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  • 标题:What Is a Digital World?
  • 作者:M. Fournier
  • 期刊名称:Communications News
  • 印刷版ISSN:0010-3632
  • 出版年度:1985
  • 卷号:March 1985
  • 出版社:Nelson Publishing

What Is a Digital World?

M. Fournier

Telecommunication technology has had a profound influence on society. More recently, major innovations in micro-electronics, opto-electronics and information processing technologies are having more far-reaching implications than in any other area of human activity. Indeed, the merging of these three technologies made possible by the availability of powerful yet inexpensive solid state devices has resulted, in a relatively short period, in changing the patterns of communications beyond recognition and in creating the basis of the information society. Analogue switching and transmission techniques are giving way to reliable, high-speed, cost-effective electronic digital swtiching and transmission systems capable of providing a myriad of new services responsive to evolving market requirements.

Communication systems based on digital techniques can process a variety of services including telephone calls, data, text, graphics and video within the same infrastructure of facilities while providing ever increasing widespread accessibility at decreasing cost.

With three-quarters of the world's population, the Pacific region has varied needs and resources. It is indeed significant that the large expenditures on telecommunications facilities by the Pacific Basin nations reflect the importance given to the role of telecommunications in national development and international exchanges. It is therefore vital at this time of rapidly evolving technology that efforts are directed towards effective and full utilization of the existing infrastructure while expanding the telecommunications facilities in the best and most cost-effective manner.

Although at various stages of development, the countries of the Pacific Basin have shown remarkable progress in the development and utilization of telecommunications technology. In this respect, the Pacific Telecommunications Council continues to provide an effective forum for the exchange of information on all aspects of telecommunications.

The process of change can only be evolutionary considering the very large investments already made in building and maintaining the present network necessary to support over 500 million telephones and terminals. The word "toward" in the theme chosen for this conference should be interpreted as reflecting a continuing evolution of the telecommunication world. Indeed, digital technology has been used since the early 1970's.

Existing local loop facilities represent a large proportion of the carriers' total capital investment in network facilities and they have a long service life expectancy. Therefore, the extension of digital communication capabilities through the local loop to the user will probably take place gradually over many years, starting with areas served by digital local exchanges and at user locations connected via copper wire pairs which can be adapted for digital operation using time burst multiplex techniques.

From the viewpoint of demand on transmission resources in the core network, the important categories of services are telephone, video and data, including computer communication electronic mail, fascimile and telex.

At present and for at least the next 15 to 20 years, the transmission requirements of the telephone service are expected to far exceed the combined requirements of all other service categories. This is particularly the case in-so-far as switched services are concerned since the great majority of telephone traffic is switched whereas a significant proportion of the video and data service demand will probably involve high speed traffic handled on a non-switched basis.

Out to the year 2000 the transmission requirement in the core network for all services in the data category is not expected to exceed 1 percent of the telephone transmission requirement based on 8-bit PCM speech encoding. However, by the year 2000, the transmission requirement of the telephone services could be compressed with speech processing and interpolation by a factor of up to 8 or 10 in the core network. In that event the total transmission requirement for services in the data category could account for as much as 10 percent of the telephone transmission requirement.

Within the data communication category it is foreseen that computer communications will account for 80 percent to 90 percent of the total traffic volume in the 1990 to 2000 time frame with the balance of data traffic divided about equally (five percent to 10 percent each) between facsimile and electronic mail in the countries which use a phonetic alphabet.

Digital communication technology is being swept rapidly forward, riding on successive waves in the development of solid state devices and ongoing enhancements to processing techniques for the production of VLSI circuit configurations.

With regard to VLSI component technology I feel safe in predicting a continuing trend towards higher speed of semiconductor operation and decreasing costs.

Over 50 percent of the circuit capacity in intercontinental segments of the international network is expected to be digital by the mid-1990's. This will approach 100 percent by about 2007 as existing analogue transmission facilities reach the end of their design life.

By about 1988, 32 k bit/s speech encoding and digital speech interpolation techniques will start to be employed on some international and long haul national toll routes to achieve bit rate compressions of up to 5:1 for real-time voice transmission.

Towards the mid-1990's it is expected that digitalization will have spread from the core of the network and be permeating the local user access environment.

The attractiveness of the digital option increases with the passage of time and we will soon be at the point (if we are not already there) when it will be preferable to accept possible risks in respect of making a transition to digital technology in lieu of incurring relatively large incremental provisioning costs and high depreciation for the expansion of existing analogue facilities.

The wide range of service offerings that are made possible by new digital network facilities opens a new vista of opportunity for telecommunication entrepreneurs.

Digitally encoded information, be it voice, data, video, text, graphics or network control information, can all be handled in a uniform way making possible an integration of services within a single network structure.

The transition toward the digital world is well underway. It is critical that this major change occurs in an organized manner in order to ensure continuing effective utilization of the existing networks and facilities while at the same time introducing the new digital systems. Clearly this will require that digitalization concepts and strategies be such that present and future service demands can be met in an optional way technically, operationally and economically.

Some administrations will choose to move more rapidly than others. Each will have to develop a strategy of transition. However, the network must continue to serve all users on a worldwide basis and therefore it is essential that the move toward the digital world be orderly and well coordinated in the spirit of international comity.

COPYRIGHT 1985 Nelson Publishing
COPYRIGHT 2004 Gale Group

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