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Telephone prehistory[edit]

Mechanical devices[edit]

A 19th century acoustic tin can or "lovers' telephone"

Before the invention of electromagnetic telephones, mechanical acoustic devices existed for transmitting speech and music over a greater distance than that of normal direct speech. The earliest mechanical telephones were based on sound transmission through pipes, or other physical media. The acoustic tin can telephone, or "lovers' phone", has been known for centuries. It connects two diaphragms with a taut string or wire, which transmits sound by mechanical vibrations from one to the other along the wire (and not by a modulated electric current). The classic example is the children's toy made by connecting the bottoms of two paper cups, metal cans, or plastic bottles with tautly held string.

Some of the earliest known experiments by the British physicist and polymath Robert Hooke from 1664 to 1685. An acoustic string phone made in 1667 is attributed to him.

For a few years in the late 1800s, acoustic telephones were marketed commercially as a niche competitor to the electrical telephone. When the Bell telephone patents expired and many new telephone manufacturers began competing, acoustic telephone makers quickly went out of business. Their maximum range was very limited. An example of one such company was the Pulsion Telephone Supply Company created by Lemuel Mellett in Massachusetts, which designed its version in 1888 and deployed it on railroad right-of-ways.

Additionally, speaking tubes have long been common, especially within buildings and aboard ships, and they are still in use today

Early Commercial Instruments

Early telephones were technically diverse. Some of them used liquid transmitters which soon went out of use. Others were dynamic: their diaphragms vibrated a coil of wire in the field of a permanent magnet or vice versa. Such sound-powered telephones survived in small numbers through the 20th century in military and maritime applications where the ability to create its own electrical power was crucial. Most, however, used Edison/Berliner carbon transmitters, which were much louder than the other kinds, even though they required induction coils, actually acting as impedance matching transformers to make it compatible to the line impedance. The Edison patents kept the Bell monopoly viable into the 20th century, by which time telephone networks were more important than the instrument.

Early telephones were locally powered by a dynamic transmitter. or else powering the transmitter with a local battery. One of the jobs of outside plant personnel was to visit each telephone periodically to inspect the battery. During the 20th century, the "common battery" operation came to dominate, and was powered by the "talk battery" from the telephone exchange over the same wires that carried the voice signals. Late in the century, wireless handsets brought a revival of local battery power.

The earliest telephones had only one wire for both transmitting and receiving of audio, and used a ground return path. as was found in telegraph systems. The earliest dynamic telephones also had only one opening for sound, and the user alternately listened and spoke (rather, shouted) into the same hole. Sometimes the instruments were operated in pairs at each end, making conversation more convenient but also more expensive. Historical marker commemorating the first telephone central office in New York State (1878) At first, the benefits of a switchboard exchange were not exploited. Instead, telephones were leased in pairs to the subscriber, for example one for his home and one for his shop, and the subscriber had to arrange with telegraph contractors to construct a line between them. Users who wanted the ability to speak to three or four different shops, suppliers etc. would obtain and set up three or four pairs of telephones. Western Union, already using telegraph exchanges, quickly extended the principle to its telephones in New York City and San Francisco, and Bell was not slow in appreciating the potential.

Signaling began in an appropriately primitive manner. The user alerted the other end, or the exchange operator, by whistling into the transmitter. Exchange operation soon resulted in telephones being equipped with a bell, first operated over a second wire and later with the same wire using a condenser. Telephones connected to the earliest Strowger automatic exchanges had seven wires, one for the knife switch, one for each telegraph key, one for the bell, one for the push button and two for speaking.

Rural and other telephones that were not on a common battery exchange had hand cranked "magneto" generators to produce an alternating current to ring the bells of other telephones on the line and to alert the exchange operator.

In 1877 and 1878, Edison invented and developed the carbon microphone used in all telephones along with the Bell receiver until the 1980s. After protracted patent litigation, a federal court ruled in 1892 that Edison and not Emile Berliner was the inventor of the carbon microphone. The carbon microphone was also used in radio broadcasting and public address work through the 1920s. 1896 Telephone (Sweden)

In the 1890s, a new, smaller style of telephone was introduced, the candlestick telephone, and it was packaged in three parts. The transmitter stood on a stand, known as a "candlestick" for its shape, hence the name. When not in use, the receiver hung on a hook with a switch in it, known as a "switchhook." Previous telephones required the user to operate a separate switch to connect either the voice or the bell. With the new kind, the user was less likely to leave the phone "off the hook". In phones connected to magneto exchanges, the bell, induction coil, battery, and magneto were in a separate bell box called a "ringer box." In phones connected to common battery exchanges, the ringer box was installed under a desk, or other out of the way place, since it did not need a battery or magneto.

Cradle designs were also used at this time, which a handle with the receiver and transmitter attached, separate from the cradle base that housed the magneto crank and other parts. They were larger than the "candlestick" and more popular.

Disadvantages of single-wire operation, such as crosstalk and hum from nearby AC power wires, had already led to the use of twisted pairs and, for long-distance telephones, four-wire circuits. Users at the beginning of the 20th century did not place long-distance calls from their own telephones but made an appointment to use a special sound-proofed long-distance telephone booth furnished with the latest technology.

Around 1893, the country leading the world in telephones per 100 persons, known as teledensity, was Sweden, with 0.55 in the whole country but 4 in Stockholm (10,000 out of a total of 27,658 subscribers). This compares with 0.4 in the US for that year. Telephone service in Sweden developed through a variety of institutional forms: the International Bell Telephone Company (a U.S. multinational), town and village co-operatives, the General Telephone Company of Stockholm (a Swedish private company), and the Swedish Telegraph Department (part of the Swedish government). Since Stockholm consists of islands, telephone service offered relatively large advantages, but had to use submarine cables extensively. Competition between Bell Telephone and General Telephone, and later between General Telephone and the Swedish Telegraph Dept., was intense.

In 1893, the U.S. was considerably behind Sweden, New Zealand, Switzerland, and Norway in teledensity. The U.S. became the world leadership in teledensity with the rise of many independent telephone companies after the Bell patents expired in 1893 and 1894.

Image of an old Japanese Telephone

21st Century developments

The modern day telephone of the 21st century is that of the iPhone, developed by Apple. In the fall of 2007, people were very excited for the release of the iPhone. People knew that the iPhone was a combination of the older iPod with cell phone and computing technology. People were not only excited for the release of the iPhone, but were also excited to see if hackers would be able to break into the iPhone. After the iPhone was released, the world learned that a teenager named George Hotz was able to hack into the iPhone. Because of this feat by Hotz, it was now possible to use the iPhone on any cell service provider's network. This made the iPhone more appealing to those who were not so interest in using AT&T for service. His hacking of the iPhone also made brought about international use of the technology. Because of Hotz's successful hacking of the iPhone, questions were then brought up about how the technology would be used in other markets, and also whether or not the Digital Millennium Copyright Act was violated. The interface of the iPhone also gave hopes to the music industry, in that the new technology would allow users to purchase music through Wi-Fi.

Background

Most people are aware that the iPhone is a combination of of the cellular phone, internet, a digital camera, and the iPod. One of it's main features is the touch screen that lets users do different tasks, such as dialing phone numbers, by just using the touch of a finger. At first, the iPhone was brought about with four- and eight-gigabyte versions, but the four-gigabyte model was discontinued after a couple of months. Some of its software features include bluetooth, Wi-Fi, email, and audio and video playback.

The iPhone comes with the capabilities of the previous iPod. It has the interactive touch screen, and provides the ability to download music over Wi-Fi from iTunes. Another feature of the iPhone, called "Cover Flow," allows users to listen to their music in a more organized fashion by showing album covers one after the other. This feature used to only be on the computer version of iTunes, and is now on the iPhone with a better display. The iPhone also has speakers that lets users listen to music without headphones, and it keeps the volume from getting too loud when switching from headphones to speaker sound.

Image of an older iPhone

Some of the limitations of the iPhone are what drove people to try and unlock it. When it was first released, the iPhone was only available in the United States and Europe. Apple made deals with service providers like T-Mobile and O2 for other places in the world such as Asia. Service was only limited to the AT&T network at first. The limits of the iPhone in terms of service providers were one of the limitations the device had in the beginning of its time. Congress was even involved due to a possible antitrust violation because the iPhone had certain limits in regards to geographical use and service providers, which frustrated many consumers.