Hubbry Logo
Printing telegraphPrinting telegraphMain
Open search
Printing telegraph
Community hub
Printing telegraph
logo
8 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Printing telegraph
Printing telegraph
Printing telegraph
View on Wikipedia
from Wikipedia
A Printing Telegraph Set built by Siemens & Halske in Saint Petersburg, Russia, ca.1900

The printing telegraph was invented by Royal Earl House in 1846. House's telegraph could transmit around 40 instantly readable words per minute, but was difficult to manufacture in bulk. The printer could copy and print out up to 2,000 words per hour. This invention was first put in operation and exhibited at the Mechanics Institute in New York.[1][2]

Printing telegraph advancements

[edit]

House's Type Printing Telegraph of 1849 was Royal Earl House's second and much improved type-printing instrument and was widely used on lines on America's east coast from 1850.[3] David Hughes telegraph devices, which also had piano style keyboards, were very popular in France, where there were likely many more piano and harpsichord players than telegraphers.[4]

Early stock ticker machines are also examples of printing telegraphs.

Operation

[edit]

Input into device was facilitated through two 28-key piano-style keyboards. Each piano key represented a letter of the alphabet and when pressed, electronically transmitted that letter to a receiving printing telegraph as code. The requested letter would then be printed by that recipient telegraph.

A "shift" key allowed an alternative character to be assigned to each key, for example a digit or punctuation mark instead of a letter. A 56-character typewheel at the sending end was synchronised to run at the same speed and to maintain the same angular position as a similar wheel at the receiving end. When the key corresponding to a particular character was pressed at the home station, it actuated the typewheel at the distant station just as the same character moved into the printing position, in a way similar to the daisy wheel printer. It was thus an example of a synchronous data transmission system.

Advantages

[edit]

The benefit of the Printing Telegraph is that it allows the operator to use a piano-style keyboard to directly input the text of the message. The receiver would then receive the instantly readable text of the message on a paper strip. This is in contrast to the telegraphs that used Morse Code dots and dashes which needed to be converted into readable text.

"The Western Union Telegraph Company is now putting in a new patent telegraph printing machine on the Chicago line and hereafter dispatches transmitted over this line will be printed as they are received at the office in this city. The machine is furnished with keys similar to a piano, each key representing a letter in the alphabet, and by a peculiar mechanical arrangement each letter is printed as it is received at the office. Thus all mistakes arising from blind chirography will be thoroughly appreciated by our citizens. The machine will be put into operation this afternoon."[5]

Disadvantages

[edit]

Printing Telegraphs were quite temperamental and suffered frequent breakdowns. Transmission speed was also much slower than the Morse system.[6] The complexity of the original House device meant that production was limited. An improved version was designed by George Phelps.[7] The Globotype was invented by David McCallum as a response to problems with the printing telegraph.[8]

Key layouts

[edit]
An example of a Cyrillic key layout on a Printing Telegraph Set built by Siemens & Halske in Saint Petersburg, Russia, ca.1900

Various layouts were produced to improve the efficiency of the keyboard system and accommodate several other alphabets.[9][10][11]

See also

[edit]

References

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Printing telegraph

View on Grokipedia
from Grokipedia
A printing telegraph is an electromechanical telegraph system that transmits textual messages over electrical wires and automatically prints them in readable characters on paper at the receiving end, bypassing the manual decoding required by earlier code-based telegraphs like Morse code. Developed primarily in the mid-19th century as an advancement over recording telegraphs that marked dots and dashes on tape, the printing telegraph used keyboards for input and synchronized mechanisms, such as typewheels or printing arms, to produce direct alphanumeric output, enabling speeds of up to 40 words per minute in early models. The first practical version was patented by American inventor Royal E. House in 1846, featuring dual piano-style keyboards connected by wire, with a 56-character typewheel that printed Roman letters on paper tape using minimal electricity for synchronization via weights. House's system, operational on lines from Boston to Cincinnati by 1855, faced manufacturing challenges and patent disputes but demonstrated the feasibility of code-free transmission. Subsequent innovations built on this foundation, with British-American inventor David E. Hughes patenting an improved printing telegraph in 1855 that employed a typewriter-like synchronized rotating typewheel mechanism for character selection, allowing keyboard-operated sending and paper-strip printing at the receiver, though it suffered from frequent mechanical breakdowns. Hughes's design gained popularity in , where it was widely adopted for its plain-text output, inspiring later developments and operating reliably after refinements by 1860. In the , French Émile Baudot advanced the technology with a multiplexed system using a five-unit , enabling multiple simultaneous transmissions over a single wire and tape-based printing, which became a standard for efficient, high-volume in and influenced global data encoding. By the early 20th century, printing telegraphs had evolved into page-printing systems like the Morkrum (1910), capable of 60 words per minute with direct keyboard input, and were integral to commercial telegraph networks, particularly in the United States under , reducing labor costs and errors compared to manual Morse operation. These devices laid the groundwork for modern teleprinters and digital communications, with their keyboard-printer integration persisting in teletype systems until the rise of electronic alternatives.

History

Early Inventions

The development of printing telegraphs emerged in the mid-19th century as an advancement over earlier non-printing electric telegraph systems, such as Samuel F. B. Morse's invention from the 1830s, which transmitted messages via coded electrical signals but required manual transcription at the receiving end. One of the earliest practical printing telegraphs was invented by American Royal Earl House, who first demonstrated a working model in 1844 at the Mechanics Institute in New York. House received U.S. Patent No. 4,464 on April 18, 1846, for his "Improvement in Magnetic Printing-Telegraphs," which enabled direct composition and printing of messages in Roman characters without codes. The system featured two synchronized 28-key piano-style keyboards connected by telegraph wire, each linked to a 56-character typewheel driven by clockwork weights and powered by galvanic batteries. At the sender, pressing a key advanced the typewheel to the selected character and sent a signal; the receiver's identical mechanism synchronized to print the character onto a continuous paper tape using an inked ribbon, achieving speeds of approximately 40 words per minute or up to 2,000 words per hour. In 1855, Anglo-American inventor introduced an improved printing telegraph, patented in Britain (No. 2085) and later in the United States (No. 14,917 in 1856), which further refined direct character transmission. Hughes' design incorporated a compact piano-like keyboard with 26 keys for alphabetic characters and basic , arranged in a musical scale layout to leverage his background as a and educator. The system employed a continuously spinning typewheel with raised characters that rotated via , while electromagnetic solenoids actuated a printing arm to ink and impress the selected letter onto paper tape upon receiving the corresponding electrical pulse from the sender. This allowed for straightforward operation without intermediate decoding, with the sender and receiver units operating in unison through precise timing mechanisms. Despite their innovations, these early printing telegraphs faced significant challenges, including high mechanical complexity from numerous synchronized like typewheels and clockworks, which made , , and reliable operation difficult. Limited transmission speeds—typically capped below 50 due to demands and electrical signal delays—further hindered practicality, often leading to frequent breakdowns and the need for skilled operators to realign mechanisms.

19th-Century Developments

The commercialization of printing telegraphs accelerated in the mid-19th century, with pioneering widespread installations in the United States during the 1850s. In 1851, the company, then known as the New York and Valley Printing Telegraph Company, acquired rights to Royal E. House's printing telegraph system and began extending lines across the country, enabling automated message printing on paper slips for faster processing in commercial networks. In , introduced printing models based on Morse and Hughes designs, such as ink-printing Morse receivers from the 1850s onward, which were deployed in extensive state networks like Russia's 10,000 km system by 1855, supporting high-speed commercial traffic including stock exchange data. These early adoptions highlighted the scalability of printing telegraphs for integrating with existing wire networks, reducing manual transcription errors and boosting throughput in financial and governmental communications. George M. Phelps made significant contributions to printing telegraph refinement from the 1860s through the 1880s, focusing on tape-based systems and stock tickers for financial applications. His 1859 Combination Printer (U.S. 26,003), a tape printer synthesizing elements of and Hughes designs, featured a 28-key piano-like keyboard, electromagnetic , and speeds up to 60 words per minute, powering major East Coast circuits for nearly two decades and transmitting up to 670 messages in 8.5 hours on high-traffic lines. In the 1870s, Phelps enhanced stock tickers with efficient resynchronization mechanisms and electro-motors (U.S. 161,151, 1875), enabling reliable, simultaneous distribution of to hundreds of offices, which facilitated Western Union's 1871 merger with the Gold and Stock Company and set standards for automated financial telegraphy. Thomas Edison advanced multiplexing with his quadruplex printing telegraph, developed between 1873 and 1877, which allowed four simultaneous signals over a single wire to enhance network capacity. The system combined duplex (bidirectional) and diplex (unidirectional) transmission, using polarity reversal via polarized relays for one pair of signals and timing variations in current strength for the other, with a "bug trap" local relay to correct distortions from line interference. Integrated with chemical recording on sensitized paper for visible traces of signals, it supported printing outputs and was patented as U.S. Patent 420,594 (filed 1877), enabling to quadruple message volumes without additional wires and reducing operational costs significantly. Émile Baudot's 1874 synchronous printing telegraph marked a breakthrough in European multiplexing, employing a 5-bit code for efficient channel sharing. Patented in France as No. 103,898 on June 17, 1874 ("Système de Télégraphie Rapide"), the system used uniform on/off intervals to encode 31 combinations (two for case-shifting), supporting the Roman alphabet, numbers, and punctuation via a keyboard interface. A rotating distributor mechanism with brushes and arms synchronized up to six channels through time-division multiplexing over one circuit, typically operating four keyboards at 30 words per minute per channel; receivers printed on tape using electromagnets inspired by Hughes. Adopted in French telegraphy after 1875 tests over 550 km, it went operational in 1877, transmitting a 360-word message in under three minutes, and expanded nationwide by 1880, influencing scalable integrations across telegraph networks.

Technical Principles

Core Mechanisms

The core mechanisms of printing telegraphs revolve around electromechanical systems that convert electrical signals into printed text on paper, primarily through selective actuation of printing elements. These systems typically employ electromagnetic solenoids to control the selection and impression of characters, ensuring precise alignment between transmitted signals and the physical output. A brief example from early designs, such as Royal E. House's synchronous typewheel mechanism, illustrates how a typewheel with 56 characters was electromagnetically controlled via an to align and print selected letters on a moving paper strip. Early designs like House's were synchronous without coding, relying on timed circuit control for typewheel alignment, while later systems introduced coded selection. In wheel-based systems, a type wheel engraved with letters on its rim is incrementally rotated by -driven pawls or shifters until the appropriate type aligns with the printing point; once positioned, a printing or spring-loaded arm presses the wheel against an inked or directly onto the , imprinting the character. pairs often provide bidirectional control for fine adjustments, with one advancing the wheel and the other retracting it to prevent over-rotation. In typebar variants, multiple independently actuate individual bars from a basket-like assembly, similar to mechanisms, where each selectively releases a bar to strike the via a linkage system. The printing hammer or platen then applies uniform pressure, typically at speeds synchronized to the signal rate, to produce clear impressions without smudging. Paper handling mechanisms ensure continuous and controlled advancement of the medium during . Continuous tape or strips are fed through the printer via motor-driven or escapement-controlled rollers, where a feed roll pulls the forward after each character impression to position it for the next print. Tension is maintained by a secondary tension roll or spring-loaded guide to prevent slack or jamming, while inking occurs either through direct contact with a rotating inked type or via an interposed mechanism that transfers under pressure. For page-style printers, additional carriage-return and line-feed solenoids advance the vertically and shift laterally, though tape systems predominate for their simplicity in high-volume transmission. These components operate under consistent mechanical tension to accommodate varying thicknesses and speeds up to several characters per second. Synchronization between transmitter and receiver is critical to align the printing elements with incoming signals, achieved primarily through start-stop protocols or motor-driven timing. In start-stop systems, a starting initializes the receiver's selector mechanism, followed by timed signal elements, and a stop halts the cycle, allowing the device to reset and idle until the next character begins; this asynchronous method uses the signal itself for timing, avoiding the need for precise clock matching over long distances. Synchronous variants employ constant-speed motors or weight-driven clockworks with governors to maintain uniform rotation of the type wheel or tape feed, ensuring the receiver's position matches the sender's without per-character restarts. These approaches mitigate drift from line noise or mechanical wear, with start-stop proving more robust for asynchronous networks. Power sources for printing telegraphs rely on stable to drive and motors without distorting signals. Local batteries, often Daniell or gravity cells providing 12-60 volts, supply the primary current for electromagnets and local circuits, ensuring consistent polarity and voltage to prevent erratic actuation. Dynamos or generators generate this power at central stations, charging batteries or directly feeding lines via commutators to maintain uniform output despite varying loads; early systems avoided due to its incompatibility with sensitive responses. was essential, as fluctuations could weaken impressions or cause misalignment. Basic circuit concepts in printing telegraphs utilize simple series configurations to transmit and interpret pulses reliably. A typical setup includes a battery, key or distributor at the sender, a single line wire, and receiver solenoids in series, where closure completes the circuit to send a "mark" pulse (current flow), and opening creates a "" (no current); these pulses sequentially energize selector magnets to position the type mechanism. Ground return completes the loop, minimizing wiring while polarizing relays to distinguish signal states; no complex is involved in the core path, keeping the design straightforward for long-distance reliability.

Signal Processing

In printing telegraphs, begins with encoding schemes that convert textual input into electrical impulses suitable for transmission over telegraph lines. The foundational encoding system was developed by in 1874 as part of his multiplex printing telegraph, utilizing a 5-unit code that generates 32 unique combinations (2^5) from binary-like pulses, sufficient to represent the Latin alphabet and basic numerals or symbols. This code employs a locking shift mechanism to double the effective character set: the letters shift (LTRS, binary 11111) selects alphabetic mode for lowercase letters, while the figures shift (FIGS, binary 11011) switches to numerals and , with the mode persisting until the next shift code is received. For example, the pulse sequence 00001 represents 'E' in LTRS mode but '3' in FIGS mode, enabling efficient use of limited combinations without dedicated codes for each variant. Variations on Baudot's code emerged to address practical limitations in printing systems. Donald Murray refined the scheme starting in , introducing a 5-unit optimized for punched tape stability and letter frequency, where common characters like E, T, and A required fewer perforations to minimize mechanical wear. Murray's version, often called the Baudot-Murray , maintained the 32-combination structure but rearranged assignments—letters followed an frequency order, while numerals aligned with keyboard positions—and formalized shift functions for two cases (letters and figures). This evolved into the International Telegraph Alphabet No. 2 (ITA2) standard in 1930, widely adopted in teleprinters for its compatibility with start-stop synchronization and inclusion of control characters like (binary 11010 in FIGS). Transmission of these encoded signals relied on pulse-duration modulation via on-off keying, where each 5-unit character consists of five equal-duration electrical —marking (current on) or spacing (current off)—sent sequentially at a fixed rate, typically 50-100 units per second for early systems. The sender's keyer or perforator generates these , with a start pulse initiating the sequence to synchronize the receiver, ensuring uniform timing despite line noise. In multiplex setups, allocates across multiple channels using rotating distributor wheels, which sequentially connect several transmitters to a single line, allowing up to six simultaneous conversations by dividing the signal stream into brief time slots. These wheels, driven by synchronous motors or weights, ensure precise allocation, with corrective maintaining alignment between distant stations. At the receiver, decoding occurs through a step-by-step selector mechanism that interprets incoming to position a typewheel or print head. Each actuates electromagnets or relays in sequence, stepping a selector arm across contacts corresponding to the 32 code combinations; for instance, a marking on the first unit advances the arm to one of positions, with subsequent narrowing the selection until the fifth identifies the exact character. Shift functions integrate seamlessly: upon receiving LTRS or FIGS, the selector latches a mode register, altering the mapping of subsequent codes from alphabetic to numeric/symbolic until toggled. This electromechanical interpretation culminates in mechanical printing, but the core logic ensures fidelity translates directly to character selection. Error handling in printing telegraph systems emphasized detection and recovery to maintain message integrity over noisy lines. Idle signals, such as all-spaces or all-marks sequences, were inserted between characters or blocks to pad transmissions and prevent synchronization loss during pauses, particularly in automatic repeat request (ARQ) modes where mutilated blocks trigger repetition. Retransmission protocols involved tracers—appended codes counting selecting elements per word—to verify reception; discrepancies activated error indicators, prompting manual or automatic resends without full message loss. Early Baudot systems relied primarily on operator-monitored idle signals for basic fault isolation.

Designs and Layouts

Keyboard-Based Systems

Keyboard-based systems in printing telegraphs emerged as a direct evolution from earlier manual signaling devices, prioritizing intuitive text input through mechanical keyboards that mirrored piano layouts for familiarity. The seminal design was David Edward Hughes' 1856 printing telegraph, which featured a 26-key piano-style keyboard dedicated to the alphabet and select punctuation marks, allowing operators to transmit characters via individual electrical pulses to a synchronized receiver that printed on paper tape. This arrangement marked a shift toward alphanumeric input, influencing subsequent models by demonstrating the feasibility of keyboard-driven telegraphy over long distances. By the 1880s, keyboard layouts had progressed toward fuller typewriter-inspired configurations to accommodate expanded character sets with features like for numerals and symbols. These designs retained core alphabetic keys while adding dedicated functions such as a figures shift key for numerals and symbols, alongside control characters like to advance the print mechanism and space for formatting. The figures shift enabled toggling between letter and numeric modes on shared keys, optimizing limited space in compact commercial units, while keys triggered mechanical resets at the receiver to align text lines. Input mechanics relied on spring-loaded keys that, when depressed, closed an electrical circuit to generate a precise corresponding to the selected character, ensuring reliable transmission without manual coding. Early implementations, such as Hughes', used simple mechanical in the key assembly to minimize signal chatter from contact bounce, though later models incorporated basic electrical filtering for cleaner pulses in noisy lines. Operators synchronized their key presses with the system's clockwork-driven receiver, which briefly referenced synchronous operation to align wheels but focused primarily on manual input timing. Effective use demanded specialized operator , emphasizing touch-typing proficiency to match transmission rates; commercial deployments required speeds of up to 60 , achieved through rigorous practice on keyboard simulators that simulated timing and correction. Initial for Hughes-style systems targeted 30 for basic proficiency, with advanced commercial operators honing over weeks to handle sustained bursts without disrupting synchronization. A prominent example was George M. Phelps' 1870s keyboard telegraph, optimized for stock quote dissemination on lines like those of the Gold and Stock Telegraph Company. This model employed a 28-key piano-like layout, with dedicated keys for letters, a dot for decimals in prices, and a , enabling rapid entry of numerical data that printed sequentially on tape at multiple receiving stations. This linear arrangement contrasted with piano-style keyboards, prioritizing rapid numerical input for financial applications. Phelps' design, patented in 1869, streamlined the keyboard for financial urgency, positioning keys in a linear array for thumb-operated spacing and featuring ivory-tipped levers for ergonomic repetition during market volatility.

Typewheel and Synchronous Variants

Typewheel printing telegraphs employed a rotating disk, or typewheel, embedded with raised characters around its periphery, which was driven by a motor and positioned precisely through electrical pulses to imprint text onto paper tape or sheets at the receiving end. In the Hughes system, developed by David E. Hughes in the 1850s, the transmitter featured a character wheel synchronized with the receiver's printing wheel; pressing a key on a piano-style keyboard sent a timed electrical pulse that activated a hammer to strike inked paper against the appropriate raised type on the wheel, producing characters at speeds up to 30 words per minute. Similarly, Émile Baudot's printing telegraph, patented in 1874, utilized a typewheel receiver that interpreted five-unit code signals to select and print characters on paper tape, marking an early adoption of relief-type wheels for automated output. Synchronous variants relied on shared clock mechanisms, such as or geared motors with governors, to maintain alignment between the sender's and receiver's typewheels, ensuring continuous rotation without start-stop interruptions. This allowed for efficient , as no idle periods were needed between characters, though mechanical slip or correcting devices—such as adjustable or electromagnetic resets—were incorporated to realign wheels if drift occurred due to variations in motor speed or line disturbances. In Baudot's -based system, a central rotating synchronized multiple transmitters and receivers over a single line, using the typewheel to print multiplexed messages directly onto tape while preserving timing across stations. Tape-based variants integrated perforated paper tape readers to automate input, feeding pre-punched codes into the for hands-free transmission and reception via typewheel printers, serving as precursors to later machines. Subsequent developments in Baudot's system during the introduced paper tape mechanisms, where the read perforations to generate electrical pulses, driving the typewheel printer at the receiver to produce output without manual keying, a design that influenced Frederick G. Creed's early 1890s punched-tape systems for automated Morse and later printing telegraphs. These tape readers enabled reliable, error-checked input by mechanically advancing the tape in sync with the typewheel's rotation. The primary advantage of typewheel and synchronous designs lay in their support for , where pre-punched tapes allowed high-volume, unattended transmission of messages, such as dispatches over long distances, reducing operator fatigue and enabling speeds suitable for wire services. For instance, Baudot's distributor-typewheel printer, refined through the , featured a 20-character typewheel optimized for European alphabets, facilitating multiplexed feeds across shared lines at rates exceeding manual Morse systems.

Advantages and Limitations

Operational Benefits

The printing telegraph offered significant improvements in readability and permanence compared to manual Morse code systems, which relied on handwritten transcripts prone to illegibility and loss over time. By automatically producing printed output in clear Roman characters on paper tape or sheets, it generated durable, archivable records that could be easily reviewed, stored, or redistributed without degradation. This feature proved invaluable for applications requiring precise documentation, such as legal dispatches or operational logs. Transmission speeds with printing telegraphs typically ranged from 40 to 60 , surpassing the 25-35 achievable by skilled Morse operators and thereby alleviating operator fatigue during prolonged sessions. Systems like the Morkrum printing telegraph enabled operators to input text via a keyboard at natural speeds, with the receiving end printing synchronously for immediate output, which streamlined workflows in high-demand environments. Error reduction was another key advantage, as standardized Baudot or similar codes minimized transcription mistakes inherent in manual Morse interpretation, where operators had to decode and rewrite messages. Perforated tape mechanisms allowed senders to inspect and correct errors before transmission, preventing delays from retransmissions; this reliability was particularly beneficial in time-sensitive sectors like financial stock quotations, where inaccuracies could lead to significant losses, and news agencies, which required verbatim accuracy for rapid reporting. Scalability was enhanced through techniques, permitting multiple simultaneous messages on a single line—such as the Multiplex system's four channels operating at up to 200 words per minute total, compared to 80 words per minute for non-multiplexed Morse. This capacity expansion supported growing network demands without proportional infrastructure increases. Economically, printing telegraphs lowered long-term operational costs for high-volume users by reducing the need for multiple skilled operators and minimizing error-related retransmissions. Railroads benefited from efficient train order transmissions that improved scheduling and safety, while press agencies like the achieved faster, more cost-effective news dissemination across vast distances.

Technical Drawbacks

Printing telegraphs suffered from significant mechanical fragility, as their intricate components, including typewheels and solenoids, were prone to wear and frequent jams that necessitated ongoing maintenance. Early designs, such as Hughes's printing telegraph, featured lightweight machinery driven by weights that constantly broke down due to the stresses of operation, requiring repeated adjustments and repairs to maintain functionality. In more advanced systems like the Baudot distributor, the delicate governors used for speed control demanded expert handling and patience, often leading to mechanical failures from even minor misalignments in mechanisms. Overall, these electromechanical printers were described as extremely delicate and overly complicated, contributing to high maintenance costs and operational unreliability in practical use. Synchronization issues further compounded reliability problems, particularly in asynchronous systems where clock drift caused character misalignment and gibberish output on receiving ends. In the Baudot system, distributors frequently lost unison despite corrective mechanisms, resulting in elevated failure rates over long-distance lines due to cumulative timing errors. Maintaining precise "in-step" operation between sender and receiver was critical, yet any deviation led to improper signal sequencing and printing errors, especially in extended transmissions. These challenges were exacerbated in systems like the Hughes printing telegraph, which were notably susceptible to synchronization breakdowns alongside general mechanical failures. Power dependency posed another limitation, with devices highly sensitive to voltage fluctuations that could produce faint prints or entirely missed signals. Operating on low-voltage DC supplies, such as 12 volts from local batteries or line power, printing telegraphs like the Morkrum Teletype were vulnerable to variations in supply, which disrupted solenoid actuation and printing consistency. In shared or long circuits, inconsistent power delivery often amplified these issues, leading to incomplete character impressions or dropped impulses during transmission. The size and cost of printing telegraph equipment also hindered widespread adoption and portability. Early models were notably bulky, with page printers requiring substantial space for moving paper feeds and printing elements; for instance, military-grade teletype keyboards weighed around 59 pounds and measured 8.5 by 15.75 by 17.4 inches, making them impractical for mobile use. High initial setup expenses further limited deployment, as systems like pneumatic printers demanded costly installations and ongoing operational outlays, restricting their use primarily to fixed, high-volume applications. Noise and electromagnetic interference added to operational challenges, particularly in shared line environments where susceptibility to external disturbances increased error rates. Grounded circuits in telegraph networks produced interference such as screeches, squawks, and other uncanny noises, often from proximity to adjacent wires, which degraded signal clarity and exacerbated printing inaccuracies. Systems like the Rowland multiplex were particularly affected, with high-frequency operations causing and disturbances on nearby lines, ultimately leading to their abandonment in favor of less interference-prone designs.

Advancements and Legacy

20th-Century Evolutions

The Morkrum Company's pioneering efforts culminated in 1910 with the first commercial installation of a reliable start-stop printing telegraph system on Postal Telegraph Company lines between New York and . This setup employed a 5-unit , enabling asynchronous operation without continuous , which addressed key reliability issues in earlier synchronous designs. The system's success demonstrated practical viability for high-speed, error-resistant message transmission over long distances. Advancements accelerated in the when introduced its Teletype system in 1924, featuring the Model 14 as a robust typebar tape printer operating at 60 words per minute. This model emphasized mechanical simplicity and durability, facilitating installation in remote telegraph offices and supporting efficient business messaging through perforated tape handling. Its widespread adoption transformed commercial communications, integrating seamlessly with emerging telephone networks for faster document exchange. International standardization emerged in 1932 with the CCITT's adoption of the International Telegraph Alphabet No. 2 (ITA2), a 5-bit code that refined earlier variants like Baudot and Murray schemes to include shift mechanisms for expanded character sets. As a precursor to 7-bit ASCII, ITA2 ensured interoperability across global telegraph networks, promoting consistent encoding for letters, figures, and symbols in printing telegraph operations. During , printing telegraphs saw extensive military deployment for secure communications, often augmented with encryption devices like the to protect high-level teletype traffic. These systems enabled rapid, encrypted transmission of tactical orders and intelligence across theaters, with add-on cipher attachments converting to inline. The U.S. Army and relied on such integrations for reliable field operations, underscoring the technology's adaptability to wartime demands. By the 1960s, printing telegraphs faced decline due to the rise of machines and early computers, which offered superior versatility for image and data transmission without mechanical printing limitations. Teletype services like TWX were phased out as digital alternatives proliferated, yet the technology persisted in specialized sectors such as for flight coordination, with general services discontinued in the United States by in 2008; use in rail for signaling largely ended by the 1980s, though aviation applications continue as of 2025.

Impact on Later Technologies

The printing telegraph's keyboard mechanisms directly inspired the development of typewriter layouts, particularly the arrangement adopted by Remington typewriters starting in the 1870s. Early printing telegraphs, such as those patented around 1848, featured piano-style keyboards that influenced ' typewriter designs, which prioritized efficient transcription for telegraph operators handling messages. This layout grouped frequently used letters and those with similar patterns—such as S, E, and Z—on the home row to enable rapid typing speeds exceeding 30 words per minute, a necessity for operators in telegraph offices. Remington's adoption of in its No. 2 model from 1878 onward standardized it across commercial typewriters, evolving from alphabetical arrangements in earlier prototypes like the 1874 Sholes & Glidden machine. The , a five-bit developed for telegraphs in the , served as a foundational precursor to modern digital encoding standards, including ASCII established in 1963. This fixed-length code enabled synchronized character transmission over telegraph lines, paving the way for efficient data handling in subsequent systems by representing the Roman alphabet, punctuation, and controls in equal on-off intervals. ASCII expanded on Baudot's principles, incorporating seven or eight bits to support a broader character set while retaining the serial, asynchronous transmission model refined in printing telegraphy. Additionally, Baudot code underpinned early protocols, as seen in 1960s acoustic couplers that transmitted five-bit Baudot signals at 110 baud over telephone lines, influencing the design of data modems for computer networking. Printing telegraphs evolved into the global network, which reached its peak in the 1970s with over 345,000 subscribers in the United States alone, facilitating international via dedicated exchanges. This system bridged analog to digital communication by standardizing error-checked, point-to-point messaging over switched telephone networks, a model that directly informed the asynchronous protocols of emerging systems in the late 1970s. 's text-based format and store-and-forward capabilities also prefigured technology, which supplanted it in the by adding image transmission while retaining serial data principles from roots. In , printing telegraph derivatives like the became integral as early terminals, interfacing with minicomputers such as the PDP-8 in the through asynchronous serial connections. The Model 33's eight-bit ASCII support and electromechanical printing allowed it to serve as a console for programming and output, enabling direct human-machine interaction in systems like the PDP-8 where it handled input via keyboard and paper tape. This integration marked a shift from to interactive , with teleprinters providing reliable, low-speed interfaces that influenced terminal designs for larger mainframes. The legacy of printing telegraphs extends to the standardization of error-corrected serial communication in modern protocols, particularly UARTs used in embedded systems and peripherals today. Early printing telegraph systems introduced parity-like checks and start-stop bits to detect transmission errors over noisy lines, principles carried forward into UART designs that append parity bits for single-bit error detection in asynchronous data streams. These mechanisms, refined from teletype error detection patents in the 1930s, ensure robust serial links in UART-based protocols, underpinning USB, , and standards with the idle-high signaling and framing inherited from 19th-century .

References

  1. https://www.historyofinformation.com/detail.php?id=5483
  2. https://eh.net/encyclopedia/history-of-the-u-s-telegraph-industry/
  3. https://www.historyofinformation.com/detail.php?id=481
  4. https://www.sparkmuseum.org/portfolio-item/hughes-telegraph/
  5. https://collection.sciencemuseumgroup.org.uk/objects/co32952/hughes-printing-telegraph-1860
  6. https://www.smithsonianmag.com/smart-news/roots-computer-code-lie-telegraph-code-180964782/
  7. https://interestingengineering.com/engineers-directory/jean-maurice-emile-baudot
  8. https://patents.google.com/patent/US4464A/en
  9. http://www.telegraphkeys.com/pages/hughes.html
  10. https://dspace.allegheny.edu/bitstreams/84f4d031-b3ce-4baa-be07-cac68cbb505b/download
  11. https://www.telegraphy.eu/pagina/artikels/WERNER%20SIEMENS%20AND%20HIS%20CONTRIBUTIONS%20IN%20THE%20FIELD%20OF%20TELEGRAPHY.pdf
  12. https://www.scientificamerican.com/article/siemens-halske-printing-telegraph-or-telecryptograph/
  13. http://www.telegraph-history.org/george-m-phelps/
  14. https://edison.rutgers.edu/life-of-edison/inventions?catid=91&id=538:quadruplex-telegraph&view=article
  15. https://www.telegraphy.eu/pagina/artikels/BAUDOT%20def%2027%20mei%202019%20--geconverteerd-1.pdf
  16. https://jonroma.net/media/signaling/railway-signaling/1921/The%20Development%20of%20the%20Printing%20Telegraph.pdf
  17. https://patents.google.com/patent/US862402A/en
  18. https://patents.google.com/patent/US1564422A/en
  19. https://www.gutenberg.org/files/53481/53481-h/53481-h.htm
  20. https://www.cryptomuseum.com/telex/files/creed_basic_tty.pdf
  21. https://edison.rutgers.edu/images/patents/00103924.PDF
  22. https://deramp.com/downloads/teletype/Model%2015/Teletype%20Baudot%20Codes.pdf
  23. https://ia601805.us.archive.org/24/items/enf-ascii/ascii.pdf
  24. https://www.circuitousroot.com/artifice/telegraphy/tty/codes/
  25. https://www.britishtelephones.com/edpamphlets/telegraphy_1_1_iss3.pdf
  26. http://www.samhallas.co.uk/telhist1/telehist2.htm
  27. https://patents.google.com/patent/US1606937A/en
  28. https://patents.google.com/patent/US2658942A/en
  29. https://patents.google.com/patent/US1972326
  30. https://repository.kulib.kyoto-u.ac.jp/dspace/bitstream/2433/139379/1/42_161.pdf
  31. https://archive.org/download/crossref-pre-1923-scholarly-works/10.1109%25252Ft-aiee.1919.4765657.zip/10.1109%25252Ft-aiee.1920.4764961.pdf
  32. https://www.prc68.com/I/StkTckPat.shtml
  33. https://www.rtty.com/England/creed2.html
  34. https://upload.wikimedia.org/wikipedia/commons/5/54/History%2C_theory%2C_and_practice_of_the_electric_telegraph_%28IA_cu31924031307196%29.pdf
  35. http://www.samhallas.co.uk/repository/telegraph/teletype_story.pdf
  36. https://www.navy-radio.com/tty.htm
  37. https://archaeologycolorado.org/sites/default/files/Birndorf_and_Ingram_2020_Tangled_Transmissions.pdf
  38. https://www.britishtelephones.com/cto/documents/gp05_short_history_of_the_telegraph.pdf
  39. https://www.rtty.com/history/krum.htm
  40. http://simson.net/ref/2001/house-teletype-corp-synopsis.pdf
  41. https://landley.net/history/mirror/pre/nelson.htm
  42. https://www.nsa.gov/portals/75/documents/about/cryptologic-heritage/historical-figures-publications/publications/technology/The_SIGABA_ECM_Cipher_Machine_A_Beautiful_Idea3.pdf
  43. https://www.smecc.org/military_teleprinters.htm
  44. https://theunis-asc.com/en/teletype-messaging/
  45. https://www.britannica.com/technology/telex
  46. https://hackaday.com/2016/03/15/the-origin-of-qwerty/
  47. https://wi101.wisc.edu/qwerty-keyboard-and-morse-code/
  48. https://www.computerhistory.org/revolution/networking/19/371
  49. https://vulcanhammer.info/2017/07/14/a-few-words-about-the-telex/
  50. https://homepage.divms.uiowa.edu/~jones/pdp8/man/tty.html
  51. http://ibiblio.org/kuphaldt/socratic/model/mod_serialcomm.pdf
  52. https://hackaday.com/2016/06/28/serially-are-you-syncing-or-asyncing/
Add your contribution
Related Hubs
User Avatar
No comments yet.