![Teletype-IMG 7287](https://upload.wikimedia.org/wikipedia/commons/3/33/Teletype-IMG_7287.jpg)
The Teletype Model 33 is an
electromechanical
In engineering, electromechanics combines processes and procedures drawn from electrical engineering and mechanical engineering. Electromechanics focuses on the interaction of electrical and mechanical systems as a whole and how the two systems ...
teleprinter
A teleprinter (teletypewriter, teletype or TTY) is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. Initia ...
designed for light-duty office use. It is less rugged and cost less than earlier Teletype machines. The
Teletype Corporation
The Teletype Corporation, a part of American Telephone and Telegraph Company's Western Electric manufacturing arm since 1930, came into being in 1928 when the Morkrum-Kleinschmidt Company changed its name to the name of its trademark equipment. ...
introduced the Model 33 as a commercial product in 1963 after being originally designed for the United States Navy. There are three versions of the Model 33:
* Model 33 ASR, (Automatic Send and Receive), which has a built-in eight-hole
punched tape
Five- and eight-hole punched paper tape
Paper tape reader on the Harwell computer with a small piece of five-hole tape connected in a circle – creating a physical program loop
Punched tape or perforated paper tape is a form of data storage ...
reader and tape punch;
* Model 33 KSR (Keyboard Send and Receive), which lacks the paper tape reader and punch;
* Model 33 RO (Receive Only) which has neither a keyboard nor a reader/punch.
The Model 33 was one of the first products to employ the newly-standardized
ASCII
ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because of ...
code, which was first published in 1963. A companion Model 32 used the older, more-established five-bit
Baudot code
The Baudot code is an early character encoding for telegraphy invented by Émile Baudot in the 1870s. It was the predecessor to the International Telegraph Alphabet No. 2 (ITA2), the most common teleprinter code in use until the advent of ASCII. ...
. Because of its low price and ASCII-compatibility, the Model 33 was widely used with early
minicomputer
A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ...
s, and the large numbers of the teleprinter which were sold strongly influenced several
de facto standard
A ''de facto'' standard is a custom or convention that has achieved a dominant position by public acceptance or market forces (for example, by early entrance to the market). is a Latin phrase (literally " in fact"), here meaning "in practice b ...
s which developed during the 1960s and 1970s.
History
![Teletype Model 33 Terminal June 1974](https://upload.wikimedia.org/wikipedia/commons/f/f9/Teletype_Model_33_Terminal_June_1974.jpg)
Teletype Corporation's Model 33 terminal, introduced in 1963, was one of the most popular terminals in the data-communications industry until the late 1970s. Over a half-million Model 32s and 33s were made by 1975, and the 500,000th was plated with gold and placed on special exhibit. Another 100,000 were made in the next 18 months, and Serial Number 600,000, manufactured in the
United States Bicentennial
The United States Bicentennial was a series of celebrations and observances during the mid-1970s that paid tribute to historical events leading up to the creation of the United States of America as an independent republic. It was a central event ...
year 1976, was painted red-white-and-blue and shown around the country during the last part of that year and the year after.
The Model 33 originally cost about $1000,
much less than other teleprinters and
computer terminal
A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal and ...
s in the mid-1960s, such as the
Friden Flexowriter
The Friden Flexowriter produced by the Friden Calculating Machine Company, was a teleprinter, a heavy-duty electric typewriter capable of being driven not only by a human typing, but also automatically by several methods, including direct atta ...
and the
IBM 1050
IBM 1050 Data Communications System is a computer terminal subsystem to send data to and receive data from another 1050 subsystem or IBM computer in the IBM 1400, IBM 7000 or System/360 series. It first became available in 1963 and was used wi ...
. In 1976, a new Model 33 RO printer cost about $600.
Early video terminals, such as the
Tektronix 4010
The Tektronix 4010 series was a family of text-and-graphics computer terminals based on storage-tube technology created by Tektronix. Several members of the family were introduced during the 1970s, the best known being the 11-inch 4010 and 19-inc ...
, did not become available until 1970, and initially cost around $10,000. However, the introduction of integrated circuits and semiconductor memory later that decade allowed the price of
cathode-ray-tube-based terminals to rapidly fall below the price of a Teletype teleprinter.
"Dumb terminals", such as the low-cost
ADM-3A
The ADM-3A was an influential early video display terminal, introduced in 1976. It was manufactured by Lear Siegler and had a 12-inch screen displaying 12 or 24 lines of 80 characters. It set a new industry low single unit price of $995. Its "du ...
(1976) began to undercut the market for Teletype terminals. Such basic video terminals, which could only sequentially display lines of text and scroll them, were often called
glass teletypes
A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal an ...
("glass TTYs") analogous to the Teletype printers. More-advanced video terminals, such as the
Digital Equipment Corporation
Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president unt ...
VT100
The VT100 is a video terminal, introduced in August 1978 by Digital Equipment Corporation (DEC). It was one of the first terminals to support ANSI escape codes for cursor control and other tasks, and added a number of extended codes for special f ...
(1978), could communicate much faster than electromechanical printers, and could support use of a full-screen
text editor
A text editor is a type of computer program that edits plain text. Such programs are sometimes known as "notepad" software (e.g. Windows Notepad). Text editors are provided with operating systems and software development packages, and can be us ...
program without generating large amounts of paper printouts. Teletype machines were gradually replaced in new installations by much faster
dot-matrix printer
A dot matrix printer is an impact printer that prints using a fixed number of pins or wires. Typically the pins or wires are arranged in one or several vertical columns. The pins strike an ink-coated ribbon and force contact between the ribbon ...
s and video terminals in the middle to late 1970s.
Because of falling sales, Teletype Corporation shut down Model 33 production in 1981.
Naming conventions
While the manufacturer called the Model 33 teleprinter with a tape punch and tape reader a "Model 33 ASR", many computer users used the shorter term "ASR-33". The earliest known source for this equipment naming discrepancy comes from
Digital Equipment Corporation
Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president unt ...
(DEC) documentation, where the September 1963 PDP-4 Brochure calls the Teletype Model 28 KSR a "KSR-28" in the paragraph titled "Printer-Keyboard and Control Type 65". This naming convention was extended from the Teletype Model 28 to other Teletype equipment in later DEC documentation, consistent with DEC's practice of designating equipment using letters followed by numerals. For example, the DEC
PDP-15
The PDP-15 was the fifth and last of the 18-bit minicomputers produced by Digital Equipment Corporation. The PDP-1 was first delivered in December 1959 and the first PDP-15 was delivered in February 1970. More than 400 of these successors to th ...
price list from April 1970 lists a number of Teletype Corporation teletypewriters using this alternative naming convention. This practice was widely adopted as other computer manufacturers published their documentation. For example,
Micro Instrumentation and Telemetry Systems
Micro Instrumentation and Telemetry Systems (MITS) was an American electronics company founded in Albuquerque, New Mexico that began manufacturing electronic calculators in 1971 and personal computers in 1975.
Ed Roberts and Forrest Mims founded ...
marketed the Teletype Model 33 ASR as "Teletype ASR-33".
The
trigram
Trigrams are a special case of the ''n''-gram, where ''n'' is 3. They are often used in natural language processing for performing statistical analysis of texts and in cryptography for control and use of ciphers and codes.
Frequency
Context is ...
"" became widely used as an informal abbreviation for "Teletype", often used to designate the main text input and output device on many early computer systems. The abbreviation remains in use by
radio amateur
An amateur radio operator is someone who uses equipment at an amateur radio station to engage in two-way personal communications with other amateur operators on radio frequencies assigned to the amateur radio service. Amateur radio operators h ...
s ("ham radio") and in the hearing-impaired community, to refer to
text input and output assistive devices.
Technical information
![TTY33ASR](https://upload.wikimedia.org/wikipedia/commons/2/23/TTY33ASR.jpg)
The design objective for the Model 33 was a machine that would fit into a small office space, match with other office equipment of the time and operate up to two hours per day on average. Since this machine was designed for light duty use, adjustments that Teletype made in previous teleprinters by turning screws were made by bending metal bars and levers. Many Model 33 parts were not heat treated and hardened. The base was
die-cast metal
A die-cast toy is a toy or a collectible model produced by using the die-casting method of putting molten lead, zinc alloy or plastic in a mold to produce a particular shape. Such toys are made of metal, with plastic, rubber, glass, or other ma ...
, but self-tapping screws were used, along with parts that snapped together without bolting.
As another cost-saving measure, the optional paper tape mechanisms were dependent on the keyboard and page printer mechanisms. The interface between the paper tape reader and the rest of the terminal was completely mechanical, with power, clock, and 8 data bits (which Teletype called "intelligence") all transmitted in parallel through metal levers. Configuration of user-selectable options was done with mechanical clips that depressed or released various levers. Sensing of punched holes by the paper tape reader was done by using metal pins which mechanically probed for their presence or absence.
Earlier Teletype machine designs, such as the Model 28 ASR, had allowed the user to operate the keyboard to punch tape while independently transmitting a previously punched tape, or to punch a tape while printing something else. Independent use of the paper tape punch and reader was not possible with the Model 33 ASR.
The tape punch required
oiled paper tape to keep its mechanism lubricated. There was a transparent, removable
chad
Chad (; ar, تشاد , ; french: Tchad, ), officially the Republic of Chad, '; ) is a landlocked country at the crossroads of North and Central Africa. It is bordered by Libya to the north, Sudan to the east, the Central African Republic ...
receptacle beneath the tape punch, which required periodic emptying. The entire Model 33 ASR mechanism required periodic application of grease and oil in approximately 500 locations.
Everything was mechanically powered by a single electric motor, located at the rear of the mechanism. The motor ran continuously as long as power was on, generating a familiar humming and slight rattle from its vibration. The noise level increased considerably whenever the printing or paper tape mechanisms were operating.
Similar noises became iconic for the sounds of an active newswire or computer terminal. There was a mechanical bell, activated by code 07 (Control-G, also known as BEL), to draw special attention when needed.
The Model 33 keyboard used the seven-bit ASCII code, also known as
CCITT
The ITU Telecommunication Standardization Sector (ITU-T) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU). It is responsible for coordinating standards for telecommunications and Information Commu ...
International Telegraphic Alphabet No. 5, with one (even)
parity bit
A parity bit, or check bit, is a bit added to a string of binary code. Parity bits are a simple form of error detecting code. Parity bits are generally applied to the smallest units of a communication protocol, typically 8-bit octets (bytes) ...
and two stop bits, with a symbol rate of 110
baud
In telecommunication and electronics, baud (; symbol: Bd) is a common unit of measurement of symbol rate, which is one of the components that determine the speed of communication over a data channel.
It is the unit for symbol rate or modulatio ...
, but it only supported an
upper-case
Letter case is the distinction between the letters that are in larger uppercase or capitals (or more formally ''majuscule'') and smaller lowercase (or more formally ''minuscule'') in the written representation of certain languages. The writing ...
subset of that code; it did not support lower-case letters or the , , and characters. The paper tape reader and punch could handle 8-bit data, allowing the devices to be efficiently used to download or upload binary data for computers.
The mechanism was usually geared to run at a maximum ten characters per second speed, or 100 words per minute (wpm), but other slower speeds were available: 60 wpm, 66 wpm, 68.2 wpm, and 75 wpm. There were also many typefont options. The Teletype Parts Bulletin listed 69 available Model 33 type element options. The type element was cylindrical, with characters arranged in four tiers, 16 characters per tier, and thus was capable of printing 64 characters. The character to be printed was selected by rotating the type element clockwise or anticlockwise and raising or lowering it, then striking the element with a padded hammer, which would impact the element against the inked ribbon and paper.
The Model 33 printed on wide paper, supplied on continuous diameter rolls, and fed via friction (instead of, for example,
tractor feed
Continuous stationery (UK) or continuous form paper (US) is paper which is designed for use with dot-matrix and line printers with appropriate paper-feed mechanisms. Other names include ''fan-fold paper'', ''sprocket-feed paper'', ''burst paper'' ...
). It printed at a fixed 10 characters per inch, and supported 74-character lines, although 72 characters is often commonly stated.
The Model 33 could operate either in
half-duplex
A duplex communication system is a point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many communications networks, either to allow ...
mode, where signals from the keyboard were sent to the print mechanism, so that characters were printed as they were typed (
local echo), or in
full-duplex
A duplex communication system is a point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many communications networks, either to allow ...
mode, where keyboard signals are sent only to the transmission line, and the receiver would have to transmit the character back to the Model 33 in order for it to be printed (
remote echo
In telecommunications, echo is the local display of data, either ''initially'' as it is locally sourced and sent, or ''finally'' as a copy of it is received back from a remote destination. Local echo is where the ''local'' sending equipment display ...
). The factory setting was half-duplex, but it could be changed to full-duplex by the user.
The Teletype Model 33 contained an answer-back mechanism that was generally used in dial-up networks such as the
TWX network. At the beginning of the message, the sending machine could transmit an
enquiry character
In computer communications, enquiry is a transmission-control character that requests a response from the receiving station with which a connection has been set up. It represents a signal intended to trigger a response at the receiving end, to se ...
or WRU ("Who aRe yoU") code, and the recipient machine would automatically initiate a response, which was encoded in a rotating drum that could be preprogrammed by breaking off tabs. The answer-back drum in the recipient machine would rotate and send a unique identifying code to the sender, so that the sender could verify connection to the correct recipient. The WRU code could also be sent at the end of the message. A correct response would confirm that the connection had remained unbroken during the message transmission. To conclude the transmission, the sending machine operator would press the disconnect button.
The receiving machine could also be set up to not require operator intervention. Since messages were often sent across multiple time zones to their destination, it was common to send a message to a location where the receiving machine was operating in an office that was closed and unstaffed overnight. This also took advantage of lower telecommunication charges for non-urgent messages which were sent at off-peak times.
The Teletype Model 33, including the stand, stood high, wide and deep, not including the paper holder. The machine weighed on the stand, including paper. It required less than 4 amperes at 115 VAC 60 Hz. The recommended operating environment was a temperature of , a relative humidity of 2 to 95 percent, and an altitude of . The printing paper was an diameter roll, and the paper tape was a roll of wide tape. Nylon fabric ink ribbons were wide by long, with plastic spools and eyelets to trigger reversal of the ribbon feed direction.
File:ASR 33 three quarter interior.jpg , Paper tape punch and reader visible in foreground
File:ASR-33 backside.jpg , Rear of unit, with bell and answer back drum to left of motor
File:ASR-33 3.jpg , Fully-exposed mechanism
Communications interface
The communications module in the Model 33 was known as a Call Control Unit (CCU), and occupied the space to the right of the keyboard and printer. Various CCU types were available. Most operated on the telephone network and included the relevant user controls; variants included rotary, DTMF ("Touch-Tone"), and
card dialing. An
acoustic coupler
In telecommunications, an acoustic coupler is an interface device for coupling electrical signals by acoustical means—usually into and out of a telephone.
The link is achieved through converting electric signals from the phone line to sound a ...
for a then-standard telephone handset was also available. Another CCU type was called "Computer Control Private Line", which operated on a local
20 mA current loop, the standard serial protocol for computer terminals before the rise of
RS-232
In telecommunications, RS-232 or Recommended Standard 232 is a standard originally introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a ''DTE'' (''data terminal equipment'') such a ...
signaling. "Private Line" CCUs had a blank panel with no user controls or displays, since the terminal was semi-permanently hard-wired to the computer or other device at the far end of communications line.
Related machines
![LCM - 1960s Teletype computer printer 01](https://upload.wikimedia.org/wikipedia/commons/a/a6/LCM_-_1960s_Teletype_computer_printer_01.jpg)
The Model 32 line used the same mechanism and looked identical, except for having a three-row keyboard and, on the ASR version, a five-hole paper tape reader and punch, both appropriate for
Baudot code
The Baudot code is an early character encoding for telegraphy invented by Émile Baudot in the 1870s. It was the predecessor to the International Telegraph Alphabet No. 2 (ITA2), the most common teleprinter code in use until the advent of ASCII. ...
.
Teletype also introduced a more-expensive ASCII Model 35 (ASR-35) for heavy-duty use, whose printer mechanism was based on the older, rugged
Model 28. The basic Model 35 was mounted in a light gray console that matched the width of the Model 33, while the Model 35 ASR, with eight-hole mechanical tape punch and reader, was installed in a console about twice as wide. The tape reader was mounted separately from the printer-punch mechanism on the left side of the console, and behind it was a tray for storing a manual, sheets of paper, or other miscellanea. To the right of the keyboard was a panel that could optionally house a rotary dial or Touch-Tone pushbuttons for dialing a connection to a network via telephone lines. The printer cover in later units also featured sound-deadening materials, making the Model 35 somewhat quieter than the Model 33 while printing and punching paper tapes. All versions of the Model 35 had a copy holder on the printer cover, making it more convenient for the operator when transcribing written material.
Teletype Model 35 is mentioned as being used in "Experiment One", in the first
RFC
RFC may refer to:
Computing
* Request for Comments, a memorandum on Internet standards
* Request for change, change management
* Remote Function Call, in SAP computer systems
* Rhye's and Fall of Civilization, a modification for Sid Meier's Civ ...
, . The Model 35 was widely used as terminals for the
minicomputer
A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ...
s and
IMP
IMP or imp may refer to:
* Imp, a fantasy creature
Arts and entertainment Fictional characters
* Imp (She-Ra), a character in ''She-Ra: Princess of Power''
* Imp a character in '' Artemis Fowl: The Lost Colony''
* Imp, a character in the '' Clan ...
s to send and receive text messages over the very early
ARPANET
The Advanced Research Projects Agency Network (ARPANET) was the first wide-area packet-switched network with distributed control and one of the first networks to implement the TCP/IP protocol suite. Both technologies became the technical fou ...
, that later evolved into the Internet.
The Model 38 (ASR-38) was constructed similar to and had all the typing capabilities of a Model 33 ASR, plus additional features. A two-color inked ribbon and additional ASCII control codes allowed automatic switching between red and black output while printing. An extended keyboard and type element supported upper- and lower-case printing with some additional special characters. A wider pin-feed platen and typing mechanism allowed printing 132 columns on fan-fold paper, making its output similar to the 132-column page size of the then industry-standard
IBM 1403
The IBM 1403 line printer was introduced as part of the IBM 1401 computer in 1959 and had an especially long life in the IBM product line.
Description
The original model can print 600 lines of text per minute and can skip blank lines at up to ...
model printers.
More-expensive Teletype systems had paper tape readers that used light sensors to detect the presence or absence of punched holes in the tape. These could work at much higher speeds (hundreds of characters per second). More sophisticated punches were also available that could run at somewhat higher speeds; Teletype's DRPE punch could operate at speeds up to 240 characters per second.
Historical impact
![ASR 33](https://upload.wikimedia.org/wikipedia/commons/1/18/ASR_33.jpg)
*
ASCII
ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because of ...
was first used commercially during 1963 as a seven-bit teleprinter code for American Telephone & Telegraph's
Teletypewriter eXchange
The telex network is a station-to-station switched network of teleprinters similar to a telephone network, using telegraph-grade connecting circuits for two-way text-based messages. Telex was a major method of sending written messages electroni ...
TWX network using Teletype Model 33 teleprinters.
* The
upper-case
Letter case is the distinction between the letters that are in larger uppercase or capitals (or more formally ''majuscule'') and smaller lowercase (or more formally ''minuscule'') in the written representation of certain languages. The writing ...
-only limitation of the widely-used Teletype Model 33 constrained many early computer languages and systems to communicate in
ALL CAPS
In typography, all caps (short for "all capitals") refers to text or a font in which all letters are capital letters, for example: "THIS TEXT IS IN ALL CAPS". All caps may be used for emphasis (for a word or phrase). They are commonly seen in ...
, establishing an association of this text stylization with early computing technology in general.
* The Teletype Model 33 series was influential in the development and interpretation of ASCII code characters. In particular, the Teletype Model 33 machine assignments for codes 17 (Control-Q, DC1, also known as XON) and 19 (Control-S, DC3, also known as XOFF) became
de facto standard
A ''de facto'' standard is a custom or convention that has achieved a dominant position by public acceptance or market forces (for example, by early entrance to the market). is a Latin phrase (literally " in fact"), here meaning "in practice b ...
s.
* The programming language
BASIC
BASIC (Beginners' All-purpose Symbolic Instruction Code) is a family of general-purpose, high-level programming languages designed for ease of use. The original version was created by John G. Kemeny and Thomas E. Kurtz at Dartmouth College ...
was designed to be written and edited on a low-speed Teletype Model 33. The slow speed of the Teletype Model 33 influenced the user interface of minicomputer operating systems, including
UNIX
Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and ot ...
.
* A Teletype Model 33 provided
Bill Gates
William Henry Gates III (born October 28, 1955) is an American business magnate and philanthropist. He is a co-founder of Microsoft, along with his late childhood friend Paul Allen. During his career at Microsoft, Gates held the positions ...
' first computing experience.
* In 1965,
Stanford University
Stanford University, officially Leland Stanford Junior University, is a private research university in Stanford, California. The campus occupies , among the largest in the United States, and enrolls over 17,000 students. Stanford is consider ...
psychology professors
Patrick Suppes
Patrick Colonel Suppes (; March 17, 1922 – November 17, 2014) was an American philosopher who made significant contributions to philosophy of science, the theory of measurement, the foundations of quantum mechanics, decision theory, psychology ...
and
Richard C. Atkinson
Richard Chatham Atkinson (born March 19, 1929) is an American professor of psychology and cognitive science and an academic administrator. He is president emeritus of the University of California system, former chancellor of the University of Cali ...
, in the pilot program for
computer assisted instruction
Educational technology (commonly abbreviated as edutech, or edtech) is the combined use of computer hardware, software, and educational theory and practice to facilitate learning. When referred to with its abbreviation, edtech, it often refers ...
, experimented with using computers to provide arithmetic and spelling drills via Teletypes and
acoustic coupler
In telecommunications, an acoustic coupler is an interface device for coupling electrical signals by acoustical means—usually into and out of a telephone.
The link is achieved through converting electric signals from the phone line to sound a ...
s to elementary school students in the
Palo Alto Unified School District
The Palo Alto Unified School District is a public school district located near Stanford University in Palo Alto, California. It consists of twelve primary schools, three middle schools, two high schools, and an adult school.
History
The distric ...
in
California
California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
and elsewhere.
* In 1971,
Ray Tomlinson
Raymond Samuel Tomlinson (April 23, 1941 – March 5, 2016) was an American computer programmer who implemented the first email program on the ARPANET system, the precursor to the Internet, in 1971; It was the first system able to send mail be ...
chose the "
@" symbol on his Teletype Model 33 ASR keyboard for use in network
email
Electronic mail (email or e-mail) is a method of exchanging messages ("mail") between people using electronic devices. Email was thus conceived as the electronic ( digital) version of, or counterpart to, mail, at a time when "mail" meant ...
addresses.
The @-symbol, part 1 of 2
Shady Characters, July 2011
* The serial ports in Unix and Linux are named "/dev/tty...", which is short for "Teletype".
See also
* Teletype Model 28 The Teletype Model 28 is a product line of page printers, typing and non-typing tape perforator and tape reperforators, fixed head single contact and pivoted head multi-contact transmitter-distributors, and receiving selector equipment. Regarded as ...
Notes
References
External links
Photo of a Model 33 ASR
Keyboard layout for Windows that simulates the ASR33 keyboard
ASR 33 Teletype Information
with movies and sound
{{authority control
Computer terminals
Telegraphy