Case Western Reserve University University Library
Audio and Video Conferencing
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Audio and video conferencing have been used for many years by both business and education. Until
recently, however, these types of conferencing required expensive and elaborate microwave, satellite,
telephone, and/or data links. Distance learning classrooms and videoconferencing rooms for business
are still very expensive to set up and to operate if they provide full-duplex audio and video in addition
to data conferencing. In the last few years, however, desktop audio and video conferencing have
become a reality. Small microphones and cameras plugged into computers allow users to send audio
and video across the Internet. Instead of “chatting” in text about a document they are creating with a
shared application, users can really talk to each other. Communication can also be personalized through
the addition of video. The desktop conferencing application best known in educational circles has been
CU-SeeMe, a freeware, multi-platform application developed at Cornell. Cu-SeeMe allows users to
connect on a one-to-one basis; for one-to-many or many-to-many conferencing, it is necessary to use a
conference server, similar to what CU-SeeMe used to call a “reflector.” The document Using Microsoft
NetMeeting introduces what has become the most popular of the available conferencing programs.
The document Using the CWRU Conference Server explains the use of the University’s experimental
MCU (multipoint conferencing unit) located at http://astolfo.cwru.edu.
The term ‘conferencing’ (or ‘teleconferencing’) refers to a number of technologies that allow commu-
nication and collaboration among people located at different sites. These technologies include those
that are text-based (chat), those that involve the sharing of data (whiteboarding, file transfer, applica-
tion sharing), and those that allow the transmission of sound and video. Conferencing applications
support some or all of these functions.
This session is an introduction to the issues involved in data, audio, and video conferencing—stan-
dards, equipment, etc.—and to general guidelines on the use of conferencing.
By the end of this session you should be able to:
• Define conferencing functions
• Match conferencing functions to curricular / programmatic goals
• Locate information about conferencing hardware and software
In order to complete these tasks, you must be able to:
• Use a WWW browser
• Find reviews of hardware and software
Note: vocabulary specific to conferencing applications can be found in the Using Microsoft NetMeeting
handout. Much of this vocabulary is adapted from Bob Summers’ Official Microsoft NetMeeting Book
(Microsoft Press, 1998).
ADSL—for asymmetric digital subscriber line, a new technology used by local telephone companies
to give home users high-speed digital access to the Internet using normal telephone wires.
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audiographics—teleconferencing that interconnects graphic display devices, such as computer moni-
tors, located at sites separated by distance. Some systems allow annotation, writing, or drawing
on the screen.
CCITT—for Consultative Committee on International Telephony and Telegraphy, an international
organization that sets standards for the interconnection of phone equipment.
firewall—a security mechanism on a network that prevents unauthorized access, a firewall analyzes
network packets for packet type (protocol port), and source and destination addresses.
gateway—a special-purpose, dedicated computer that attaches to two or more networks or terminal
adapters to route packets between them. An H.323 telephony gateway can connect a computer
telephony application to the public phone network. An H.320-to-H.323 video conferencing
gateway translates between these two protocols.
interoperability—the ability of software and hardware on multiple machines from multiple vendors to
communicate. Interoperability is the goal of standards.
ISDN—for Integrated Services Digital Network, a digital network provided to customers by phone
companies that sends data and voice services through the same medium.
ITU—for International Telecommunications Union, an international organization of communications
manufacturers and providers that sets standards for the interoperability of communications equip-
ment and services.
G.723.1—an ITU standard for audio compression and decompression that is part of the H.323
H.263—an ITU standard for video compression and decompression that is part of the H.323 stan-
H.320—an ITU standard for video and audio conferencing using switched connections such as
ISDN, T1, etc.
H.323—an ITU standard for video and audio conferencing on packet-switched networks such as
T.120—an ITU standard for data conferencing. H.320 and H.323 are part of the T.120 standard.
LDAP—for Lightweight Directory Access Protocol, a protocol to allow standards-based directory
servers and applications to query and exchange directory information.
MCU—for Multipoint Conferencing Unit, a device that allows three or more sites to interact during an
audio and/or video conference. Each site connects to the MCU rather than to another computer.
packet—a unit of data sent on a network.
teleconferencing—the use of technology to facilitate communication among people at different loca-
telephony—the use of computing for telephone applications.
3. Equipment and Software for Conferencing
Conferencing technology is constantly evolving, so anyone who desires to implement it—particularly
if one is constrained by existing machines and operating systems—needs to be able to find up-to-date
information. Good resources for NetMeeting-compatible hardware and software are listed in the Us-
ing Microsoft NetMeeting handouts. Search engines and web directories can also help, but tend to
yield an overwhelming number of results. The resources listed in the For More Information section are
good places to start.
Hints about desktop video equipment: When buying a camera, one often has the choice between one
that plugs into a port on the computer and a capture card/camera system. Windows users often can buy
very inexpensive cameras that work through the computer’s parallel port. The quality of these may be
inadequate for any serious purpose. Cameras that attach via a serial port usually provide higher-quality
video; USB cameras are even better. Make sure the manufacturer provides drivers for your operating
system! (This is a particular problem for NT users.) The capture card/camera combination is usually
a much better choice in terms of both versatility and quality. It is quite possible to purchase capture
cards that will accept input from any video device you have. That means that you can use any video
camera you may already own (and camcorders produce better video than the small webcams) and you
can probably capture video from a VCR as well.
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4. Instructional Uses of Conferencing
The traditional use of audio and video conferencing is for distance education. In this context, while
desktop conferencing is generally not a good technology to link classrooms, it can be used to link pairs
or small groups of students for collaborative learning. The holding of “virtual office hours” is a com-
mon use at academic institutions. Application sharing allows a teacher to illustrate a response for a
student on his/her own computer. It also allows students located at different sites to complete joint
projects. Conferencing is also a tool for professional development not only through on-line continuing
education but also through the ability to offer “virtual” professional conferences. Although these are
typically offered in on-line virtual environments, desktop audio and video are often used to present
guest speakers to conference attendees in both virtual and traditional situations.
5. Guidelines for Conferencing
If you are using expensive conferencing facilities (like the distance classrooms at CWRU, off-site
facilities like Kinko’s, etc.), you need to plan the conference carefully so that you don’t waste any
expensive time. Although desktop or Internet-based conferencing can be much less expensive, plan-
ning is still essential.
Conferencing applications normally offer several different methods of accomplishing a task; each has
advantages and inconveniences. Audio and video, for example, require more bandwidth than text-
based chat but in NetMeeting using chat and application sharing can be quite difficult. Using video to
greet each other at the beginning of a conference and then switching to audio-only while sharing soft-
ware is often suggested as the best way to use conferencing technology. Planning a conference in-
cludes matching objectives to the best method(s) of accomplishing them.
The following guidelines are based on the experiences of others who have written and spoken about
their use of conferencing.
a. Plan to use the first conferencing session (1) to debug the hardware and software, and (2) to famil-
iarize everyone with applications and procedures.
b. Realize that equipment fails and plan back-up methods of accomplishing your goals. If this is
impossible, schedule make-up dates well in advance.
c. When using video, avoid wearing white, red, or anything striped. Try to keep backgrounds unclut-
tered. When using desktop video, try to avoid too much movement.
d. Audio use is greatly facilitated by the use of headsets; feedback can be a problem when a micro-
phone and speakers are used in close proximity. Remember, too, that there will be a time lag in
audio and video connections.
e. Remember that collaboration allows someone else at least partial control of your computer. Back up
your files before you begin and don’t leave your computer—even for a minute—without turning
f. Always use a virus scanner.
a. Set one or more specific goals for the conference; make sure all participants are aware of these goals.
b. Set an agenda / time schedule for the conference and make it known to all participants.
c. Have a “facilitator” at each site to “direct traffic” and keep the conference going.
d. If specific knowledge or skills are necessary for the successful completion of the conference, de-
velop a method of assessing conference “readiness.”
e. Because it is often difficult to gauge audience reaction to what is being discussed, plan a method to
gather audience feedback at regular intervals.
f. Remember that conferencing is intended to be interactive; structure the conference to encourage
participation by all involved.
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6. For More Information
General Information on Videoconferencing:
http://www.webreference.com (search “conferencing”)
Sandia National Laboratories’ Information on Desktop Conferencing:
Some hints from the business world:
A good source of product news is ZDNet at http://www.zdnet.com Search for “conferencing” for