Videophone

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An artist's conception of video telephony, as imagined in 1910

A videophone is a telephone with a video screen, and is capable of full duplex (bi-directional) video and audio transmissions for communication between people in real-time.

Videophones are particularly useful to the deaf who can use them with sign language or with a video relay service, and also to those with mobility issues or those who are located in distant places and are in need of telemedical or tele-educational services.

[edit] Descriptive names, terminology and brands

A Deutsche Telekom T-View 100 ISDN type videophone meant for home offices and small businesses. Note the lens cover which can be rotated upward to assure privacy when needed

The name videophone is not as standardized as its earlier counterpart, the 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 telephones and often by an early trademarked name "Picturephone", which was the world's first commercial videophone produced in volume. The compound name 'videophone' entered into general use approximately 1950,^[1] although 'video telephone' likely entered the lexicon earlier after the noun 'video' was coined in 1935.^[2]

Videophone calls differ from videoconferencing in that they expect to serve individuals, not groups. However that distinction is becoming increasingly blurred with technology improvements such as increased bandwidth, which can allow for multiple parties on a call. Videophone calls (noun) are also referred to as videocalls, with the related verb form similarly taking videocalling.

Telepresence is a high-end videoconferencing system and service usually employed by enterprise-level corporate offices. Telepresence conference rooms use state-of-the art room designs, video cameras, displays, sound-systems and processing systems, coupled with high to very high capacity bandwidth transmissions, with a resulting cost up to US$500,000 per room.

Webcams 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 video calls.

Videoconference systems are generally higher cost than videophones and deploy greater capabilities with their service. In the corporate sphere, high end turnkey systems could cost $25,000 and upwards as recently as 2002.

Other names that have been used are: Viewphone, found chiefly in British usage^[3], and visiophone, a popular French translation that has also crept into limited English usage. Latin-based translations also include vidéophone (French), bildtelefon (German), videotelefono (Italian), videófono and videoteléfono (Spanish), and both beeldtelefoon and videofoon (Dutch).

For videophone brands, see this list of video telecommunication services and product brands.

[edit] Early history

A fictional early combination videophone/television concept by George du Maurier, published in 1878

Barely two years after the telephone was first patented in the United States, an early concept of a combined videophone/wide-screen television called a telephonoscope was conceptualized in the popular periodicals of the day. It was also mentioned in various early science fiction works such as Le Vingtième siècle: La vie électrique (The 20th Century: The Electrical Life) and other works written by Albert Robida, and was also sketched in various cartoons by George du Maurier as a fictional invention of Thomas Edision. One such sketch was published on December 9th, 1878 in Punch magazine.^[4][5][6]

In April 1891, Alexander Graham Bell recorded conceptual notes of an electrical radiophone that discussed "....the possibility of seeing by electricity" using devices that employed tellurium or selenium imaging components.^[7] Bell went on to later predict that: "...the day would come when the man at the telephone would be able to see the distant person to whom he was speaking."^[8][9]

The compound name 'videophone' entered general usage cir. 1950,^[1] although 'video telephone' likely entered the lexicon earlier after the noun 'video' was coined in 1935.^[2] Prior to that time there appeared to be no standard terms for 'video telephone', with 'sight-sound television system' and 'visual radio' being used to describe the marriage of telephone and television technologies used in early experiments.^[10][11][12]

The technological precursor to the videophone was the teleostereograph machine developed by AT&T's Bell Labs in the 1920s, which was a forerunner of today's fax (facsimile) machines. By 1927 AT&T had created its earliest videophone which operated at 18 frames per second and occupied half a room full of equipment cabinets.^[13] An early U.S. test in 1927 had their then-Commerce Secretary Herbert Hoover address an audience in New York City from Washington, D.C.; although the audio portion was two-way, the video portion was one-way with only those in New York being able to see Hoover.^[12]

The first public video telephone service was developed by Dr. Georg Schubert and opened by the German Reichspost in 1938, ^[14] but which quickly closed in 1940 due to the WWII.^{[citation needed]} In that service trial, video telephone lines linked Berlin to Nuremberg, Munich, and Hamburg, with terminals integrated within public telephone booths and transmitting at the same resolution as the first German TV sets, at 440 lines.^{[citation needed]} The Deutsche Bundespost postal service would later develop and deploy its BIGFON video telephony network from 1981 to 1988, serving several large German cities.^[14]

In the United States AT&T conducted extensive research and development of videophones, leading to public demonstrations of its trademarked Picturephone product and service in the 1960s, including displays at the 1964 New York World's Fair.^[15] The demonstration units usually used small oval housings on swivel stands, intended to stand on desks. Similar AT&T Picturephone units were also featured at the Telephone Association of Canada Pavilion (the 'Bell' Pavilion) at Expo 67, an International World's Fair held in Montreal, Canada in 1967.^[16][17][15] Demonstration units were available at these fairs for the public to test, with fair-goers permitted to make videophone calls to volunteer recipients at other locations.

An Ericsson videophone trial, Sweden, 1971; the Ericsson model was a contemporary to AT&T's 'Picturephone'. (image courtesy: Ericsson Archives/Centre for Business History, Stockholm)

The United States would not see its first public video telephone booths until 1964, when AT&T installed their earliest commercial videophone unit, the Picturephone Mod I, in public booths in three cities: New York, Washington, D.C. and Chicago.^[13] Picturephone booths were set up in New York's Grand Central Station and elsewhere. With fanfare, Picturephones were also installed in offices of Westinghouse in Pittsburgh, and at other progressive companies. However the use of reservation time slots and their initial cost of US$16 per three minute call at public booths greatly limited their appeal to the point that they were discontinued by 1968.^[8][13]

Unrelated difficulties at New York Telephone also slowed AT&T's efforts, and few customers signed up for the service in either city. A CNN report on 6 September 2001 stated that Picturephone service only had a total of 500 subscribers at its peak, and the service faded away by 1974.^{[citation needed]} AT&T's initial Picturephone II program spanned 15 years and consumed US$500 million, eventually meeting with commercial failure.^[18] AT&T concluded that its early videophone was a "concept looking for a market" and discontinued its Picturephone service in the late 1970s.^[18]

Color on AT&T's Picturephone was not employed with their early models. These Picturephone units packaged Plumbicon^® cameras and small CRT displays within their housings. The cameras were located atop their screens to help users see eye to eye. See this section for more information on Picturephone technology. Later generation display screens were larger than in the original demonstration units, approximately six inches (15 cm) square in a roughly cubical cabinet.

AT&T would then market its VideoPhone 2500 to the general public from 1992 to 1995 with prices starting at US$1,500 and later dropping to $1,000.^[19]

In 2007, the Smithsonian's National Museum of American History received a wireless videophone prototype known as Intellect, developed in 1993 by inventor Daniel A. Henderson.^[20] The device was designed to receive pictures and video data from a message originator via a message center, for use with a cellular telephone type device. See also camera phone.

[edit] General lack of public acceptance

Early AT&T Picturephones had few users, in part because the service was relatively expensive, approximately US$90 per month in 1974.^{[citation needed]} However as modern technology reduced the costs to nominal (see: webcams and UMTS), videophone calling continued to be marginally used.^{[citation needed]} This contrasts to the unanimous certainty of pundits through many decades that videophones would be an obvious, highly sought-after technology.

One reason may be that even today videophone calling is a poor analog for face-to-face conversation.^{[citation needed]} Video cellphone users commonly look at the video screen and not at the video camera, causing the eyes to take on an unnatural downward glance, as the camera is usually just positioned above the screen on almost all videocall enabled cellphones. Some argue that this effect is easily countered by holding the cellphone slightly further away when videocalling.^{[citation needed]}

Another reason may be that people actually desire less fidelity in their communication, as evidenced by the popularity of written conversation (i.e. texting and instant messaging, which are commonly available on all video-enabled cell phones and webchat programs).^{[citation needed]}

Although it could also be argued that for users who would benefit greatly from videophone services (e.g. members of a family living far apart and who may have a strong desire, but little opportunity for face-to-face conversations), costs are still largely prohibitive for video cellphone calls: inexpensive international solutions for these calls (such as Hutchison 3's Skype enabled cell phones) only cover a handful of countries as of late 2008.^{[citation needed]}

[edit] Current usage

Mobile video call between Sweden and Singapore

The widest deployment of video telephony now occurs in mobile phones, as nearly all mobile phones supporting UMTS networks work as videophones using an internal camera, and are able to make video calls wirelessly to other UMTS users in the same country or internationally.^{[citation needed]} 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.^{[citation needed]}

Videophones are used by the deaf to communicate with sign language.^{[citation needed]} The United States Federal Communication Commission pays companies for providing Video Relay Services to deaf and hard-of-hearing individuals. These people can use a videophone to talk to others via a sign language interpreter, who uses conventional phones to communicate with the deaf person's party. Several other countries also offer video relay services for the deaf.

Videophones are also used to do on-site sign language translation (Video Remote Interpreting). The relatively low cost and widespread availability of mobile phones with video calling capabilities have given deaf people new possibilities to communicate with the same ease as others, with some wireless operators even starting up free sign language gateways.^{[citation needed]}

Videophones are increasingly used in the provision of telemedicine to the elderly and to those in remote locations, where the ease and convenience of quickly obtaining diagnostic and consultative medical services are readily apparent.^[21] 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 has allowed 60 pensioners to be assessed by medics without travelling to the surgery."^[21]

Of further note is that new technology is being incorporated into video telephone units to permit remote diagnostic services, such as blood sugar level, blood pressure and vital signs monitoring. Such units are capable of relaying both regular audiovideo plus medical data over either standard telephone lines or broadband data lines.^[22]

Videotelephony has also been deployed in large corporate conferencing set-ups.

Today the principles, if not the precise mechanisms of a videophone are employed by many users worldwide in the form of webcam 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.

A videophone can also be created by using an old or inexpensive computer and dedicating it to run as a video softphone.^{[citation needed]} This shows that some users may want to use use conventional videophones, but are likely to trade ease of use for lower costs.

Some have argued that unless conventional videophones add considerable value at low cost, and as long as less expensive alternatives (such as webphones) are available, it will be unlikely that dedicated videophones will become popular.^{[citation needed]}

[edit] Modern trends in videophone calling

In 2004 Telmex, the biggest telephone service provider in Mexico, introduced Videophone service over regular phone lines (apparently H.324). The service, as of March 2006, had not enjoyed widespread adoption. Telecom Italia supplies LG-Nortel videophones, which also appear to be used by Telmex.

Also as of late 2008, special high value vertically integrated market segments were undergoing changes as data speeds and hardware technology improved to catch up to the requirements and demands of videocalling. Healthcare, education, construction, government, and other enterprise level applications continued to drive the growth of video conferencing.^{[citation needed]}

[edit] Technology

[edit] Bandwidth requirements

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 more limited and poorer image quality. 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 sketchy 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 Standardization Sector (ITU-T) recommendation I.113 has defined broadband as a transmission capacity at 1.5 to 2 Mbit/s. The United States Federal Communications Commission definition of broadband is 768 kbit/s (0.8 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 video conferencing applications, and rates as low as 100 kbit per second used for videophones using H.264/MPEG-4 AVC compression protocols. The newer MPEG-4 video and audio compression format can deliver high-quality video at 2 Mbit/s, which is at the low end of cable modem and ADSL broadband performance.^{[citation needed]}

[edit] Picturephone technology

The Picturephone's video bandwidth was 1 MHz with a vertical scan rate of 30 Hz, horizontal scan rate of 8 kHz, and about 250 visible scan lines.^{[citation needed]} The equipment included a Speakerphone hands free telephone, with an added box to control picture transmission. Each Picturephone line used three twisted pairs of ordinary telephone cable, two pairs for video and one for audio and signaling. Cable amplifiers were spaced about a mile apart (1.6 kilometres) with built-in six-band adjustable equalization filters. For distances of more than a few miles, the signal was digitized at 2 MHz and 3 bits per sample DPCM, and transmitted on a T-2 carrier.^{[citation needed]}

The original Picturephone system used contemporary crossbar and multi-frequency operation. Lines and trunks were six wire, one pair each way for video and one pair two way for audio. MF address signaling on the audio pair was supplemented by a Video Supervisory Signal (VSS) looping around on the video quad to ensure continuity. More complex protocols were later adopted for conferencing.^{[citation needed]}

To deploy Picturephone service new wideband crossbar switches were designed and installed into the Bell System's 5XB switch offices, this being the most widespread of the relatively modern kinds.^{[citation needed]} Hundreds of technicians attended schools to learn to operate the Cable Equalizer Test Set and other equipment, and to install Picturephones.

AT&T later marketed the VideoPhone 2500 to the general public from 1992 to 1995.^{[citation needed]} It was limited by analog phone line connection speeds of about 19 Kilobits per second, the video portion being 11,200 bits/s, and with a maximum frame rate of 10 frames per second, but typically much lower. The VideoPhone 2500 used proprietary technology protocols.^{[citation needed]}

[edit] Call setup

Videoconferencing in the late 20th century was limited to the H.323 protocol (notably Cisco's SCCP implementation was an exception), but newer videophones often use SIP, which is often easier to set up in home networking environments.^{[citation needed]} 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 also now provide video. The principal open systems SIP source is Counterpath Corp., which provides support for British Telecom, Deutsche Telekom, Sprint, Telmex, AT&T's Callvantage, and the unified communicator of Cisco and Verizon.^{[citation needed]}

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 framerate. 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 networks.^{[citation needed]}

There is also H.320 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 digital phone protocol or a fractionated high bandwidth T1 lines. Modern products based on H.320 standard usually support also H.323 standard.^[23]

[edit] Video compression

The most commonly used video codecs are H.263 and H.264. Skype uses the proprietary protocol VP7.^[24] VZOchat uses proprietary Visicron codec.^{[citation needed]}

This section requires expansion.

[edit] Video cellphone technology and usage

The most frequent usage of cell phone videocalling over HSDPA 3.5G networks in Europe as of 2008 appears to be aimed at locale transmission, i.e. live video of where one is as opposed to self-image.^{[citation needed]} The preferred method of cell phone videocalling is to use the larger megapixel camera on the back of the phone rather than the smaller camera in front. In this way the sender can maintain an overview of the live video transmission on the screen as it is being sent.^{[citation needed]}

[edit] Videophones in popular culture

• In many science fiction movies and TV programs that are set in the future, videophones are used as a primary method of communication. One of the first movies where a videophone was used was Fritz Lang’s Metropolis. Other famous examples of videophones include 2001: A Space Odyssey, Space: 1999, and Blade Runner. Of particular note, the videophone was a staple, everyday technology in the futuristic Hanna Barbera cartoon The Jetsons.
• In science fiction literature, other names variously used for videophone include vidphone, visiphone, and viewphone.
• A videophone was featured in the 1944 Warner Bros. cartoon, "Plane Daffy", in which the female spy Hatta Mari used a videophone to communicate with Adolf Hitler.
• In the British cartoon DangerMouse, where the title character regularly communicated with headquarters via videophones from both his home and his car.
• A device with the same functionality has been used by the comic strip character Dick Tracy since 1964. Called the "2-Way Wrist TV", the fictional detective often used the phone to communicate with police headquarters.
• AT&T's VideoPhone 2500 prototypes are visible in the movie Gremlins 2: The New Batch.
• In the animated television program Futurama, the videophone is often used within the delivery service spaceship.
• Videophones are occasionally used in the Pokémon anime.
• A "Picturephone" is used in The Simpsons episode "Lisa's Wedding".
• Pee-wee Herman often used a videophone on Pee-wee's Playhouse. He whimsically talked into a can on a string creating an interesting juxtaposition of technology and fantasy.

[edit] References

This article is missing citations or needs footnotes. Please help add inline citations to guard against copyright violations and factual inaccuracies. (March 2009)

Please expand this article with text translated from the corresponding article in the Japanese Wikipedia. (April 2009) After translating, {{Translated|ja|テレビ電話}} must be added to the talk page to ensure copyright compliance. Translation instructions · Translate via Google

Please expand this article with text translated from the corresponding article in Dutch Wikipedia. (April 2009) After translating, {{Translated|nl|Beeldtelefoon}} must be added to the talk page to ensure copyright compliance. Translation instructions · Translate via Google

Please expand this article with text translated from the corresponding article in French Wikipedia. (April 2009) After translating, {{Translated|fr|Visiophonie}} must be added to the talk page to ensure copyright compliance. Translation instructions · Translate via Google

[edit] See also

[edit] External links

• "Amazing New Picturephone: A Step Closer to In-Person Visits" by W. Stevenson Bacon, Popular Science, June 1968, pp. 46–47. Google books

Look up videophone in Wiktionary, the free dictionary.