Electronics Guide

The French Semaphore System

Claude Chappe developed the first practical optical telegraph in France during the 1790s. His semaphore system used a series of towers, each equipped with movable wooden arms that could be configured into different positions visible through telescopes from adjacent towers. Operators would observe the configuration of a distant tower and reproduce it for the next station in the chain.

The Chappe system could transmit a message from Paris to Lille, a distance of approximately 230 kilometers, in just minutes under favorable conditions. At its peak, the French optical telegraph network consisted of 556 stations covering over 4,800 kilometers. Napoleon recognized its military value, using it to coordinate troop movements and receive intelligence far faster than couriers could travel.

British and Swedish Systems

Other nations developed their own optical telegraph networks. The British Admiralty operated a shutter telegraph system designed by Lord George Murray that connected London to major naval ports. Sweden developed the Edelcrantz system, which used a series of shuttered panels. These systems demonstrated that governments and militaries would invest substantially in rapid communication infrastructure.

Limitations of Optical Systems

Optical telegraphs suffered from significant constraints. They required clear visibility, making them useless at night or during fog, rain, or snow. Each relay station needed trained operators who had to remain constantly vigilant. The systems demanded substantial capital investment in towers and ongoing operational costs for staffing. These limitations created strong incentives for inventors to explore electrical alternatives.

Early Experiments

Following Hans Christian Oersted's 1820 discovery that electric current creates a magnetic field, experimenters quickly recognized the potential for electrical signaling. In 1832, Pavel Schilling demonstrated an electromagnetic telegraph to Tsar Nicholas I of Russia. His system used multiple wires and magnetic needles that would deflect to indicate letters. While technically successful, Schilling's telegraph was never deployed commercially before his death in 1837.

William Fothergill Cooke and Charles Wheatstone patented an electromagnetic telegraph in Britain in 1837. Their initial design used five magnetic needles that could point to any of twenty letters on a diamond-shaped grid. Though complex, this system was installed on British railways beginning in 1839, making it the first commercial electric telegraph. Cooke and Wheatstone later simplified their design to use only two needles.

Carl Friedrich Gauss and Wilhelm Weber

German physicists Gauss and Weber constructed an electromagnetic telegraph connecting Gauss's observatory to Weber's physics laboratory in Gottingen in 1833. While primarily intended for scientific research rather than commercial communication, their system demonstrated the feasibility of transmitting messages over significant distances using electricity. Their work influenced subsequent inventors and contributed to the mathematical understanding of electrical transmission.

Morse's Background and Motivation

Morse was an accomplished portrait painter who became interested in electromagnetism after attending scientific lectures. According to his own account, the idea for the telegraph came to him during an 1832 sea voyage when a fellow passenger demonstrated electromagnetic experiments. Morse reportedly made sketches of his telegraph concept during that voyage, though he would spend years developing a practical system.

Personal tragedy may have motivated Morse's dedication to rapid communication. In 1825, while away from home painting a portrait, he received news that his wife was ill. By the time a second message reached him and he returned home, she had already died and been buried. This experience of delayed communication may have intensified his commitment to developing faster means of transmitting information.

Development of the System

Morse collaborated with Leonard Gale, a chemistry professor, and Alfred Vail, a skilled mechanic whose family provided financial support. Gale helped Morse understand the importance of relay circuits to extend transmission distance, while Vail contributed crucial mechanical improvements to the sending and receiving apparatus. The team demonstrated their telegraph to Congress in 1838, though funding for a practical line was not approved until 1843.

The first operational Morse telegraph line connected Washington, D.C., to Baltimore, Maryland, a distance of approximately 60 kilometers. On May 24, 1844, Morse transmitted the famous message "What hath God wrought" from the Supreme Court chamber in the Capitol to Vail in Baltimore. This demonstration launched the telegraph era in America.

The Morse Code

The coding system that bears Morse's name, though substantially modified by Vail, became the universal language of telegraphy. Morse code represents letters, numbers, and punctuation as sequences of short signals (dots) and long signals (dashes). The code was designed with efficiency in mind, with the most common letters in English receiving the shortest codes: E is a single dot, T is a single dash, while less common letters like Q and Z require four symbols.

The original American Morse code differed slightly from the International Morse Code standardized in 1865 for use on submarine cables and later adopted worldwide. Both versions proved remarkably robust for transmission over noisy electrical circuits, as operators could often interpret signals even when partially corrupted by interference.

The Register versus Sound Reading

Morse's original design included a mechanical register that embossed or inked dots and dashes onto paper tape. However, skilled operators discovered they could interpret messages faster by listening to the clicking sounds of the receiver mechanism than by reading the paper tape. Sound reading, or "reading by ear," became the standard practice, demonstrating how users often find more efficient methods than inventors anticipate.

Early Attempts and Failures

Cyrus West Field, an American businessman, organized the Atlantic Telegraph Company in 1856 to lay a cable between Ireland and Newfoundland. The technical challenges were immense: the cable had to span over 3,000 kilometers of ocean reaching depths of nearly 4 kilometers, using materials and methods never before tested at such scales.

The first attempted laying in 1857 ended when the cable broke after only about 600 kilometers had been paid out. A second attempt in 1858 succeeded in establishing a connection. Queen Victoria and President James Buchanan exchanged congratulatory messages, and the public celebrated the achievement with bonfires and parades. However, the cable's insulation deteriorated rapidly, and after transmitting about 400 messages over three weeks, it failed completely.

Scientific Investigations

The 1858 failure prompted serious scientific investigation into submarine cable design. William Thomson (later Lord Kelvin) had warned that the long cable would require extremely sensitive receiving instruments and careful transmission procedures. His theoretical work on signal propagation in cables led to improved designs and operating methods.

Investigations revealed that the 1858 cable had been damaged by excessive voltages applied in attempts to speed transmission. Thomson developed the mirror galvanometer, an exquisitely sensitive detector that could respond to the minute currents arriving through thousands of kilometers of cable. His "siphon recorder" later automated the recording of these signals.

Success in 1866

After the American Civil War delayed further attempts, Field organized a new expedition using the Great Eastern, the largest ship in the world, which was capable of carrying the entire cable without splicing at sea. The 1865 attempt nearly succeeded but the cable broke with only 1,000 kilometers remaining. The 1866 expedition successfully completed the connection and then recovered and spliced the 1865 cable, providing two working transatlantic links.

The success of the Atlantic cable inspired similar projects worldwide. By the early 1870s, submarine cables connected Britain to India and beyond. The British Empire's strategic interest in rapid communication with its colonies drove investment in a global cable network that, by century's end, touched every continent.

Impact on Global Communication

The transatlantic cable reduced the time to send a message between Europe and America from about ten days (the fastest steamship crossing) to minutes. This transformation affected commerce, diplomacy, and journalism profoundly. Stock prices, commodity markets, and business decisions could now be coordinated across oceans. News that once took weeks to cross the Atlantic now arrived almost instantaneously.

Duplex and Quadruplex Systems

Duplex telegraphy, enabling simultaneous transmission in both directions on a single wire, was developed by several inventors including Joseph Stearns and Thomas Edison. The technique relied on electrical balancing so that a station's own transmitted signal would not interfere with the incoming signal from the other end.

Edison's quadruplex telegraph of 1874 doubled the duplex capacity by combining the differential duplex method with a technique using different current strengths to encode two separate messages. The quadruplex effectively provided four message channels on a single wire, quadrupling the capacity of existing infrastructure. Western Union eagerly adopted this innovation, which Edison sold for a substantial sum that helped fund his subsequent inventions.

Harmonic and Acoustic Telegraphs

Elisha Gray and Alexander Graham Bell independently worked on harmonic telegraphs that would transmit multiple messages simultaneously using different audio frequencies. Each message would be assigned a distinct tone, and tuned receivers would respond only to their designated frequency. While neither succeeded in commercializing a harmonic telegraph, Bell's research led directly to his invention of the telephone, which transmitted the full range of voice frequencies rather than just a few tones.

Time-Division Multiplexing

Jean-Maurice-Emile Baudot developed a system in which multiple operators used a rotating distributor to interleave their messages. Each operator had access to the line for a brief time slot, and the receiving distributor synchronized to separate the messages. Baudot's system also introduced a five-bit code that became an important ancestor of later digital communication codes. The unit of symbol rate, the baud, is named in his honor.

Origins and Early Systems

Edward Calahan developed the first practical stock ticker in 1867, building on earlier work by David Hughes. The device used a printing telegraph mechanism to record stock symbols and prices on a narrow paper tape. Subscribers in brokerage offices and other locations received continuous updates as prices changed on the exchange floor.

Thomas Edison improved the stock ticker significantly, developing the Universal Stock Printer in 1871. Edison's design was more reliable and faster than earlier tickers. The income from selling his ticker patents provided capital for establishing his famous Menlo Park laboratory, where he would develop the phonograph, the practical incandescent lamp, and countless other inventions.

Impact on Markets

The stock ticker democratized access to market information that had previously been available only to those physically present on the exchange floor. This wider distribution of price information affected market dynamics, enabling faster responses to news and price movements. The ticker tape became a symbol of Wall Street itself, and ticker tape parades using discarded tape from financial district offices became a New York tradition for celebrating heroes and achievements.

Wheatstone Automatic Telegraph

Charles Wheatstone developed an automatic telegraph system using perforated paper tape. An operator would punch the message into tape at leisure, then feed the tape through a high-speed transmitter that could send at rates far exceeding manual keying. A matching receiver could print the message automatically. This system found use on busy routes where traffic volume justified the additional equipment costs.

The Teletype and Printing Telegraphs

Various inventors developed printing telegraphs that produced readable text rather than requiring Morse code expertise. The Hughes printing telegraph used a type wheel synchronized between sender and receiver. Later developments culminated in the teletype or teletypewriter, which combined a typewriter-style keyboard with automatic transmission and printing. The teletype made telegraph operation accessible to typists without special training in Morse code.

Pneumatic Tube Integration

Major telegraph offices integrated pneumatic tube systems to move messages rapidly between receiving stations and delivery departments. In cities like London, Paris, and Berlin, underground pneumatic networks connected main telegraph offices to branches throughout the urban area. This infrastructure demonstrated the complex organizational and logistical systems that developed around telegraph technology.

European Networks

European nations rapidly built telegraph networks following the successful demonstrations of the 1840s. Governments typically controlled telegraph systems as extensions of postal services, recognizing their strategic importance for administration and military coordination. The International Telegraph Union, established in 1865, became one of the first international organizations, standardizing practices and rates for cross-border communication.

American Expansion

In the United States, private companies initially dominated telegraph development. Western Union, formed through consolidation of smaller companies, emerged as the dominant carrier by the 1860s. The transcontinental telegraph, completed in 1861 just as the Civil War began, connected California to the eastern states and rendered the Pony Express obsolete after only eighteen months of operation.

Colonial and Imperial Networks

Colonial powers built telegraph networks linking their overseas territories to metropolitan centers. The British Empire prioritized the "All Red Line," a cable network connecting London to every major British possession entirely through British-controlled territory or waters. This strategic communication advantage proved valuable during conflicts and for coordinating imperial administration.

Development in Asia, Africa, and Latin America

Telegraph lines reached major Asian cities by the 1870s. Japan embraced telegraphy as part of its Meiji-era modernization, building a national network and training Japanese operators. In Latin America, telegraph networks connected major cities and facilitated trade in commodities like coffee and rubber. Africa received telegraph connections primarily along colonial trade routes and to administrative centers.

Transformation of Business

The telegraph enabled coordination of business activities across vast distances. Railroad companies used telegraph lines running alongside their tracks to schedule train movements, dramatically improving safety and efficiency. Commodity traders could track prices in distant markets and execute trades rapidly. The telegraph facilitated the growth of large, geographically dispersed corporations by enabling central management to communicate with remote operations.

Revolution in Journalism

News gathering and distribution transformed fundamentally. Wire services like the Associated Press pooled resources to gather and distribute news by telegraph, creating a more standardized and rapid news cycle. Newspapers could now report on distant events the same day or the day after they occurred rather than waiting weeks for mail dispatches. War correspondence gained immediacy, as reports from battlefields reached home audiences within days or hours.

The telegraph also affected writing style. Because telegraph charges were based on word count, writers learned to compose terse, economical prose, contributing to the development of modern journalistic style.

Military Applications

Military organizations quickly recognized the telegraph's strategic value. During the American Civil War, both sides used telegraph extensively for command and control. The Union established the Military Telegraph Corps, which constructed thousands of kilometers of field telegraph lines. President Lincoln spent many hours in the War Department telegraph office, receiving reports from commanders and sending orders.

Personal Communication

While the telegraph was initially too expensive for routine personal use, it became the preferred method for urgent family communication. Telegrams announcing births, deaths, and emergencies became important rituals. The arrival of a telegram could provoke anxiety, as recipients wondered whether it bore good news or bad. Western Union's singing telegram service, introduced in 1933, attempted to add warmth to the medium for celebrations.

Conceptual Shifts

The telegraph contributed to changing conceptions of time and space. Standard time zones were adopted partly to coordinate railway schedules that depended on telegraph dispatching. The near-instantaneous nature of telegraph communication created new expectations about the pace of business and government. Some contemporary observers worried about the psychological effects of this acceleration, concerns that would recur with each subsequent communication technology.