The telephone, a groundbreaking telecommunications device, revolutionized human communication by allowing conversations across great distances. Initially developed by Alexander Graham Bell in 1876, the telephone has evolved significantly over the years.
At its core, a telephone consists of a microphone (transmitter) to capture the human voice and an earphone (receiver) to reproduce the sound at a remote location. These components are typically integrated into a handheld device, known as a handset, facilitating easy communication. The word “telephone” is derived from the Greek words “tēle” (far) and “phōnē” (voice), emphasizing its ability to transmit distant voices.
The early telephones were connected directly between two locations, but this method became impractical as the number of users increased. Manual switchboards were introduced, connecting calls through operators, and eventually evolving into an automated global network known as the public switched telephone network (PSTN). This network allowed for seamless communication worldwide.
In the mid-20th century, radio systems were developed to enable mobile communication on ships and automobiles. The introduction of hand-held mobile phones in 1973 marked a significant milestone, providing personal communication on the go. Over time, analog cellular systems transitioned into digital networks, offering enhanced capabilities at a lower cost.
In recent years, the convergence of communication services has given rise to the smartphone, the predominant type of telephone today. Smartphones go beyond traditional voice communication, incorporating features such as mobile computing, internet access, and a wide range of applications, making them indispensable in modern life. The evolution of the telephone highlights the continuous innovation in telecommunications, shaping the way people connect and communicate globally.
Early history
Before the advent of the electric telephone, the term “telephone” was applied to various inventions, and early researchers of electrical devices did not universally use the term. One of the earliest instances of the term was the “telephon” created by Johann Sigismund Gottfried Huth in 1796. Huth proposed an alternative communication system to Claude Chappe’s optical telegraph, suggesting “speaking tubes” or giant megaphones for operators in signaling towers to shout to each other.
In 1844, Captain John Taylor invented a communication device for sailing vessels called the “telephone,” which used four air horns to communicate in foggy weather.
Johann Philipp Reis, around 1860, referred to his invention as the Reis telephone, likely the first device based on converting sound into electrical impulses. The term “telephone” became part of the vocabulary of many languages, derived from the Greek words “tēle” (far) and “phōnē” (voice), meaning “distant voice.”
Credit for the invention of the electric telephone is a subject of dispute, much like other influential inventions. Charles Bourseul, Antonio Meucci, Johann Philipp Reis, Alexander Graham Bell, and Elisha Gray, among others, have been credited with its invention.
Alexander Graham Bell was awarded the first patent for the electric telephone by the United States Patent and Trademark Office in March 1876. His patent introduced the concept of fluctuating currents as the basis for reproducing sounds in the telephone, differentiating it from previous methods that used vibrations and circuits.
Shortly after Bell’s patent, Hungarian engineer Tivadar Puskás proposed the telephone switch in 1876, allowing the formation of telephone exchanges and networks.
In the United Kingdom, “blower” is slang for a telephone, originating from navy slang for a speaking tube. In the U.S., a somewhat dated slang term refers to the telephone as “the horn,” as in phrases like “I’ll be off the horn in a moment” or “I couldn’t get him on the horn.”
In the timeline of the early development of the telephone:
- 1844: Innocenzo Manzetti suggests the concept of a “speaking telegraph” or telephone. The terms “speaking telegraph” and “sound telegraph” eventually give way to the now-distinct name, “telephone.”
- 26 August 1854: Charles Bourseul publishes an article in L’Illustration (Paris) titled “Transmission électrique de la parole” (electric transmission of speech), describing a “make-and-break” type telephone transmitter later recreated by Johann Reis.
- 26 October 1861: Johann Philipp Reis publicly demonstrates the Reis telephone before the Physical Society of Frankfurt. Reis’s telephone is not limited to musical sounds and can transmit spoken words.
- 22 August 1865: La Feuille d’Aoste reports that English technicians, after Manzetti’s demonstration, plan to apply the telephone invention in England on private telegraph lines. However, actual telephone demonstrations in England would not occur until 1876, using telephones from Alexander Graham Bell.
- 28 December 1871: Antonio Meucci files patent caveat No. 3335 in the U.S. Patent Office, titled “Sound Telegraph,” describing voice communication by wire. A patent caveat is a notice of intent to file a patent application.
- 1874: Meucci does not renew the patent caveat after two years, and it lapses.
- 6 April 1875: Bell’s U.S. Patent 161,739 for “Transmitters and Receivers for Electric Telegraphs” is granted, utilizing vibrating steel reeds in make-break circuits.
- 11 February 1876: Elisha Gray invents a liquid transmitter for the telephone but does not build one.
- 14 February 1876: Gray files a patent caveat for transmitting the human voice through a telegraphic circuit.
- 14 February 1876: Alexander Graham Bell applies for the patent “Improvements in Telegraphy,” describing electromagnetic telephones using what is now called amplitude modulation.
- 19 February 1876: Gray is notified of an interference between his caveat and Bell’s patent application and decides to abandon his caveat.
- 7 March 1876: Bell’s U.S. Patent 174,465 is granted, covering the method and apparatus for transmitting vocal or other sounds telegraphically using electrical undulations.
- 10 March 1876: The first successful telephone transmission of clear speech occurs when Bell speaks into his device, saying, “Mr. Watson, come here, I want to see you,” and Watson hears each word distinctly.
- 30 January 1877: Bell’s U.S. Patent 186,787 is granted for an electromagnetic telephone using permanent magnets, iron diaphragms, and a call bell.
- 27 April 1877: Thomas Edison files a patent application for a carbon (graphite) transmitter, which is published on 3 May 1892, after a 15-year delay due to litigation. Edison is granted patent 222,390 for a carbon granules transmitter in 1879.
During the early commercial phase of telephone development, there was considerable technical diversity in the instruments used:
- Water Microphone and Metal Diaphragm: Early telephones used various technologies, including a water microphone, metal diaphragms inducing current in an electromagnet around a permanent magnet, and dynamic designs where the diaphragm vibrated a coil of wire in the field of a permanent magnet or vice versa.
- Edison/Berliner Carbon Transmitter: Most early telephones, however, adopted the Edison/Berliner carbon transmitter. Although louder, it required an induction coil for compatibility with the line’s impedance. Edison’s patents, crucial for the Bell monopoly, remained influential into the 20th century.
- Local Powering: Early telephones were locally powered, either using a dynamic transmitter or by a local battery powering a transmitter. Outside plant personnel had the task of inspecting batteries periodically.
- Single-Wire System: Early telephones used a single wire for the subscriber’s line, with ground return completing the circuit. Dynamic telephones had a single port for both listening and speaking.
- Telephone Exchange: Initially, telephone exchanges were not fully utilized. Instead of a central exchange, telephones were leased in pairs, requiring subscribers to arrange for a telegraph contractor to construct a line between them.
- Signaling and Bell Boxes: Signaling was initially primitive, with users alerting the other end by whistling. Bell boxes with bells operated over separate wires or with a condenser in series with the bell coil for AC signals became common.
- Magneto Hand-Cranked Generator: Rural telephones had a magneto hand-cranked generator for high-voltage signals to ring bells and alert the operator. Some farming communities set up barbed wire telephone lines.
- New Telephone Designs: In the 1890s, a new telephone style emerged with three parts: a “candlestick” transmitter stand, a receiver on a hook with a switch, and a separate bell box. Cradle designs and handsets were also popular.
- Twisted Pairs and Four-Wire Circuits: To address issues like crosstalk and hum, twisted pairs and four-wire circuits were introduced. Long-distance calls were often made with the assistance of a telephone operator.
- Bell’s 202-Type Desk Set: The early 20th century introduced popular designs like Bell’s 202-type desk set, featuring a carbon granule transmitter and electromagnetic receiver in a single molded plastic handle.
- Touch-Tone Signaling: In 1963, Touch-Tone signaling using push-button telephones was introduced by American Telephone & Telegraph Company (AT&T), marking a breakthrough in telephone technology.
Digital telephones and voice over IP
The introduction of the transistor in 1947 marked a transformative moment for telephone systems and long-distance transmission networks, catalyzing technological advancements over the subsequent decades. The development of stored program control, MOS integrated circuits, and transmission technologies like pulse-code modulation (PCM) paved the way for the evolution of telephony into the digital age. Digital telephony not only enhanced network capacity, quality, and cost-efficiency but also led to the launch of Integrated Services Digital Network (ISDN) in the 1980s, offering users access to a range of digital services including data, voice, video, and fax.
As digital data communication methods progressed, the digitization of voice became feasible, allowing real-time transmission over computer networks and the Internet. This breakthrough gave rise to Internet Protocol (IP) telephony, commonly known as Voice over Internet Protocol (VoIP), which has proven to be a disruptive force, gradually replacing traditional telephone network infrastructure.
By January 2005, approximately 10% of telephone subscribers in Japan and South Korea had already migrated to digital telephone services. Newsweek, in a January 2005 article, foresaw Internet telephony as “the next big thing.” This technology has since spawned a burgeoning industry, with numerous VoIP companies providing services to both consumers and businesses. As of October 2021, the global VoIP market was reported to be $85.2 billion, with a projected growth to $102.5 billion by 2026.
Cordless telephones
A cordless telephone, also known as a portable telephone, is comprised of a base station unit and one or more cordless handsets. The base station is connected to a telephone line or provides service through Voice over Internet Protocol (VoIP). Communication between the handset and the base station occurs via radio frequency signals, with the handset’s operational range typically limited to within the same building or a short distance from the base station.
Base Station: The base station plays a crucial role, featuring a radio transceiver that facilitates full-duplex communication—both outgoing and incoming signals and speech with the cordless handsets. It often incorporates a microphone, audio amplifier, and a loudspeaker, allowing for hands-free speakerphone conversations without the need for a handset. Additional features may include a numeric keypad for dialing, a display for caller ID, and even an integrated answering machine function.
Cordless Handset: The cordless handset is equipped with a rechargeable battery, which the base station replenishes when the handset is resting in its cradle. Multi-handset systems commonly come with additional charging stands for convenience. To function optimally, a cordless telephone requires a continuous electricity supply to power the base station and charging units. This is typically achieved through a DC transformer that plugs into a wall AC power outlet.
Cordless telephones provide users with the flexibility to move around within a certain range while maintaining the ability to make and receive calls. The technology has become a standard choice for residential and business environments, offering convenience and mobility in comparison to traditional wired telephones.
Mobile phones
A mobile phone, commonly known as a cellphone or handphone, is a handheld device that connects to a cellular telephone network through radio transmissions. The cellular network comprises ground-based transmitter/receiver stations with antennas, typically situated on towers or buildings. This network infrastructure connects to land-based telephone lines. Analog cellular networks made their debut in 1979, paving the way for digital cellular networks in the early 1990s.
Mobile phones have evolved significantly since their inception. They commonly feature LCD or OLED displays, with smartphones often incorporating touch screens. Beyond their primary function as telephones, mobile phones, especially smartphones, have gained a plethora of additional features since the 1990s. These include text messaging, calendars, alarm clocks, personal schedulers, cameras, music players, games, and, in later years, internet access and advanced smartphone functionalities.
The ability to send text messages via the Short Message Service (SMS) protocol is a standard feature on nearly all mobile phones. Additionally, the Multimedia Messaging Service (MMS) protocol enables users to send and receive multimedia content, such as photos, audio files, and videos.
With the increasing functionality of mobile phones, especially smartphones, the need for an operating system has become essential. Operating systems like Symbian, Palm OS, BlackBerry OS, and mobile versions of Windows were prevalent in the past. However, as of 2022, the most widely used operating systems are Google’s Android and Apple’s iOS.
In the era preceding smartphones, telecommunications equipment companies like Nokia, Motorola, and Ericsson dominated mobile phone manufacturing. The advent of smartphones led to a shift, with consumer electronics companies such as Apple, Samsung, and Xiaomi emerging as prominent mobile phone manufacturers. This evolution reflects the continuous integration of advanced technologies and features into these handheld devices.
Mobile phone usage
In 2002, a mere 10% of the global population utilized mobile phones, marking a relatively modest adoption of this technology. However, within just three years, by 2005, the landscape had undergone a substantial transformation, with the percentage of mobile phone users soaring to an impressive 46%.
As technology continued to advance, particularly in the realm of telecommunications, the world witnessed a remarkable surge in mobile and fixed-line telephone subscriptions. By the close of 2009, the global tally reached a staggering total of nearly 6 billion subscribers. This encompassed 1.26 billion fixed-line subscribers, demonstrating the enduring relevance of traditional telephony, and an even more substantial figure of 4.6 billion mobile subscribers.
This swift and widespread adoption of mobile phones over this short period underscores the rapid integration of telecommunications into the daily lives of people across the globe, marking a pivotal moment in the history of communication technology.
Smartphones
As of 2022, the predominant trend in mobile phones is the widespread prevalence of smartphones, which seamlessly combine the functionality of a mobile phone with that of a personal computing device within a single unit. The operation of most smartphones revolves around a user-friendly graphical interface and a touch screen, making them highly intuitive and accessible.
Smartphones often feature a secondary voice user interface, exemplified by Apple’s Siri on iPhones, allowing users to perform various functions through spoken commands. Alphanumeric text input is typically achieved through an on-screen virtual keyboard, although some smartphones still incorporate a physical keyboard.
These versatile devices provide a multitude of capabilities, including internet access through cellular networks or Wi-Fi, and direct connectivity to other devices via Bluetooth, USB, or Lightning connectors. The introduction of apps has significantly expanded the functionality of smartphones compared to their predecessors. With internet access and built-in cameras, smartphones facilitate easy video calling through IP connections.
The extensive capabilities of smartphones extend beyond communication, offering tools such as cameras, media players, web browsers, email clients, interactive maps, satellite navigation, and various sensors like a compass, accelerometers, and GPS receivers. Despite their advanced functionalities, smartphones are constrained by their relatively compact screen size and keyboard dimensions.
In addition to traditional voice calls, smartphone users commonly engage in diverse messaging formats, including SMS, MMS, email, and proprietary services like iMessage, along with various social media platforms. This comprehensive integration of features has effectively positioned smartphones as multifaceted devices that bear similarities to traditional computers, with the caveat of a smaller screen size and keyboard. The evolution of smartphones reflects their adaptability to meet the diverse needs of modern communication and computing.
Satellite phones
A satellite telephone, commonly known as a satphone, is a type of mobile phone that establishes connections with other phones or the telephone network via radio signals transmitted through satellites orbiting the Earth. This stands in contrast to traditional cellphones, which rely on terrestrial cell sites for connectivity. The distinctive feature of satellite phones is their ability to function in diverse geographic locations across the Earth’s surface, requiring only an open sky and a clear line-of-sight between the phone and the satellite.
The coverage of satellite phones varies based on the system’s architecture, spanning either the entire Earth or specific regions. Despite the differences in connectivity, satellite phones offer functionality akin to terrestrial mobile telephones, supporting voice calling, text messaging, and low-bandwidth Internet access across most systems.
The primary advantage of satellite phones lies in their usability in regions where local terrestrial communication infrastructures, such as landline and cellular networks, are absent. This makes them highly sought after for expeditions into remote locations, maritime activities, hunting, fishing, humanitarian missions, business trips, and mining ventures in hard-to-reach areas.
Satellite phones demonstrate their reliability during emergencies, as they are less susceptible to disruptions caused by natural disasters or human actions like war. Their resilience in adverse conditions makes them valuable communication tools in situations where local communication systems may be compromised. This capability has solidified the importance of satellite phones in ensuring dependable communication, particularly when traditional means may not be readily available.
