ERIC Identifier: ED304111
Publication Date: 1988-05-00
Author: Schamber, Linda
Source: ERIC Clearinghouse on
Information Resources Syracuse NY.
Delivery Systems for Distance Education. ERIC Digest.
Distance education is defined as an educational system in which the student
is formally enrolled in a school or college but receives instruction at some
remote site. Traditionally, correspondence has been the primary delivery medium.
However, the delivery systems most common today are based on video, audio, and
computer technologies. An interesting facet of these technologies is that they
have been adapted to transmit information in unexpected forms: visual images via
telephone lines, for example. A variety of such adaptations make live
transmission of lectures, demonstrations, and audiovisual resource materials
possible, often in an interactive context.
Video information can be transmitted at
least six ways: by radio broadcast frequency, telephone line, coaxial cable,
satellite, microwave, and optic fiber. A commercial communications satellite
maintains a position 22,300 miles in the sky, offering continuous line-of-sight
contact with each station sending and receiving signals. Microwave relays are
often the "final mile" links from satellite relays to destinations, transmitting
where satellites don't. Microwave towers at line-of-sight intervals can also
serve as primary stations, transmitting one-way and two-way video and audio.
Optic fiber is a hair-thin glass tube that can transmit light less expensively
and more accurately than copper wire. Video communications systems vary in their
Videoconferencing is a full-motion, full-color system whose one-way or
two-way video portion may be transmitted by satellite, and whose two-way audio
portion is also carried by satellite or on telephone lines. This system permits
a range of information forms, including videotape, film, graphics, slides, and
data. It is a good medium for drama, demonstrations, and simulations. It is also
costly, to the point that links to as many as 30 locations are required in order
for it to be economically feasible. Communication with multiple sites in turn
hampers or prevents two-way audio communication. Satellite transmission is
useful for national organizations, especially those with large and homogeneous
Low-power television (LPTV) depends on a 1- to 5-kilowatt broadcast signal
that covers 10 to 20 square miles. It is relatively low in cost and often used
in rural areas.
Closed-circuit television (CCTV) is a private hard-wired system often used on
Instructional fixed television service (ITFS) uses microwave technology for
one-way or two-way audio and video transmissions that cover a radius of 25
miles. ITFS networks use channels reserved by the FCC for educational and
cultural programming. Receiving sites must have appropriate antennas and
Cable television (CATV) offers two-way communication for institutions that
want to send local programming to the cable station. The information is then
distributed to the community by way of special access channels on the normal
Television is the most attractive, complex, and expensive delivery system;
its use requires a strong commitment on the part of educational administrators
and public television personnel.
Audiographic teleconferencing is the
transmission of still image and audio signals over telephone lines.
With an electronic blackboard, the image is drawn or written on a
pressure-sensitive surface that converts the writing to audible telephone tones.
A relatively inexpensive decoder at the receiving site converts the signal for
display on a special screen. The instructor's voice is transmitted over a second
telephone line and amplified in the classroom. Two-way audio allows students to
interact with the instructor. Telewriters and electronic pens and tablets are
variations on this technology.
Telefacsimile (facsimile, FAX) is a low-cost means of sending paper copies of
documents using telephone lines. A page is scanned by a FAX machine at one end,
transmitted, and printed at the other end in about 45 seconds. The cost, after
the initial equipment investment, is that of the telephone call. FAX is used for
important, high-quality images such as conference papers, contracts, design
plans, and graphics. FAX machines can also interface with microcomputers and can
double as copy machines.
Freeze-frame or slow scan video can best be described as an electronic slide
show transmitted by telephone lines. A narrowband frequency transmits video over
one line; audio over another. Transmission takes a few seconds to more than a
Compressed video uses a telephone data circuit. The video signal is
compressed by a picture processor to eliminate redundant electronic information.
A moving video signal appears instantly at the receiving end, but rapid motion
may be jerky or blurred.
AUDIO TELEPHONE DELIVERY
Telephone lines have long allowed
audioconferencing, i.e., two-way voice communication among several people using
a simple telephone amplifier. Voice-only conferences can use public lines or
dedicated leased lines. Participants may want to supplement audio with visual
material sent by facsimile, electronic blackboard, or materials sent by mail
before the teleconference.
Touchtone phones have a direct-dial option for small conferences of
For two-way interaction among groups at three or more locations, an audio
bridge may be necessary. A telephone company will provide the service at an
hourly rate. Additional costs are high-quality speaker phones, and long-distance
Computer teleconferencing is the transfer of information from one computer to
another. A modem is necessary to convert signals for sending over telephone
lines. Participants at any number of sites can engage in live interaction by
entering messages at the keyboard and reading messages as they appear on the
screen. Messages can also be held by the computer until the user checks in.
Information can be text, graphics, or data, but not audio.
Electronic mail networks provide communication among designated groups, and
also permit individual two-person communication. These systems, which can be
local, national, or international, usually charge a use fee, although an
educational institution may pick up all or part of the cost for faculty and
Bulletin board services (BBSs) provide a means for users to post messages and
to download other messages to their own computers. Literally thousands of BBSs
exist, most of them free. An individual teacher can set up a bulletin board for
exchange of schedules, assignments, and tests. Some public BBSs focus on
education, and large-scale information utilities such as the Source and
Compuserve offer special-interest BBSs as part of a subscription fee. Online
database vendors also offer electronic mail and BBSs.
Teletext and videotex turn the television set into a terminal to receive
still video images from a database stored in a computer. Signals are transmitted
via telephone lines or cable. A decoder is required to display information in
the usually unseen vertical blanking interval of the television screen. Teletext
is often described as one-way and videotex as two-way communication. The
information appears in the form of "pages" of color text and graphics. Existing
networks offer educational material, news, home shopping services, and travel
and entertainment information.
Information systems that integrate computers with new technologies are
rapidly being developed. For example, microcomputers can be linked to laser
readers that access information stored on optical disks. Optical disks such as
CD-ROM can store large databases, and interactive videodisks allow manipulation
of still and moving video images. These new technologies allow users to exchange
large quantities of information as well as to communicate directly with each
other. Still other more traditional delivery systems, such as radio transmission
and postal services, continue to exist and sometimes to support the newer
DISTANCE EDUCATION PROGRAMS
For educational institutions,
distance education can mean wide dissemination of information, links with the
community, and optimal allocation of resources. For students, it can mean
opportunities for continuing education, often for those who are unable to attend
conventional courses because of distance, cost, time, or physical incapacity.
Seminar and conference participants benefit from a flexible format and a high
level of interaction without the time and expense of travel.
Distance education can be expensive, however, and it requires careful
planning, management, and course design. When choosing a delivery method, the
institution must also consider whether the system can save money, reach its
intended audience, and provide better instruction than the traditional teacher.
It also helps to study existing programs, many of which cover the larger and
more rural states, such as Alaska. These programs often take the form of
inservice training or university credit courses, and are directed to
agriculture, health, and social work professionals. Canada, Australia, parts of
Western Europe, and the Soviet Union are active in distance education, and in
developing countries around the world it is a mainstay.
For those interested in starting a distance education program, an excellent
reference is the Minnesota Technology Resource Notebook (Telecommunications
Development Center of the Minnesota Extension Service, 1986). Intended to
encourage use of new technologies in the delivery of outreach education, it
contains tables for media selection; descriptions of national and state
resources for video, audio, and computer technologies, and for traditional
audiovisual classroom materials; directories of resources such as videodisks and
audiotapes; and 70 case studies of higher education institutions. It is
available for $15 from the Distribution Center, Minnesota Extension Service, 3
Coffey Hall, 1420 Eckles Ave., St. Paul, MN 55108.
Anderson, Joseph S. (1987). A historical
overview of telecommunications in the health care industry. THE AMERICAN JOURNAL
OF DISTANCE EDUCATION, 1(2), 53-60.
Barker, Bruce O. (1987, April). THE EFFECTS OF LEARNING BY SATELLITE ON RURAL
SCHOOLS. Paper presented at the Learning by Satellite Conference (Tulsa, OK,
April 12-14, 1987), 12pp. ED 284 693
Barker, Bruce O. (1987, March). USING INTERACTIVE TECHNOLOGIES TO INCREASE
COURSE OFFERINGS IN SMALL AND RURAL SCHOOLS. Paper presented at the Annual
Conference for Microcomputers and Technology in K-12 Education (7th, Carbondale,
IL, March 12-13, 1987), 20pp. ED 279 465
Benson, Gregory M. & Hirschen, William. (1987, August). Distance
learning: New windows for education. T.H.E. TECHNOLOGICAL HORIZONS IN EDUCATION,
Creutz, Alan. (1986, May). Telecommunications management: Institutional
imperative. CAUSE/EFFECT, 9(3), 12-17.
Dean, Jay W. (1986, September). The long-term effects of distance education.
VOCATIONAL EDUCATION JOURNAL, 61(6), 28-30.
Faibisoff, Sylvia & Willis, Deborah J. (1987, Spring). Distance
education: Definition and overview. JOURNAL OF EDUCATION FOR LIBRARY AND
INFORMATION SCIENCE, 27(4), 223-232.
Ferguson, Douglas K. (ed.). (1987). Electronic information delivery systems:
Reports on five projects sponsored by The Fred Meyer Charitable Trust. LIBRARY
HIGH TECH, 18/5(2), 65-93. (Reports by V. A. Anderson, L. Brander, M. F.
Johnson, B. Morton, S. Smith, and J. R. Matthews)
Hansel, Daytra. (1987, Spring). Teleconferencing policy development for
higher education: An overview of factors involved in the development and
implementation of policy. MEDIA MANAGEMENT JOURNAL, 6(3), 20-22.
Maricopa County Community College District: College and university computing
environment. (1987, January). CAUSE/EFFECT, 9(1), 22-24.
Phillips, David L. (1987, April). Videoconferencing at Penn State. T.H.E.
TECHNOLOGICAL HORIZONS IN EDUCATION, 14(8), 52-54.
Wilson, Savan. (1987, Spring). The sky's the limit: A technology primer.
JOURNAL OF EDUCATION IN LIBRARY AND INFORMATION SCIENCE 27(4), 233-239.
Winer, Toby R. & Winer, Russell S. (1987). Integrating strategic planning
concepts into the negotiating process. PLANNING FOR HIGHER EDUCATION, 15(4),
Zacher, Candace M. (1987). DESIGN AND DELIVERY OF TRAINING FOR A STATE-WIDE
DATA COMMUNICATION NETWORK. Paper presented at the Annual Conference of the
Association for the Educational Communications and Technology (Atlanta, GA,
February 26-March 1, 1987), 9pp.