The telautograph, an analog precursor to the modern fax machine, transmits electrical impulses recorded by potentiometers at the sending station to servomechanisms attached to a pen at the receiving station, thus reproducing at the receiving station a drawing or signature made by the sender. It was the first such device to transmit drawings to a stationary sheet of paper; previous inventions in Europe had used rotating drums to make such transmissions.

The telautograph's invention is attributed to Elisha Gray, who patented it on July 31, 1888. Gray's patent stated that the telautograph would allow "one to transmit his own handwriting to a distant point over a two-wire circuit." It was the first facsimile machine in which the stylus was controlled by horizontal and vertical bars.[1] The telautograph was first publicly exhibited at the 1893 World's Columbian Exposition held in Chicago.

Telautograph-1888 electronic writing device
Telautograph patent schema

While the patent schema's geometry implies vertical and horizontal coordinates, systems used in the 20th Century (and presumably before) had a different coordinate scheme, based on transmitting two angles.

In an 1888 interview in The Manufacturer & Builder (Vol. 24: No. 4: pages 85–86) Gray made this statement:[2]

By my invention you can sit down in your office in Chicago, take a pencil in your hand, write a message to me, and as your pencil moves, a pencil here in my laboratory moves simultaneously, and forms the same letters and words in the same way. What you write in Chicago is instantly reproduced here in fac-simile. You may write in any language, use a code or cipher, no matter, a fac-simile is produced here. If you want to draw a picture it is the same, the picture is reproduced here. The artist of your newspaper can, by this device, telegraph his pictures of a railway wreck or other occurrences just as a reporter telegraphs his description in words.

PSM V14 D424 Elisha Gray
The inventor Elisha Gray

By the end of the 19th century, the telautograph was modified by Foster Ritchie. Calling it the telewriter, Ritchie's version of the telautograph could be operated using a telephone line for simultaneous copying and speaking.[1]

The telautograph became very popular for the transmission of signatures over a distance, and in banks and large hospitals to ensure that doctors' orders and patient information were transmitted quickly and accurately. Teleautograph systems were installed in a number of major railroad stations to relay hand-written reports of train movements from the interlocking tower to various parts of the station.[3][4] The teleautograph network in Grand Central Terminal included a public display in the main concourse into the 1960s; a similar setup in Chicago Union Station remained in operation into the 1970s.

PSM V44 D062 Sample work of telautograph
Sample work of telautograph

A Telautograph was used in 1911 to warn workers on the 10th floor about the Triangle Shirtwaist Factory fire that had broken out two floors below. An example of a Telautograph machine writing script can be seen in the 1956 movie Earth vs the Flying Saucers as the output device for the mechanical translator.

Telautograph Corporation changed its name several times. In 1971, it was acquired by Arden/Mayfair. In 1993, Danka Industries purchased the company and renamed it Danka/Omnifax. In 1999, Xerox corporation purchased the company and called it the Omnifax division, which has since been absorbed by the corporation.

An early telautograph


  1. ^ a b The worldwide history of telecommunications. Wiley-IEEE.
  2. ^ "Elisha Gray Deserves Top Billing In Brownsville History". Glenn Tunney.
  3. ^ Chicago, Illinois. Reading the teleautograph in the trainmaster's office of the Union Station. The messages originate in the interlocking tower and are carried to teleautographs in various parts of the station; the trainmaster's office, the passenger agent's office, information desk, etc., photograph by Jack Delano, Feb. 1943 Feb., Farm Security Administration - Office of War Information Photograph Collection (Library of Congress).
  4. ^ Walter J. Armstrong, Mechanical and Electrical Equipment of the Toronto Union Station, Journal of the Engineering Institute of Canada, Vol. 4 (1921); pages 87-97, see particularly page 95.

External links


Patent images in TIFF format

Analog-to-digital timeline

This page serves as a timeline to show when analog devices were first made with digital circuits and systems.

1642: Blaise Pascal invents the mechanical calculator. This calculator could work in base 6, 10, 12 and 20.

1820: Thomas de Colmar invents the arithmometer. Its production release in 1851 marks the beginning of the mechanical calculator industry.

1822: Difference engine: First mechanical computer created by Charles Babbage.

1837: Analytical engine: Mechanical general-purpose computer created by Charles Babbage.

1843: fax machine: a scanning, rasterized, digital replacement for the vectorized, analog telautograph."The Secret Life of the Fax Machine" by Tim Hunkin

1847 (?) : piano roll: a digital recording of which notes were played.

1877: gramophone record: an analog recording that more-or-less replaces the digital piano roll.

1921: Edith Clarke patents the "Clarke calculator", a graphical calculator for simplifying calculations of inductance and capacity for electrical transmission lines.

1920s, Bell Labs designed the first digital speaker. The product was abandoned before its release due to cost, size, unreliability, and overall impracticality. Even though many analog speakers have labels that say "digital", digital speakers today remain unavailable commercially.Digital speakers

1940(?) bookkeeping using Charga-Plates to imprint account numbers, rather than writing them by hand.

1941, Computer: Konrad Zuse develops the first digital computer, the Z3 (computer)

17 November 1947, Transistor: John Bardeen, Walter Brattain, and Bill Shockley at AT&T Bell Labs made the first transistor.

1951, Audio recording: Geoff Hill plays back the first digital audio recording of Colonel Bogey's March.

1954, digital voltmeter replaces analog galvanometer.

1970, Watch: Pulsar (watch) helped Hamilton Watch Company make real the prototype for the digital watch that Hamilton Watch Co. designed for the 1968 film 2001: A Space Odyssey. The watch was completed in 1972 and sold for US$2,100.Watch#Digital

1973, Telephone service: The first digital phone message was relayed over the ARPANET system.[1]

December 1975, Still image: Kodak engineer Steven Sasson creates the first digital camera, weighing eight pounds and saving images to a cassette tape. Exposure time was 23 seconds. Digital camera#Early development

1979 (?), Compact Disc

1982, Video recording: The first digital video technology was made available.[2]

March 1, 1997, Player Piano: QRS and Baldwin collaborate to produce the first MIDI-compatible player piano.[3]

February 13, 1998, Player Violin: QRS patents the first MIDI-compatible player violin.[4]

October 1, 1998, Television: British Sky Broadcasting launches the first digital television network. British Sky Broadcasting#Move to Digital

January 31, 2005, Credit card: Fujitsu patents the Wireless Wallet, a cell phone that doubles as an electronic credit card for more secure transactions.[5](?) digital filter

(?) magnetic stripe card, an even more digital replacement of Charga-Plates

(?) smart card, an even more digital replacement of magnetic stripe card

Analog device

Analog device is usually a combination of both analog machine and analog media that can together measure, record, reproduce, or broadcast continuous information, for example, the almost infinite number of grades of transparency, voltage, resistance, rotation, or pressure. In theory, the continuous information (also analog signal) has an infinite number of possible values with the only limitation on resolution being the accuracy of the analog device.


An autopen or signing machine is a device used for the automatic signing of a signature or autograph. Many celebrities, politicians and public figures receive hundreds of letters a day, many of which request a personal reply; this leads to a situation in which either the individual must artificially reproduce their signature or heavily limit the number of recipients who receive a personal response. Given the exact verisimilitude to the real hand signature, the use of the autopen allows for a small degree of wishful thinking and plausible deniability as to whether a famous autograph is real or reproduced, thus increasing the perception of the personal value of the signature by the lay recipient. However, known or suspected autopen signatures are also vastly less valuable as philographic collectibles; legitimate hand-signed documents from individuals known to also use an autopen usually require verification and provenance to be considered valid.

The early autopens used a plastic matrix of the original signature which is a channel cut into an engraved plate in the shape of a wheel. A stylus driven by an electric motor followed the x and y axis of a profile or shape engraved in the plate (which is why it is called a matrix). The stylus is mechanically connected to an arm which can hold almost any common writing instrument, so the favourite pen and ink can be used to suggest authenticity. The Autopen signature is made with even pressure (and indentation in the paper), which is how these machines are distinguishable from original handwriting where the pressure varies.Modern day autopens use a signature smart card or USB flash drive to store signatures and phrases instead of the plastic matrices. In addition, certain models can replicate entire pages of writing once a custom font has been created in a user's handwriting.

Communications receiver

A communications receiver is a type of radio receiver used as a component of a radio communication link. This is in contrast to a broadcast receiver which is used to receive radio broadcasts. A communication receiver receives parts of the radio spectrum not used for broadcasting, that includes amateur, military, aircraft, marine, and other bands. They are often used with a radio transmitter as part of a two way radio link for shortwave radio or amateur radio communication, although they are also used for shortwave listening.

Elisha Gray

Elisha Gray (August 2, 1835 – January 21, 1901) was an American electrical engineer who co-founded the Western Electric Manufacturing Company. Gray is best known for his development of a telephone prototype in 1876 in Highland Park, Illinois. Some recent authors have argued that Gray should be considered the true inventor of the telephone because Alexander Graham Bell allegedly stole the idea of the liquid transmitter from him, although Gray had been using liquid transmitters in his telephone experiments for more than two years previously. Bell's telephone patent was upheld in numerous court decisions.

Gray is also considered to be the father of the modern music synthesizer, and was granted over 70 patents for his inventions. He was one of the founders of Graybar, purchasing a controlling interest in the company shortly after its inception.

Elliott Cresson Medal

The Elliott Cresson Medal, also known as the Elliott Cresson Gold Medal, was the highest award given by the Franklin Institute. The award was established by Elliott Cresson, life member of the Franklin Institute, with $1,000 granted in 1848. The endowed award was to be "for some discovery in the Arts and Sciences, or for the invention or improvement of some useful machine, or for some new process or combination of materials in manufactures, or for ingenuity skill or perfection in workmanship." The medal was first awarded in 1875, 21 years after Cresson's death.The Franklin Institute continued awarding the medal on an occasional basis until 1998 when they reorganized their endowed awards under one umbrella, The Benjamin Franklin Awards. A total of 268 Elliott Cresson Medals were given out during the award's lifetime.


Fax (short for facsimile), sometimes called telecopying or telefax (the latter short for telefacsimile), is the telephonic transmission of scanned printed material (both text and images), normally to a telephone number connected to a printer or other output device. The original document is scanned with a fax machine (or a telecopier), which processes the contents (text or images) as a single fixed graphic image, converting it into a bitmap, and then transmitting it through the telephone system in the form of audio-frequency tones. The receiving fax machine interprets the tones and reconstructs the image, printing a paper copy. Early systems used direct conversions of image darkness to audio tone in a continuous or analog manner. Since the 1980s, most machines modulate the transmitted audio frequencies using a digital representation of the page which is compressed to quickly transmit areas which are all-white or all-black.

Graphics tablet

A graphics tablet (also known as a digitizer, drawing tablet, drawing pad, digital drawing tablet, pen tablet, or digital art board) is a computer input device that enables a user to hand-draw images, animations and graphics, with a special pen-like stylus, similar to the way a person draws images with a pencil and paper. These tablets may also be used to capture data or handwritten signatures. It can also be used to trace an image from a piece of paper which is taped or otherwise secured to the tablet surface. Capturing data in this way, by tracing or entering the corners of linear poly-lines or shapes, is called digitizing.The device consists of a flat surface upon which the user may "draw" or trace an image using the attached stylus, a pen-like drawing apparatus. The image is displayed on the computer monitor, though some graphic tablets now also incorporate an LCD screen for a more realistic or natural experience and usability.

Some tablets are intended as a replacement for the computer mouse as the primary pointing and navigation device for desktop computers.

Henry Sutton (inventor)

Henry Sutton (4 September 1855, Ballarat, Victoria – 28 July 1912) was an Australian designer, engineer, and inventor credited with contributions to early developments in electricity, aviation, wireless communication, photography and telephony.

History of tablet computers

The history of tablet computers and the associated special operating software is an example of pen computing technology, and thus the development of tablets has deep historical roots.

The first patent for a system that recognized handwritten characters by analyzing the handwriting motion was granted in 1914.

The first publicly demonstrated system using a tablet and handwriting recognition instead of a keyboard for working with a modern digital computer dates to 1956.In addition to many academic and research systems, there were several companies with commercial products in the 1980s: Pencept, Communications Intelligence Corporation, and Linus were among the best known of a crowded field. Later, GO Corp. brought out the PenPoint OS operating system for a tablet computer product: a patent from GO corporation was the subject of an infringement lawsuit concerning the Tablet PC operating system.


The LongPen is a remote signing device conceived of by writer Margaret Atwood in 2004 and debuted in 2006. It allows a person to remotely write in ink anywhere in the world via tablet PC and the Internet and a robotic hand.

It also allows for an audio and video conversation between the endpoints, such as a fan and author, while a book is being signed.

The system was used by Conrad Black who was under arrest to "attend" a book signing event without leaving his home.

Louisiana Purchase Exposition

The Louisiana Purchase Exposition, informally known as the St. Louis World's Fair, was an international exposition held in St. Louis, Missouri, United States, from April 30 to December 1, 1904. Local, state, and federal funds totaling $15 million were used to finance the event. More than 60 countries and 43 of the 45 American states maintained exhibition spaces at the fair, which was attended by nearly 19.7 million people.

Historians generally emphasize the prominence of themes of race and empire, and the fair's long-lasting impact on intellectuals in the fields of history, art history, architecture and anthropology. From the point of view of the memory of the average person who attended the fair, it primarily promoted entertainment, consumer goods and popular culture.


In telecommunications and computer networks, multiplexing (sometimes contracted to muxing) is a method by which multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share a scarce resource. For example, in telecommunications, several telephone calls may be carried using one wire. Multiplexing originated in telegraphy in the 1870s, and is now widely applied in communications. In telephony, George Owen Squier is credited with the development of telephone carrier multiplexing in 1910.

The multiplexed signal is transmitted over a communication channel such as a cable. The multiplexing divides the capacity of the communication channel into several logical channels, one for each message signal or data stream to be transferred. A reverse process, known as demultiplexing, extracts the original channels on the receiver end.

A device that performs the multiplexing is called a multiplexer (MUX), and a device that performs the reverse process is called a demultiplexer (DEMUX or DMX).

Inverse multiplexing (IMUX) has the opposite aim as multiplexing, namely to break one data stream into several streams, transfer them simultaneously over several communication channels, and recreate the original data stream.

NPL network

The NPL Network or NPL Data Communications Network was a local area computer network operated by a team from the National Physical Laboratory in England that pioneered the concept of packet switching. Following a pilot experiment during 1967, elements of the first version of the network, Mark I, became operational during 1969 then fully operational in 1970, and the Mark II version operated from 1973 until 1986. The NPL network, followed by the wide area ARPANET in the United States, were the first two computer networks that implemented packet switching, and were interconnected in the early 1970s. The NPL network was designed and directed by Donald Davies.

Pen computing

Pen computing refers to any computer user-interface using a pen or stylus and tablet, over input devices such as a keyboard or a mouse.

Pen computing is also used to refer to the usage of mobile devices such as tablet computers, PDAs and GPS receivers. The term has been used to refer to the usage of any product allowing for mobile communication. An indication of such a device is a stylus or digital pen, generally used to press upon a graphics tablet or touchscreen, as opposed to using a more traditional interface such as a keyboard, keypad, mouse or touchpad.

Historically, pen computing (defined as a computer system employing a user-interface using a pointing device plus handwriting recognition as the primary means for interactive user input) predates the use of a mouse and graphical display by at least two decades, starting with the Stylator and RAND Tablet systems of the 1950s and early 1960s.


In control engineering a servomechanism, sometimes shortened to servo, is an automatic device that uses error-sensing negative feedback to correct the action of a mechanism. It usually includes a built-in encoder or other position feedback mechanism to ensure the output is achieving the desired effect.The term correctly applies only to systems where the feedback or error-correction signals help control mechanical position, speed or other parameters. For example, an automotive power window control is not a servomechanism, as there is no automatic feedback that controls position—the operator does this by observation. By contrast a car's cruise control uses closed-loop feedback, which classifies it as a servomechanism.

Tablet computer

A tablet computer, commonly shortened to tablet, is a mobile device, typically with a mobile operating system and touchscreen display processing circuitry, and a rechargeable battery in a single thin, flat package. Tablets, being computers, do what other personal computers do, but lack some input/output (I/O) abilities that others have. Modern tablets largely resemble modern smartphones, the only differences being that tablets are relatively larger than smartphones, with screens 7 inches (18 cm) or larger, measured diagonally, and may not support access to a cellular network.

The touchscreen display is operated by gestures executed by finger or digital pen (stylus), instead of the mouse, trackpad, and keyboard of larger computers. Portable computers can be classified according to the presence and appearance of physical keyboards. Two species of tablet, the slate and booklet, do not have physical keyboards and usually accept text and other input by use of a virtual keyboard shown on their touchscreen displays. To compensate for their lack of a physical keyboard, most tablets can connect to independent physical keyboards by wireless Bluetooth or USB; 2-in-1 PCs have keyboards, distinct from tablets.

The form of the tablet was conceptualized in the middle of the 20th century (Stanley Kubrick depicted fictional tablets in the 1968 science fiction film 2001: A Space Odyssey) and prototyped and developed in the last two decades of that century. In 2010, Apple released the iPad, the first mass-market tablet to achieve widespread popularity. Thereafter tablets rapidly rose in ubiquity and soon became a large product category used for personal, educational and workplace applications, with sales stabilizing in the mid-2010s.


The telex network was a public switched network of teleprinters similar to a telephone network, for the purposes of sending text-based messages. Telex was a major method of sending written messages electronically between businesses in the post-World War II period. Its usage went into decline as the fax machine grew in popularity in the 1980s.

The "telex" term refers to the network, not the teleprinters; point-to-point teleprinter systems had been in use long before telex exchanges were built in the 1930s. Teleprinters evolved from telegraph systems, and, like the telegraph, they used binary signals, which means that symbols were represented by the presence or absence of a pre-defined level of electric current. This is significantly different from the analog telephone system, which used varying voltages to represent sound. For this reason, telex exchanges were entirely separate from the telephone system, with their own signalling standards, exchanges and system of "telex numbers" (the counterpart of telephone numbers).

Telex provided the first common medium for international record communications using standard signalling techniques and operating criteria as specified by the International Telecommunication Union. Customers on any telex exchange could deliver messages to any other, around the world. To lower line usage, telex messages were normally first encoded onto paper tape and then read into the line as quickly as possible. The system normally delivered information at 50 baud or approximately 66 words per minute, encoded using the International Telegraph Alphabet No. 2. In the last days of the telex networks, end-user equipment was often replaced by modems and phone lines, reducing the telex network to what was effectively a directory service running on the phone network.

Voice of Russia

The Voice of Russia (Russian: Голос России, tr. Golos Rossii), commonly abbreviated VOR, was the Russian government's international radio broadcasting service from 1993 until 2014, when it was reorganised as Radio Sputnik. Its interval signal was a chime version of 'Majestic' chorus from the Great Gate of Kiev portion of Pictures at an Exhibition by Mussorgsky.

Network topology
and switching

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