Distance education courses involve two core activities by the learners:
- Independent study of course materials and resources—the courseware that makes up
the physical, mediated content of the course
- Interaction with other course participants (tutors, instructors, other learners,
resource people).
It is through a package of courseware, specifically designed for independent study,
that the teaching in a distance education course is mediated—using text, audio,
audiovisual, or electronic media. The form that an item of courseware takes, and how it is
studied by the learner, depends on the technology used to support and deliver the media
(for example, text can be delivered on paper, as print, or by the Web, as hypertext files;
video can be delivered as broadcast TV, on cassette, or digitized, in a computer file).
The same technology—such as videoconferencing, audiographic conferencing, or the
Web— be used to both transmit content and support interactions, but in most cases
different technologies are used for these purposes.
In distance education the use of national broadcasting networks has generally been
justified only for a mass education program or as a "shop window" for a
program's courses, to attract new students. The exceptions have been educational use of
state-controlled broadcasting networks (when the ministry of education receives access to
a certain amount of air time each week) or networks operated by educational or religious
organizations. Narrowcasting of instructional TV programs to registered students, through
private access cable, satellite channels, or instructional television fixed service
(ITFS), is used in some countries, notably the United States. The arrival in the near
future of digital broadcasting networks using satellite systems will vastly increase the
number of channels for narrowcasting, and some of these could conceivably be used in
distance education programs.
Where potential students have access to networked terminals or personal
computers—whether at work, at local study centers, or at home—technologies for
delivering electronic, or digital, media are being used more and more in distance
education. Digital systems transmit all information as bits (BInary digiTs) and can send
different types of information (text, numerical data, sound, images) down the same channel
at the same time. Digital systems use transmission channels far more efficiently than do
analogue systems such as traditional telephone or television broadcast networks. They also
reproduce the information more accurately and can be copied or amplified with little or no
distortion. Telecommunications networks increasingly are being replaced with digital
systems such as digital broadcasting and integrated services digital network (ISDN).
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