Buddhist Ayurvedic Medicine

Functions of Majja Dhatu Nervous System – Communication

What is AyurvedaBuddhist Ayurvedic Medicine, Seven Dhatus – Bodily Tissues

History Software Engineering

Telebit TrailBlazer Modems Break 9600 bps – 1984 AD

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Telebit Modems Break 9600 bps

The TrailBlazer modem, from the US-based company Telebit, was a computer-networking breakthrough. In 1984, at a time when most dial-up computer users were just beginning to make the transition from modems that could send 1200 bits per second (bps) to those that could send 2400 bps, Telebit introduced a modem that could transfer data over an ordinary phone line at speeds between 14,400 and 19,200 bits per second.

The secret to the TrailBlazer’s speed was its proprietary channel-measuring protocol. At the time, phone calls traveled over many analog wires to reach from one end to another, creating something communications engineers called a channel, and every channel was slightly different. Telebit’s Packetized Ensemble Protocol (PEP) divided that channel into 512 different analog slots. When one TrailBlazer sensed it was communicating with another, the two modems would measure the channel and determine which of those slots could be used for high-speed data transfer. In any given instance, the modems would allot the majority of slots to the modem transferring the most data. The TrailBlazer also had direct support for the UNIX-to-UNIX-Copy protocol (UUCP), making it a hit with Usenet sites.

In 1985, each TrailBlazer cost $2,395. The modems frequently paid for themselves in the first year, however, through savings on long-distance charges.

The TrailBlazer triggered what came to be known as the “modem wars.” They started when Telebit’s primary competitor, US Robotics Corporation®, introduced its own 9600 bits per second modem for $995 in 1986. The two modems were not compatible. Telebit responded by slashing the price of the TrailBlazer to $1,345 in 1987.

The industry knew the path to riches would come only from a larger, multivendor market—and that required standardization. The first high-speed standard was the V.32 9600 bits per second in 1987; prices for external models dropped to $400. A succession of faster and lower-priced models followed until, finally, the International Telecommunication Union (ITU) released the draft V.90 standard in February 1998, which supported 56-kilobit-per-second download speeds to consumers from specially equipped internet service providers (ISPs). This was as fast as was theoretically possible over an analog phone line without the use of compression.

SEE ALSO The Bell 101 Modem (1958), Usenet (1980), PalmPilot (1997)

This spectrograph shows the tones made by a pair of modems during the first 22 seconds of a particular high-speed connection.

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History Software Engineering

Fiber Optics – Optical-Fiber – 1965 AD

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Fiber Optics

Narinder Singh Kapany (b. 1926), Jun-ichi Nishizawa (b. 1926), Manfred Börner (1929–1996), Robert Maurer (b. 1924), Donald Keck (b. 1941), Peter Schultz (b. 1942), Frank Zimar (dates unavailable)

Fiber-optic transmission takes information in the form of 1s and 0s, encodes it as pulses of light, and shoots it through a tiny cylindrical glass pipe no wider than a human hair. After moving through the glass at the speed of light, the pulses are converted back into their original electronic form. For computer data, that would be 1s and 0s. Voice must go through an additional step of being digitized to 1s and 0s before being sent, and being reconstructed into analog waves on the receiving end.

The idea of bending or controlling light and using it to solve everyday problems, including faster transmission of information, was not new. Early examples of optical communication include the heliograph from the 1800s, which used mirrors to produce flashes of sunlight coded for letters or numbers. Later in the century, Alexander Graham Bell (1847–1922) and his assistant Thomas Augustus Watson (1854–1934) invented the photophone, which used modulated beams of light against a selenium receiver to carry spoken words.

Many contributed to the modern era of fiber-optic communications, including Indian American physicist Narinder Singh Kapany and Jun-ichi Nishizawa of Japan’s Tohoku University. In 1965, Manfred Börner, a German based in Ulm, created the first working fiber-optic data transmission system. But it wasn’t until the 1970s, when four scientists at Corning Glass Works®—Robert Maurer, Donald Keck, Peter Schultz, and Frank Zimar—developed a kind of glass that could carry the light from light-emitting diodes (LEDs) and semiconductor lasers over dozens of miles without significant loss of power, that the technology was mature enough to be adopted as a general purpose communication system.

Compared to wire communications such as traditional copper or a T1 line, a single fiber optic can carry more than a thousand billion times more information in the same amount of time.

SEE ALSO Digital Long Distance (1962)

Fiber-optic cables, shown here, shoot information encoded as pulses of light through tiny cylindrical glass pipes.

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History Networking

Digital Long Distance Telephone Calls – 1962 AD

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Digital Long Distance

Picture this: It’s Mother’s Day around 1960. All over the country, sons and daughters who live far away from their mothers are calling to wish them a happy day and say thank you for all they do. Except many of them can’t, because they can’t get their calls to go through. All they hear when they dial is a busy signal or an automated voice saying to try again later. That was because there was a relatively small number of copper wire pairs crisscrossing the country as part of the telecommunications network, and each pair could carry just a single conversation.

With the introduction of AT&T’s digital T1 carrier service, the capacity of each pair of copper wires dramatically increased. Rather than one conversation per pair of twisted wires, two pairs could carry 24 conversations simultaneously. The T1 service did this by converting all the analog voice data to digital format and sequencing or organizing that data to travel together on a copy pair and then get accurately separated for delivery to the intended residence or phone line. In essence, there was suddenly more than 10 times the capacity on each copper pair. (For technical reasons, the T1 required a copper pair to carry data in each direction.) The first T1 was installed in Chicago, where the city had run out of space in places to add more buried cable under the city streets.

The digital long-distance service required three things: the T1 digital communication protocol, a technology called a multiplexer to combine the 24 conversations into a single data stream, and a converter that changed analog data to digital and digital back to analog.

The T1 created the possibility of connecting two computers with a high-speed digital network ordered from the phone company. The evolution and maturation of the specifications and standards surrounding the T1 carrier service, popularly referred to as a T1 line, was fundamental to a lot of other innovation occurring, including both the early internet and the eventual computerization of the local telephone network with the invention of the 5ESS switch.

SEE ALSO Computerization of the Local Telephone Network (1983)

Engineers at Bell Telephone replace the T1 interface deep within a telephone switch.

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Cloud Data Science - Big Data History Networking Software Engineering

Time-Sharing – The Original “Cloud Computing” – 1961 AD

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John Warner Backus (1924–2007), Fernando J. Corbató (b. 1926)

A computer’s CPU can run only one program at a time. Although it was possible to sit down at the early computers and use them interactively, such personal use was generally regarded as a waste of fantastically expensive computing resources. That’s why batch processing became the standard way that most computers ran in the 1950s: it was more efficient to load many programs onto a tape and run them in rapid succession, and then make the printouts available to the much slower humans in due time.

But while batch processing was efficient for the computer, it was lousy for humans. Tiny programming bugs resulting from a single mistyped letter might not be discovered for many hours—typically not until the next day—when the results of the batch run were made available.

Researchers at MIT realized that a single CPU could be shared between several people at the same time if the CPU switched between different programs, running each for perhaps a 10th of a second. From the users’ point of view, the computer would appear to be running slower, but for the users, this system still would be more efficient, because they would find out about their bugs in seconds, rather than hours.

John Backus first proposed this method in 1954 at an MIT summer session sponsored by the Office of Naval Research, but it couldn’t be demonstrated until IBM delivered its 7090 computer to MIT—a computer that was large enough to hold several programs in memory at the same time.

MIT professor Fernando J. Corbató demonstrated his Experimental Time-Sharing System in November 1961. The system time-shared between four users. The operating system had 18 commands, including login, logout, edit (an interactive text editor), listf (list files), and mad (an early programming language). Later, this became the Compatible Time-Sharing System (CTSS), so named because it could support both interactive time-sharing and batch processing at the same time. Corbató was awarded the 1990 A.M. Turing award for his work on CTSS and Multics.

Time-sharing soon became the dominant way of interactive computing and remained so until the PC revolution of the 1980s.

SEE ALSO Utility Computing (1969), UNIX (1969)

Photograph of Fernando Corbató at MIT in the 1960s.

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History Networking

Recommended Standard 232 (RS-232) – 1960 AD

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Recommended Standard 232

For more than three decades, the Electronics Industries Association’s Recommended Standard 232 was the communications protocol that connected the wired world. Systems of all kinds came equipped with RS-232 connectors on their back sides that allowed them to transmit bytes of data as a series of serialized bits sent down a single transmit data wire; the same connector had a second receive data wire that could receive bytes from something at the other end.

Standardized in 1960, by the mid-1970s the RS-232 protocol was “spoken” by practically every computer on the planet. The original purpose was to enable worldwide communication of terminals and computers using the telephone network. In the machine room, RS-232 connected the computer with a dial-up telephone modem. Getting online meant making a phone call and having the two modems communicate using audio tones.

The original RS-232 connector had 25 pins. In addition to the data pins, one pin indicated that the phone was ringing, another pin that the carrier tone was present, and two pins indicated that each side was ready to accept data; two others indicated if each side had data to transmit. The 25-pin standard allowed the extra pins to be used as a second data channel. In practice, that channel was rarely used, so early PCs had 9-pin RS-232 connectors, necessitating 9-to-25 pin converters. At many universities, it was common for terminals to be connected with just three wires, with the others “looped back.” This setup was less reliable, but it allowed schools to use cheaper telephone cable to connect their machines.

Early terminals and modems ran RS-232 at 110, 300, or 1200 bits per second; in 1981, the IBM PC was introduced with a new chip from the National Semiconductor® company: the 8250 UART (universal asynchronous receiver/transmitter). The 8250 had a programmable bit-rate generator that could run RS-232 up to 115,200 bits per second.

The introduction of the Universal Serial Bus (USB) in 1996 marked the beginning of RS-232’s decline. Today few PCs have RS-232 connectors, although many motherboards still have the necessary hardware. Meanwhile, RS-232 is still widely used for communicating with embedded computers, such as computerized door locks.

SEE ALSO The Bell 101 Modem (1958), Universal Serial Bus (USB) (1996)

First developed in 1960, RS-232 ports are still incorporated into modern circuit boards.

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History Networking

Bell 101 Modem – 1958 AD

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The Bell 101 Modem

“A modem (short for modulator/demodulator) converts digital information into an analog signal (a process known as modulation) so that the signal can be transmitted, and then, on the receiving side, converts the analog signal back into digital bits (the demodulation). From 1958 until the late 1990s, acoustic modems that interfaced with the analog telephone network were the primary way that computers communicated with remote users.

The first acoustic modem was probably SIGSALY, a voice-encryption system developed by the Allies during World War II to let Winston Churchill speak directly with Franklin Roosevelt. That modem might have been developed by the Air Force Cambridge Research Center (AFCRC), which developed a digital device for sending radar images over the telephone lines.

Then, in 1958, AT&T released the Bell 101 modem for use with SAGE (Semi-Automatic Ground Environment), a US air defense system. The modem allowed communications over ordinary phone lines at 110 bits per second (bit/s). The following year, AT&T made the device available for commercial customers. The Bell 101 was superseded in 1962 with the Bell 103 modem that could send and receive data at 300 bit/s.

The Bell modems connected directly to ordinary telephone lines, but AT&T, which at the time provided both long-distance and local telephone service, prohibited its customers from attaching equipment manufactured by other companies. Then, in 1968, the US Federal Communications Commission (FCC) ruled that AT&T could not prohibit devices from connecting to telephone lines if they used an acoustic coupler. Within a few years, companies like Novation® and Hayes Microcomputer Products® were offering Bell-compatible 300-baud modems.

A 300-baud modem can deliver text at 30 characters per second or 250 words per minute. In 1979, AT&T introduced the Bell 212 modem, which could send and receive information four times faster. Hayes released the Smartmodem 1200, which was compatible with the Bell 212 but cost much less, in 1982 for $699. Two years later, the International Telegraph and Telephone Consultative Committee (CCITT) released v.22bis, a worldwide standard for 2400-baud modems. Those modems set the ground for the first dial-up time-sharing services.”

SEE ALSO SAGE Computer Operational (1958), Telebit Modems Break 9600 bps (1984)

The Bell 101 Dataset (1958) was the first commercial modem able to transmit digital data.

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History Software Engineering

The Bit – Binary Digit 0 or 1 – 1948 AD

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The Bit

Claude E. Shannon (1916–2001), John W. Tukey (1915–2000)

“It was the German mathematician Gottfried Wilhelm Leibniz (1646–1716) who first established the rules for performing arithmetic with binary numbers. Nearly 250 years later, Claude E. Shannon realized that a binary digit—a 0 or a 1—was the fundamental, indivisible unit of information.

Shannon earned his PhD from MIT in 1940 and then took a position at the Institute for Advanced Study in Princeton, New Jersey, where he met and collaborated with the institute’s leading mathematicians working at the intersection of computing, cryptography, and nuclear weapons, including John von Neumann, Albert Einstein, Kurt Gödel, and, for two months, Alan Turing.

In 1948, Shannon published “A Mathematical Theory of Communication” in the Bell System Technical Journal. The article was inspired in part by classified work that Shannon had done on cryptography during the war. In it, he created a mathematical definition of a generalized communications system, consisting of a message to be sent, a transmitter to convert the message into a signal, a channel through which the signal is sent, a receiver, and a destination, such as a person or a machine “for whom the message is intended.”

Shannon’s paper introduced the word bit, a binary digit, as the basic unit of information. While Shannon attributed the word to American statistician John W. Tukey, and the word had been used previously by other computing pioneers, Shannon provided a mathematical definition of a bit: rather than just a 1 or a 0, it is information that allows the receiver to limit possible decisions in the face of uncertainty. One of the implications of Shannon’s work is that every communications channel has a theoretical upper bound—a maximum number of bits that it can carry per second. As such, Shannon’s theory has been used to analyze practically every communications system ever developed—from handheld radios to satellite communications—as well as data-compression systems and even the stock market.

Shannon’s work illuminates a relationship between information and entropy, thus establishing a connection between computation and physics. Indeed, noted physicist Stephen Hawking framed much of his analysis of black holes in terms of the ability to destroy information and the problems created as a result.”

SEE ALSO Vernam Cipher (1917), Error-Correcting Codes (1950)

Mathematician and computer scientist Claude E. Shannon.

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Strowger Step-by-Step Switch – 1891 A.D.

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Strowger Step-by-Step Switch

Almon Brown Strowger (1839–1902)

“The Bell Telephone Company was incorporated in July 1877, and by the 1880s it was quickly expanding. The switchboards that connected phones together and completed calls were manually run by operators.

The early phone system didn’t have dials or buttons. Instead, there was a crank, connected to a tiny electrical generator. Users would pick up the phone and turn the crank, and electricity would travel down the phone line to signal the operator.

Almon Strowger was an undertaker in Kansas City, Missouri. He noticed that his business had declined as the telephone became more popular. Strowger learned that one of the telephone operators was married to his competitor, and whenever a phone call came in for the undertaker, she would direct the call to her husband. Motivated, Strowger invented the step-by-step switch, an electromechanical device that would complete a circuit between one phone and a bank of others depending on a sequence of electric pulses sent down the phone line. Instead of relying on an operator to connect, Strowger envisioned that people would tap out a code using a pair of push buttons.

Working with his nephew, Strowger built a working model and got a patent. Although other inventors had experimented with operator-free dialing systems—thousands of patents were filed—this system “worked with reasonable accuracy,” according to a 1953 article in the Bell Laboratories Record.

Strowger, family members, and investors then created the Strowger Automatic Telephone Exchange Company in 1891. They went to La Porte, Indiana, which had recently lost its telephone system because of a patent dispute between the local independent operator and the Bell Telephone System, and set up the world’s first automated telephone exchange with direct dialing—at least for local calls—in 1892.

The switch was called “step-by-step” because of the way that a telephone call was completed, one dialed digit at a time. Step-by-step exchanges remained in service throughout the United States until 1999, when the last was removed from service, replaced by the #5ESS computerized local exchange.”

SEE ALSO Digital Long Distance (1962)

“The friction drive of the Western Electric 7A Rotary, No. 7001 Line Finder. The bevel gear on the right has a steady rotary motion and does not use an electromagnet for stepping.”

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Baudot Code – 1874 A.D.

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Baudot Code

Jean-Maurice-Émile Baudot (1845–1903), Donald Murray (1865–1945)

“Early telegraph systems relied on human operators to encode and transmit the sender’s message, and then to perceive, decode, and transcribe the message on paper upon receipt. Relying on human operators limited the maximum speed at which a message could be sent and required operator skills that were not easily available.

Émile Baudot developed a better approach. A trained French telegraph operator, Baudot devised a system that used a special keyboard with five keys (two for the left hand and three for the right) to send each character. Thirty-one different combinations arise from pressing one or more of the five keys together; Baudot assigned each code to a different letter of the alphabet. To send a message, the operator would type the codes in sequence as the machine clicked, roughly four times a second. With each click, a rotating part that Baudot called the distributor would read the position of each key in order and, if the key was pressed, send a corresponding pulse down the telegraph wire. At the other end, a remote printer would translate the codes back into a printed character on a piece of paper tape.

Baudot was one of the first people to combine key inventions by others into one working system. He patented his invention in 1874, started selling devices to the French Telegraph Administration in 1875, and was awarded the gold medal at the Paris Exposition Universelle in 1878. Baudot’s code was adopted as the International Telegraph Alphabet No. 1 (ITA1), one of the original international telecommunications standards. In recognition of his contribution, the baud, a unit of data transmission speed equal to the number of signal changes per second, is named after him.

In 1897, the Baudot system expanded to incorporate punched paper tape. The keyboard was disconnected from the telegraph line and connected to a new device that could punch holes across a strip of paper tape, with one hole corresponding to each key. Once punched, the tape could be loaded into a reader and the message sent down the telegraph wire faster than a human could type. In 1901, the inventor Donald Murray developed an easier-to-use punch that was based on a typewriter keyboard. Murray also made changes to Baudot’s code; the resulting code was known as the Baudot-Murray code (ITA2) and remained in use for more than 50 years.”

SEE ALSO ASCII (1963), Unicode (1992)

“Paper tape punched with the five-level Baudot code. The large holes correspond to the 5 bits of the code, while a rotating toothed tractor wheel fit into the small holes and used them to pull the tape through the machine.”

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First Electromagnetic Spam Message – 1864 A.D.

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First Electromagnetic Spam Message

“William Fothergill Cooke and Charles Wheatstone’s electromagnetic telegraph took England by storm shortly after commercial service began in 1837. By 1868, there were more than 10,000 miles of telegraph wire in the United Kingdom supporting 1,300 telegraph stations; four years later, there were 5,179 stations, serviced by more than 87,000 miles of wire.

With a capability to reach large numbers of people quickly and easily, the world’s first unsolicited, electrically enabled advertisement was sent in London late in the evening of May 29, 1864, according to historian Matthew Sweet. The message was from Messrs. Gabriel, a group of unregistered dentists, who sold a variety of false teeth, gums, toothpaste, and tooth powder.

The message, sent to current and former members of Parliament, read as follows:

Messrs. Gabriel, dentists, Harley-street, Cavendish-square. Until October Messrs. Gabriel’s professional attendance at 27, Harley-street, will be 10 till 5.

In 1864 there were no telegraphs in private residences; the message appeared on the swinging needles of the Cooke-Wheatstone electromagnetic telegraph, where it was transcribed by operators, carried by a boy sent from the London District Telegraph Company, and placed into the hand of a member of Parliament.

That M.P. wrote about his annoyance in a letter to the editor of the local paper: “I have never had any dealings with Messrs. Gabriel, and beg to know by what right do they disrupt me by a telegram which is simply the medium of advertisement? A word from you would, I feel sure, put a stop to this intolerable nuisance.”

But it wasn’t shame that put a halt to spam sent by telegram: it was the cost. Advertising by telegraph just wasn’t cost effective, due to the high price of sending the messages. That price plummeted with the birth of email, which was used to send a bulk, unsolicited advertisement for the first time in 1978.

SEE ALSO First Internet Spam Message (1978)

On May 29, 1864, Messrs. Gabriel, a group of unregistered dentists, sent members of the British Parliament the earliest known unsolicited electronic message. One recipient complained to the newspaper.

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Fax Machine Patented – 1843 A.D.

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Fax Machine Patented

Alexander Bain (1811–1877), Giovanni Caselli (1815–1891)

“Before the telephone, before radio, there was the fax machine. It wasn’t the fax machine of the 1990s — the machine that transmitted information over ordinary phone lines — but rather a machine comprising of a pair of synchronized pendulums connected to each other over distance by an electrified wire.

Alexander Bain was a Scottish clockmaker with an interest in both electricity and invention. In 1843, he built an “electric printing telegraph” that used a pair of precisely timed pendulums, one configured to function like a scanner, the other to function as a remote printer. A message scanned by the first pendulum would print out at the second.

The scanning pendulum had an arm that moved back and forth across a metal plate holding raised metal printers type. After each swing, the plate advanced in the perpendicular direction. Thus, the arm scanned a path of parallel horizontal lines across the type. When a small contact on the arm swept over part of a letter, a circuit would be completed and an electric current would flow down the wire to the remote system, where the synchronized pendulum was scanning horizontal lines over a piece of chemically treated paper. When electricity flowed, the paper under the second pendulum would change color.

Although Bain’s system worked, he ended up in disputes with both Charles Wheatstone (1802–1875) and Samuel Morse (1791–1872). Bain died in poverty in 1877.

Italian inventor Giovanni Caselli improved on Bain’s basic idea with a more compact device called a pantelegraph, which transmitted a message written with insulating ink on a metal plate over a set of wires. Commercial operation of the pantelegraph began in 1865 between Paris and Lyon, mostly to verify signatures on banking instructions.

The discovery that the element selenium was also a photoconductor meant that its electrical resistance changed with light, making it possible to send photographic images. This was put to use in 1907 with a “wanted” poster that was sent from Paris to London help catch a jewel thief. Soon newspapers were routinely printing photos that had been sent by wire. In 1920, the Bartlane cable picture transmission system routinely sent digitized newspaper photographs from London to New York, taking three hours to transmit each photograph.”

SEE ALSO First Digital Image (1957)

Alexander Bain’s “electric printing telegraph” paved the way for later fax machines, such as this 1960 machine by Alexander Muirhead.”

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Electrical Telegraph – 1836 A.D.

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Electrical Telegraph

John Frederic Daniell (1790–1845), Joseph Henry (1797–1878), Samuel Morse (1791–1872), William Fothergill Cooke (1806–1879), Charles Wheatstone (1802–1875)

“Using electricity to send messages through wires was the subject of much experimentation in Europe and the United States during the early 19th century. The key invention was John Daniell’s wet-cell battery (1836), a reliable source of electricity. Various forms of metal wire had existed since ancient times, and air was a reasonably good insulator, so sending electricity over distance required little more than stringing up a wire, modulating the signal with some kind of code, and having a device at the other end to turn the coded electrical pulses back into something a human could perceive.

American inventor Samuel Morse is credited with inventing, patenting, and promoting the first practical telegraph in 1836. The original Morse system started with a message that was encoded as a series of bumps on small, puzzle-like pieces that were placed into a tray. The operator turned a crank that moved the tray past a switch that completed and broke an electric circuit as it moved up and down. At the other end, an electromagnet moved a fountain pen or pencil up and down as a strip of paper moved underneath. To transmit text, each letter and number needed to be translated into a series of electrical pulses, which we now call dots and dashes, after how they were recorded on the paper strip. To operate over distances, the Morse system relied on Joseph Henry’s amplifying electromechanical relay, which allowed faint electrical signals sent over a long distance to trigger a second circuit.

In England, meanwhile, William Fothergill Cooke and Charles Wheatstone developed their own telegraph system based on the ability of electricity moving through wire to deflect a magnetic compass. The original Cooke–Wheatstone telegraph used five needles arranged in a line on a board, along with a pattern of 20 letters: by sending electricity down a pair of wires, two of the needles would deflect and point at one of the letters.

Cooke and Wheatstone’s system was the first to be commercialized. A few years later, with $30,000 in federal funding, Morse built an experimental telegraph line from Washington, DC, to Baltimore, Maryland. On May 24, 1844, Morse sent his famous message—“What hath God wrought?”—between the two cities.”

SEE ALSO First Electromagnetic Spam Message (1864)

Drawings from Samuel Morse’s sketchbook, illustrating his first conception of the telegraph.

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Optical Telegraph – 1792 A.D.

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Optical Telegraph

Claude Chappe (1763–1805)

“People had used signal fires, torches, and smoke signals since ancient times to send messages rapidly over long distances. The ancient Athenians used flashes of sunlight from their shields to send messages from ship to shore. The Romans coded flags to send messages over a distance—a practice that the British Navy also employed as early as the 14th century.

In 1790, an out-of-work French engineer named Claude Chappe started a project with his brothers to develop a practical system for sending messages quickly over the French countryside. The idea was to set up a series of towers constructed on hills, with each tower in view of the next. Each tower would be equipped with a device that had big, movable arms and a telescope, so that the position of the arms could be determined and then relayed to the next tower. An operator in the first tower would move the arms into different positions, each position signaling a letter, and the operator in the second tower would write it down—essentially sending letters over distance (tele-graph) with light. A second telescope would allow for messages to be conveyed in the opposite direction.

After successfully sending a message nearly 9 miles (14 kilometers) on March 2, 1791, Claude and his younger brothers, Pierre François (1765–1834), René (1769–1854), and Abraham (1773–1849), moved to Paris to continue the experiments and drum up support from the new government. Their older brother, Ignace Chappe (1760–1829), was a member of the revolutionary Legislative Assembly, which probably helped somewhat. Soon the brothers were authorized by the Assembly to construct three stations as a test. That test went well, and in 1793 the Assembly decided to replace its system of couriers with optical telegraph lines. Claude Chappe was appointed lieutenant of engineering for the construction of a telegraph line between Paris and Lille, under the control of the Ministry of War.

The first practical demonstration of the telegraph came on August 30, 1794, when the Assembly learned that its army in Condé-sur-l’Escaut had been victorious. That message was transmitted in about half an hour. In the following years, telegraph lines were built across France, connecting all of the major cities. At its height, the system had 534 stations covering more than 3,000 miles (5,000 kilometers). Not surprisingly, Napoléon Bonaparte made heavy use of the technology during his conquest of Europe.”

SEE ALSO Fax Machine Patented (1843)

An artist’s impression of Claude Chappe, demonstrating his aerial telegraph semaphore system, from the Paris newspaper Le Petit Journal, 1901.”

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Scytale – circa 700 B.C.

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c. 700 BCE


“During Roman times, Sparta’s military needed to send messages over long distances. To be useful, the messages had to travel fast, which meant that they couldn’t be transported by a large, slow-moving battalion. And the messages needed to remain secret, in case they were intercepted.

To protect its messages, the military devised a secure communications system involving two wooden staffs of identical diameter and a strip of parchment. Two parties needing to communicate each would have a single staff. To create a message, the sending party would wrap the parchment around his staff and then write a message across; when the parchment was unwrapped, the message would be scrambled. At the other end, the recipient would wrap the message around his staff, and the message would be legible once again.

The scytale is mentioned in the writings of Archilochus, a Greek poet who lived from 680 BCE to 645 BCE. Today, nearly every modern cryptography textbook features a description of the scytale. Although there are examples of cryptography and encipherment from ancient Egypt, Mesopotamia, and Judaea, the scytale is the first example of a cryptographic device—with the diameter of the staff being akin to the encryption key. (A key is a secret—typically a word, number, or phrase—that controls the encryption algorithm. The key determines how the message is encrypted; for most encryption algorithms, the same key is used to decrypt the encrypted message. Thus, keeping the key secret is critical to message security.)

But while the writings of Archilochus certainly do mention a scytale as a means of communication, references to it as an encryption device do not appear until nearly 700 years later, in the writings of Plutarch.

Another encryption cipher from the ancient world was Julius Caesar’s cipher, used in the first century BCE by the general to scramble military communications. Several hundred years later, the Kama Sutra, by Vatsyayana, advised men and women to know how to compose and read secret messages.

SEE ALSO On Deciphering Cryptographic Messages (c. 850), Vernam Cipher (1917)

A scytale uses parchment wrapped around a cylinder to encrypt a message; the recipient wraps the message around a cylinder of the same diameter to read the coded content.”

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