DE Basics: Technologies for Distance Education

January 26, 2004

Technologies for Distance Education

In distance education, a variety of technologies ranging from print to recorded audio, radio, recorded video, television and the computer are used for communication between instructors and learners. Rarely, a single technology is used for such communication. Often printed study guides are supplemented with an audio tape, or a program on television. The Internet, since the mid 1990’s, has provided a multimedia environment in which a variety of modes of representation that include text, audio and video can be displayed together. However, because of lack of adequate bandwidth, distance educators are sometimes compelled, for example, to use the Internet only for text and still images, and if a course involves large sections on video, distribute the video to students via videotape or on a compact disk.

Books, study guides, and self-instructional manuals are the oldest and most ubiquitous technologies for distance education. From its inception, distance educators relied on books, and study guides to reach their learners. The use of print technology gave rise to correspondence education, which was very popular until the 1950’s. Today, print remains to be the most popular form of communication in distance education. Correspondence education is still practiced by many institutions. Newer technologies, such as videoconferencing via the satellite, the Internet, and web-based instruction are replacing correspondence education rapidly.

Educators used radio for reaching vast numbers of students in the US and elsewhere in the world starting inthe 1920’s. Although radio remains to be one of the most popular media, in countries with advanced economies its direct use for instructional purposes began to wane in the 1950’s as television’s popularity increased. In many developing countries, specially those in Africa, and the Indian subcontinent radio remains to be a useful means for direct instruction.

Recorded Audio
Educators have used recorded analog audio in a variety of shapes and forms including phonographs, ¼ inch reel-to-reel audio tapes and audio cassettes for distributing instruction. Recently, however, audio recordings have moved into digital forms as computer files on CDs and Internet servers. In any of its technological formats, analog and digital audio that can carry a lecture to learners remains to be a very cost effective means of instruction.

Educators use the ordinary telephone to converse with a single student, or a number of students through telephone sets equipped with a speakerphone, countless times on a regular basis. In tutoring, consulting or direct instruction the phone has proven to be a very useful instrument of communication in distance education. Video-conferences of various kinds and formats are also augmented by the use of the phone to provide an inexpensive and accessible means for students to converse with an instructor in a television studio thousands of miles away.

Facsimile is also used to provide instructional information to students, or receive questions and comments from them in a variety of distance teaching and learning settings. Very often, during a video conference, the audience fax in their questions for the presenter and receive an answer on the air.

Electronic Boards
Various forms of pressure sensitive boards have been introduced to the market over the years that could be connected to a display monitor at a distance via the ordinary phone lines, or on the Internet. Instructors could write or draw on these boards for the local audience, while the remote students could see the result of their writing or drawing on the display screen at a distance. these electronic boards are often augmented with another phone line carrying the voice of the instructor in real time.
In the 1950’s instructional use of television grew rapidly in colleges and universities, as well as in K-12 schools. Open air television was augmented by cable television, and communication satellites to give new life to this powerful medium. These telecommunication technologies made instructional television more available to learners in schools and homes alike. Open air broadcast television, cable and the satellite are used by numerous institutions for distance education on a daily basis.
Recorded Video

Since the advent of inexpensive video cassettes distance educators have used it to distribute lectures, and other forms of instruction. In the 1970�s and throughout the 80’s video cassettes were widely used for disseminating instruction in distance education. Today, the ordinary video cassette remains popular, but it is rapidly being replaced by recorded video on CD (Compact Discs) and DVDs (Digital Video Discs) or digital computer files that either can be downloaded or streamed via the Internet.
Streaming Video
Live video in real time or pre-recorded video can be streamed on the Internet, providing yet another means of audio and video communication to distance educators. With new streaming video software it is becoming increasingly simple to webcast a course session live, or provide pre-recorded segments for students to view at a later time.
Educators use broadcast television, digital room conferencing systems and desktop videoconferencing technologies for distance teaching and learning.
Satellite-based Videoconferencing– In the 1980’s telecommunication satellites became numerous, powerful, and relatively affordable for educators to take advantage of them. No longer would the reach of educational television be limited by the power of one local transmitter. Educators could uplink to telecommunication satellites and transmit their programs to the continental United States and beyond. Availability of satellites was a boon to educational television in both K-12 and higher education. Since then, many institutions have used broadcast television for videoconferencing. Very often students use an ordinary telephone or fax to interact with the instructor in the broadcast studio. These video conferences are dubbed as “two-way audio, one-way video.”

Compressed Video-and compressed audio, made it possible to use the ordinary phone as a carrier for two-way audio and video conferencing. These so-called “room video conferencing systems” became available in the 1980’s, and during the 90’s their cost rapidly decreased. Many corporate training departments, K-12 schools, institutions of higher education and government organizations, including the military, adopted compressed video systems for instructional purposes. Today, using the ordinary twisted pair telephone copper wire, videoconferencing systems offer a cost-effective means of two-way audio, and video conferencing for numerous institutions worldwide.

Desktop videoconferencing– New software applications such as Flash Communication provide for interactive audio, video, text, and whiteboard communication on most high-end computers. These applications that were limited to one-to-one, or one-to-many communication are now providing many-to-many interaction online. Still limited by the bandwidth available to the end user, desktop video conferencing is expected to increase in popularity with more consumers using high speed broadband telecommunication systems such as those offered by cable companies via a cable modem or by telephone companies via DSL (Digital Subscribers Line).