The world of computing is littered with acronyms, some of which, if the concepts they represent become widely accepted as standards, pass into everyday speech to take on a linguistic life of their own. Many people who know comparatively little about computers regularly use terms such as DOS (Disk Operating System) or CD-ROM (Compact Disc Read Only Memory), yet would be unable to say what such acronyms stand for, even perhaps that they are acronyms at all. ISDN has not yet reached that stage, although there are signs that the term is beginning to escape from its specialist boundaries. In the meantime, educators who wish fully to grasp its benefits as well as its limitations, must begin with its full form: Integrated Services Digital Network. It is a network because it uses the telephone system. Strictly speaking, the integration of its services is a synthesis of switching techniques at the telephone exchange, but it also achieves a more readily understood integration by simultaneously offering different forms of telecommunication (voice, computer-readable data, telex, facsimile) and different media (sound, images, text that is, multimedia). Above all, it is digital as opposed to analogue.

The chapter will survey the current applications running over ISDN, commenting on the range of teaching/learning strategies possible, and looking forward to developmental trends in software. A critical analysis will be made of the vogue for interaction in education and training, including a review of the kind of interaction which actually takes place through typical ISDN applications. Finally, the chapter will put ISDN in the context of other educational technologies and indicate those areas in which its implementation is most appropriate.

This chapter aims to place the discussion in the last two chapters about Basic Rate ISDN and educational applications in an overall context of educational networks. A subsidiary aim is to give general information about applications of ISDN in the education and training market that have not been included as specific case studies in the book, either because they are not widely deployed as yet or because they affect education in a 'behind the scenes' manner.

This chapter will cover the ongoing evolution of Columbia University's Off-Campus Graduate Education Program and the Columbia Video Network (CVN) from the original base of assumptions, instructional methodologies, technologies, clients and cultures to the current situation and projections for the future. Although a variety of delivery systems are in use at Columbia (all of which have their advantages and disadvantages) the focus will be on the university's seven years of experience with two way videoconferencing.

Digital videoconference transmission is often discussed in terms of alternate delivery channels, either via computer networks, terrestrial broadcast, cable, satellite broadcast or telecommunication delivery. In fact, the future availability of digital video should result in a plurality of concurrent options, where the determinant for delivery of videoconferencing will simply be the location of the user and the convenience of the user, irrespective of whether the user is in the home, classroom or office. In this scenario educational videoconferencing is proposed as one of a range of future value-added information services together with other tele-working and leisure options. Current advances in the technology of educational videoconferencing abound, particularly in the areas of image compression, information processing, digital storage, available bandwidth. However, the most important pointers to success will be determined by the future levels of usability and user acceptance.

Given Australia's vast distances between cities, institutions, campuses and rural and remote centres, it is not surprising that Australian tertiary institutions are making growing use of videoconferencing. By July 1993, 22 of Australia's 35 public universities had videoconferencing facilities at 51 sites and most of the remaining universities were at some stage of planning to acquire systems. A further 20 sites were operational in the technical and further education (TAFE) sector with plans for further development in several states. The number of tertiary education sites may therefore easily become 80-100 in a short period of time. The most common form of videoconferencing involves two-way audio and two-way video transmitted as compressed digital signals via ISDN at 128 kbit/s. In July-September 1992, a survey team was commissioned by the Commonwealth Department of Employment, Education and Training (DEET) to inquire into the adoption and use of videoconferencing in higher education in Australia and to make recommendations about the future potential of this technology in the light of Australian and overseas experience. The resultant report (Mitchell et al, 1992), which was part of a DEET Review of Modes of Delivery in Higher Education, is summarised and updated in this chapter.

The use of videoconferences (2 Mbit/s) in distance education has expanded in Norway as in many other countries. Universities and colleges use videoconferences to distribute lectures to groups of students that are widely spread geographically. Teachers in high schools have the opportunity to increase their knowledge of special education with the aid of videoconferences. Workers in the fish processing industry are offered further education, and schools that are short of qualified teachers may supplement their teaching schedule by putting up distant teachers on screen. The videotelephone, with its requirement of only one single digital telephone line, is of particular interest to distant educators. Through ISDN, visual communication will be available at a much lower price than the 2 Mbit/s videoconferences of today. At the same time, accessibility will be greatly improved. With this prospect in mind, the Norwegian Telecom Research has spent the last few years experimenting with the use of videotelephones in distance education.

The following sections are discussed: benefits of videoconferencing; videoconferencing operating costs; tele-learning equipment; and cost-benefit analysis.

The Ecole Nouvelle d'Ingenieurs en Communication (ENIC) has developed distant learning equipment using ISDN, called the Visiocentre. The school has used the equipment for its own undergraduate training, and found that students and professors are enthusiastic about it. This equipment allows the school to increase its effectiveness both by being able to use busy external specialists for teaching and by bringing the school nearer to the students in their workplace.

In many parts of the world there is increasing emphasis on school-based teacher education. Similarly there is an emphasis on children achieving their maximum potential. However it is difficult to locate sufficient expertise and resources in each school. One answer could be multimedia teaching from a distance, a form of computer supported co-operative work (CSCW) tailored to the needs of education and training. New forms of more accessible multimedia communication have recently become available which permit new forms of working. In business and commerce, research and development are currently suggesting ways in which computers can support collaborative work between workers at the same location and those at a distance from each other. Gale (1992) notes that facilities of this new technology have been available for some time, but have not been taken up by users. Therefore the strengths and the weaknesses of this new medium require careful study within the social and curriculum contexts of education. The Exeter University Computer Conferencing Project was one of the first in the world to describe the use of multimedia communications over a distance to enhance education and training with ISDN-2. The project therefore fulfilled its aim to produce case studies in which this new form of communication and collaborative group work could benefit education and training. It also provides guidance for other uses of an integrated communications service.

Co-Learn is a research and development project in the current DELTA Programme, involving the design of an integrated groupware environment for collaborative learning at a distance, based on personal computers connected through ISDN links to a central host. The Co-Learn environment contains several tools for real-time and asynchronous communication via text, graphics and speech, as well as tools for the preparation, sharing and annotation of multimedia courseware. Co-Learn is one of the first of a new generation of prototypes which aim to integrate in one environment a range of tools and communication modes for collaboration between actors in distance education and open learning programmes.

ECOLE addresses the problem of integrating real-time and deferred-time interaction and group communication into a Europe-wide multimedia distance learning service. Although the project is essentially a technical one, its success will be measured by its contribution to the effectiveness of training.

The application of ISDN described here is essentially complementary to, and extending the functionality of, a broadband network (LIVE-NET) designed for interactive visual communications. The availability of ISDN enables a new form of outreach from this 'island' network both nationally and internationally which could not be realised otherwise because of technology and cost constraints. In this chapter we will first consider the nature of visual communications, interaction, and technology options for implementation. We will then review the aims, architecture and applications of LIVE-NET (the London Interactive Video for Education Network) and the outreach of this network through satellite and ISDN. A particular application described is the Image Server: a shared resource with access from ISDN for image loading, retrieval and interactive browsing. We next consider models for 229multi-site interaction including the integration of ISDN links into LIVE NET and satellite sessions. As a further development, a hub model with LIVE-NET functionality for the interworking of ISDN-connected videoconferencing terminals is proposed. In conclusion, scenarios for the future migration of the LIVE-NET broadband network to an all ISDN on demand network are suggested.