Academic journal article
By Gellerman, Elizabeth
T H E Journal (Technological Horizons In Education) , Vol. 22, No. 3
The International Teleconferencing Association indicates that the teleconferencing industry had total revenues of $2.3 billion in 1993, a growth of 31% over the $1.75 billion reported in 1992. And 1994 revenues are forecasted to break the $3 billion mark.
There can be no denying that teleconferencing as an industry is growing faster than predicted. From beginnings in large-group corporate conference rooms, this technology has been heartily embraced by education. Distance learning and telecommunications have brought instruction to students and teachers nationwide and all over the world.
Teachers can now provide instruction to students in numberous remote classrooms; one trainer can provide information to employees at various sites across the country. These group or multipoint scenarios have been the standard for many years. A new revolution is taking place, however, that brings teleconferencing to the desktop.
The technology is currently available in several stages. Desktop conferencing begins with simple document sharing, a plus for collaborative writing and project work as well as text-based lessons. Imagine "classes" of 15 to 30 adult learners, where each student is at his or her own home computer. A teacher posts a document for discussion; online chats, mark-up capabilities and printing out final copies enhance the learning experience.
Several desktop teleconferencing packages have emerged, most recently Intel's ProShare, that add video windows and audio capabilities for one-to-one videoconferencing. In addition, several systems provide multi-point videoconferencing for small groups.
* High Standards
Multi-point videoconferencing has adopted the video portion of the H.320 standard developed by the telecommunications industry. Unfortunately, this high-quality standard is unacceptable in desktop applications because it is compute-intensive, expensive and supports switched digital networks versus LANs.
Intel chose instead to implement their Indeo video compression algorithm in their ProShare package. This keeps the overall cost manageable for users but limits quality. Also, ProShare users can only interact with each other. Standards will need to be developed that will allow group users of H.320 to communicate with PC-based videoconferencers.
Another point is transmission method. ISDN telephone-based service is only offered in specific areas nationwide, however as videoconferencing takes off, fueled by increased business and personal users, service is sure to spread.
Two services that utilize ISDN telephone lines are currently being offered: Primary Rate and Basic Rate. Both provide a number of 64 Kbps channels (B channels) for digitized voice, data or video and a single data (D) channel.
An emerging digital service that complements Primary Rate is called Multi-Rate ISDN. This circuit-switched service allows users to make calls from 128 Kbps to 1.472 Mbps in 64 Kbps increments over an ISDN network. Users make calls through a public network on a per-call basis at different data rates.
Other emerging transmission technologies such as asynchronous transfer mode (ATM) could handle video in a less expensive manner.
* Large-Group Systems
PictureTel Corp. has identified education as an important market for their videoconferencing products. PictureTel Learning Applications provide video and audio telecommunications with additional teaching tools. The Classroom System comprises a complete videoconferencing system that is part of the PictureTel System 4000 Family; a 46" rearprojection monitor; and a range of teaching tools including a special interface that provides instructors with one-button control of selected functions via a desktop keypad; a 1/2" CCD document camera, a wide-angle auxiliary camera and tripod, 3" preview monitor for the document camera, and both tabletop and lapel microphones. The tools are offered optionally as a Learning Option Package. …