History of videotelephony
the history of video telephony covers the historical development of several technologies which enable the use of live video in addition to voice telecommunications the concept of video telephony was first popularized in the late 1870s in both the united states and europe although the basic sciences to permit its very earliest trials would take nearly a half century to be discovered this was first embodied in the device which came to be known as the video telephone or videophone and it evolved from intensive research and experimentation in several telecommunication fields notably electrical telegraphy telephony radio and television the development of the crucial video technology first started in the latter half of the 1920s in the united kingdom and the united states spurred notably by john logie baird and at t's bell labs this occurred in part at least with at t to serve as an adjunct supplementing the use of the telephone a number of organizations believed that video telephony would be superior to plain voice communications however video technology was to be deployed in analog television broadcasting long before it could become practical or popular for video phones video telephony developed in parallel with conventional voice telephone systems from the mid to late 20th century very expensive video conferencing systems rapidly evolved throughout the 1980s and 1990s from proprietary equipment software and network requirements to standards-based technologies that were readily available to the general public at a reasonable cost only in the late 20th century with the advent of powerful video codecs combined with high-speed internet broadband and isdn service did video telephony become a practical technology for regular use with the rapid improvements and popularity of the internet video telephony has become widespread through the deployment of video-enabled mobile phones plus video conferencing and computer webcams which utilize internet telephony in the upper echelons of government business and commerce telepresence technology an advanced form of video conferencing has helped reduce the need to travel early history barely two years after the telephone was first patented in the united states in 1876 by dr alexander graham bell an early concept of a combined videophone and widescreen television called a telephonoscope was conceptualized in the popular periodicals of the day it was also mentioned in various early science fiction works such as la vintai me siekel la vie electrique and other works written by albert robita and was also sketched in various cartoons by george du maurier as a fictional invention of thomas edison one such sketch was published on december 9 1878 in punch magazine the term teleco was also used in 1878 by french writer and publisher luis figuer to popularize an invention wrongly interpreted as real and incorrectly ascribed to dr bell possibly after his volta laboratory discreetly deposited a sealed container of a graphophone phonograph at the smithsonian institution for safekeeping written under the pseudonym electrician one article earlier claimed that an eminent scientist had invented a device whereby objects or people anywhere in the world could be seen anywhere by anybody the device among other functions would allow merchants to transmit pictures of their wares to their customers and the contents of museum collections to be made available to scholars in distant cities in the era prior to the advent of broadcasting electrical seeing devices were conceived as adjuncts to the telephone thus creating the concept of a video phone fraudulent reports of amazing advances in video telephones would be publicized as early as 1880 and would reoccur every few years such as the episode of dr silvestre of paris who claimed in 1902 to have invented a powerful video telephone termed at spectograph the intellectual property rights he believed were worth 5 million after reviewing his claim dr bell denounced the supposed invention as a fairy tale and publicly commented on the charlatans promoting bogus inventions for financial gain or self-promotion however dr alexander graham bell personally thought that video telephony was achievable even though his contributions to its advancement were incidental in april 1891 dr bell actually did record conceptual notes on an electrical radiophone which discussed the possibility of seeing by electricity using devices that employed tellurium or selenium imaging components bell wrote decades prior to the invention of the image dissector should it be found is illuminated then an apparatus might be constructed in which each piece of selenium is a mere speck like the head of a small pin the smaller the better the darkened selenium should be placed in a cup like receiver which can fit over the eye then when the first selenium speck is presented to an illuminated object it may be possible that the eye in the darkened receiver should perceive not merely light but an image of the object bell went on to later predict that thought the day would come when the man at the telephone would be able to see the distant person to whom he was speaking the discoveries in physics chemistry and materials science underlying video technology would not be in place until the mid-1920s first being utilized in electromechanical television more practical all electronic video and television would not emerge until 1939 but would then suffer several more years of delays before gaining popularity due to the onset and effects of world war ii the compound term videophone slowly entered into general usage after 1950 although video telephone likely entered the lexicon earlier after video was coined in 1935 prior to that time there appeared to be no standard terms for video telephone with expressions such as sight sound television system visual radio and nearly 20 others being used to describe the marriage of telegraph telephone television and radio technologies employed in early experiments among the technological precursors to the videophone were telegraphic image transmitters created by several companies such as the wire photo used by western union and the teleostereograph developed by a tnt's bell labs which were forerunners of today's fax machines such early image transmitters were themselves based on previous work by ernest hummel and others in the 19th century by 1927 at t had created its earliest electromechanical television videophone called the iconophone which operated at 18 frames per second and occupied half a room full of equipment cabinets an early u.s test in 1927 had their then commerce secretary herbert hoover address an audience in new york city from washington dc although the audio portion was two-way the video portion was one way with only those in new york being able to see hoover by 1930 at t's two-way television telephone system was in full-scale experimental use the bell labs manhattan facility devoted years of research to it during the 1930s led by dr herbert ives along with his team of more than 200 scientists engineers and technicians intending to develop it for both telecommunication and broadcast entertainment purposes there were also other public demonstrations of two-way television telephone systems during this period by inventors and entrepreneurs who sought to compete with at t although none appeared capable of dealing with the technical issues of signal compression that bell labs would eventually resolve signal compression and its later sibling data compression were fundamental to the issue of transmitting the very large bandwidth of low resolution black and white video through the very limited capacity of low-speed copper pstn telephone lines after the second world war bell labs resumed its efforts during the 1950s and 1960s eventually leading to a t's picture phone closed-circuit videophone systems 1936-1940 in early 1936. the first public video telephone service germany's daiginson ferns prechanligan was developed by dr george schubert who headed the development department at the fernsae ag a technical combine for television broadcasting technology two closed circuit televisions were installed in the german rights post in berlin and leipzig and connected together via a dedicated broadband coaxial cable to cover the distance of approximately 160 kilometres the system's opening was inaugurated by the minister of posts paul von eltz rubenak in berlin on march 1 1936 who viewed and spoke with leipzig's chief burgamaster schubert's system was based on gunter crawwinkle's earlier research of the late 1920s that he displayed at the 1929 international funkhouse telugu berlin shubet's higher performance system employed a nipkow disk flying spot scanner for its transmitter and a 20 centimeters cathode ray display tube with a resolution of 150 lines running at 25 frames per second after a period of experimentation the system entered public use and was soon extended with another 160 kilometres of coaxial cable from berlin to hamburg and then in july 1938 from leipzig to nuremberg and munich point-to-point video calling required swapping connections on a telephone switchboard the system eventually operated with more than 1000 kilometres of coaxial cable transmission lines the video phones were integrated within large public videophone boos with two boos provided per city calls between berlin and leipzig cost erm three and a half approximately one-sixth of a british pound sterling or about 1 15 of the average weekly wage the video telephone equipment used in berlin was designed and built by the german post office laboratory videophone equipment used in other german cities were developed by fernsae a.g partly owned by baird television
limited of the uk inventors of the world's first functional television during its life the german system underwent further development and testing resulting in higher resolutions and a conversion to an all-electronic camera tube transmission system to replace its mechanical nipkow scanning disk while the system's image quality was primitive by modern standards it was deemed impressive in contemporary reports of the era with users able to clearly discern the hands on wristwatches the videophones were offered to the general public which had to visit special post office francespreschtelen simultaneously in their respective cities but which at the same time also had nazi political and propagandistic overtones similar to the broadcasting of the 1936 olympic games in berlin the german post office announced ambitious plans to extend their public videophone network to cologne frankfurt and vienna austria but expansion plans were discontinued in 1939 with the start of the second world war after germany subsequently became fully engaged in the war its public videophone system was closed in 1940 with its expensive intercity broadband cables converted to telegraphic message traffic and broadcast television service a similar commercial post office system was also created in france during the late 1930s the deutsche bundespost postal service would decades later develop and deploy its bigfon videotelephony network from 1981 to 1988 serving several large german cities and also created one of europe's first public-switched broadband services in 1989. a t and t picturephonemadai 1964-1970 in the united states bell labs conducted extensive research and development of videophones eventually leading to public demonstrations of its trademark picturephone product in the 1960s its large manhattan experimental laboratory devoted years of technical research during the 1930s led by dr herbert ives along with his team of more than 200 scientists engineers and technicians the bell labs early experimental model of 1930 had transmitted uncompressed video through multiple phone lines a highly impractical and expensive method unsuitable for commercial use during the mid-1950s its laboratory work had produced another early test prototype capable of transmitting still images every two seconds over regular analog pstn telephone lines the images were captured by the picturephone's compact viticon camera and then transferred to a storage tube or magnetic drum for transmission over regular phone lines at two second intervals to the receiving unit which displayed them on a small cathode ray television tube a t had earlier promoted its experimental video for telephone service at the 1939 new york world's fair the more advanced picturephoned modi had public evaluation displays at disneyland and the 1964 new york world's fair with the first transcontinental video call between the two venues made on april 20 1964. these demonstration units used small oval housings on swivel stands intended to stand on desks similar at t picture phone units were also featured at the telephone pavilion at expo 67 an international world's fair held in montreal canada in 1967. demonstration units were available at the fairs for the public to test with fairgoers permitted to make videophone calls to volunteer recipients at other locations the united states would not see its first public videophone booths until 1964 when a t and t installed the earliest commercial videophone units the picturefunk modi in booths that were set up in new york's grand central terminal washington dc and chicago the system was the result of decades of research and development at bell labs its principal supplier western electric plus other researchers working under contract to the bell labs however the use of reservation time slots and their cost of 16 united states dollars to 27 for a three-minute call at the public videophone booths greatly limited their appeal resulting in their closure by 1968. first video conferencing service 1970 at t developed a refined picture phone throughout the late 1960s resulting in the mod 2 which served as the basis for at t's launch of the first true video conferencing service unlike earlier systems in which people had to visit public videophone booths any company or individual could pay to be connected to the system after which they could call anyone in the network from their home or office the inaugural video call occurred on june 30 1970 between pittsburgh mayor peter flaherty and chairman and ceo john harper of alcoa the service officially launched the next day july 1 1970 with 38 picture phones located at eight pittsburgh companies among the first subscribers westinghouse electric corporation became bell's largest picturephone customer leasing 12 sets the following year picturephone service expanded to central chicago and the suburb of oak brook before expanding to other large east coast cities service pricing in addition to an installation charge of 150 for the first set companies paid 160 per month for the service on the first set and 50 per month for each additional set 30 minutes of video calling was included with each picture phone with extra minutes costing 25 cents a t later reduced the price to 75 per month with 45 minutes of video calling included to stimulate demand picture phone mod 2 the picture phone's video bandwidth was 1 megahertz with a vertical scan rate of 30 hertz horizontal scan rate of 8 kilohertz and about 250 visible scan lines the equipment included a speakerphone with an added box to control picture transmission each picturephone line used three twisted pairs of ordinary telephone cable two pairs for video and one for audio and signalling cable amplifiers were spaced about a mile apart with built-in six-band adjustable equalization filters for distances of more than a few miles the signal was digitized at two megahertz and three bits per sample dpcm and transmitted on at2 carrier color on a tnt's picture phone was not employed with their early models these picture phone units packaged plumbicon cameras and small crt displays within their housings the cameras were located atop their screens to help users see eye to eye later generation display screens were larger than in the original demonstration units approximately six inches square in a roughly cubical cabinet the original picturephone system used contemporary crossbar and multi-frequency operation lines and trunks were six wire one pair each way for video and one pair two-way for audio mf address signaling on the audio pair was supplemented by a video supervisory signal looping around on the video quad to ensure continuity more complex protocols were later adopted for conferencing to deploy picturephone service new wideband crossbar switches were designed and installed into the bell system's 5xb switch offices this being the most widespread of the relatively modern kind hundreds of technicians attended schools to learn to operate the cable equalizer test set and other equipment and to install picture phones commercial failure a t and t's initial picturephone modi and then its upgraded mod 2 programs were a continuation of its many years of prior research during the 1920s 1930s late 1940s and 1950s both picturephone programs like their experimental a t and t predecessors were researched principally at its bell labs formerly spent some 15 years and consumed more than 500 million united states dollars eventually meeting with commercial failure at the time of its first launch at t 4 saw a hundred thousand picture phones in use across the bell system by 1975. however by the end of july 1974 only five picture phones were being leased in pittsburgh and u.s wide there
were only a few hundred mostly in chicago unrelated difficulties at new york telephone also slowed at t's efforts and few customers signed up for the service in either city customers peaked at 453 in early 1973. at t ultimately concluded that its early picture phones were a concept looking for a market later development a t and t would later market its videophone 2500 to the general public from 1992 to 1995 with prices starting at 1 500 united states dollars and later dropping to 1 000. marketed by its global videophone systems unit the videophone 2500 was designed to provide low frame rate compressed color video on ordinary plain old telephone service lines circumventing the significantly higher cost adsl telephone service lines used by several other video conferencing manufacturers it was limited by analog phone line connection speeds of about 19 kilobits per second the video portion being 11200 bit s and with a maximum frame rate of 10 frames per second but typically much slower as low as a third of a video frame per second the videophone 2500 used proprietary technology protocols including a t and t's global videophone standard again at t met with very little commercial success selling only about 30 000 units mainly outside the united states despite at t's various videophone products meeting with commercial failure they were widely viewed as technical successes which expanded the limits of the telecommunication sciences in several areas its videotelephony programs were critically acclaimed for their technical brilliance and even the novel uses they experimented with the research and development programs conducted by bell labs were highly notable for their beyond the state-of-the-art results produced in materials science advanced telecommunications microelectronics and information technologies at t's published research additionally helped pave the way for other companies to later enter the field of video conferencing the company's video phones also generated significant media coverage in science journals the general news media and in popular culture the image of a futuristic a and t video phone being casually used in the science fiction film 2001 a space odyssey became iconic of both the movie and arguably the public's general view of the future other early video phones 1968-1984 beginning in the late 1960s several countries worldwide sought to compete with at t's advanced development of its picturephone service in the united states however such projects were research and capital-intensive and fraught with difficulties in being deployed commercially france france's post office telecommunications branch had earlier set up a commercial videophone system similar to the german reichsbost public videophone system of the late 1930s in 1972 the defense and electronics manufacturer matra was one of three french companies that sought to develop advanced videophones in the early 1970s spurred by a tnt's picturephone in the united states initial plans by matra included the deployment of 25 units to france's center national datudes de tele communications for their internal use cnet intended to guide its initial use towards the business sector to be later followed by personal home usage its estimated unit cost in 1971 was the equivalent of 325 pounds with a monthly usage subscription charge of 3 pounds and 35 pence studies of applications of video telephony were conducted by cnet in france in 1972 with its first commercial applications for videophones appearing in 1984. the delay was due to the problem of insufficient bandwidth with 2 megabits per second being required for transmitting both video and audio signals the problem was solved worldwide by the creation of software for data encoding and compression via video coding and decoding algorithms also known as codex sweden in sweden electronics maker ericsson began developing a videophone in the mid-1960s intending to market it to government institutions businesses and industry but not to consumers due to at t's lack of success in that market segment tests were conducted in stockholm including trial communications and banking ultimately ericsson chose not to proceed with further production united kingdom in 1970 the british general post office had 16 demonstration models of its viewphone build meant to be the equivalent to a tnt's picture phone their initial attempt at a first-generation commercial video phone later led to the british telecom relate 2000 which was released for sale in 1993 costing between 400 pounds to 500 pounds each the relate 2000 featured a 74 millimeters flip up color lcd display screen operating at a nominal rate of 8 video frames per second which could be depressed to 3 to four frames per second if the pstn bandwidth was limited in the era prior to low-cost high-speed broadband service its video quality was found to be generally poor by the public with images shifting jerkily between frames due to british phone lines that generally provided less than 3.4 kilohertz of bandwidth british telecom had initially expected the device manufactured by marconi electronics to sell at a rate of 10 000 per year but its actual sales were minimal its second-generation videophone thus also proved to be commercially unsuccessful similar to att's videophone 2500 of the same time period digital video telephony 1985-1999 this time period saw the research development and commercial roll out of what would become powerful video compression and decompression software codecs which would eventually lead to low-cost video telephony in the early 2000s video compression practical digital video telephony was only made possible with advances in video compression due to the impractically high bandwidth requirements of uncompressed video to achieve video graphics array quality video with raw uncompressed video it would require a bandwidth of over 92 megabits per second the most important compression technique that enabled practical digital video telephony and video conferencing is the discrete cosine transform the dct a form of lossy compression was proposed in 1972 by nasir ahmed who developed the algorithm with t natarajan and k r rao at the university of texas in 1973. the dct algorithm became the basis for the first practical video coding standard that was useful for video conferencing 8.261 standardized by the itu-t in 1988.
japanese video phones in japan the lumophone was developed and marketed by mitsubishi in 1985. the project was originally started by the ataritel division of the atari video game company in 1983 under the direction of atari steve bristow atari then sold its division to mitsubishi electric in 1984. the lumophone was marketed by mitsubishi electric of america in 1986 as the lumalu 1000 costing 1500 united states dollars designed with a small black and white video display approximately four centimeters in size and a video camera adjacent to the display which could be blocked with a sliding door for privacy although promoted as a videophone it operated similar to bell lab's early experimental image transfer phone of 1956 transmitting still images every three to five seconds over analog pots lines it could also be hooked up to a printer or connected to a regular tv or monitor for improved teleconferencing mitsubishi also marketed its lower-cost visi telephone lu 500 image phone in 1988 costing about 400 united states dollars aimed at the consumer market it came with reduced capabilities but had with a larger black and white display other japanese electronic manufacturers marketed similar image transfer phones during the late 1980s including sony's pct-15 and two models from panasonic it's wgr-2 and its kxtv10 much later the kyocera corporation an electronics manufacturer based in kyoto conducted a two-year development campaign from 1997 to 1999 that resulted in the release of the vp 210 visual phone the world's first mobile color videophone that also doubled as a camera phone for still photos the camera phone was the same size as similar contemporary mobile phones but sported a large camera lens and a five centimeters color tft display capable of displaying 65 000 colors and was able to process two video frames per second the 155-gram camera could also take 20 photos and convey them by email with the camera phone retailing at the time for 40 000 yen about 325 united states dollars in 1999. the vp210 was released in may 1999 and used its single front-facing 110 000 pixel camera to send two images per second through japan's phs mobile phone network system although its frame rate was crude and its memory is considered tiny in the present day the phone was viewed as revolutionary at the time of its release the kyocera project was initiated at the yokohama research and development center by kazumi sabhari one of their section managers his explanation for the project was around that time cellular handsets with enabled voice and sms communication capabilities were considered to be just one among many personal communication tools one day a simple idea hit us what if we were able to enjoy talking with the intended person watching his her face on the display we were certain that such a device would make cell phone communications much more convenient and enjoyable sabri also stated that their r d section had nourished for several years before they received project approval from their top management which had encouraged such forward thinking research because they also believed that such a product would improve kyocera's brand image their research showed that a cell phone with a camera and color display provided a completely new value for users it could be used as a phone a camera and a photo album technical challenges handled by about a dozen engineers at kyocera over the two-year development period included the camera module's placement within the phone at a time when electronic components had not been fully reduced in size as well as increasing its data transmission rate after its release the mobile video camera phone was commercially successful spawning several other competitors such as the ddi pocket and one from vodafone kk videophone improvements post 2000 significant improvements in video call quality of service for the deaf occurred in the united states in 2003 when sorenson media inc a video compression software coding company developed its vp100 model standalone video phone specifically for the deaf community it was designed to output its video to the user's television in order to lower the cost of acquisition and to offer remote control and a powerful video compression codec for unequaled video quality and ease of use with a video relay service favorable reviews quickly led to its popular usage at educational facilities for the deaf and from there to the greater deaf community coupled with similar high-quality video phones introduced by other electronics manufacturers the availability of high-speed internet and sponsored video relay services authorized by the u.s federal communications commission in 2002 vrs services for the deaf underwent rapid growth in that country