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From Telegraph to the Invention of the Telephone

The invention of the electric telegraph in the 1830s marked the beginning of telecommunications. Now, for the first time in history messages could be sent over enormous distances in an instant. The telegraph quickly gained popularity and attempts to modify and improve the device were fervent. Successive attempts at improvements to the telegraph ultimately lead to the invention of the telephone.

Alexander Graham Bell's Box Telephone, 1877-78. — Alexander Graham Bell’s Box Telephone, 1877-78.
(Credit: National Museums Scotland)

Both the telegraph and the telephone are wire based electrical systems and thus similar in concept. Alexander Graham Bell was experimenting with how to send multiple messages along the same wire at one time, a technique known as multiplexing. This was the goal of several inventors at the time, including the US inventor Elisha Gray. In the early 1870s Gray was using a harmonic telegraph, which consisted of a transmitter and a receiver connected to sets of metallic reeds, in order to investigate speech transmission. A harmonic telegraph was known to be capable of sending multiple messages at the same time on a single wire by using varying frequencies. Bell also began his experiments in 1873 using a harmonic telegraph in his search for a multiplexing device but he quickly hit on the idea of using it for speech transmission too.

By 1875 Bell had proved that different frequencies could vary the strength of the electrical signal in a wire. Now all he needed to do was to develop a working transmitter that could send varying electronic currents and a working receiver that could reproduce these frequencies in audible form. On March 7th, 1876 Bell awarded a patent for his telephone as an “apparatus for transmitting vocal or other sounds telegraphically”. The telephone is considered one of the most valuable patents ever awarded by the U.S. Patent Office.

Bell’s telephone was composed of various elements that largely remained unchanged for many years. First a power source such as a battery was needed to power the electric current generated by the transmitter. The transmitter converted the speaker’s voice into a direct current and on the other end a receiver converted the current back into an audible voice. While not in use the receiver hung on a hook with a switch on it, known as a switch hook. The switch hook connects the telephone to the direct current through a loop. When the telephone is on the hook, contact to the loop is broken. Pick up the telephone and contact is restored with current now flowing through the loop. A dialer and a ringer were also critical components. Lastly an anti-sidetone circuit, and assemblage of transformers, resistors, and capacitors, was used to reduce various forms of noise and electrical feedback.

The Telephone: A Revolution in Telecommunications

The telephone continued to evolve and improve over time. Early telephones needed to be connected directly with each other and Bell quickly realized that all telephones needed to be connected to all other telephones in service for the device to be practical. By the late 1870s the first switchboard had been invented, solving the problem. By the 1880s telephone were being assigned numbers to make operations easier, introducing the first telephone numbers. For that point on the innovations haven’t stopped.

The Ever Evolving Telephone
(Credit: Wikimedia Commons)

The 20th century saw enormous leaps in telephone technology. The dial tone was introduced in Germany in 1908 but it took until the 1920s until it was adapted in the United States. That same decade witnessed the first transatlantic call in 1927, from the United States to the United Kingdom and was transmitted by radio waves. Also by the 1920s it is estimated that there were over ten million telephones that were in service in the United States. The 1960s saw the appearance first Touch-Tone telephones and launch of the worlds first international communications satellite, Telstar. Around this time first cellular phone had started to appear. Digital telephone technology combined with cellular phones have drastically changed the telephone in the later part of the 20th century. Today most people have converted from using their land lines to carrying around their versatile smartphones.

For most of human history information could only travel at the speed a person could run, a horse could ride, or a ship could sail. The persisted until only very recently. For instance only around 250 years ago during the American Revolution it would take months to communicate from the colonies to Britain across the Atlantic. Today that same communication can happen in an instant. The electric telegraph was the first major breakthrough of modern telecommunications.

Early Forms of Telegraphy

A Tower with a Semaphore Signal
(Credit: Wikimedia Commons)

A telegraph is a from of long distant communication, as spelled out in the root meaning of its name: tele – at a distant, and graph – to write. Some of the earliest forms of long distant communication include light signals, drum beats and smoke signals. These measures were employed with varying but mostly minimal success. In Ancient China, soldiers positioned in towers along the Great Wall would use smoke signals to warn of impending attackers. Native Americans were particularly well known for using smoke signals to communicate over long distances. First, tribes would agree on a communication system – such as one puff for a greeting, two puffs for danger, and so on. However despite some effectiveness these communication systems were limited in their ability to communicate complex messages and required certain weather conditions.

When people think of a telegraph today most are probably referring to the electric telegraph. However the first true telegraph that was put into widespread use was the optical telegraph, invented by Claude Chappe in the late 1700s during the tumultuous time of the French Revolution. With events happening at a frantic pace, French government was in need of fast and reliable communication during the revolution. Claude Chappe, along with his brother Ignace Chappe began working on the problem in the summer of 1790. The system they developed used semaphore shutters positioned on top of towers to transmit light signals that corresponded to letters. Relay towers could be positioned approximately every 20 miles and messages could be transmitted distances of over a hundred miles at a rate of approximately two words per minute.

The Electric Telegraph Transforms Communications

The electrical telegraph harnessed the new science of electricity to revolutionize long distance communication. Early experiments in the 18th century demonstrated effects of electricity and showed that it could be transmitted across a wire almost instantly. Alessandro Volta developed a battery providing a steady source of energy. The electric telegraph combined these new discoveries, making it was the first valuable invention of applied electricity before 1860s, the decade James Clark Maxwell brought together all the laws of electromagnetism in his mathematical formulations.

To transmit a telegraph electrically there needs to be two or more stations connected by a wire. The first working electrical telegraph was made by a British inventor named Francis Ronald in 1816. His invention was met with little fanfare by the British government. Over the next few decades several other inventors built improved versions of the electric telegraph with limited success. It was Samuel Morse in the 1830s and 1840s who finally brought the invention into the mainstream. The telegraphic system Morse developed is still used sparingly today and is known to most as Morse Code. Morse Code encodes 26 letters and 10 numbers into a series of dots and dashes that that can be used to communication a written message electrically across a wire.

Morse Telegraph
(Credit: Wikimedia Commons)

Morse used his new system to send his first message across a two mile wire in Morristown, New Jersey in 1838. The United States Congress quickly realized the benefits of Morse’s system and they provided the funds to set up a wire from Baltimore to Washington D.C. in 1843. On May 21, 1844 the famous first message “what hath god wrought” was transmitted across this 44 mile line. Within two years the telegraph become such an integral part of communication in the United States that the Associated Press was formed. The telegraph grew so rapidly that by 1875 there were over 250,000 miles of telegraph wires in the United States alone and over 100,000 miles of wire undersea, linking with world together as never before.

A Short Lived Reign

The electric telegraph took only a few generations complete its full product life cycle complete – an ominous sign of things to come for the telecommunications industry. The telephone, invented 40 years after the telegraph, can be said to mark the beginning of the end for the telegraph. Radio communications only accelerated its decline. Today telecommunication technologies can rise and fall in a single generation. However many of these technologies owe its scientific roots to the invention of the electric telegraph.

Continue reading more about the exciting history of science!

1876: The Telephone

From Telegraph to the Invention of the Telephone

The Telephone: A Revolution in Telecommunications

1830s: The Electric Telegraph

Early Forms of Telegraphy

The Electric Telegraph Transforms Communications

A Short Lived Reign