to prevent jamming of letters that occurred together frequently in English.

Telephone

In 1877, Edison was working on the technology of both the telephone and the telegraph. Out of this work came the phonograph. For the first time spoken words could be stored on a wax cylinder and replayed later [28].

James Clerk Maxwell predicted existence of electromagnetic waves in 1873 in his A Treatise on Electricity and Magnetism. In this work, he formulated his equations for electricity and magnetism, now known as Maxwell's equations and showed that electromagnetic waves must be transverse waves with a defined, constant speed. He also proposed that light was a form of electromagnetic wave. Like many before him, Maxwell believed that these waves propagated through the "ether" [29] .

In 1887, Emile Berliner developed the gramophone, which used a flat disc made of hardened rubber to record sound [30].

Also in 1887, Albert Michelson and Edward Morley carried out an experiment designed to measure the difference in light speed in different directions due to the Earth's motion through the ether. They were unable to detect any such difference and were forced to conclude that the ether did not exist [31].

Hertz's experiment

In 1888, Heinrich Hertz shows that electromagnetic waves exist by building an apparatus that could both produce and detect such waves. They were to become known as radio waves [32,33].

AT&T

In the mid-1880s the American Telephone and Telegraph Company (AT&T) had begun offering private line telephone services Band by 1900 was offering subscriber services to 850,000 customers. By 1910, this has increased to nearly 6 million [25].

In 1901, Guglielmo Marconi transmitted radio waves across the Atlantic Ocean. Following on from Hertz's work he devised the first practical system of wireless telegraphy, set up a company, the The Marconi Wireless Telegraph Co. Ltd. And laid the foundations for radio communications [34]. Controversy arose as to whether Marconi or Nikola Tesla actually invented radio [35].  
Marconi also pioneered "bouncing" radio waves off the ionosphere.

Electronic Valves

In 1904, while working for the Marconi Company, Sir John Ambrose Fleming invented the thermionic valve. The device had two electrodes and could rectify an electrical signal. Two years later Lee deForest invented the three-element electron tube or "triode". Unlike Flemings valve, the triode could amplify signals and generate oscillations, making it possible to transmit sound over wireless communication systems [36].

Tuned Circuits

In 1915, the first trans-continental (US) telephone line becomes operational, Marconi developed his wireless telephone and the first trials of transmitting speech across the Atlantic were begun. With the advent of tuned circuits and improvements in valve technology radio communications was also playing its part in warfare [25,37].

After the end of the First War, and only 15 years since the Wright brothers first powered flight, regular airmail services began in the US. The range of early planes was very limited and these services used a relay system reminiscent of the Pony Express [38,39].

Photon

In 1917, Albert Einstein published an article entitled On the Quantum Theory of Radiation. In it, he introduced the concept (although not the name) of the photon, argued that there must be both stimulated and spontaneous emission of light from atoms and that stimulated emission must be identical in all relevant aspects to the incident radiation. This work formed the basis for the laser [40,41].

Deep-sea Telephone Cables

In 1921, the first deep-sea telephone cables were laid from Havana to Key West. Within a few years the US Bell telephone system has expanded to 15 million users [25].

In 1925, Lohn Logie Baird gave the first public demonstration of the transmission of images i.e. television [42]. The very first television systems used a spinning disc to scan the image. The BBC began experimental transmissions using this system in 1929 but it was later replaced by electronics systems. Around the same time, Baird and Clarence W. Hansell patented the idea of using arrays of transparent rods to transmit images for television [43].

1927 saw the establishment of the major radio networks, NBC and CBS in the US and the release of the first successful talking motion picture, "The Jazz Singer" [44] .

Golden Age of Radio

In the 1930s, radio had its "Golden Age". During this period the first commercial tape recorder was invented, teletype services were introduced and scheduled television broadcasts, using an all electronic system, began in the US and Britain [44].

Magnetron

Transistor

In 1947, John Bardeen and Walter Brattain, from Bell Labs, made a three terminal device - the first "point contact" transistor. They were trying to understand what happened to electrons at the point of contact between a metal and a semiconductor. Later, William Shockley developed the junction transistor. It used thin layers of different types of semiconductor pressed together. Bardeen, Brattain and Shockley were awarded the Nobel Prize in Physics, 1956 [48].

Commercial Computers

Following their success with ENIAC, Eckert and Mauchly formed a company to build the first commercial computer, the UNIVAC, which was sold to the US Census Bureau in 1951. By 1957, 46 UNIVACs had been sold [49,50].

In 1952, IBM introduced the IBM 701, its first large computer based on the vacuum tubes and in 1958 introduces one of the first all-transistor computers [51].

Colour TV

The first colour television broadcasts, in 1951, were based on Baird's design from 1928. This approach wasn't successful due to incompatibility with the large number of monochrome sets already sold. An alternative system, which was compatible, was introduced by RCA in 1954 but sales did not really take off until the early 60s. Colour TV came to Australia in 1972 [52,53].

The 50s also marked advances towards optical communications. In 1954, Dutch scientist Abraham Van Heel made optical fibres with a transparent cladding of a lower refractive index. These fibres were used in bundles for medical imaging and the cladding greatly reduced light losses from the fibres [54].

In 1958, Jack Kilby at Texas Instruments, built the first integrated circuit. All the parts of the circuit were made from the same block of material with a metal layer on top to connect them. Without discrete components or wires the circuits could be made smaller and manufacturing automated. Kilby received the Nobel Prize in Physics in 2000 [55].

Laser

In 1960, Theodore Maiman built the first optical wavelength laser using a ruby rod and a flash lamp [56]. Maiman's laser followed the idea developed by Charles H. Townes and Arthur L. Schawlow, at Bell Labs in 1958, and utilised the principles first described by Einstein in 1917. The laser's invention was to open up the whole field of optical communications but once again its development was shrouded in controversy with Gordon Gould, of TRG, also claiming to have had the idea first [57].

ARPANET

In response to the USSR launching sputnik in 1957, the US Government set up the Advanced Research Projects Agency or ARPA. ARPA wanted to find a way of maintaining command and control of its missiles and bombers in the event of a nuclear attack. The solution was ARPANET, which was set up in 1969 and used packet switching to communicate between 4 sites. This was the forerunner of the Internet [58].

In 1962, Telstar, was put into orbit beginning the era of satellite communications. Although not the first communication satellite, it captured popular imagination with the first transmission of live television across the Atlantic Ocean. The first successful synchronous orbit satellite, Syncom, was launched a year later. Australia's first geostationary communications satellite became operational in 1985 [59].

The first usable microprocessor (computer on a chip) was the 8080, released by Intel in 1974 [60]. Soon after, on April Fool's Day, 1976, Steve Wozniak and Steve Jobs released the Apple I computer which they had designed and built in a garage. In 1977 they released the Apple II, the first truly mass market personal computer [61].

Mobile Telephone

The first cellular mobiles appeared in Japan in 1979. The US system didn't began operating until 1983 having been held up for many years by government approval processes [62]. In 2003, the estimated global population of mobile subscribers was over 1.5 billion [63].

In 1979, Philips and Sony developed the Compact Disc (CD) which used a 780 nm wavelength semiconductor laser to read the data on the disc. They went into mass production in 1982 [64] and have since revolutionised the recording of music, videos and computer data.

In 1980, the growth in the market for home computers, which was dominated by the Apple II, was of great concern to IBM. In 1981 they released their new computer, the IBM PC [65].

In 1988, the first transatlantic fibre optic cable was completed between the US, the UK and France [25]. Over these distances, light loss from the fibres becomes a significant problem. To resolve this, it was necessary to place amplifiers along the length of the cable. The light signal would first be converted to an electronic signal, amplified and converted back to light.

World Wide Web

During the 1980s the original ARPANET grew into the Internet. But, it remained a system with little general appeal due to the need for technical computer knowledge. All that changed when scientists at CERN invented the World Wide Web in 1989 [66]. Suddenly a whole world of information became available to anyone with a computer and an internet connection. The result of this, of course, is ever larger requirements on data capacity and bandwidth.

During the 90s most mobile traffic switched from analog systems to digital. This was necessary, as bandwidth requirements increased with the rapid growth in users and traffic [67]. The nineties saw the steady convergence between the technology of telephony, digital technology and computers, and advanced optics.

In the nineties the field of photonics emerged into communications research. A major problem for long-range optical communications is the need for amplification to overcome losses. Light signals were converted into electronic signals, processed and then converted back to light. A 1000 km optical cable might need 25 electronic repeaters and have limited capacity [68]. In 1990, Bell labs began using Erbium Doped Fibre Amplifiers (EDFAs) to provide optical amplification to signals [69]. With EDFAs, the 1000 km link might only need 9 amplifiers but have 100s of times more capacity.

Photonic Switch

In 1999, scientists at Bell Labs built the first microscopic optical switch [70]. To turn the switch on, a voltage is applied at the other end of the bar, beneath an attached plate; the electrostatic forces pull the plate down, lifting the bar so the mirror reflects the light instead of letting it move from one fiber to the other.