![Teliris VL Modular](https://upload.wikimedia.org/wikipedia/commons/c/c9/Teliris_VL_Modular.JPG)
Videotelephony, also known as videoconferencing and video teleconferencing, is the two-way or multipoint reception and transmission of
audio
Audio most commonly refers to sound, as it is transmitted in signal form. It may also refer to:
Sound
*Audio signal, an electrical representation of sound
*Audio frequency, a frequency in the audio spectrum
*Digital audio, representation of sound ...
and
video
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) syste ...
signals by people in different locations for
real time
Real-time or real time describes various operations in computing or other processes that must guarantee response times within a specified time (deadline), usually a relatively short time. A real-time process is generally one that happens in defined ...
communication.
[McGraw-Hill Concise Encyclopedia of Engineering]
Videotelephony
McGraw-Hill, 2002. Retrieved from the FreeDictionary.com website, January 9, 2010 A videophone is a
telephone
A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into e ...
with a
video camera
A video camera is an optical instrument that captures videos (as opposed to a movie camera, which records images on film). Video cameras were initially developed for the television industry but have since become widely used for a variety of other ...
and
video display
A display device is an output device for presentation of information in visual or tactile form (the latter used for example in tactile electronic displays for blind people). When the input information that is supplied has an electrical signal the ...
, capable of simultaneous video and audio communication. Videoconferencing implies the use of this technology for a group or organizational meeting rather than for individuals, in a videoconference.
[Mulbach et al, 1995. pg. 291.] Telepresence
Telepresence refers to a set of technologies which allow a person to feel as if they were present, to give the appearance or effect of being present via telerobotics, at a place other than their true location.
Telepresence requires that the user ...
may refer either to a high-quality videotelephony system (where the goal is to create the illusion that remote participants are in the same room) or to meetup technology, which can go beyond video into robotics (such as moving around the room or physically manipulating objects). Videoconferencing has also been called "visual collaboration" and is a type of
groupware.
While development of video-conferring started in the late 19th century, the technology only became available to the public starting in the 1930s. These early demonstrations were installed at "booths" in post offices and shown at various world expositions. It took until 1970 for AT&T to launch the first true video-conferring system, where anyone could subscribe to the service and have the technology in their home or office. Video-telephony also included "image phones" which would exchange still images between units every few seconds over conventional
plain old telephone service
Plain old telephone service (POTS), or plain ordinary telephone system, is a retronym for voice-grade telephone service employing analog signal transmission over copper loops. POTS was the standard service offering from telephone companies from 1 ...
(POTS) lines, essentially the same as
slow-scan TV
Slow-scan television (SSTV) is a picture transmission method, used mainly by amateur radio operators, to transmit and receive static pictures via radio in monochrome or color.
A literal term for SSTV is narrowband television. Analog broadcast tel ...
. The development of advanced
video codecs
The following is a list of compression formats and related codecs.
Audio compression formats
Non-compression
* Linear pulse-code modulation (LPCM, generally only described as PCM) is the format for uncompressed audio in media files and it is al ...
, more powerful
CPUs, and high-bandwidth
Internet telecommunication services in the late 1990s allowed videophones to provide high quality low-cost colour service between users almost any place in the world where the
Internet
The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, pub ...
is available.
Although not as widely used in everyday communications as audio-only and text communication, useful applications include
sign language
Sign languages (also known as signed languages) are languages that use the visual-manual modality to convey meaning, instead of spoken words. Sign languages are expressed through manual articulation in combination with non-manual markers. Sign l ...
transmission for
deaf
Deafness has varying definitions in cultural and medical contexts. In medical contexts, the meaning of deafness is hearing loss that precludes a person from understanding spoken language, an Audiology, audiological condition. In this context it ...
and
speech-impaired people,
distance education
Distance education, also known as distance learning, is the education of students who may not always be physically present at a school, or where the learner and the teacher are separated in both time and distance. Traditionally, this usually in ...
,
telemedicine, and overcoming
mobility issues. It is also used in commercial and corporate settings to facilitate meetings and conferences, typically between parties that already have established relationships.
News media
The news media or news industry are forms of mass media that focus on delivering news to the general public or a target public. These include news agencies, print media (newspapers, news magazines), broadcast news (radio and television), and th ...
organisations have begun to use desktop technologies like
Skype
Skype () is a proprietary telecommunications application operated by Skype Technologies, a division of Microsoft, best known for VoIP-based videotelephony, videoconferencing and voice calls. It also has instant messaging, file transfer, deb ...
to provide higher-quality audio than the cellular phone network, and video links at much lower cost than sending professional equipment or using a professional studio. More popular videotelephony technologies use the Internet rather than the traditional landline phone network, even though modern phone networks use digital packet protocols, and videotelephony software commonly runs on
smartphone
A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...
s over digital radiotelephony networks.
History
![France in XXI Century](https://upload.wikimedia.org/wikipedia/commons/f/fe/France_in_XXI_Century._Correspondance_cinema.jpg)
The concept of videotelephony was first conceived in the late 1870s, both in the United States and in 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
Electrical telegraphs were point-to-point text messaging systems, primarily used from the 1840s until the late 20th century. It was the first electrical telecommunications system and the most widely used of a number of early messaging systems ...
,
telephony
Telephony ( ) is the field of technology involving the development, application, and deployment of telecommunication services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is i ...
,
radio
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmit ...
, and
television
Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertisin ...
.
Simple analog videophone communication could be established as early as the invention of the
television
Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertisin ...
. Such an antecedent usually consisted of two
closed-circuit television
Closed-circuit television (CCTV), also known as video surveillance, is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors. It differs from broadcast television in that the signal is not openly t ...
systems connected via
coax cable
Coaxial cable, or coax (pronounced ) is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric ( insulating material); many coaxial cables also have a p ...
or
radio
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmit ...
. An example of that was the German Reich Postzentralamt (post office) videotelephone network serving Berlin and several German cities via coaxial cables between 1936 and 1940.
The development of videoconferencing as a subscription service started in the latter half of the 1920s in the United Kingdom and the United States, spurred notably by
John Logie Baird
John Logie Baird FRSE (; 13 August 188814 June 1946) was a Scottish inventor, electrical engineer, and innovator who demonstrated the world's first live working television system on 26 January 1926. He went on to invent the first publicly demo ...
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 videotelephony would be superior to plain voice communications. Attempts at using normal
telephony
Telephony ( ) is the field of technology involving the development, application, and deployment of telecommunication services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is i ...
networks to transmit slow-scan video, such as the first systems developed by
AT&T Corporation
AT&T Corporation, originally the American Telephone and Telegraph Company, is the subsidiary of AT&T Inc. that provides voice, video, data, and Internet telecommunications and professional services to businesses, consumers, and government agen ...
, first researched in the 1950s, failed mostly due to the poor picture quality and the lack of efficient
video compression
In information theory, data compression, source coding, or bit-rate reduction is the process of encoding information using fewer bits than the original representation. Any particular compression is either lossy or lossless. Lossless compression ...
techniques.
During the first crewed
space flight
Spaceflight (or space flight) is an application of astronautics to fly spacecraft into or through outer space, either human spaceflight, with or uncrewed spaceflight, without humans on board. Most spaceflight is uncrewed and conducted mainly w ...
s,
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding t ...
used two radio-frequency (
UHF
Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter (on ...
or
VHF
Very high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter.
Frequencies immediately below VHF ...
) video links, one in each direction.
TV channels routinely use this type of videotelephony when reporting from distant locations. The news media were to become regular users of mobile links to
satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...
s using specially equipped trucks, and much later via special satellite videophones in a briefcase. This technique was very expensive, though, and could not be used for applications such as
telemedicine,
distance education
Distance education, also known as distance learning, is the education of students who may not always be physically present at a school, or where the learner and the teacher are separated in both time and distance. Traditionally, this usually in ...
, and business meetings.
Decades of research and development culminated in the 1970 commercial launch of AT&T's Picturephone service, available in select cities. However, the system was a commercial failure, chiefly due to consumer apathy, high subscription costs, and lack of
network effect
In economics, a network effect (also called network externality or demand-side economies of scale) is the phenomenon by which the value or utility a user derives from a good or service depends on the number of users of compatible products. Netw ...
—with only a few hundred Picturephones in the world, users had extremely few contacts they could actually call, and
interoperability
Interoperability is a characteristic of a product or system to work with other products or systems. While the term was initially defined for information technology or systems engineering services to allow for information exchange, a broader defi ...
with other videophone systems would not exist for decades.
Very expensive videoconferencing systems continued to evolve throughout the 1980s and 1990s. Proprietary equipment, software, and network requirements gave way to standards-based technologies that were available for anyone to purchase at a reasonable cost. Only in the late 20th century with the advent of powerful
video codec
A video codec is software or hardware that compresses and decompresses digital video. In the context of video compression, ''codec'' is a portmanteau of ''encoder'' and ''decoder'', while a device that only compresses is typically called an '' ...
s combined with high-speed
Internet broadband and
ISDN
Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Wo ...
service did videotelephony become a practical technology for regular use.
Digital
Advances in
video compression
In information theory, data compression, source coding, or bit-rate reduction is the process of encoding information using fewer bits than the original representation. Any particular compression is either lossy or lossless. Lossless compression ...
allowed
digital video
Digital video is an electronic representation of moving visual images (video) in the form of encoded digital data. This is in contrast to analog video, which represents moving visual images in the form of analog signals. Digital video comprises ...
streams to be transmitted over the Internet, which was previously difficult due to the impractically high bandwidth requirements of
uncompressed video
Uncompressed video is digital video that either has never been compressed or was generated by decompressing previously compressed digital video. It is commonly used by video cameras, video monitors, video recording devices (including general-pur ...
. To achieve
Video Graphics Array
Video Graphics Array (VGA) is a video display controller and accompanying de facto graphics standard, first introduced with the IBM PS/2 line of computers in 1987, which became ubiquitous in the PC industry within three years. The term can now ...
(VGA) quality video (
480p
480p is the shorthand name for a family of video display resolutions. The p stands for progressive scan, i.e. non-interlaced. The ''480'' denotes a vertical resolution of 480 pixels, usually with a horizontal resolution of 640 pixels and 4:3 ...
resolution and
256 colors
8-bit color graphics are a method of storing image information in a computer's memory or in an image file, so that each pixel is represented by 8 bits (1 byte). The maximum number of colors that can be displayed at any one time is 256 or 28.
Color ...
) with raw uncompressed video, it would require a bandwidth of over 92
Mbps
In telecommunications, data-transfer rate is the average number of bits (bitrate), characters or symbols (baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are multi ...
.
A common compression technique used to significantly reduce bandwidth requirements in videotelephony and videoconferencing is the
discrete cosine transform (DCT),
developed by
Nasir Ahmed, T. Natarajan and
K. R. Rao in 1973.
The DCT algorithm was the basis for the first practical
video coding standard
A video coding format (or sometimes video compression format) is a content representation format for storage or transmission of digital video content (such as in a data file or bitstream). It typically uses a standardized video compression algo ...
that was useful for online videoconferencing,
H.261
H.261 is an ITU-T video compression standard, first ratified in November 1988. It is the first member of the H.26x family of video coding standards in the domain of the ITU-T Study Group 16 Video Coding Experts Group (VCEG, then Specialists Gro ...
, standardised by the
ITU-T
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 ...
in 1988, and subsequent
H.26x
The Video Coding Experts Group or Visual Coding Experts Group (VCEG, also known as Question 6) is a working group of the ITU Telecommunication Standardization Sector (ITU-T) concerned with standards for compression coding of video, images, audio, ...
video coding standard
A video coding format (or sometimes video compression format) is a content representation format for storage or transmission of digital video content (such as in a data file or bitstream). It typically uses a standardized video compression algo ...
s.
In the 1980s,
digital telephony
Telephony ( ) is the field of technology involving the development, application, and deployment of telecommunication services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is i ...
transmission networks became possible, such as with
ISDN
Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Wo ...
networks, assuring a minimum
bit rate
In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time.
The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction w ...
(usually 128 kilobits/s) for compressed video and audio transmission. During this time, there was also research into other forms of digital video and audio communication. Many of these technologies, such as the
Media space
Media spaces are "electronic settings in which groups of people can work together, even when they are not present in the same place and time. In a media space, people can create real-time visual and acoustic environments that span physically s ...
, are not as widely used today as videoconferencing but were still an important area of research. The first dedicated systems started to appear as ISDN networks were expanding throughout the world. One of the first commercial videoconferencing systems sold to companies came from
PictureTel Corp.
PictureTel Corporation, often shortened to PictureTel Corp., was one of the first commercial videoconferencing product companies. It achieved peak revenues of over $490 million in 1996 and 1997 and was eventually acquired by Polycom in October ...
, which had an
initial public offering
An initial public offering (IPO) or stock launch is a public offering in which shares of a company are sold to institutional investors and usually also to retail (individual) investors. An IPO is typically underwritten by one or more investment ...
in November, 1984.
In 1984, Concept Communication in the United States replaced the , US$100,000 computers necessary for teleconferencing, with a $12,000
circuit board
A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in Electrical engineering, electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a L ...
that doubled the video
frame rate
Frame rate (expressed in or FPS) is the frequency (rate) at which consecutive images (frames) are captured or displayed. The term applies equally to film and video cameras, computer graphics, and motion capture systems. Frame rate may also be ca ...
from 15 to 30 frames per second, and which reduced the equipment to the size of a circuit board fitting into standard
personal computer
A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...
s.
The company also secured a patent for a
codec
A codec is a device or computer program that encodes or decodes a data stream or signal. ''Codec'' is a portmanteau of coder/decoder.
In electronic communications, an endec is a device that acts as both an encoder and a decoder on a signal or da ...
for full-motion videoconferencing, first demonstrated at
AT&T Bell Labs
Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984),
then AT&T Bell Laboratories (1984–1996)
and Bell Labs Innovations (1996–2007),
is an American industrial research and scientific development company owned by mult ...
in 1986.
Videoconferencing systems throughout the 1990s rapidly evolved from very expensive proprietary equipment, software, and network requirements to a standards-based technology readily available to the general public at a reasonable cost.
Finally, in the 1990s,
Internet Protocol
The Internet Protocol (IP) is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet.
IP h ...
-based videoconferencing became possible, and more efficient video compression technologies were developed, permitting desktop, or personal computer (PC)-based videoconferencing. In 1992
CU-SeeMe
CU-SeeMe is an Internet videoconferencing client. CU-SeeMe can make point to point video calls without a server or make multi-point calls through server software first called a "reflector" and later called a "conference server" or Multipoint Co ...
was developed at Cornell by Tim Dorcey et al. In 1995 the
first public videoconference between North America and Africa took place, linking a technofair in
San Francisco
San Francisco (; Spanish language, Spanish for "Francis of Assisi, Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the List of Ca ...
with a techno-rave and cyberdeli in
Cape Town
Cape Town ( af, Kaapstad; , xh, iKapa) is one of South Africa's three capital cities, serving as the seat of the Parliament of South Africa. It is the legislative capital of the country, the oldest city in the country, and the second largest ...
. At the
1998 Winter Olympics
The 1998 Winter Olympics, officially known as the and commonly known as Nagano 1998 ( ja, 長野1998), was a winter multi-sport event held from 7 to 22 February 1998, mainly in Nagano, Japan, with some events taking place in the ...
opening ceremony in
Nagano Nagano may refer to:
Places
* Nagano Prefecture, a prefecture in Japan
** Nagano (city), the capital city of the same prefecture
*** Nagano 1998, the 1998 Winter Olympics
*** Nagano Olympic Stadium, a baseball stadium in Nagano
*** Nagano Universi ...
, Japan,
Seiji Ozawa
Seiji (written: , , , , , , , , , , , , , , , , , , , , , or in hiragana) is a masculine Japanese given name. Notable people with the name include:
*, Japanese ski jumper
*, Japanese racing driver
*, Japanese politician
*, Japanese film directo ...
conducted the
Ode to Joy
"Ode to Joy" (German language, German: , literally "To heJoy") is an ode written in the summer of 1785 by German poet, playwright, and historian Friedrich Schiller and published the following year in ''Thalia (magazine), Thalia''. A slightl ...
from
Beethoven's Ninth Symphony
The Symphony No. 9 in D minor, Op. 125, is a choral symphony, the final complete symphony by Ludwig van Beethoven, composed between 1822 and 1824. It was first performed in Vienna on 7 May 1824. The symphony is regarded by many critics and music ...
simultaneously across five continents in near-real-time.
While videoconferencing technology was initially used primarily within internal corporate communication networks, one of the first community service uses of the technology started in 1992 through a unique partnership with PictureTel and IBM, which at the time were promoting a jointly developed desktop based videoconferencing product known as the PCS/1. Over the next 15 years,
Project DIANE Project DIANE, an acronym for Diversified Information and Assistance NEtwork, was a very early videoconferencing based community service network created in the United States. DIANE was a grassroots driven regional videoconferencing consortium which ...
(Diversified Information and Assistance Network) grew to use a variety of videoconferencing platforms to create a multi-state cooperative public service and distance education network consisting of several hundred schools, libraries, science museums, zoos and parks, and many other community oriented organizations.
Kyocera
is a Japanese multinational ceramics and electronics manufacturer headquartered in Kyoto, Japan. It was founded as in 1959 by Kazuo Inamori and renamed in 1982. It manufactures industrial ceramics, solar power generating systems, telecommuni ...
conducted a two-year development campaign from 1997 to 1999 that resulted in the release of the VP-210 Visual Phone, the first mobile colour videophone that also doubled as a
camera phone
A camera phone is a mobile phone which is able to capture photographs and often record video using one or more built-in digital cameras. It can also send the resulting image wirelessly and conveniently. The first commercial phone with color cam ...
for still photos.
[Kyocera visual phone VP-210, Japan, 1999](_blank)
Science & Society Picture Library, retrieved August 9, 2013.[First mobile videophone introduced](_blank)
CNN
CNN (Cable News Network) is a multinational cable news channel headquartered in Atlanta, Georgia, U.S. Founded in 1980 by American media proprietor Ted Turner and Reese Schonfeld as a 24-hour cable news channel, and presently owned by the M ...
.com website, May 18, 1999. The camera phone was the same size as similar contemporary
mobile phone
A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whil ...
s, but sported a large camera lens and a 5 cm (2 inch) colour
TFT display
A thin-film-transistor liquid-crystal display (TFT LCD) is a variant of a liquid-crystal display that uses thin-film-transistor technology to improve image qualities such as addressability and contrast. A TFT LCD is an active matrix LCD, in cont ...
capable of displaying 65,000 colors, and was able to process two video frames per second.
[Yegulalp, Serdar]
Camera phones: A look back and forward
''Computerworld
''Computerworld'' (abbreviated as CW) is an ongoing decades old professional publication which in 2014 "went digital." Its audience is information technology (IT) and business technology professionals, and is available via a publication website ...
'', May 11, 2012.
Videotelephony was popularized in the 2000s, via free Internet services such as
Skype
Skype () is a proprietary telecommunications application operated by Skype Technologies, a division of Microsoft, best known for VoIP-based videotelephony, videoconferencing and voice calls. It also has instant messaging, file transfer, deb ...
and
iChat
iChat (previously iChat AV) is a discontinued instant messaging software application developed by Apple Inc. for use on its Mac OS X operating system. It supported instant text messaging over XMPP/Jingle or OSCAR ( AIM) protocol, audio and video ...
, web plugins supporting
H.26x
The Video Coding Experts Group or Visual Coding Experts Group (VCEG, also known as Question 6) is a working group of the ITU Telecommunication Standardization Sector (ITU-T) concerned with standards for compression coding of video, images, audio, ...
video standards, and on-line telecommunication programs that promoted low cost, albeit lower quality, videoconferencing to virtually every location with an Internet connection.
![Medvedev and Nurgaliev TANDBERG Tactical MXP](https://upload.wikimedia.org/wikipedia/commons/c/cd/Medvedev_and_Nurgaliev_TANDBERG_Tactical_MXP.jpg)
With the rapid improvements and popularity of the Internet, videotelephony has become widespread through the deployment of video-enabled
mobile phone
A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whil ...
s such as 2010's
iPhone 4
The iPhone 4 is a smartphone that was designed and marketed by Apple Inc. It is the fourth generation of the iPhone lineup, succeeding the iPhone 3GS and preceding the 4S. Following a number of notable leaks, the iPhone 4 was first unvei ...
, plus videoconferencing and
computer webcams which use
Internet telephony
Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet t ...
. In the upper echelons of government, business, and commerce,
telepresence technology
Telepresence refers to a set of technologies which allow a person to feel as if they were present, to give the appearance or effect of being present via telerobotics, at a place other than their true location.
Telepresence requires that the user ...
, an advanced form of videoconferencing, has helped reduce the need to travel.
In May 2005, the first
high definition videoconferencing systems, produced by
LifeSize Communications
Lifesize is a video and audio telecommunications company in the United States which provides high definition videoconferencing endpoints and accessories, touchscreen conference room phones and a cloud-based video collaboration platform. Lifesiz ...
, were displayed at the
Interop
Interop is an annual information technology conference organised by Informa PLC. It takes place in the US and Tokyo
Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city ...
trade show in
Las Vegas
Las Vegas (; Spanish for "The Meadows"), often known simply as Vegas, is the 25th-most populous city in the United States, the most populous city in the state of Nevada, and the county seat of Clark County. The city anchors the Las Vegas ...
,
Nevada
Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...
, able to provide video at 30 frames per second with a 1280 by 720
display resolution
The display resolution or display modes of a digital television, computer monitor or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is ...
.
Polycom
Poly, formerly Polycom, a part of HP Inc., is an American multinational corporation that develops video, voice and content collaboration and communication technology.
Polycom was co-founded in 1990 by Brian L Hinman and Jeffrey Rodman. In 2018 P ...
introduced its first high definition videoconferencing system to the market in 2006. As of the 2010s, high definition resolution for videoconferencing became a popular feature, with most major suppliers in the videoconferencing market offering it.
Technological developments by videoconferencing developers in the 2010s have extended the capabilities of videoconferencing systems beyond the boardroom for use with
hand-held mobile devices that combine the use of video, audio and on-screen drawing capabilities broadcasting in real time over secure networks, independent of location.
Mobile collaboration Mobile collaboration is a technology-based process of communicating using electronic assets and accompanying software designed for use in remote locations. Newest generation hand-held electronic devices feature video, audio, and telestration (on-scr ...
systems now allow people in previously unreachable locations, such as workers on an offshore oil rig, the ability to view and discuss issues with colleagues thousands of miles away. Traditional videoconferencing system manufacturers have begun providing mobile applications as well, such as those that allow for live and still image streaming.
The highest ever video call (other than those from aircraft and spacecraft) took place on May 19, 2013, when British adventurer Daniel Hughes used a
smartphone
A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...
with a
BGAN satellite modem to make a videocall to the
BBC #REDIRECT BBC #REDIRECT BBC #REDIRECT BBC
Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board ex ...
from the summit of
Mount Everest
Mount Everest (; Tibetan: ''Chomolungma'' ; ) is Earth's highest mountain above sea level, located in the Mahalangur Himal sub-range of the Himalayas. The China–Nepal border runs across its summit point. Its elevation (snow heig ...
, at above sea level.
The
COVID-19 pandemic
The COVID-19 pandemic, also known as the coronavirus pandemic, is an ongoing global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The novel virus was first identif ...
resulted in a significant increase in the use of videoconferencing. Berstein Research found that
Zoom
Zoom may refer to:
Technology Computing
* Zoom (software), videoconferencing application
* Page zooming, the ability to magnify or shrink a portion of a page on a computer display
* Zooming user interface, a graphical interface allowing for image ...
added more subscribers during the first two months of 2020 alone than in the entire year 2019.
GoToMeeting
GoTo Meeting (formerly GoToMeeting) is a web conferencing software by GoTo. It is an online meeting, desktop sharing, and video conferencing software package that enables the user to meet with other computer users, customers, clients, or colleag ...
had a 20 percent increase in usage, according to
LogMeIn
GoTo, formerly LogMeIn Inc., is a flexible-work provider of software as a service (SaaS) and cloud-based remote work tools for collaboration and IT management, with products including GoTo Connect, GoTo Resolve, Rescue, Central, and more, built ...
. UK based
StarLeaf
StarLeaf was a global video conferencing and collaboration software company that provided cloud-based messaging, meeting and calling for business users. StarLeaf enabled people to meet and collaborate from their desktop and mobile devices, as wel ...
reported a 600 percent increase in national call volumes. Videoconferencing became so widespread during the pandemic that the term "
Zoom fatigue
Zoom fatigue is tiredness, worry or Occupational burnout, burnout associated with the overuse of virtual platforms of communication, particularly videotelephony. The name derives from the cloud based videoconferencing and online chat software Z ...
" came to prominence, referring to the taxing nature of spending long periods of time on videocalls.
On 21 September 2021,
Facebook
Facebook is an online social media and social networking service owned by American company Meta Platforms. Founded in 2004 by Mark Zuckerberg with fellow Harvard College students and roommates Eduardo Saverin, Andrew McCollum, Dustin M ...
launched two new versions of its Portal video-calling devices, the Portal Go and Portal Plus. The new video calling devices include the first portable variety of the hardware and number of updates.
Major categories
![USB webcam for PC](https://upload.wikimedia.org/wikipedia/commons/6/63/USB_webcam_for_PC.jpg)
Videotelephony can be categorized by its functionality and intended purpose, and also by its method of transmission.
Videophones were the earliest form of videotelephony, dating back to initial tests in 1927 by AT&T. During the late 1930s, the post offices of several European governments established public videophone services for person-to-person communications using dual cable circuit telephone transmission technology. In the present day, standalone videophones and
UMTS
The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the Inte ...
video-enabled
mobile phone
A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whil ...
s are usually used on a person-to-person basis.
Videoconferencing saw its earliest use with AT&T's Picturephone service in the early 1970s. Transmissions were analog over short distances, but converted to digital forms for longer calls, again using telephone transmission technology. Popular corporate video-conferencing systems in the present day have migrated almost exclusively to digital
ISDN
Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Wo ...
and
IP transmission modes due to the need to convey the very large amounts of data generated by their cameras and microphones. These systems are often intended for use in conference mode, that is by many people in several different locations, all of whom can be viewed by every participant at each location.
Telepresence
Telepresence refers to a set of technologies which allow a person to feel as if they were present, to give the appearance or effect of being present via telerobotics, at a place other than their true location.
Telepresence requires that the user ...
systems are a newer, more advanced subset of videoconferencing systems, meant to allow higher degrees of video and audio fidelity. Such high-end systems are typically deployed in corporate settings.
Mobile collaboration Mobile collaboration is a technology-based process of communicating using electronic assets and accompanying software designed for use in remote locations. Newest generation hand-held electronic devices feature video, audio, and telestration (on-scr ...
systems are another recent development, combining the use of video, audio, and on-screen drawing capabilities using newest generation
hand-held electronic devices broadcasting over secure networks, enabling multi-party conferencing in real time, independent of location.
Proximity chat
Proximity chat or spatial chat is type of internet platform that overlays video teleconferencing software on a virtual world environment, so that users can navigate freely and have conversations among small groups. Proximity chat as a genre has e ...
is another alternative mode, focused on the flexibility of small group conversations.
A more recent technology encompassing these functions is TV cams. TV cams enable people to make video "phone" calls using video calling services, like Skype on their TV, without using a PC connection. TV cams are specially designed video cameras that feed images in real time to another TV camera or other compatible computing devices like smartphones, tablets and computers.
''
Webcam
A webcam is a video camera which is designed to record or stream to a computer or computer network. They are primarily used in videotelephony, livestreaming and social media, and security. Webcams can be built-in computer hardware or peripheral d ...
s'' are popular, relatively low cost devices which can provide live video and audio streams via
personal computer
A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...
s, and can be used with many
software clients for both video calls and videoconferencing.
[Solomon Negash, Michael E. Whitman. Editors: Solomon Negash, Michael E. Whitman, Amy B. Woszczynski, Ken Hoganson, Herbert Mattord]
Handbook of Distance Learning for Real-Time and Asynchronous Information Technology Education
, Idea Group Inc (IGI), 2008, p. 17, , . Note costing: "...students had the option to install a webcam on their end (a basic webcam costs about $40.00) to view the class in session."
Each of the systems has its own advantages and disadvantages, including
video quality
Video quality is a characteristic of a video passed through a video transmission or processing system that describes perceived video degradation (typically, compared to the original video). Video processing systems may introduce some amount of dist ...
,
capital cost
Capital costs are fixed, one-time expenses incurred on the purchase of land, buildings, construction, and equipment used in the production of goods or in the rendering of services. In other words, it is the total cost needed to bring a project to a ...
, degrees of sophistication,
transmission
Transmission may refer to:
Medicine, science and technology
* Power transmission
** Electric power transmission
** Propulsion transmission, technology allowing controlled application of power
*** Automatic transmission
*** Manual transmission
*** ...
capacity requirements, and
cost of use.
By cost and quality of service
From the least to the most expensive systems:
*
Web camera
A webcam is a video camera which is designed to record or stream to a computer or computer network. They are primarily used in videotelephony, livestreaming and social media, and security. Webcams can be built-in computer hardware or peripheral de ...
videophone and videoconferencing systems, either stand-alone or built-in, that serve as complements to personal computers, connected to other participants by
computer
A computer is a machine that can be programmed to Execution (computing), carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as C ...
and
VoIP
Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet t ...
networks—lowest direct cost, assuming the users already possess computers at their respective locations. Quality of service can range from low to very high, including
high definition video available on the latest model webcams. A related and similar device is a TV camera which is usually small, sits on top of a TV, and can connect to it via its
HDMI
High-Definition Multimedia Interface (HDMI) is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controller, ...
port, similar to how a webcam attaches to a computer via a USB port.
*
Videophone
Videotelephony, also known as videoconferencing and video teleconferencing, is the two-way or multipoint reception and transmission of audio and video signals by people in different locations for real time communication.McGraw-Hill Concise Ency ...
s—low to midrange cost. The earliest standalone models operated over either
plain old telephone service
Plain old telephone service (POTS), or plain ordinary telephone system, is a retronym for voice-grade telephone service employing analog signal transmission over copper loops. POTS was the standard service offering from telephone companies from 1 ...
(POTS) lines on the
PSTN
The public switched telephone network (PSTN) provides infrastructure and services for public telecommunication. The PSTN is the aggregate of the world's circuit-switched telephone networks that are operated by national, regional, or local teleph ...
telephone networks or more expensive
ISDN
Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Wo ...
lines, while newer models have largely migrated to
Internet protocol
The Internet Protocol (IP) is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet.
IP h ...
line service for higher image resolutions and sound quality. Quality of service for standalone videophones can vary from low to high;
* Huddle room or all-in-one systems —low to midrange cost, newer endpoint category based on standard videoconferencing systems, but defined by the camera, microphone(s), speakers, and codec contained in a single piece of hardware. Typically used in small to medium spaces where
beamforming
Beamforming or spatial filtering is a signal processing technique used in sensor arrays for directional signal transmission or reception. This is achieved by combining elements in an antenna array in such a way that signals at particular angles e ...
microphone array
A microphone array is any number of microphones operating in tandem. There are many applications:
* Systems for extracting voice input from ambient noise (notably telephones, speech recognition systems, hearing aids)
* Surround sound and relate ...
s located in the system are sufficient, in lieu of table or ceiling microphones in closer proximity to the in room participants. Quality of service is comparable to standard videoconferencing systems, varying from moderate to high. Some manufacturers' huddle room systems do not include the codec within the soundbar shaped unit, rather only camera, microphone, and speakers. These systems are usually still classified as huddle room systems, but, like webcams, rely on a USB connection to an external device, usually a PC, to process the video codec responsibilities. Despite its name, video conferencing systems for Huddle Rooms prevent participants from huddling close together to be seen in the camera. All-in-one systems for these types of rooms range from wide angles such as 110° Horizontal field of view (FOV) to as much as 360° FOV that allow a full view of the room.
*
Videoconferencing systems—midrange cost, usually using
multipoint control units or other bridging services to allow multiple parties on videoconference calls. Quality of service can vary from moderate to high.
*
Telepresence systems—highest capabilities and highest cost. Full ''high-end'' systems can involve specially built teleconference rooms to allow expansive views with very high levels of audio and video fidelity, to permit an 'immersive' videoconference. When the proper type and capacity transmission lines are provided between facilities, the quality of service reaches state-of-the-art levels.
Security concerns
Computer security
Computer security, cybersecurity (cyber security), or information technology security (IT security) is the protection of computer systems and networks from attack by malicious actors that may result in unauthorized information disclosure, the ...
experts have shown that poorly configured or inadequately supervised videoconferencing systems can permit an easy "virtual" entry by
computer hackers
A security hacker is someone who explores methods for breaching defenses and exploiting weaknesses in a computer system or network. Hackers may be motivated by a multitude of reasons, such as profit, protest, information gathering, challenge ...
and criminals into company premises and corporate boardrooms.
[Perlroth, Nicole]
Cameras May Open Up the Board Room to Hackers
, ''The New York Times'' online, January 22, 2012. A version of this article appeared in print on January 23, 2012, on page B1 of the New York edition with the headline: "Conferences Via the Net Called Risky".
Adoption
For over a century,
futurist
Futurists (also known as futurologists, prospectivists, foresight practitioners and horizon scanners) are people whose specialty or interest is futurology or the attempt to systematically explore predictions and possibilities abou ...
s have envisioned a future where telephone conversations will take place as actual face-to-face encounters with video as well as audio. Sometimes it is simply not possible or practical to have face-to-face meetings with two or more people. Sometimes a telephone conversation or conference call is adequate. Other times,
e-mail
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 ...
exchanges are adequate. However, videoconferencing adds another option, and can be considered when:
* A live conversation is needed
* Non-verbal (visual) information is an important component of the conversation
* The parties of the conversation can't physically come to the same location
* The expense or time of travel is a consideration
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 ...
said in 2001 that he used videoconferencing "three or four times a year", because digital scheduling was difficult and "if the overhead is super high, then you might as well just have a face-to-face meeting".
Some observers argue that three outstanding issues have prevented videoconferencing from becoming a widely adopted form of communication, despite the ubiquity of videoconferencing-capable systems.
[Van Meggelen, Jim]
The Problem With Video Conferencing
, 2005.
* Eye contact:
Eye contact
Eye contact occurs when two people look at each other's eyes at the same time. In humans, eye contact is a form of nonverbal communication and can have a large influence on social behavior. Coined in the early to mid-1960s, the term came from t ...
plays a large role in conversational
turn-taking
Turn-taking is a type of organization in conversation and discourse where participants speak one at a time in alternating turns. In practice, it involves processes for constructing contributions, responding to previous comments, and transitioning ...
, perceived attention and intent, and other aspects of group communication. While traditional telephone conversations give no eye contact cues, many videoconferencing systems are arguably worse in that they provide an incorrect impression that the remote interlocutor is avoiding eye contact. Some telepresence systems have cameras located in the screens that reduce the amount of
parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...
observed by the users. This issue is also being addressed through research that generates a synthetic image with eye contact using stereo reconstruction.
Telcordia Technologies
iconectiv is a supplier of network planning and network management services to telecommunications providers. Known as Bellcore after its establishment in the United States in 1983 as part of the break-up of the Bell System, the company's name ...
, formerly Bell Communications Research, owns a patent for eye-to-eye videoconferencing using rear projection screens with the video camera behind it, evolved from a 1960s U.S. military system that provided videoconferencing services between the
White House
The White House is the official residence and workplace of the president of the United States. It is located at 1600 Pennsylvania Avenue NW in Washington, D.C., and has been the residence of every U.S. president since John Adams in 1800. ...
and various other government and military facilities. This technique eliminates the need for special cameras or image processing.
* Appearance consciousness: A second psychological problem with videoconferencing is being on camera, with the video stream possibly even being recorded. The burden of presenting an acceptable on-screen appearance is not present in audio-only communication. Early studies by Alphonse Chapanis found that the addition of video actually impaired communication, possibly because of the consciousness of being on camera.
* Signal latency: The information transport of digital signals in many steps need time. In a telecommunicated conversation, an increased
latency (time lag) larger than about 150–300 ms becomes noticeable and is soon observed as unnatural and distracting. Therefore, next to a stable large bandwidth, a small
total round-trip time is another major technical requirement for the communication channel for interactive videoconferencing.
[Percy, Alan]
''Understanding Latency''
* Bandwidth and quality of service: In some countries, it is difficult or expensive to get a high quality connection that is fast enough for good-quality videoconferencing. Technologies such as
ADSL
Asymmetric digital subscriber line (ADSL) is a type of digital subscriber line (DSL) technology, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. ...
are usually provided as two separate lines (for uplink/downlink) because each has limited upload speeds and cannot upload and download simultaneously at full speed. As Internet speeds increase, higher quality and high definition videoconferencing will become more readily available.
* Complexity of systems: Most users are not technically experienced and want a simple interface. In hardware systems, an unplugged cord or an unresponsive remote control is seen as a failure, contributing to a perceived unreliability. Successful systems are backed by support teams who can provide fast assistance when required.
* Perceived lack of interoperability: Not all systems can readily interconnect; for example, ISDN and IP systems require a gateway. Popular software solutions cannot easily connect to hardware systems. Some systems use different standards, features, and qualities which can require additional configuration when connecting to dissimilar systems. Free software systems circumvent this limitation by making it relatively easy for a single user to communicate over multiple incompatible platforms.
* Expense of commercial systems: Well-designed
telepresence
Telepresence refers to a set of technologies which allow a person to feel as if they were present, to give the appearance or effect of being present via telerobotics, at a place other than their true location.
Telepresence requires that the user ...
systems require specially designed rooms which can cost hundreds of thousands of dollars to fit out their rooms with codecs, integration equipment (such as
Multipoint Control Units), high fidelity sound systems, and furniture. Monthly charges may also be required for bridging services and high capacity broadband service.
These are some of the reasons many organizations only use the systems internally, where there is less risk of loss of customers. An alternative for those lacking dedicated facilities is the
rental of videoconferencing-equipped meeting rooms in cities around the world. Clients can book rooms and turn up for the meeting, with all technical aspects being prearranged and support being readily available if needed. The issue of eye-contact may be solved with advancing technology, including smartphones which have the screen and camera in essentially the same place. In developed countries, the near-ubiquity of
smartphone
A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...
s,
tablet computer
A tablet computer, commonly shortened to tablet, is a mobile device, typically with a mobile operating system and touchscreen display processing circuitry, and a rechargeable battery in a single, thin and flat package. Tablets, being comput ...
s, and computers with built-in audio and webcams removes the need for expensive dedicated hardware.
Technology
Components and types
![GoogleHangoutsMeeting](https://upload.wikimedia.org/wikipedia/commons/f/ff/GoogleHangoutsMeeting.jpg)
The core technology used in a videotelephony system is digital compression of audio and video streams in real time. The hardware or
software
Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work.
At the lowest programming level, executable code consists ...
that performs compression is called a
codec
A codec is a device or computer program that encodes or decodes a data stream or signal. ''Codec'' is a portmanteau of coder/decoder.
In electronic communications, an endec is a device that acts as both an encoder and a decoder on a signal or da ...
(coder/decoder). Compression rates of up to 1:500 can be achieved. The resulting digital stream of 1s and 0s is subdivided into labeled
packets, which are then transmitted through a
digital network
A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections are ...
of some kind (usually
ISDN
Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Wo ...
or
IP).
The other components required for a videoconferencing system include:
* Video input: (
PTZ /
360° /
Fisheye)
video camera
A video camera is an optical instrument that captures videos (as opposed to a movie camera, which records images on film). Video cameras were initially developed for the television industry but have since become widely used for a variety of other ...
, or
webcam
A webcam is a video camera which is designed to record or stream to a computer or computer network. They are primarily used in videotelephony, livestreaming and social media, and security. Webcams can be built-in computer hardware or peripheral d ...
* Video output:
computer monitor
A computer monitor is an output device that displays information in pictorial or textual form. A discrete monitor comprises a visual display, support electronics, power supply, housing, electrical connectors, and external user controls.
The di ...
,
television
Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertisin ...
, or
projector
A projector or image projector is an optical device that projects an image (or moving images) onto a surface, commonly a projection screen. Most projectors create an image by shining a light through a small transparent lens, but some newer types ...
* Audio input:
microphone
A microphone, colloquially called a mic or mike (), is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public ...
s, CD/DVD player, cassette player, or any other source of PreAmp audio outlet.
* Audio output: usually
loudspeaker
A loudspeaker (commonly referred to as a speaker or speaker driver) is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound. A ''speaker system'', also often simply referred to as a "speaker" or " ...
s associated with the display device or telephone
* Data transfer: analog or digital telephone network,
LAN, or
Internet
The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, pub ...
* Computer: a data processing unit that ties together the other components, does the compressing and decompressing, and initiates and maintains the data linkage via the network.
There are basically three kinds of videoconferencing and videophone systems:
# Dedicated systems have all required components packaged into a single piece of equipment, usually a console with a high quality
remote control
In electronics, a remote control (also known as a remote or clicker) is an electronic device used to operate another device from a distance, usually wirelessly. In consumer electronics, a remote control can be used to operate devices such as ...
led video camera. These cameras can be controlled at a distance to pan left and right, tilt up and down, and zoom. They became known as PTZ cameras. The console contains all electrical interfaces, the control computer, and the software or hardware-based codec. Omnidirectional microphones are connected to the console, as well as a TV monitor with loudspeakers and/or a
video projector
A video projector is an image projector that receives a video signalling (telecommunication), signal and projects the corresponding image on a projection screen using a lens (optics), lens system. Video projectors use a very bright ultra-high-per ...
. There are several types of dedicated videoconferencing devices:
## Large group videoconferencing are built-in, large, expensive devices used for large rooms such as conference rooms and auditoriums.
## Small group videoconferencing are either non-portable or portable, smaller, less expensive devices used for small meeting rooms.
## Individual videoconferencing are usually portable devices, meant for single users, and have fixed cameras, microphones, and loudspeakers integrated into the console.
# Desktop systems are add-ons (hardware boards or software codec) to normal PCs and laptops, transforming them into videoconferencing devices. A range of different cameras and microphones can be used with the codec, which contains the necessary codec and transmission interfaces. Most of the desktops systems work with the
H.323
H.323 is a recommendation from the ITU Telecommunication Standardization Sector (ITU-T) that defines the protocols to provide audio-visual communication sessions on any packet network. The H.323 standard addresses call signaling and control, m ...
standard.
#
WebRTC
WebRTC (Web Real-Time Communication) is a free and open-source project providing web browsers and mobile applications with real-time communication (RTC) via application programming interfaces (APIs). It allows audio and video communication to wor ...
platforms use a web browser instead of dedicated
native application
In computing, native software or data-formats are those that were designed to run on a particular operating system. In a more technical sense, native code is code written specifically for a certain processor. In contrast, cross-platform software c ...
software. Solutions such as
Adobe Connect
Adobe Connect (formerly '' Presedia Publishing System'', ''Macromedia Breeze'', and ''Adobe Acrobat Connect Pro'') is a suite of software for remote training, web conferencing, presentation, and desktop sharing. All meeting rooms are organized in ...
and
Cisco WebEx
Webex by Cisco is an American company that develops and sells web conferencing, videoconferencing and contact center as a service applications. It was founded as WebEx in 1995 and taken over by Cisco Systems in 2007. Its headquarters are in San ...
can be accessed using a URL sent by the meeting organizer, and various degrees of security can be attached to the virtual "room". Often the user must download and install a
browser extension
A browser extension is a small software module for customizing a web browser. Browsers typically allow a variety of extensions, including user interface modifications, cookie management, ad blocking, and the custom scripting and styling of web p ...
to enable access to the local camera and microphone and establish a connection to the meeting. But WebRTC doesn't require any special software, instead a WebRTC compliant internet browser itself provides the facilities for 1-to-1 and 1-to-many videoconferencing calls. Several enhancements to WebRTC are provided by independent vendors.
Videoconferencing modes
Videoconferencing systems use two methods to determine which video feed or feeds to display.
''Continuous Presence'' simply displays all participants at the same time,
usually with the exception that the viewer either does not see their own feed, or sees their own feed in miniature.
''Voice-Activated Switch'' selectively chooses a feed to display at each endpoint, with the goal of showing the person who is currently speaking. This is done by choosing the feed (other than the viewer) which has the loudest audio input (perhaps with some filtering to avoid switching for very short-lived volume spikes). Often if no remote parties are currently speaking, the feed with the last speaker remains on the screen.
Echo cancellation
Acoustic echo cancellation
Echo suppression and echo cancellation are methods used in telephony to improve voice quality by preventing echo from being created or removing it after it is already present. In addition to improving subjective audio quality, echo suppression i ...
(AEC) is a processing
algorithm
In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algorithms are used as specificat ...
that uses the knowledge of audio output to monitor audio input and filter from it noises that echo back after some time delay. If unattended, these echoes can be re-amplified several times, leading to problems including:
* The remote party hearing their own voice coming back at them (usually significantly delayed)
* Strong
reverberation
Reverberation (also known as reverb), in acoustics, is a persistence of sound, after a sound is produced. Reverberation is created when a sound or signal is reflected causing numerous reflections to build up and then decay as the sound is abso ...
, which makes the voice channel useless
* Howling created by feedback
Echo cancellation is a processor-intensive task that usually works over a narrow range of sound delays.
Bandwidth requirements
![Bildtelefon T-View 100](https://upload.wikimedia.org/wikipedia/commons/9/91/Bildtelefon_T-View_100.JPG)
Videophones have historically employed a variety of transmission and reception bandwidths, which can be understood as data transmission speeds. The lower the transmission/reception bandwidth, the lower the data transfer rate, resulting in a progressively limited and poorer image quality (i.e. lower resolution and/or frame rate). Data transfer rates and live video image quality are related, but are also subject to other factors such as
data compression techniques. Some early videophones employed very low data transmission rates with a resulting poor video quality.
''Broadband bandwidth'' is often called "''high-speed''", because it usually has a high rate of data transmission. In general, any connection of 256 kbit/s (0.256 Mbit/s) or greater is more concisely considered broadband Internet. The
International Telecommunication Union Telecommunication Standardization Sector (ITU-T) recommendation
I.113 has defined broadband as a transmission capacity at 1.5 to 2Mbit/s. The
Federal Communications Commission
The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdiction ...
(United States) definition of broadband is 25 Mbit/s.
Currently, adequate video for some purposes becomes possible at data rates lower than the ITU-T broadband definition, with rates of 768 kbit/s and 384 kbit/s used for some videoconferencing applications, and rates as low as 100 kbit/s used for videophones using
H.264/MPEG-4 AVC compression protocols. The newer
MPEG-4
MPEG-4 is a group of international standards for the compression of digital audio and visual data, multimedia systems, and file storage formats. It was originally introduced in late 1998 as a group of audio and video coding formats and related tec ...
video
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) syste ...
and
audio compression format can deliver high-quality video at 2Mbit/s, which is at the low end of
cable modem
A cable modem is a type of network bridge that provides bi-directional data communication via radio frequency channels on a hybrid fibre-coaxial (HFC), radio frequency over glass (RFoG) and coaxial cable infrastructure. Cable modems are primaril ...
and
ADSL
Asymmetric digital subscriber line (ADSL) is a type of digital subscriber line (DSL) technology, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. ...
broadband performance.
Standards
![TANDBERG E20](https://upload.wikimedia.org/wikipedia/commons/6/61/TANDBERG_E20.jpg)
The
International Telecommunication Union
The International Telecommunication Union is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established on 17 May 1865 as the International Telegraph Unio ...
(ITU) has three umbrellas of standards for videoconferencing:
* ITU
H.320
H.320 or Narrow-band visual telephone systems and terminal equipment is an ''umbrella Recommendation'' by the ITU-T for running Multimedia (Audio/Video/Data) over ISDN based networks. The main protocols in this suite are H.221, H.230, H.242, au ...
is known as the standard for
public switched telephone network
The public switched telephone network (PSTN) provides Communications infrastructure, infrastructure and services for public Telecommunications, telecommunication. The PSTN is the aggregate of the world's circuit-switched telephone networks that ...
s (PSTN) or videoconferencing over integrated services digital networks. While still prevalent in Europe,
ISDN
Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Wo ...
was never widely adopted in the United States and Canada.
* ITU
H.264
Advanced Video Coding (AVC), also referred to as H.264 or MPEG-4 Part 10, is a video compression standard based on block-oriented, motion-compensated coding. It is by far the most commonly used format for the recording, compression, and distri ...
Scalable Video Coding (SVC) is a compression standard that enables videoconferencing systems to achieve highly error resilient
Internet Protocol
The Internet Protocol (IP) is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet.
IP h ...
(IP) video transmissions over the public Internet without quality-of-service enhanced lines. This standard has enabled wide scale deployment of high definition desktop videoconferencing and made possible new architectures, which reduces latency between the transmitting sources and receivers, resulting in more fluid communication without pauses. In addition, an attractive factor for IP videoconferencing is that it is easier to set up for use along with web conferencing and data collaboration. These combined technologies enable users to have a richer multimedia environment for live meetings, collaboration and presentations.
* ITU ITU-T V-Series Recommendations, V.80: videoconferencing is generally compatibilized with H.324 standard point-to-point videotelephony over regular (POTS) phone lines.
The Unified Communications Interoperability Forum (UCIF), a non-profit alliance between communications vendors, launched in May 2010. The organization's vision is to maximize the interoperability of UC based on existing standards. Founding members of UCIF include Hewlett-Packard, HP, Microsoft,
Polycom
Poly, formerly Polycom, a part of HP Inc., is an American multinational corporation that develops video, voice and content collaboration and communication technology.
Polycom was co-founded in 1990 by Brian L Hinman and Jeffrey Rodman. In 2018 P ...
, Logitech/LifeSize, LifeSize Communications, and Juniper Networks.
Call setup
Videoconferencing in the late 20th century was limited to the
H.323
H.323 is a recommendation from the ITU Telecommunication Standardization Sector (ITU-T) that defines the protocols to provide audio-visual communication sessions on any packet network. The H.323 standard addresses call signaling and control, m ...
protocol (notably Cisco's Skinny Client Control Protocol, SCCP implementation was an exception), but newer videophones often use Session Initiation Protocol, SIP, which is often easier to set up in home networking environments. It is a text-based protocol, incorporating many elements of the Hypertext Transfer Protocol (HTTP) and the Simple Mail Transfer Protocol (SMTP). H.323 is still used, but more commonly for business videoconferencing, while SIP is more commonly used in personal consumer videophones. A number of call-setup methods based on instant messaging protocols such as
Skype
Skype () is a proprietary telecommunications application operated by Skype Technologies, a division of Microsoft, best known for VoIP-based videotelephony, videoconferencing and voice calls. It also has instant messaging, file transfer, deb ...
also now provide video.
Another protocol used by videophones is H.324, which mixes call setup and video compression. Videophones that work on regular phone lines typically use H.324, but the bandwidth is limited by the modem to around 33 kbit/s, limiting the video quality and frame rate. A slightly modified version of H.324 called 3G-324M defined by 3GPP is also used by some cellphones that allow video calls, typically for use only in
UMTS
The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the Inte ...
networks.
[
IMTC]
IMTC Press Coverage
, International Multimedia Telecommunications Consortium (IMTC), April 1, 2001 to November 16, 2004.
There is also
H.320
H.320 or Narrow-band visual telephone systems and terminal equipment is an ''umbrella Recommendation'' by the ITU-T for running Multimedia (Audio/Video/Data) over ISDN based networks. The main protocols in this suite are H.221, H.230, H.242, au ...
standard, which specified technical requirements for narrow-band visual telephone systems and terminal equipment, typically for videoconferencing and videophone services. It applied mostly to dedicated circuit-based switched network (point-to-point) connections of moderate or high bandwidth, such as through the medium-bandwidth
ISDN
Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Wo ...
digital phone protocol or a fractionated high bandwidth T1 lines. Modern products based on H.320 standard usually support also H.323 standard.
The IAX2 protocol also supports videophone calls natively, using the protocol's own capabilities to transport alternate media streams. A few hobbyists obtained the Nortel 1535 Color SIP Videophone cheaply in 2010 as surplus after Nortel's bankruptcy and deployed the sets on the Asterisk (PBX) platform. While additional software is required to patch together multiple video feeds for conference calls or convert between dissimilar video standards, SIP calls between two identical handsets within the same PBX were relatively straightforward.
Conferencing layers
The components within a videoconferencing system can be divided up into several different layers: User Interface, Conference Control, Control or Signaling Plane, and Media Plane.
Videoconferencing User Interfaces (VUI) can be either graphical or voice-responsive. Many in the industry have encountered both types of interface, and normally a graphical interface is encountered on a computer. User interfaces for conferencing have a number of different uses; they can be used for scheduling, setup, and making a videocall. Through the user interface the administrator is able to control the other three layers of the system.
Conference Control performs resource allocation, management, and routing. This layer along with the User Interface creates meetings (scheduled or unscheduled) or adds and removes participants from a conference.
Control (Signaling) Plane contains the stacks that signal different endpoints to create a call and/or a conference. Signals can be, but aren't limited to,
H.323
H.323 is a recommendation from the ITU Telecommunication Standardization Sector (ITU-T) that defines the protocols to provide audio-visual communication sessions on any packet network. The H.323 standard addresses call signaling and control, m ...
and Session Initiation Protocol (SIP) Protocols. These signals control incoming and outgoing connections as well as session parameters.
The Media Plane controls the audio and video mixing and streaming. This layer manages Real-Time Transport Protocols, User Datagram Packets (UDP) and RTP Control Protocol, Real-Time Transport Control Protocol (RTCP). The RTP and UDP normally carry information such the payload type which is the type of codec, frame rate, video size, and many others. RTCP on the other hand acts as a quality control Protocol for detecting errors during streaming.
Multipoint control
Simultaneous videoconferencing among three or more remote points is possible in a hardware-based system by means of a
Multipoint Control Unit (MCU). This is a bridge that interconnects calls from several sources (in a similar way to the audio conference call). All parties call the MCU, or the MCU can also call the parties which are going to participate, in sequence. There are MCU bridges for IP and ISDN-based videoconferencing. There are MCUs which are pure software, and others which are a combination of hardware and software. An MCU is characterised according to the number of simultaneous calls it can handle, its ability to conduct transposing of data rates and protocols, and features such as Continuous Presence, in which multiple parties can be seen on-screen at once. MCUs can be stand-alone hardware devices, or they can be embedded into dedicated videoconferencing units.
The MCU consists of two logical components:
# A single multipoint controller (MC), and
# Multipoint Processors (MP), sometimes referred to as the mixer.
The MC controls the conferencing while it is active on the signaling plane, which is simply where the system manages conferencing creation, endpoint signaling and in-conferencing controls. This component negotiates parameters with every endpoint in the network and controls conferencing resources.
While the MC controls resources and signaling negotiations, the MP operates on the media plane and receives media from each endpoint. The MP generates output streams from each endpoint and redirects the information to other endpoints in the conference.
Some systems are capable of multipoint conferencing with no MCU, stand-alone, embedded or otherwise. These use a standards-based H.323 technique known as "decentralized multipoint", where each station in a multipoint call exchanges video and audio directly with the other stations with no central "manager" or other bottleneck. The advantages of this technique are that the video and audio will generally be of higher quality because they don't have to be relayed through a central point. Also, users can make ad hoc multipoint calls without any concern for the availability or control of an MCU. This added convenience and quality comes at the expense of some increased network bandwidth, because every station must transmit to every other station directly.
Cloud storage
Cloud-based videoconferencing can be used without the hardware generally required by other videoconferencing systems, and can be designed for use by Small and medium enterprises, SMEs, or larger international or multinational corporations like
Facebook
Facebook is an online social media and social networking service owned by American company Meta Platforms. Founded in 2004 by Mark Zuckerberg with fellow Harvard College students and roommates Eduardo Saverin, Andrew McCollum, Dustin M ...
.
Cloud-based systems can handle either 2D or 3D video broadcasting. Cloud-based systems can also implement mobile calls, VOIP, and other forms of video calling. They can also come with a video recording function to archive past meetings.
Impact
![Video Call](https://upload.wikimedia.org/wikipedia/commons/6/65/Video_Call.jpg)
High speed Internet connectivity has become more widely available and affordable, as has good-quality video capture and display hardware. Consequently, personal videoconferencing systems based on webcams, personal computer systems, software compression, and the Internet have become progressively more affordable by the general public. The availability of freeware (often as part of chat programs) has made software based videoconferencing accessible to many.
The widest deployment of videotelephony now occurs in
mobile phone
A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whil ...
s. Nearly all mobile phones supporting
UMTS
The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the Inte ...
networks can work as videophones using their internal cameras and are able to make video calls wirelessly to other UMTS users anywhere. As of the second quarter of 2007, there are over 131 million UMTS users (and hence potential videophone users), on 134 networks in 59 countries. Mobile phones can also use broadband wireless Internet, whether through the cell phone network or over a local Wi-Fi connection, along with software-based videophone apps to make calls to any video-capable Internet user, whether mobile or fixed.
Hearing impairment, Deaf, hard-of-hearing, and mutism, mute individuals have a particular role in the development of affordable high-quality videotelephony as a means of communicating with each other in
sign language
Sign languages (also known as signed languages) are languages that use the visual-manual modality to convey meaning, instead of spoken words. Sign languages are expressed through manual articulation in combination with non-manual markers. Sign l ...
. Unlike Video Relay Service, which is intended to support communication between a caller using sign language and another party using spoken language, videoconferencing can be used directly between two deaf signers.
Videophones are increasingly used in the provision of
telemedicine to the elderly, disabled, and to those in remote locations, where the ease and convenience of quickly obtaining diagnostic and consultative medical services are readily apparent.
[Videophone Scheme Could Provide 'Virtual Care' for Elderly Residents](_blank)
, Aberdeen Press & Journal (UK), published in Europe Intelligence Wire, 13 November 2006, retrieved 2009-04-14; In one single instance quoted in 2006: "A nurse-led clinic at Letham has received positive feedback on a trial of a video-link which allowed 60 pensioners to be assessed by medics without travelling to a doctor's office or medical clinic."
A further improvement in telemedical services has been the development of new technology incorporated into special videophones to permit remote diagnostic services, such as blood sugar level, blood pressure, and vital signs monitoring. Such units are capable of relaying both regular audio-video plus medical data over either standard (POTS) telephone or newer broadband lines.
["Motion Media Unveils Two New Healthcare Videophones—CareStation 156s and CareStation 126s", Business Wire, May 3, 2004.]
![Tandberg Image Gallery - telepresence-t3-side-view-hires](https://upload.wikimedia.org/wikipedia/commons/c/cc/Tandberg_Image_Gallery_-_telepresence-t3-side-view-hires.jpg)
Videotelephony has also been deployed in corporate teleconferencing, also available through the use of public access videoconferencing rooms. A higher level of videoconferencing that employs advanced telecommunication technologies and high-resolution displays is called ''
telepresence
Telepresence refers to a set of technologies which allow a person to feel as if they were present, to give the appearance or effect of being present via telerobotics, at a place other than their true location.
Telepresence requires that the user ...
''.
Today the principles, if not the precise mechanisms, of a videophone are employed by many users worldwide in the form of
webcam
A webcam is a video camera which is designed to record or stream to a computer or computer network. They are primarily used in videotelephony, livestreaming and social media, and security. Webcams can be built-in computer hardware or peripheral d ...
videocalls using personal computers, with inexpensive webcams, microphones, and free videocalling Web client programs. Thus an activity that was disappointing as a separate service has found a niche as a minor feature in software products intended for other purposes.
According to Juniper Research, smartphone videophone users will reach 29 million by 2015 globally.
[Smartphone Video Call Users to reach 29 million by 2015 Globally, finds Juniper Research](_blank)
A study conducted by Pew Research in 2010, revealed that 7% of Americans have made a mobile video call.
Government and law
In the United States, videoconferencing has allowed testimony to be used for an individual who is unable or prefers not to attend the physical legal settings or would be subjected to severe psychological stress in doing so, however, there is a controversy on the use of testimony by foreign or unavailable witnesses via video transmission, regarding the violation of the Sixth Amendment to the United States Constitution, Confrontation Clause of the Sixth Amendment of the U.S. Constitution.
In a military investigation in North Carolina, Afghanistan, Afghan witnesses have testified via videoconferencing.
In Hall County, Georgia, videoconferencing systems are used for initial court appearances. The systems link jails with court rooms, reducing the expenses and security risks of transporting prisoners to the courtroom.
The Social Security Administration, U.S. Social Security Administration (SSA), which oversees the world's largest administrative judicial system under its Social Security (United States)#Office of Disability Adjudication and Review (ODAR), Office of Disability Adjudication and Review (ODAR),
[U.S. Social Security Administration]
New National Hearing Centre
has made extensive use of videoconferencing to conduct hearings at remote locations. In Fiscal Year (FY) 2009, the U.S. Social Security Administration (SSA) conducted 86,320 videoconferenced hearings, a 55% increase over FY 2008. In August 2010, the SSA opened its fifth and largest videoconferencing-only National Hearing Center (NHC), in St. Louis, Missouri. This continues the SSA's effort to use video hearings as a means to clear its substantial hearing backlog. Since 2007, the SSA has also established NHCs in Albuquerque, New Mexico, Baltimore, Maryland, Falls Church, Virginia, Falls Church, Virginia, and Chicago.
Education
![American, Indonesian Students Link Hands Via Distance Learning](https://upload.wikimedia.org/wikipedia/commons/2/2a/American%2C_Indonesian_Students_Link_Hands_Via_Distance_Learning.jpg)
Videoconferencing provides students with the chance to learn by participating in two-way communication forums. Because it is live, videotelephony allows teachers to access remote or otherwise isolated learners. Students from diverse communities and backgrounds can come together to learn about one another through practices known as telecollaboration(in foreign language education) and virtual exchange, although language barriers will continue to be present. Such students are able to explore, communicate, analyze, and share information and ideas with one another.
Through videoconferencing, students can visit other parts of the world, including museums and other cultural and educational sites. Such history of virtual learning environments, virtual field trips can provide enriched learning opportunities to students, especially those who are geographically isolated or economically disadvantaged. Small schools can use these technologies to pool resources and provide courses, such as in foreign languages, which could not otherwise be offered.
Some benefits that videoconferencing can provide to education include:
* faculty members keeping in touch with classes while attending conferences;
* faculty members attending conferences 'virtually'
* guest lecturers brought in classes from other institutions;
* researchers collaborating with colleagues at other institutions on a regular basis without loss of time due to travel;
* schools with multiple campuses collaborating and sharing professors;
* schools from two separate nations engaging in Virtual exchange, cross-cultural exchanges;
* faculty members participating in thesis defenses at other institutions;
* administrators on tight schedules collaborating on budget preparation from different parts of campus;
* faculty committee auditioning scholarship candidates;
* researchers answering questions about grant proposals from agencies or review committees;
* alternative enrollment structures to purely in-person attendance;
* student interviews with employers in other cities, and
* teleseminars.
Medicine and health
Videoconferencing is a highly useful technology for real time
telemedicine and telenursing applications, such as remote diagnostics, diagnosis, consulting, prevention, treatment, and transmission of medical imaging, medical images. With videoconferencing, patients may contact nurses and physicians in medical emergency, emergency or routine situations; physicians and other paramedical professionals can discuss cases across large distances. Rural areas can use this technology for diagnostic purposes, thus saving lives and making more efficient use of health care money. For example, a rural medical center in Ohio used videoconferencing to successfully cut the number of transfers of sick infants to a hospital away. This had previously cost nearly $10,000 per transfer.
Special peripherals such as microscopes fitted with digital cameras, endoscopy, videoendoscopes, medical ultrasound imaging devices, otoscopes, etc., can be used in conjunction with videoconferencing equipment to transmit data about a patient. Recent developments in mobile collaboration on hand-held mobile devices have also extended video-conferencing capabilities to locations previously unreachable, such as a remote community, long-term care facility, or a patient's home.
Business
Videoconferencing can enable individuals in distant locations to participate in meetings on short notice, with time and money savings. Technology such as
VoIP
Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet t ...
can be used in conjunction with desktop videoconferencing to enable low-cost face-to-face business meetings without leaving the desk, especially for businesses with widespread offices. The technology is also used for remote work. One research report based on a sampling of 1,800 corporate employees showed that, as of June 2010, 54% of the respondents with access to videoconferencing used it "all of the time" or "frequently".
[By Alison Diane, InformationWeek.]
Executives Demand Communications Arsenal
." September 30, 2010. Retrieved October 5, 2010.[How We Work: Communication Trends of Business Professionals](_blank)
, Plantronics Inc., 2010. Retrieved October 13, 2010.
Intel Corporation have used videoconferencing to reduce both costs and environmental impacts of its business operations.
[E. Curry, B. Guyon, C. Sheridan, and B. Donnellan]
"Developing a Sustainable IT Capability: Lessons From Intel's Journey"
MIS Quarterly Executive, vol. 11, no. 2, pp. 61–74, 2012.
Videoconferencing is also currently being introduced on online networking websites, in order to help businesses form profitable relationships quickly and efficiently without leaving their place of work. This has been leveraged by banks to connect busy banking professionals with customers in various locations using video banking technology.
Videoconferencing on hand-held mobile devices (mobile collaboration technology) is being used in industries such as manufacturing, energy, healthcare, insurance, government, and public safety. Live, visual interaction removes traditional restrictions of distance and time, often in locations previously unreachable, such as a manufacturing plant floor thousands of miles away.
In the increasingly Globalization, globalized film industry, videoconferencing has become useful as a method by which creative talent in many different locations can collaborate closely on the complex details of film production. For example, for the 2013 award-winning animated film ''Frozen (2013 film), Frozen'', Burbank, California, Burbank-based Walt Disney Animation Studios hired the New York City-based husband-and-wife songwriting team of Robert Lopez and Kristen Anderson-Lopez to write the songs, which required two-hour-long transcontinental videoconferences nearly every weekday for about 14 months.
With the development of lower-cost endpoints, the integration of video cameras into personal computers and mobile devices, and software applications such as FaceTime, Skype, Microsoft Teams, Teams and Zoom, videoconferencing has changed from just a business-to-business offering to include business-to-consumer (and consumer-to-consumer) use.
Although videoconferencing has frequently proven its value, research has shown that some non-managerial employees prefer not to use it due to several factors, including anxiety. Some such anxieties can often be avoided if managers use the technology as part of the normal course of business. Remote workers can also adopt certain behaviors and best practices to stay connected with their co-workers and company.
Researchers also find that attendees of business and medical videoconferences must work harder to interpret information delivered during a conference than they would if they attended face-to-face. They recommend that those coordinating videoconferences make adjustments to their conferencing procedures and equipment.
Press
The concept of press videoconferencing was developed in October 2007 by the PanAfrican Press Association (APPA), a Paris France-based non-governmental organization, to allow African journalists to participate in international press conferences on developmental and good governance issues.
Press videoconferencing permits international press conferences via videoconferencing over the Internet. Journalists can participate on an international press conference from any location, without leaving their offices or countries. They need only be seated by a computer connected to the Internet in order to ask their questions.
In 2004, the International Monetary Fund introduced the Online Media Briefing Center, a password-protected site available only to professional journalists. The site enables the IMF to present press briefings globally and facilitates direct questions to briefers from the press. The site has been copied by other international organizations since its inception. More than 4,000 journalists worldwide are currently registered with the IMF.
Sign language
![Video interpreter](https://upload.wikimedia.org/wikipedia/commons/a/a4/Video_interpreter.svg)
One of the first demonstrations of the ability for telecommunications to help sign language users communicate with each other occurred when AT&T's videophone (trademarked as the "Picturephone") was introduced to the public at the 1964 New York World's Fair—two deaf users were able to communicate freely with each other between the fair and another city.
Various universities and other organizations, including BT Research#History, British Telecom's Martlesham facility, have also conducted extensive research on sign language, signing via videotelephony.
[
New Scientist]
Telephones Come To Terms With Sign Language
, New Scientist, 19 August 1989, Vol.123, Iss.No.1678, pp.31.
[
Whybray, M.W]
Moving Picture Transmission at Low Bitrates for Sign Language Communication
, Martlesham, England: British Telecom Laboratories, 1995.
The use of sign language via videotelephony was hampered for many years due to the difficulty of its use over slow Plain old telephone service, analogue copper phone lines,
coupled with the high cost of better quality Integrated Services Digital Network, ISDN (data) phone lines.
Those factors largely disappeared with the introduction of more efficient and powerful
video codec
A video codec is software or hardware that compresses and decompresses digital video. In the context of video compression, ''codec'' is a portmanteau of ''encoder'' and ''decoder'', while a device that only compresses is typically called an '' ...
s and the advent of lower cost high-speed ISDN data and Internet Protocol, IP (Internet) services in the 1990s.
21st-century improvements
Significant improvements in video call quality of service for the deaf occurred in the United States in 2003 when Sorenson Media Inc. (formerly Sorenson Vision Inc.), a video compression software coding company, developed its VP-100 model stand-alone videophone 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 Sorenson codec, video compression codec for unequaled video quality and ease of use with video relay services. Favourable reviews quickly led to its popular usage at educational facilities for the deaf, and from there to the greater deaf community.
[
Fitzgerald, Thomas J]
For the Deaf, Communication Without the Wait
The New York Times, December 18, 2003.
Coupled with similar high-quality videophones introduced by other electronics manufacturers, the Broadband Internet access, availability of high speed Internet, and Video Relay Service#U.S. VRS regulation, sponsored video relay services authorized by the U.S.
Federal Communications Commission
The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdiction ...
in 2002, VRS services for the deaf underwent rapid growth in that country.
Using such video equipment in the present day, the deaf, hard-of-hearing, and speech-impaired can communicate between themselves and with hearing individuals using
sign language
Sign languages (also known as signed languages) are languages that use the visual-manual modality to convey meaning, instead of spoken words. Sign languages are expressed through manual articulation in combination with non-manual markers. Sign l ...
. The United States and several other countries compensate companies to provide "Video Relay Services" (VRS). Telecommunication equipment can be used to talk to others via a sign language interpreter, who uses a conventional telephone at the same time to communicate with the deaf person's party. Video equipment is also used to do on-site sign language translation via Video Remote Interpreting (VRI). The relatively low cost and widespread availability of 3G
mobile phone
A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whil ...
technology with video calling capabilities have given deaf and speech-impaired users a greater ability to communicate with the same ease as others. Some wireless operators have even started free sign language gateways.
Sign language interpretation services via VRS or by VRI are useful in the present day where one of the parties is
deaf
Deafness has varying definitions in cultural and medical contexts. In medical contexts, the meaning of deafness is hearing loss that precludes a person from understanding spoken language, an Audiology, audiological condition. In this context it ...
, hard-of-hearing, or Speech disorder, speech-impaired (mute). In such cases the interpretation flow is normally within the same principal language, such as French Sign Language (LSF) to spoken French, Spanish Sign Language (LSE) to spoken Spanish, British Sign Language (BSL) to spoken English, and American Sign Language (ASL) also to spoken English (since BSL and ASL are completely distinct from each other), German Sign Language (DGS) to spoken German, and so on.
Multilingual Interpreters#Sign language interpreting, sign language interpreters, who can also translate as well across principal languages (such as a multilingual interpreter interpreting a call from a deaf person using ASL to reserve a hotel room at a hotel in the Dominican Republic whose staff speaks Spanish only, therefore the interpreter has to use ASL, spoken Spanish, and spoken English to facilitate the call for the deaf person), are also available, albeit less frequently. Such activities involve considerable mental processing efforts on the part of the translator, since sign languages are distinct natural languages with their own Linguistics, construction, semantics and syntax, different from the aural version of the same principal language.
With video interpreting,
sign language
Sign languages (also known as signed languages) are languages that use the visual-manual modality to convey meaning, instead of spoken words. Sign languages are expressed through manual articulation in combination with non-manual markers. Sign l ...
interpreters work remotely with live
video
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) syste ...
and Sound recording and reproduction, audio feeds, so that the interpreter can see the deaf or mute party, and converse with the hearing party, and vice versa. Much like telephone interpreting, video interpreting can be used for situations in which no on-site Interpreters#Sign language interpreting, interpreters are available. However, video interpreting cannot be used for situations in which all parties are speaking via telephone alone. VRS and VRI interpretation requires all parties to have the List of video telecommunication services and product brands, necessary equipment. Some advanced equipment enables interpreters to control the video camera remotely, in order to Zoom lens, zoom in and out or to point the camera toward the party that is signing.
Comparison of Sign Language communication tools
Descriptive names and terminology
The name "videophone" never became as standardized as its earlier counterpart "telephone", resulting in a variety of names and terms being used worldwide, and even within the same region or country. Videophones are also known as "video phones", "videotelephones" (or "video telephones") and often by an early trademarked name ''Picturephone'', which was the world's first commercial videophone produced in volume. The compound name "videophone" slowly entered into general use after 1950,
[Videophone definition](_blank)
, Merriam-Webster Online. Retrieved April 13, 2009
although "video telephone" likely entered the lexicon earlier after ''video'' was coined in 1935.
[Video definition](_blank)
, Online Etymology Dictionary
''Videophone calls'' (also: ''videocalls'', ''video chat'') as well as Skype, ''Skype'' and ''Skyping'' in verb form
[Howell, Peter]
The Lasting Appeal of 2001: A Space Odyssey
, ''Toronto Star'' website, November 1, 2014; also published in print as "Forever 2001: Why Stanley Kubrick's Sci-Fi Masterpience Is More Popular Now Than In 1968", November 1, 2014, p. E1, E10. Retrieved November 2, 2014 from TheStar.com. Quote: "Public esteem and critical estimation of 2001 has grown steadily ever since, even as the title date has come and gone with very few of its far-out advancements having been realized—although... innovations like iPads and Skyping have finally caught up with Kubrick's view of future living. [2001 actor] Lockwood marvels at how he's now able to Skype his wife and daughter, just as he does his movie parents in the space-to-Earth communication scene in 2001." differ from videoconferencing in that they expect to serve individuals, not groups.
However that distinction has become increasingly blurred with technology improvements such as Broadband Internet access, increased bandwidth and sophisticated software clients that can allow for multiple parties on a call. In general everyday usage the term ''videoconferencing'' is now frequently used instead of ''videocall'' for point-to-point calls between two units. Both videophone calls and videoconferencing are also now commonly referred to as a ''video link''.
''
Webcam
A webcam is a video camera which is designed to record or stream to a computer or computer network. They are primarily used in videotelephony, livestreaming and social media, and security. Webcams can be built-in computer hardware or peripheral d ...
s'' are popular, relatively low-cost devices which can provide live video and audio streams via personal computers, and can be used with many
software clients for both video calls and videoconferencing.
A ''List of video telecommunication services and product brands#Videoconferencing systems meant for multiple participants, videoconference system'' is generally higher cost than a videophone and deploys greater capabilities. A ''videoconference'' (also known as a ''videoteleconference'') allows two or more locations to communicate via live, simultaneous two-way video and audio transmissions. This is often accomplished by the use of a
multipoint control unit (a centralized distribution and call management system) or by a similar non-centralized multipoint capability embedded in each videoconferencing unit. Again, technology improvements have circumvented traditional definitions by allowing multiple party videoconferencing via web-based applications.
A ''Telepresence, telepresence system'' is a high-end videoconferencing system and service usually employed by company, enterprise-level corporate offices. Telepresence conference rooms use state-of-the art room designs, video cameras, displays, sound-systems and processors, coupled with high-to-very-high capacity bandwidth transmissions.
Typical uses of the various technologies described above include calling one-to-one or conferencing one-to-many or many-to-many for personal, business, educational, Video Relay Service, deaf Video Relay Service and telemedicine, tele-medical, diagnostic and telerehabilitation, rehabilitative purposes.
[
USA Today. ''"Video Chat Growing by Light-Year Leaps''", ''USA Today'', March 31, 2010, p. L01d.
] personal videocalls to prison, inmates incarcerated in penitentiaries, and videoconferencing to resolve Aircraft maintenance checks, airline engineering issues at hangar, maintenance facilities, are being created or evolving on an ongoing basis.
Other names for ''videophone'' that have been used in English are: ''Viewphone'' (the British Telecom equivalent to History of videotelephony#AT&T Picturephone Mod I: 1964–1970, AT&T's Picturephone),
and ''visiophone'', a common French translation that has also crept into limited English usage, as well as over twenty less common names and expressions. Latin-based translations of ''videophone'' in other languages include ''vidéophone'' (French), ''Bildtelefon'' (German), ''videotelefono'' (Italian), both ''videófono'' and ''videoteléfono'' (Spanish), both ''beeldtelefoon'' and ''videofoon'' (Dutch), and ''videofonía'' (Catalan).
A ''telepresence robot'' (also telerobotics) is a robotically controlled and motorized videoconferencing display to help give a better sense of remote physical presence for communication and collaboration in an office, home, school, etc. when one cannot be there in person. The robotic avatar device can move about and look around at the command of the remote person it represents.
Popular culture
In science fiction literature, names commonly associated with videophones include "telephonoscope", "telephote", ''viewphone'', ''vidphone'', ''vidfone'', and ''visiphone''. The first example was probably the cartoon "Edison's Telephonoscope" by George du Maurier in ''Punch'' 1878. In «In the year 2889», published 1889, the French author Jules Verne predicts that «''The transmission of speech is an old story; the transmission of images by means of sensitive mirrors connected by wires is a thing but of yesterday.''» In many science fiction movies and TV programs that are set in the future, videophones were used as a primary method of communication. One of the first movies where a videophone was used was Fritz Lang, Fritz Lang's ''Metropolis (1927 film), Metropolis'' (1927).
Other notable examples of videophones in popular culture include an iconic scene from the 1968 film 2001: A Space Odyssey (film), ''2001: A Space Odyssey'' set on List of spacecraft from the Space Odyssey series#Space Station V, Space Station V. The movie was released shortly before AT&T began its efforts to commercialize its Picturephone Mod II service in several cities and depicts a video call to Earth using an advanced AT&T videophone—which it predicts will cost $1.70 for a two-minute call in 2001 (a fraction of the company's real rates on Earth in 1968). Film director Stanley Kubrick strove for scientific accuracy, relying on interviews with scientists and engineers at Bell Labs in the United States. Dr. Lawrence Rabiner, Larry Rabiner of Bell Labs, discussing videophone research in the documentary ''2001: The Making of a Myth'', stated that in the mid-to late-1960s videophones "...captured the imagination of the public and... of Mr. Kubrick and the people who reported to him". In one ''2001'' movie scene a central character, Dr. Heywood Floyd, calls home to contact his family, a social feature noted in the ''Making of a Myth''. Floyd talks with and views his daughter from a space station in Geocentric orbit, orbit above the Earth, discussing what type of present he should bring home for her.
A portable videophone is also featured prominently in the 2009 science fiction movie ''Moon (2009 film), Moon'', where the story's protagonist, Sam Bell, also calls home as well to communicate with loved ones. Bell, the lone occupant of a mining station on the far side of the Earth's moon, finally succeeds in making his video call after an extended work period, but becomes traumatized when viewing his daughter.
Other earlier examples of videophones in popular culture included a videophone that was featured in the Warner Bros. cartoon, ''Plane Daffy'', in which the female spy Hatta Mari used a videophone to communicate with Adolf Hitler (1944), as well as a device with the same functionality has been used by the comic strip character Dick Tracy#Evolution of the strip, ''Dick Tracy'', who often used his "2-way wrist TV" to communicate with police headquarters. (1964–1977).
By the early 2010s videotelephony and videophones had become commonplace and unremarkable in various forms of media, in part due to their real and ubiquitous presence in common electronic devices and laptop computers. Additionally, TV programming increasingly used videophones to interview subjects of interest and to present live coverage by news correspondents, via the Internet or by satellite links. In the mass market media, the popular U.S. TV talk show hostess Oprah Winfrey incorporated videotelephony into her TV program on a regular basis from May 21, 2009, with an initial episode called ''Where the Skype Are You?'', as part of a marketing agreement with the Internet telecommunication company
Skype
Skype () is a proprietary telecommunications application operated by Skype Technologies, a division of Microsoft, best known for VoIP-based videotelephony, videoconferencing and voice calls. It also has instant messaging, file transfer, deb ...
.
[
Julianne Pepitone]
Oprah's Skypefest Draws Backlash
, CNNMoney.com online, May 21, 2009. Retrieved October 22, 2009.
Additionally, videophones have been featured in:
* "Lisa's Wedding", an episode of ''The Simpsons'' which depicted a Picturephone (1995).
[
* "The Farnsworth" in Warehouse 13 which showed that a phone could video-call as desktop computer.]
Lisa's Wedding
''BBC.co.uk''. Retrieved on March 20, 2007.
* a Beyoncé Knowles pop single and music video called Video Phone (song), "Video Phone" from her album ''I Am... Sasha Fierce, I Am... Sasha Fierce'' (2008).
[
]
See also
* 3GP and 3G2
* Comparison of web conferencing software
* H.331
* Information appliance
* List of video telecommunication services and product brands
* Media phone
* Mobile VoIP
* Press videoconferencing
*
Project DIANE Project DIANE, an acronym for Diversified Information and Assistance NEtwork, was a very early videoconferencing based community service network created in the United States. DIANE was a grassroots driven regional videoconferencing consortium which ...
—a large U.S. business and social services videoconferencing network
* Smartphone
* Telecollaboration
* Teleconference
* Telephony—the ancestral technology
* Teletraining
* U.S.–Soviet Space Bridge
* Visual communication
* VROC (Virtual Researcher on Call)
* Web conferencing
Notes
Bibliography
* Santanu Brahma & Axlator Communication
''Audio Video Telephony'', Real time updates and news about WebRTC technology and browser-based audio and videotelephony.
* Burns, R.W.
Television: ''An International History of the Formative Years''in IEE Publication Series, Institution of Electrical Engineers, Science Museum, London, Science Museum (Great Britain), 1998, ,
* Daly, Edward A. & Hansell, Kathleen J
''Visual Telephony'' Artech House, Boston, 1999, , , CIPD HD9697.T452D35 651.7'3-dc21.
*
* Nellist, John G
''Understanding Telecommunications And Lightwave Systems: An Entry-Level Guide'' John Wiley and Sons, IEEE Press, 2002, , .
*
* Shepard, Steven
Videoconferencing Demystified: Making Video Services Work McGraw-Hill Professional, 2002, ,
* Stevenson Bacon, W
Amazing New Picturephone: A Step Closer to In-Person Visits ''Popular Science'', June 1968, pp. 46–47.
* Valinder, Anne
Like a window in your living room: Video-mediated communication for extended families separated by space University of Gothenburg: Department of Applied Information Technology, pp. 6–18, October 5, 2012. Web. January 23, 2013 (PDF).
* Wilcox, James R. & Gibson, David K
''Video Communications: The Whole Picture'' Focal Press, CMP Books, San Francisco, 2005, , .
Further reading
Unsorted
* Greenberg, Alan D
Taking the Wraps off Videoconferencing in the US Classroom Wainhouse Research, April 2009.
* Kopytoff, Verne G
Hewlett-Packard Sells Its Video Conferencing Business ''The New York Times'', June 1, 2011.
* Lawlor, Julia
Videoconferencing: From Stage Fright to Stage Presence ''The New York Times'', August 27, 1998.
* Lohr, Steve
As Travel Costs Rise, More Meetings Go Virtual ''The New York Times'', July 22, 2008.
* Miller, Claire Cain
Logitech Buying a Maker Of Videoconference Tools ''The New York Times'', November 11, 2009.
* Miller, Claire Cain
Logitech Breaks Into Videoconferencing ''The New York Times'', November 10, 2009 on line, and November 11, 2009, in print, p. B3. Discusses the acquisition of LifeSize Communications.
* Millman, Howard
The Videoconference as a Bicoastal Pas de Deux ''The New York Times'', July 12, 2001.
* O'Brien, Kevin
Stranded Travelers Turn to Videoconferencing ''The New York Times'', April 19, 2010. Article discusses the increased use of videoconferencing due to the eruption of an Icelandic volcano which severely curtailed air travel for several months.
* Ramirez, Anthony
More Than Just a Phone Call; Video Conferencing And Photocopies, Too ''The New York Times'', September 15, 1993. Discusses the deployment of videoconferencing rooms in several hundred Kinkos locations.
* Shannon, Victoria
Videoconferencing's virtual leap forward ''The New York Times'', August 29, 2007.
* Sharkey, Joe
A Meeting in New York? Can't We Videoconference? ''The New York Times'', May 11, 2009 online, and in print on May 12, 2009, p. B6 of the New York edition.
* Vance, Ashlee
Cisco Buys Norwegian Firm for $3 Billion ''The New York Times'', October 1, 2009 online, and October 2, 2009, in print, p. B7. Discusses the acquisition of Tandberg.
* Wang, Se
Open source tool detects videoconferencing equipment vulnerabilities Help Net Security, 17 February 2012.
* Wayner, Peter
''The New York Times'', June 16, 2005.
General
* Adeshina, Emmanuel
In-Person Visits Fade as Jails Set Up Video Units for Inmates and Families ''The New York Times'' website, August 7, 2012, pg. A15 of the New York Edition.
* Bajaj, Vikas
Transparent Government, Via Webcams in India ''The New York Times'', July 18, 2011, pg.B3. Published online: July 17, 2011.
* Davis, Andrew W.; Weinstein, Ira M
The Business Case for Videoconferencing Wainhouse Research, March 2005.
* Fairlie, Rik
Skype Puts Video Calls on Your TV ''The New York Times'', July 2, 2010.
* Hoffman, Jan
When Your Therapist Is Only a Click Away ''The New York Times'', September 25, 2011, pg. ST1. Also published September 23, 2011 online at www.nytimes.com.
* Miller, Hugh., Department of Social Sciences, Nottingham Trent University, June 16, 2002. Discusses social issues related to videotelephony.
* Perlroth, Nicole
Cameras May Open Up the Board Room to Hackers ''The New York Times, The New York Times online'', January 22, 2012. A version of this article appeared in print on January 23, 2012, on page B1 of the New York edition with the headline: "Conferences Via the Net Called Risky".
* ProAV Magazine
Being There ''ProAV Magazine'', November 7, 2008.
* Saint Louis, Catherine
''The New York Times'', January 10, 2012 (online), January 11, 2012 (in print, New York Edition, pg. A1). Retrieved online January 11, 2012. Synopsis: a look at the pros and cons of videotelephony used for private, individual, music lessons.
* Steinberg, Neil
Dude, Where's My Video Phone? ''Forbes#Forbes.com, Forbes.com'' website, October 15, 2007
Environmental benefits
* Biello, David
Can Videoconferencing Replace Travel? ''Scientific American'', March 18, 2009.
* Coroama, V.C., et al
Effects of Internet-Based Multiple-Site Conferences on Greenhouse Gas Emissions, ''Telematics and Informatics'', 2011, doi:10.1016/j.tele.2011.11.006
* Pachner, Joanna
The Next Best Thing to Being There Toronto: ''The Globe and Mail'', October 13, 2009.
Historical and technical
* Ebel, H. "Subjective Assessment of Picture Interference in the Videophone" i
4th International Symposium on Human Factors in Telephony Bad Wiessee, Germany, September 23–27, 1968, Information Gatekeepers Inc., pp. 289–298.
* Fischer, K.; Ebel, H.; "Problems Of How To Position Users In Front Of The Videophone" in
4th International Symposium on Human Factors in Telephony Bad Wiessee, Germany, September 23–27, 1968, Information Gatekeepers Inc., pp. 269–282.
* Hall, A.D. "Experiments with Picturephone Service" in: ''Bell Laboratories RECORD'', 1964, Vol. 42, pp. 114–120.
* Herbert E. Ives, Ives, Herbert E.]
Two-Way Television and a Pictorial Account of its Backgroundin: ''Bell Laboratories Record'', 1930, Vol. 8, pp. 399–404, an
* Herbert E. Ives, Ives, Herbert E.]
Picture Transmission and Televisionin: ''Bell Labs Quarterly'', April 1932, Vol. 11, pp. 118–142.
* Jaur, Francis. "Usage Domestiques du Visiophone", Technologies de l'Information et Société, 2, 1990, pp. 89–102. (French)
* Schunack, Von Johannes; Maly, Rolf
Die Fernseh-Sprechtechnikin: ''Fernseh A.G.: 10 Jahre'', Berlin: Hausmitteilungen Aus Forshunsg Und Betrieb Der Fernseh Aktiengellschaft, July 1939, pp. 138–143. (PDF, German)
* Schulte, Olaf A
"The Next Best Thing To Being There"—Ein Überblick Zu 25 Jahren Videokonferenzforschung(An Overview of 25 years of videoconferencing research) in: ''Medien & Kommunikations-wissenschaft'', Baden-Baden: Hans-Bredow-Institut, April 2002, pp. 551–570 (PDF, German).
External links
Debut of the First Picturephone 1970 video courtesy of AT&T Archives and History Center, Warren, N.J.
British Pathé news clip: Videophone 1970 a movie reel news clip on the assembly and demonstration of a prototype British General Post Office 'Viewphone' at Taplow, Buckinghamshire; (February 1, 1970; video, 1:16 seconds length)
Wirlpool Forums: Movies that feature videophones
{{Authority control
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