NAPLPS
Encyclopedia
NAPLPS is a graphics language for use originally with videotex
and teletext
services. NAPLPS was developed from the Telidon
system developed in Canada, with a small number of additions from AT&T
. The basics of NAPLPS were later used as the basis for several other microcomputer
based graphics systems.
(CRC), based in Ottawa
, had been working on various graphics systems since the late 1960s, much of it led by Herb Bown. Through the 1970s they turned their attention to building out a system of "picture description instructions", which encoded graphics commands as a text stream. Graphics were encoded as a series of instructions (graphics primitives) each represented by a single ASCII
character. Graphic coordinates were encoded in multiple 6 bit strings of XY coordinate data, flagged to place them in the printable ASCII range so that they could be transmitted with conventional text transmission techniques. ASCII SI/SO characters were used to differentiate the text from graphic portions of a transmitted "page". These instructions were decoded by separate programs to produce graphics output, on a plotter
for instance. Other work produced a fully interactive version. In 1975, the CRC gave a contract to Norpak to develop an interactive graphics terminal that could decode the instructions and display them on a color display.
During this period, a number of companies were developing the first teletext
systems, notably the BBC
's Ceefax
system. Ceefax encoded character data into the lines in the vertical blanking interval
of normal television
signals where they could not be seen on-screen, and then used a buffer and decoder in the user's television to convert these into "pages" of text on the display. The Independent Broadcasting Authority
quickly introduced their own ORACLE
system, and the two organizations subsequently agreed to use a single standard, the "Broadcast Teletext Specification".
At about the same time, other organizations were developing videotex
systems, similar to teletext except they used modems to transmit their data instead of television signals. This was potentially slower and used up a telephone line, but had the major advantage of allowing the user to transmit data back to the sender. England's General Post Office
developed a system using the Ceefax/ORACLE standard, launching it as Prestel
, while France prepared the first steps for its ultimately very successful Minitel
system, using a rival display standard called Antiope
.
By 1977 the Norpak system was running, and from this work the CRC decided to create their own teletext/videotext system. Unlike the systems being rolled out in Europe, the CRC decided from the start that the system should be able to run on any combination of communications links. For instance, it could use the vertical blanking interval to send data to the user, and a modem to return selections to the servers. It could be used in a one-way or two-way system.
In teletext mode, character codes were sent to users' televisions by encoding them as dot patterns in the vertical blanking interval of the video signal. Various technical "tweaks" and details of the NTSC
signals used by North American televisions allowed the downstream videotex channel to increase to 600 bit/s, about twice that used in the European systems. In videotext mode, Bell 202 modems were typical, offering a 1,200 bit/s download rate. A set top box attached to the TV decoded these signals back into text and graphic pages, which the user could select among.
The system was publicly launched as Telidon on August 15, 1978. Compared to the European standards, the CRC system was faster, bi-directional, and offered real graphics as opposed to simple character graphics. The downside of the system was that it required much more advanced decoders, typically featuring Zilog Z80
or Motorola 6809
processors with RGB and/or RF output. The Department of Communications (DOC) launched a four-year plan to fund public roll-outs of the technology in an effort to spur the development of a commercial Telidon system.
AT&T
was so impressed by Telidon that they decided to join the project. They added a number of useful extensions, notably the ability to define your own graphics commands (macro) and character sets (DRCS). They also tabled algorithms for proportionally spaced text, which greatly improved the quality of the displayed pages. A joint CSA/ANSI working group (X3L2.1) revised the specifications, which were submitted to the ANSI
board for standardization and became ANSI T500, NAPLPS. The data encoding system was also standardized as the NABTS
protocol.
Business models for Telidon services were poorly developed. Unlike the UK, where teletext was supported by one of only two large companies whose whole revenue model was based on a read-only medium (television), in North America
Telidon was being offered by companies who worked on a subscriber basis.
was tested in a few North American trials in the early 1980s — CBC
IRIS, TVOntario
, MTS
-sponsored Project IDA, to name a few.
NAPLPS was also part of the NABTS
teletext standard, for the encoding and display of teletext pages.
In the late 1980s and early 1990s, SportsChannel ran a service called Sports Plus Network
, which ran sports news and scores while SportsChannel was not otherwise on the air. The screens, which frequently featured team logos or likenesses of players in addition to text, were drawn entirely with NAPLPS graphics and resembled the loading of Prodigy
pages over a modem, though slightly faster.
's Viewtron
(based in Miami) and the Los Angeles Times
' Gateway service (based in Orange County
). Both used the Sceptre
NAPLPS terminal from AT&T. The Sceptre contained a slow modem that connected over the consumer's telephone line to host computers. The Sceptre was expensive whether purchased or rented. Despite huge investments by their parent companies, neither Viewtron nor Gateway lasted into the second half of the decade.
Other early-1980s NAPLPS technology was deployed in Canada, both as a way for rural Canadians to get news and weather information and as the platform for touchscreen information kiosks. In Vancouver
these were featured at Expo 86
. The kiosks became ubiquitous in Toronto
under the name Teleguide, and were deployed in many shopping centres and at major tourist attractions. The latter city was the North American nexus of NAPLPS and the home of Norpak
, the most successful of NAPLPS-oriented developers. Norpak created and sold hardware and software for NAPLPS development and display. TVOntario
also developed NAPLPS content creation software.
London, Ontario - based Cableshare used NAPLPS as the basis of touch-screen information kiosks for shopping malls, the flagship of which was deployed at Toronto's Eaton Centre
. The system relied on an 8085-based microcomputer which drove several NAPLPS terminals fitted with touch screens, all communicating via Datapac
to a back end database. The system offered news, weather and sports information along with shopping mall guides and coupons. Cableshare also developed and sold a leading NAPLPS page creation utility called the "Picture Painter."
In the late 1980s, Tribune Media Services
(TMS) and the Associated Press
operated a cable television channel called AP News Plus that provided NAPLPS-based news screens to cable television
subscribers in many U.S. cities. The news pages were created and edited by TMS staffers working on an Atex editing system in Orlando
, Florida
, and sent by satellite to NAPLPS decoder devices located at the local cable television companies. Among the firms providing technology to TMS and the Associated Press for the AP News Plus channel was Minneapolis-based Electronic Publishers Inc. (1985–1988).
In 1981, two amateur radio operators (VE3FTT and VE3GQW) received special permission from the Canadian Department of Communications to carry out on-air experiments using NAPLPS syntax which was technically not legal at the time because it was a "coded transmission". Following their report on the success of the tests, the DOC then permitted general use of NAPLPS on amateur radioteletype. This was reported in the ARRL Radio Handbook for several years following.
online service. Some bulletin board
s were able to serve NAPLPS content to callers on their 1200 and 2400 bit/s modem
s. But the technology's chief advantage in an era of slow telecommunication - its ability to encode complex graphics in terse object commands - became moot as data communication speeds increased and raster graphics
compression became popular.
(GKS) library
, based on a 1970s specification with a not dissimilar basic geometry and command structure to NAPLPS, was widely implemented on microcomputers, and became the basis of Digital Research
's "GSX" graphics system used in their GEM
GUI
. GKS was later extended into a 3D version, and additions to this resulted in PHIGS
(Programmer's Hierarchical Interactive Graphics System), a competitor to OpenGL
.
Videotex
Videotex was one of the earliest implementations of an "end-user information system". From the late 1970s to mid-1980s, it was used to deliver information to a user in computer-like format, typically to be displayed on a television.In a strict definition, videotex refers to systems that provide...
and teletext
Teletext
Teletext is a television information retrieval service developed in the United Kingdom in the early 1970s. It offers a range of text-based information, typically including national, international and sporting news, weather and TV schedules...
services. NAPLPS was developed from the Telidon
Telidon
Telidon was a videotex/teletext service developed by the Canadian Communications Research Centre during the late 1970s and early 1980s...
system developed in Canada, with a small number of additions from AT&T
AT&T
AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...
. The basics of NAPLPS were later used as the basis for several other microcomputer
Microcomputer
A microcomputer is a computer with a microprocessor as its central processing unit. They are physically small compared to mainframe and minicomputers...
based graphics systems.
History
The Canadian Communications Research CentreCommunications Research Centre
The Communications Research Centre Canada is a Canadian government scientific laboratory for research and development in the field of advanced telecommunications. For over 40 years, it has made significant contributions to the information and communications technology sector in Canada and abroad...
(CRC), based in Ottawa
Ottawa
Ottawa is the capital of Canada, the second largest city in the Province of Ontario, and the fourth largest city in the country. The city is located on the south bank of the Ottawa River in the eastern portion of Southern Ontario...
, had been working on various graphics systems since the late 1960s, much of it led by Herb Bown. Through the 1970s they turned their attention to building out a system of "picture description instructions", which encoded graphics commands as a text stream. Graphics were encoded as a series of instructions (graphics primitives) each represented by a single ASCII
ASCII
The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...
character. Graphic coordinates were encoded in multiple 6 bit strings of XY coordinate data, flagged to place them in the printable ASCII range so that they could be transmitted with conventional text transmission techniques. ASCII SI/SO characters were used to differentiate the text from graphic portions of a transmitted "page". These instructions were decoded by separate programs to produce graphics output, on a plotter
Plotter
A plotter is a computer printing device for printing vector graphics. In the past, plotters were widely used in applications such as computer-aided design, though they have generally been replaced with wide-format conventional printers...
for instance. Other work produced a fully interactive version. In 1975, the CRC gave a contract to Norpak to develop an interactive graphics terminal that could decode the instructions and display them on a color display.
During this period, a number of companies were developing the first teletext
Teletext
Teletext is a television information retrieval service developed in the United Kingdom in the early 1970s. It offers a range of text-based information, typically including national, international and sporting news, weather and TV schedules...
systems, notably the BBC
BBC
The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...
's Ceefax
Ceefax
Ceefax is the BBC's teletext information service transmitted via the analogue signal, started in 1974 and will run until April 2012 for Pages from Ceefax, while the actual interactive service will run until 24 October 2012, in-line with the digital switchover.-History:During the late 60s, engineer...
system. Ceefax encoded character data into the lines in the vertical blanking interval
Vertical blanking interval
The vertical blanking interval , also known as the vertical interval or VBLANK, is the time difference between the last line of one frame or field of a raster display, and the beginning of the first line of the next frame. It is present in analog television, VGA, DVI and other signals. During the...
of normal television
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...
signals where they could not be seen on-screen, and then used a buffer and decoder in the user's television to convert these into "pages" of text on the display. The Independent Broadcasting Authority
Independent Broadcasting Authority
The Independent Broadcasting Authority was the regulatory body in the United Kingdom for commercial television - and commercial/independent radio broadcasts...
quickly introduced their own ORACLE
ORACLE (teletext)
ORACLE was a commercial teletext service first broadcast on ITV in 1974 and later on Channel 4 in the United Kingdom, finally ending on both channels at 23:59 GMT on 31 December 1992....
system, and the two organizations subsequently agreed to use a single standard, the "Broadcast Teletext Specification".
At about the same time, other organizations were developing videotex
Videotex
Videotex was one of the earliest implementations of an "end-user information system". From the late 1970s to mid-1980s, it was used to deliver information to a user in computer-like format, typically to be displayed on a television.In a strict definition, videotex refers to systems that provide...
systems, similar to teletext except they used modems to transmit their data instead of television signals. This was potentially slower and used up a telephone line, but had the major advantage of allowing the user to transmit data back to the sender. England's General Post Office
General Post Office
General Post Office is the name of the British postal system from 1660 until 1969.General Post Office may also refer to:* General Post Office, Perth* General Post Office, Sydney* General Post Office, Melbourne* General Post Office, Brisbane...
developed a system using the Ceefax/ORACLE standard, launching it as Prestel
Prestel
Prestel , the brand name for the UK Post Office's Viewdata technology, was an interactive videotex system developed during the late 1970s and commercially launched in 1979...
, while France prepared the first steps for its ultimately very successful Minitel
Minitel
The Minitel is a Videotex online service accessible through the telephone lines, and is considered one of the world's most successful pre-World Wide Web online services. It was launched in France in 1982 by the PTT...
system, using a rival display standard called Antiope
Antiope (teletext)
Antiope was a French teletext standard in the 1980s. It also formed the basis for the display standard used in the French videotex service Minitel....
.
By 1977 the Norpak system was running, and from this work the CRC decided to create their own teletext/videotext system. Unlike the systems being rolled out in Europe, the CRC decided from the start that the system should be able to run on any combination of communications links. For instance, it could use the vertical blanking interval to send data to the user, and a modem to return selections to the servers. It could be used in a one-way or two-way system.
In teletext mode, character codes were sent to users' televisions by encoding them as dot patterns in the vertical blanking interval of the video signal. Various technical "tweaks" and details of the NTSC
NTSC
NTSC, named for the National Television System Committee, is the analog television system that is used in most of North America, most of South America , Burma, South Korea, Taiwan, Japan, the Philippines, and some Pacific island nations and territories .Most countries using the NTSC standard, as...
signals used by North American televisions allowed the downstream videotex channel to increase to 600 bit/s, about twice that used in the European systems. In videotext mode, Bell 202 modems were typical, offering a 1,200 bit/s download rate. A set top box attached to the TV decoded these signals back into text and graphic pages, which the user could select among.
The system was publicly launched as Telidon on August 15, 1978. Compared to the European standards, the CRC system was faster, bi-directional, and offered real graphics as opposed to simple character graphics. The downside of the system was that it required much more advanced decoders, typically featuring Zilog Z80
Zilog Z80
The Zilog Z80 is an 8-bit microprocessor designed by Zilog and sold from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes...
or Motorola 6809
Motorola 6809
The Motorola 6809 is an 8-bit microprocessor CPU from Motorola, designed by Terry Ritter and Joel Boney and introduced 1978...
processors with RGB and/or RF output. The Department of Communications (DOC) launched a four-year plan to fund public roll-outs of the technology in an effort to spur the development of a commercial Telidon system.
AT&T
AT&T
AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...
was so impressed by Telidon that they decided to join the project. They added a number of useful extensions, notably the ability to define your own graphics commands (macro) and character sets (DRCS). They also tabled algorithms for proportionally spaced text, which greatly improved the quality of the displayed pages. A joint CSA/ANSI working group (X3L2.1) revised the specifications, which were submitted to the ANSI
American National Standards Institute
The American National Standards Institute is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international...
board for standardization and became ANSI T500, NAPLPS. The data encoding system was also standardized as the NABTS
NABTS
NABTS, the North American Broadcast Teletext Specification, is a protocol used for encoding NAPLPS-encoded teletext pages, as well as other types of digital data, within the vertical blanking interval of an analog video signal...
protocol.
Business models for Telidon services were poorly developed. Unlike the UK, where teletext was supported by one of only two large companies whose whole revenue model was based on a read-only medium (television), in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
Telidon was being offered by companies who worked on a subscriber basis.
One-way systems
Telidon-based teletextTeletext
Teletext is a television information retrieval service developed in the United Kingdom in the early 1970s. It offers a range of text-based information, typically including national, international and sporting news, weather and TV schedules...
was tested in a few North American trials in the early 1980s — CBC
Canadian Broadcasting Corporation
The Canadian Broadcasting Corporation, commonly known as CBC and officially as CBC/Radio-Canada, is a Canadian crown corporation that serves as the national public radio and television broadcaster...
IRIS, TVOntario
TVOntario
TVOntario, often referred to only as TVO , is a publicly funded, educational English-language television station and media organization in the Canadian province of Ontario. It is operated by the Ontario Educational Communications Authority, a Crown corporation owned by the Government of Ontario...
, MTS
Manitoba Telecom Services
Manitoba Telecom Services Inc. , or MTS , formerly Manitoba Telephone System, is the primary telecommunications carrier in the Canadian province of Manitoba and the fourth largest telecommunications provider in Canada with 7000 employees...
-sponsored Project IDA, to name a few.
NAPLPS was also part of the NABTS
NABTS
NABTS, the North American Broadcast Teletext Specification, is a protocol used for encoding NAPLPS-encoded teletext pages, as well as other types of digital data, within the vertical blanking interval of an analog video signal...
teletext standard, for the encoding and display of teletext pages.
In the late 1980s and early 1990s, SportsChannel ran a service called Sports Plus Network
Sports Plus Network
Sports Plus Network was a service run by SportsChannel in the late 1980s and early 1990s that filled the airtime when SportsChannel was not on the air...
, which ran sports news and scores while SportsChannel was not otherwise on the air. The screens, which frequently featured team logos or likenesses of players in addition to text, were drawn entirely with NAPLPS graphics and resembled the loading of Prodigy
Prodigy (ISP)
Prodigy Communications Corporation was an online service that offered its subscribers access to a broad range of networked services, including news, weather, shopping, bulletin boards, games, polls, expert columns, banking, stocks, travel, and a variety of other features.Initially subscribers...
pages over a modem, though slightly faster.
Two-way systems
Various two-way systems using NAPLPS appeared in North America in the early 1980s. The biggest North American examples were Knight RidderKnight Ridder
Knight Ridder was an American media company, specializing in newspaper and Internet publishing. Until it was bought by The McClatchy Company on June 27, 2006, it was the second-largest newspaper publisher in the United States, with 32 daily newspapers sold.- History :The corporate ancestors of...
's Viewtron
Viewtron
Viewtron was an early online service offered by Knight-Ridder and AT&T. It started as a videotex service requiring users to have a special terminal, the AT&T Sceptre, then became a computer-based service as Commodore and other personal computers became important in the marketplace...
(based in Miami) and the Los Angeles Times
Los Angeles Times
The Los Angeles Times is a daily newspaper published in Los Angeles, California, since 1881. It was the second-largest metropolitan newspaper in circulation in the United States in 2008 and the fourth most widely distributed newspaper in the country....
' Gateway service (based in Orange County
Orange County, California
Orange County is a county in the U.S. state of California. Its county seat is Santa Ana. As of the 2010 census, its population was 3,010,232, up from 2,846,293 at the 2000 census, making it the third most populous county in California, behind Los Angeles County and San Diego County...
). Both used the Sceptre
AT&T Sceptre
The AT&T Sceptre was a graphical terminal launched by AT&T in October 1983, used for the two largest deployments of videotex in the United States: Knight Ridder's Viewtron service in Florida, and the Los Angeles Times' Gateway service in Southern California...
NAPLPS terminal from AT&T. The Sceptre contained a slow modem that connected over the consumer's telephone line to host computers. The Sceptre was expensive whether purchased or rented. Despite huge investments by their parent companies, neither Viewtron nor Gateway lasted into the second half of the decade.
Other early-1980s NAPLPS technology was deployed in Canada, both as a way for rural Canadians to get news and weather information and as the platform for touchscreen information kiosks. In Vancouver
Vancouver
Vancouver is a coastal seaport city on the mainland of British Columbia, Canada. It is the hub of Greater Vancouver, which, with over 2.3 million residents, is the third most populous metropolitan area in the country,...
these were featured at Expo 86
Expo 86
The 1986 World Exposition on Transportation and Communication, or simply Expo '86, was a World's Fair held in Vancouver, British Columbia, Canada from Friday, May 2 until Monday, October 13, 1986...
. The kiosks became ubiquitous in Toronto
Toronto
Toronto is the provincial capital of Ontario and the largest city in Canada. It is located in Southern Ontario on the northwestern shore of Lake Ontario. A relatively modern city, Toronto's history dates back to the late-18th century, when its land was first purchased by the British monarchy from...
under the name Teleguide, and were deployed in many shopping centres and at major tourist attractions. The latter city was the North American nexus of NAPLPS and the home of Norpak
Norpak
Norpak Corporation was a company headquartered in Kanata, Ontario, Canada, that specialized in the development of systems for television-based data transmission...
, the most successful of NAPLPS-oriented developers. Norpak created and sold hardware and software for NAPLPS development and display. TVOntario
TVOntario
TVOntario, often referred to only as TVO , is a publicly funded, educational English-language television station and media organization in the Canadian province of Ontario. It is operated by the Ontario Educational Communications Authority, a Crown corporation owned by the Government of Ontario...
also developed NAPLPS content creation software.
London, Ontario - based Cableshare used NAPLPS as the basis of touch-screen information kiosks for shopping malls, the flagship of which was deployed at Toronto's Eaton Centre
Eaton Centre
Eaton Centre is a name associated with shopping malls in Canada, originating with Eaton's, one of Canada's largest department store chains at the time that these malls were developed. Eaton's partnered with development companies throughout the 1970s and 1980s to develop downtown shopping malls in...
. The system relied on an 8085-based microcomputer which drove several NAPLPS terminals fitted with touch screens, all communicating via Datapac
DATAPAC
DATAPAC was Canada's packet switched X.25-equivalent data network. Operated first by Trans-Canada Telephone System, then Telecom Canada, then the Stentor Alliance, it finally reverted to Bell Canada when the Stentor Alliance was dissolved.-Use:...
to a back end database. The system offered news, weather and sports information along with shopping mall guides and coupons. Cableshare also developed and sold a leading NAPLPS page creation utility called the "Picture Painter."
In the late 1980s, Tribune Media Services
Tribune Media Services
Tribune Media Services is a syndication company owned by the Tribune Company.The company has two divisions, "News and Features" and "Entertainment Products"...
(TMS) and the Associated Press
Associated Press
The Associated Press is an American news agency. The AP is a cooperative owned by its contributing newspapers, radio and television stations in the United States, which both contribute stories to the AP and use material written by its staff journalists...
operated a cable television channel called AP News Plus that provided NAPLPS-based news screens to cable television
Cable television
Cable television is a system of providing television programs to consumers via radio frequency signals transmitted to televisions through coaxial cables or digital light pulses through fixed optical fibers located on the subscriber's property, much like the over-the-air method used in traditional...
subscribers in many U.S. cities. The news pages were created and edited by TMS staffers working on an Atex editing system in Orlando
Orlando, Florida
Orlando is a city in the central region of the U.S. state of Florida. It is the county seat of Orange County, and the center of the Greater Orlando metropolitan area. According to the 2010 US Census, the city had a population of 238,300, making Orlando the 79th largest city in the United States...
, Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, and sent by satellite to NAPLPS decoder devices located at the local cable television companies. Among the firms providing technology to TMS and the Associated Press for the AP News Plus channel was Minneapolis-based Electronic Publishers Inc. (1985–1988).
In 1981, two amateur radio operators (VE3FTT and VE3GQW) received special permission from the Canadian Department of Communications to carry out on-air experiments using NAPLPS syntax which was technically not legal at the time because it was a "coded transmission". Following their report on the success of the tests, the DOC then permitted general use of NAPLPS on amateur radioteletype. This was reported in the ARRL Radio Handbook for several years following.
Decline
NAPLPS lived on into the early 1990s as the graphical basis for the ProdigyProdigy (ISP)
Prodigy Communications Corporation was an online service that offered its subscribers access to a broad range of networked services, including news, weather, shopping, bulletin boards, games, polls, expert columns, banking, stocks, travel, and a variety of other features.Initially subscribers...
online service. Some bulletin board
Bulletin board system
A Bulletin Board System, or BBS, is a computer system running software that allows users to connect and log in to the system using a terminal program. Once logged in, a user can perform functions such as uploading and downloading software and data, reading news and bulletins, and exchanging...
s were able to serve NAPLPS content to callers on their 1200 and 2400 bit/s modem
Modem
A modem is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data...
s. But the technology's chief advantage in an era of slow telecommunication - its ability to encode complex graphics in terse object commands - became moot as data communication speeds increased and raster graphics
Raster graphics
In computer graphics, a raster graphics image, or bitmap, is a data structure representing a generally rectangular grid of pixels, or points of color, viewable via a monitor, paper, or other display medium...
compression became popular.
Legacy
In the 1980s the Graphical Kernel SystemGraphical Kernel System
The Graphical Kernel System was the first ISO standard for low-level computer graphics, introduced in 1977. GKS provides a set of drawing features for two-dimensional vector graphics suitable for charting and similar duties...
(GKS) library
Library (computer science)
In computer science, a library is a collection of resources used to develop software. These may include pre-written code and subroutines, classes, values or type specifications....
, based on a 1970s specification with a not dissimilar basic geometry and command structure to NAPLPS, was widely implemented on microcomputers, and became the basis of Digital Research
Digital Research
Digital Research, Inc. was the company created by Dr. Gary Kildall to market and develop his CP/M operating system and related products. It was the first large software company in the microcomputer world...
's "GSX" graphics system used in their GEM
Graphical Environment Manager
GEM was a windowing system created by Digital Research, Inc. for use with the CP/M operating system on the Intel 8088 and Motorola 68000 microprocessors...
GUI
Gui
Gui or guee is a generic term to refer to grilled dishes in Korean cuisine. These most commonly have meat or fish as their primary ingredient, but may in some cases also comprise grilled vegetables or other vegetarian ingredients. The term derives from the verb, "gupda" in Korean, which literally...
. GKS was later extended into a 3D version, and additions to this resulted in PHIGS
PHIGS
PHIGS is an API standard for rendering 3D computer graphics, at one time considered to be the 3D graphics standard for the 1990s. Instead a combination of features and power led to the rise of OpenGL, which became the most popular professional 3D API of the 1990s...
(Programmer's Hierarchical Interactive Graphics System), a competitor to OpenGL
OpenGL
OpenGL is a standard specification defining a cross-language, cross-platform API for writing applications that produce 2D and 3D computer graphics. The interface consists of over 250 different function calls which can be used to draw complex three-dimensional scenes from simple primitives. OpenGL...
.
External links
- NAPLPS, Michael Dillon's description of the format
- Telidon Introduction, IEEE Canada
- IEEE Canada's Telidon: Two-way TV is Here, IEEE Canada
- Canadian Journal of Communications: Interactivity and the Popular Support for Telidon
- The Telidon History Project
- ONE BBSCON 1993: NAPLPS: Universal Graphics for BBSs to the Internet, presented by Dave Hughes (August 27, 1993)
- "NAPLPS", user-created documentation of the NAPLPS standard
- "Television Broadcast Videotex", Industry Canada, BS-14 (Issue 1, Provisional), 19 June 1981 - NABTS standard