Doors open for fed use of videoconferencing tools
Videoconferences are transmitted over many types of media, from LANs, Integrated
Services Digital Network connections, one-on-one telephone links, videophones and
conference rooms with built-in circuits.
The LAN and ISDN connections are fine for internal use, but no agency can fully benefit
from face-to-face electronic meetings until telephone or Internet conferences become
Desktop conferencing systems are the most affordable for business-grade video and audio
connections. They fall short, however, in two ways.
First, inexpensive desktop systems often lack important functions such as
whiteboarding, file transfer and multipoint connectivity. Low-end systems do a good job
for only two users at a time.
Second, and more important, desktop bandwidth bottlenecks are severe. Dial-up
connections sag under the large data transfers needed for smooth, high-resolution
videoconferences. Most networks cannot tolerate desktop conferencing by more than one
group of users at a time.
Industry sources warn that global bandwidth will have to improve substantially for
desktop conferencing to become practical. They said they believe group conference rooms
have more value for federal agencies.
Several developments could change that situation over the next decade. A new class of
consumer conferencing devices is on the way for 1998, and the cost savings could reach
business users next.
A big obstacle is the need for standardization. Vendors are struggling to alter their
proprietary devices, which must be bought and installed in pairs, for use with other
Only if the industry clears this barrier can sales volume rise to the point at which
the manufacturing scale will bring prices down.
How far would fax machines or telephones or televisions have gotten if each technology
had been forced to straddle several incompatible standards?
Personal videoconferencing products will increase in popularity as standards jell and
buyers feel confident of connecting with anyone who has videoconferencing hardware of any
Videophones have flopped, despite several reinventions since 1960, because you must buy
them in pairs and give one to the person you want to call.
But change is on the way from the International Telecommunications Union's emerging
standards for telephone and LAN videoconferencing.
Under ITU's 1980s-era H.320 standard, ISDN conferencing failed to catch on everywhere
because ISDN failed to do so.
Different federal sites videoconference over ISDN lines. They can't reach much of the
outside world, though, so videoconferences have never taken off as they should,
considering the savings on travel.
The H.320 standard's technical value has been eroded by a vicious cycle: ISDN lines are
expensive and hard to get, so ISDN videoconferencing hardware sales are low. So there is
less demand for ISDN lines.
ITU's new standards will likely gain greater acceptance because they allow
videoconferencing over existing circuits.
H.324, for ordinary phone lines, lags the ISDN standard by five years and may overtake
it fast enough to move into the small business and consumer markets next year.
That will give manufacturers an incentive to build H.324-compliant chip sets into the
hardware, as they do for modems and fax machines.
If telephone videoconferencing increases among businesses and consumers in the next
decade, government offices will have to adopt it to get the best-priced equipment and to
communicate outside federal walls.
ITU's other new standard is H.323, a LAN standard for nonisochronous connections such
as those over Ethernet or token-ring LANs. H.323 works over links that aren't dedicated to
video and audio signals and that vary widely in available bandwidth.
As H.323 products emerge, LAN managers are asking for tools to manage videoconferences
on their IP networks.
Now NetScout Systems Inc. of Chelmsford, Mass., formerly Frontier Software Development
Inc., has announced that by the end of the year it will sell extensions to its RMON and
RMON-2 remote monitoring probes to measure H.323 videoconference traffic.
The three standards--H.320, H.323 and H.324--must coexist and work together for
videoconferencing to achieve universal acceptance the way fax, data communications and the
Three streams of signals must work together, too: voice, video and data. Voice is by
far the most important.
If you have an H.320 ISDN setup and want to communicate with someone who has an H.324
videophone, the video and data sharing may be useful, but the effort is pointless if you
can't talk easily.
Once a connection has been made, most people will put up with delays in file exchange
and a few dropped video frames. If audio quality falls below what they get from just
picking up a phone, however, they will abandon videoconferencing.
The leading chip set for videoconferencing is an integrated 32-bit
reduced-instruction-set-computing microcontroller and digital signal processor from
Hitachi Computer Products America Inc. It delivers 60 million-instruction-per-second
performance, which common desktop Pentium PCs can't equal.
The Hitachi chip works with the three speech coder-decoders, or codecs, that are
mandated by the three H.32x standards. The chip, or something similar, will form the basis
of the next generation of videoconferencing systems.
Most current hardware uses a separate microcontroller and one or more signal
processors, one for each audio codec and sometimes one to support a speakerphone with echo
The next-generation chip will pack enough processing power to connect these diverse
systems. Putting all the power into a single chip will lower energy consumption, simplify
construction and eventually lower prices.
ITU, based in Geneva, has a Telecommunications Standardization Sector known as ITU-T
and a study group on transmission systems and equipment that sets the "H."
standards. The "T." standards come from ITU-T's protocols study group. T.120 is
a protocol for fax, file transfer and point-to-point videoconferences.
The State Department handles official U.S. submissions to the ITU study groups, but the
concepts mostly come from the telecommunications and chip companies.
Several years ago, the Defense Department promulgated Mil-Std-188-331 for
videoconferencing based on Federal Information Processing Standard 178, but the military
relies on commercial standards now.
Intel Corp. plans to bridge the ISDN and LAN environments with its Intel Business
Videoconferencing 4.0 bundle for networked PCs running Microsoft Windows 95 or Windows NT
4.0. Priced at $1,199 including ISDN adapter, camera, headset, desktop microphone and
acoustic echo cancellation, the bundle could point the way toward more open, cheaper LAN
Another up-and-coming alternative is Internet Mbone, or Multicast Backbone. Instead of
connecting participants point-to-point or over LANs, the multicast transmits the same
lecture or meeting to every subscribing station via the Internet.
NASA, the Energy Department and the Federal World Wide Web Consortium make use of
multicasting. Visit Mbone at Lawrence Berkeley Laboratory's site at http://www.itg.lbl.gov/7Eclarson/vconf/vconf-faq.html.
More information can be had from a 1994 DOE study titled Beyond Telecommuting: A New
Paradigm for the Effect of Telecommunications on Travel at http://www.lbl.gov/ICSD/Niles.
John McCormick, a free-lance writer and computer consultant, has been working with
computers since the early 1960s.