Transcript ppt - Princeton University

The Picturephone: Basis for
Video/Audio Distance Learning
Gail Palumbo
July 2006
Princeton University
Teachers As Scholars
The Beginnings
• The seed for Full-Motion Video Distance
Learning started with Video Conferencing
• The basis for Video Conferencing was the
Telephone
"This 'telephone' has too many
shortcomings to be seriously
considered as a means of
communication. The device is
inherently of no value to us."
-- Western Union internal memo,
1876.
Engineers at Bell Laboratories began
discussing the concept of simultaneous
transmission of video and voice over
telephone lines in the 1920's.
In 1927, the Bell Telephone System sent
live television images of Herbert Hoover,
then Secretary of Commerce, over
telephone lines from Washington, D.C. to
an auditorium in Manhattan, N.Y. This was
the first public demonstration in the United
States of long-distance video
transmission.
Video Conferencing
• 1956: AT&T builds the first Picturephone
test system
• 1964: AT&T introduces Picturephone at
the World's Fair, New York
• 1970: AT&T offers Picturephone for $160
per month
The Bell System
(AT&T/Western Electric)
PicturePhone (developed
in Bell Labs as a
prototype in 1956, but
never test marketed until
the early 1960's) never
became popular after it
was briefly offered
commercially in Chicago.
The first "PicturePhone" was
completed by Bell Laboratory
engineers in 1956. This first
system was crude and
cumbersome and required
three standard wire pairs to
operate: one pair to carry the
video transmission, one pair to
carry video reception, and the
third to carry the audio signal.
Requiring 1,000,000 Hertz of
bandwidth, the PicturePhone
video signal exceeded by more
than 300 times the bandwidth
allotted to a typical telephone
voice signal.
(about 1962)
Joseph A. Mazzeo of Bell Telephone Laboratories removes one of the circuit
packages in the experimental PICTUREPHONE system.
The comparatively small size of the visual telephone, the PICTUREPHONE is
made possible by the development of modern circuits using transistors and
other miniature components.
(about 1962)
Joseph A. Mazzeo of Bell Telephone Laboratories removes one of the circuit
packages in the experimental PICTUREPHONE system.
The comparatively small size of the visual telephone, the PICTUREPHONE is
made possible by the development of modern circuits using transistors and
other miniature components.
The Bell system Picturephone,
1964
The PicturePhone was connected to the Central Office via 3 standard wire
pairs (for comparison, a regular telephone line uses a single wire pair). One
pair carried the 1 MHz PicturePhone video signal in one direction, the other
carried video the in the opposite direction. These had to be specially
equalized to carry the signal but were still otherwise just ordinary telephone
wire. The third pair carried the normal 2-way voice call plus carried the
TouchTone dialing to set up the call.
A PicturePhone Central Office had a second switch (an electromechanical
"crossbar" switch in those days!) operating in parallel to the regular switch
for those making PicturePhone calls. That takes care of local calls.
The fun comes when a call has to be connected to someone served via
another Central Office. Telephone calls are multiplexed together to go from
one office to another. Many calls share the same communications system
whether microwave, coaxial cable, or (nowadays) fiber optic is the medium.
Even when offices are connected via ordinary wire pairs many calls share the
same wires. A voice channel is allotted only 3000 Hz (this is after all
telephony, not 20,000 Hz high-fidelity audio!) for each direction. But a
PicturePhone video signal takes 1,000,000 Hz. That's 333 times the
bandwidth! A few video calls would fill up all available bandwidth.
By 1964, a somewhat improved version of the
PicturePhone, dubbed the "Mod 1," had been developed
and was debuted at the New York World's Fair. To test
public reaction to the PicturePhone, visitors were invited to
place calls between special exhibits of the PicturePhone at
the World's Fair and Disneyland.
Survey results indicated that most people did not like
PicturePhone. The controls were awkward and the picture
was small. Moreover, most people were not comfortable
with the idea of being seen during a phone conversation.
However, the system's developers at Bell Laboratories were
convinced that PicturePhone was viable and could find a market.
AT&T inaugurated commercial PicturePhone service between
New York City, Chicago, and Washington, D.C., June 24, 1964,
with a call from Lady Bird Johnson, wife of President Linden
Johnson, in Washington; to Dr. Elizabeth A. Wood of Bell
Laboratories in New York City.
A three-minute PicturePhone call from Washington to New York
City cost $16. The most expensive connection, between New York
City and Chicago, cost $27 for three minutes. This inaugural
PicturePhone service never caught the attention of consumers.
"A logical extension of today's telephone service...BELL
SYSTEM INTRODUCES PICTUREHONE SERVICE... both
ends of telephone conversation are pictures; people phone by
appointment from family-type booths in attended centers. Bell
System PICTUREPHONE service now lets callers see as well
as talk on the telephone. And 'handsfree if they wish'. For the
first time people can make a visual telephone call to another
city-the latest example of the research, invention and
development that are constantly providing the
communications we provide. The new service is being offered
in the cities listed ar the left. Bell Systems attendants at each
local center help callers enjoy prearranged face to face visits
with friends and relatives in either of the other cities." (the
cities are New York, Chicago, Washington)
The Bell System estimated three million PicturePhone
units would be operating in homes and offices by the mid1980s, bringing in a combined revenue of $5 billion a year.
Initial reaction to PicturePhone had been very positive.
However, these positive marketing reactions were soon
dampened by the realities of cost and the hesitation of
people to be accidentally seen by others in the private
affairs of their homes. AT&T abandoned its plans to market
the Mod II in 1973.
In January 1992, AT&T executives again predicted the success
of a videophone system with the introduction of the AT&T
VideoPhone 2500-the first full-color, home video phone system
to use standard home telephone lines.
During the system's debut, Robert Kavner, AT&T group
executive for AT&T Communications Products, said, "This is
the way people want to communicate. The time is right. The
price is right. The technology is right."
Video phones finding niche after 40 years in development
by Al Moyers
Air Force Communications Agency Office of History
(http://infosphere.safb.af.mil/~rmip/97dec/intercom.htm)
Note: The original web link above is no longer valid. I managed to find a text file of this
article on another server at:
http://zia.hss.cmu.edu/miller/eep/news/video2.ne.txt
The Air Force is testing video telephones at locations both in the United States and
overseas to provide "video morale calls" for deployed members.
"I have never seen a better morale booster," was the report of one Air Force first
sergeant during a recent test of video telephone technology at Incirlik AB, Turkey.
The video phone concept is actually more than four decades old, but new low-cost
technologies are providing the Air Force a rare opportunity to permit families and
deployed airmen to be able to see, as well as talk, to one another.
AT&T executives reported that the video phone would
become as popular as cordless and cellular phones. Yet, a
large market has yet to be found.
According to the calculations of telecommunications author
Stephen J. Maudsley, the great decrease in the cost of video
telephones is due to the continued development of silicon
technology. Maudsley reports the cost of a video telephone
in the 1960's was nearly $500,000. The AT&T VideoPhone
2500 was introduced in 1992 at a cost of approximately
$1500 and within a year was selling for less than $1000. The
video telephone system being tested by the Air Force sells
for about $500 for each unit. This dramatic increase in
savings, according to Maudsley, comes from two areas-the
integration of functions and the compression of imagesassociated with the continued decrease in the size of
electronic devices.
The functions required for video phone operation have been
integrated onto fewer pieces of silicon. This is a direct result of
the decrease in the size of component transistors. During the
early period of video telephone development, the smallest
feature on a silicon chip was about 10 microns. Currently,
silicon chips are being manufactured with features as small as
.3 microns.
Video compression ratios have also improved to increase the
rate of image transmission from PicturePhone's one frame
every two seconds to the present state-of-the-art 20 frames
per second. By comparison, broadcast television transmits at
30 frames per second.
Now, video telephones have taken two distinct venues.
Seemingly, the larger share of the industry was concentrating
its efforts in personal computer-based systems, or desktop
video teleconferencing technology, which requires computer
networks. The smaller effort was aimed at the video phonethrough-your-television market which requires no more than a
television, a video telephone, and POTS, the industry
acronym for plain old telephone service.
The Air Force is testing the latter. According to Col. David L.
Rakestraw, director of technology at the Air Force
Communications Agency, "because they are so easy to set up
and use, video phones are an excellent way for the Air Force
to add a video dimension to phone calls home."
Moreover, the television-based systems cost no more for line
transmission than a standard voice call.
Whether consumers on a large scale will finally be attracted
to video telephone technology remains to be seen. The
technology does seem to have found a niche among those
Air Force members who have taken part in the Air Force
trials.
After seeing and speaking to his wife in Hawaii from his
deployed location in Turkey, SSgt. Lionel Price remarked, "I
have been blessed to take part in this."
"Someday you'll be a star!" was one of the advertising slogans
the Bell System used decades ago to try to promote this high
tech and futuristic communications device called the
"PicturePhone". But no matter how much the Bell System tried,
it was one of the most visible flops in communications
technology history.
The picturephone limped along
briefly and then was quietly pulled
at a loss of $1 billion.
Distance Communication
• 1971: Ericsson demonstrates the first
trans-atlantic video telephone (LME) call –
commercial use first realized
• 1973 Dec: ARPAnet packet voice
experiments
• 1976 Mar: Network Voice Protocol (NVP),
by Danny Cohen, USC/ISI
• 1981 Jul: Packet Video Protocol (PVP), by
Randy Cole, USC/ISI
CU-SeeMe 1992
• Macintosh Based at first
• 1996 International Telecommunications
Union (ITU) began developing standards
• 2001 World’s first transatlantic tele-surgery
• 2003 Interactive classrooms