ISDN and the Internet

Current integrated services digital networks (ISDN) can provide subscribers with access to the Internet and can support variable data rate connections between Internet switching nodes. This paper describes how ISDN and the Internet can be further integrated and communication capabilities improved by expanding the role of ISDN switching centers to include certain packet switching functions. Enhancements are identified that allow narrowband ISDN (N-ISDN) to support full motion video in addition to voice and data communications. These enhancements, along with the further integration of ISDN and the Internet, would facilitate a smooth transition from N-ISDN to broadband (B-ISDN).     

ISDN: A Global Solution to Transmission Needs

The concept of the integrated services digital network (ISDN) could revolutionize information management. The purpose of the ISDN is to provide a worldwide network that offers end-to-end digital connectivity supporting a wide variety of communications services. ISDN subscribers will have direct access to a high-speed digital pipeline capable of supporting simultaneous voice, data, facsimile, and various other services and calling features.     

ISDN: A Global Solution to Transmission Needs

The concept of the integrated services digital network (ISDN) could revolutionize information management. The purpose of the ISDN is to provide a worldwide network that offers end-to-end digital connectivity supporting a wide variety of communications services. ISDN subscribers will have direct access to a high-speed digital pipeline capable of supporting simultaneous voice, data, facsimile, and various other services and calling features.     

The coming of ISDN

Integrated Services Digital Network, or ISDN, is the latest catch phrase in the field of telecommunications. Much effort has been put into establishing a standard for this new technology, but still more remains before the dream of a seamless communications network will be realized. This paper discusses the process taking place and the problems that this new technology faces. First, an overview of ISDN technology is given: its development, concepts, and capabilities. Then, we examine the major obstacles facing ISDN implementation, with a comparison of the pros and cons of some features. Finally, The technology is considered from an information manager's point of view: how can a manager prepare for the arrival of a mature technology?     

基于Web的用户需求灰预测软件开发

获取用户需求信息是进行产品设计的前提。开发了一个用户需求灰预测软件,实现了将Web网页中用户需求统计项信息提交到Access数据库,并利用灰色系统理论的预测方法对近4年的数据进行预测计算,以得到下一年度对应需求的预测值。以汽车的用户需求预测为例说明了软件设计过程。该软件为设计需求知识库的建立打下了基础。     

用通信服务器和MODEM实现远程联网和远程通信的连接

需要远程联网和远程通信的用户,多数需要利用ＭＯＤＥＭ在现有的电话公共交换网上实现。本文对如何选择、配置网络ＭＯＤＥＭ和通信服务器,以实现远程联网和远程通信的连接作了深入的讨论。     

Testing Mixed-Signal Devices

Testing ISDN devices, which mix analog voice information and digital data, puts special demands on the test system. The ISDN has multiple interfaces with devices that perform a variety of functions. What was usually performed by many individual ICs is now performed by a single ISDN device. Particularly challenging are network interface and device feature tests because the test system must generate and detect the specialized frame structures in the network communication links-structures that change not only between transmit and receive but also between interfaces. Techniques to conduct these tests are described in detail. The benefits of these techniques can be increased with the use of the proper hardware and interactive, graphics-based software tools.     

Conversations Over Video Conferences: An Evaluation of the Spoken Aspects of Video-Mediated Communication

Recent trends toward telecommuting, mobile work, and wider distribution of the work force, combined with reduced technology costs, have made video communications more attractive as a means of supporting informal remote interaction. In the past, however, video communications have never gained widespread acceptance. Here we identify possible reasons for this by examining how the spoken characteristics of video-mediated communication differ from face-to-face interaction, for a series of real meetings. We evaluate two wide-area systems. One uses readily available Integrated Services Digital Network (ISDN) lines but suffers the limitations of transmission lags, a half-duplex line, and poor quality video. The other uses optical transmission and video-switching technology with negligible delays, full duplex audio, and broadcast quality video. To analyze the effects of video systems on conversation, we begin with a series of conversational characteristics that have been shown to be important in face-to-face interaction. We identify properties of the communication channel in face-to-face interaction that are necessary to support these characteristics, namely, that it has low transmission lags, it is two way, and it uses multiple modalities. We compare these channel properties with those of the two video-conferencing systems and predict how their different channel properties will affect spoken conversation. As expected, when compared with face-to-face interaction, communication using the ISDN system was found to have longer conversational turns; fewer interruptions, overlaps, and backchannels; and increased formality when switching speakers. Communication over the system with broadcast quality audio and video was more similar to face-to-face meetings, although it did not replicate face-to-face interaction. Contrary to our expectations, formal techniques were still used to achieve speaker switching. We suggest that these may be necessary because of the absence of certain speaker-switching cues. The results imply that the advent of high-speed multimedia networking will improve but not remove all the problems of video conferencing as an interpersonal communications tool, and we describe possible solutions to the outstanding problems.     

Reorganization of a police communications network

The area covered by the West Mercia police force is hilly, with scattered towns, and so a policy of decentralization of communications has been followed. The design and operation of the network is described.     

Of Nets and Nits

To increase their organization's competitiveness, IS managers must gain a broader knowledge of the most current technologies and critical business issues. This column reviews two books that focus on two communications technologies— ISDN and computer networks—and two books that address the laws of EDI and equipment leasing.     

基于SIP信令的个性呼叫策略

随着通信技术的不断进步,如何更好地针对客户提供个性、一对一的服务成为企业建立呼叫中心的目标之一.单纯按照传统呼叫中心ACD( Automatic Call Distributor)策略的呼叫方式显然不能满足企业倡导的一对一的服务宗旨.本文提出一种基于SIP( Session Initiation Protocol)协议...     

ISDN awareness: implications for the management of telecommunication technology

Rapid changes in telecommunication technology (TT) and its usage have elevated it to a strategic role. This strategic thrust of TT has certain implications for TT management. This paper reports on a study conducted to identify and analyse the factors that influence ISDN technology awareness in an organization. Based on a statistical analysis of the responses to a survey instrument, our hypotheses of a positive relationship between desirability of ISDN adoption and influence of external customers, strategic importance of TT, operational importance of TT, TT management awareness of ISDN, top management awareness of ISDN and extent of resource-sharing are tested. The implications of these factors for achieving enhanced connectivity through ISDN are discussed.     

论ISDN协议实现的标准化测试

本文围绕着窄带ＩＳＤＮ协议标准化测试这一主题，对ＩＳＤＮ终端和交换机的标准化测试进行了讨论，根据笔者参加的北京邮电大学合作项目－“综合业务数字网ＩＳＤＮ协议测试与验证技术”研究工作的经验为背影，给出一种通用ＩＳＤＮ测试系统，我们的经验表明，以渡船原理为基础，建立的ＩＳＤＮ测试系统是可行，实用的，而且，它具有通用性好，功能全面，实现容易等优点。     

OSI implementations in Korea

Research and development on OSI became a key issue in many Korean R&D projects related to computer, telecommunications and services. The Korean computer and communications industry also finds their possible area of expansion through OSI-compatible products. But claiming OSI as the future direction in Korea at the national/government level is not near. This short paper presents various present and future R&D projects on OSI in Korea. These include ISDN, LAN, Videotex, Teletex, protocol testing, mixed mode terminal, network architecture etc.     

ALCA — automated local area networks configuration aid

Abstract: Solving the customer's LAN/WAN interconnect problem is difficult because of the need to explore many possible configurations (e.g. bridging/routing, packet/channels) and then to choose the best configuration using economic, performance and other criteria. The rapid introduction of new standards, protocols and products to the networking field brings additional complications to the solution and can cause confusion when configuring a network. ALCA is intended to generate all feasible LAN/WAN configuration possibilities automatically and to pick the most appropriate solution to solve the customer's problem, while specifically addressing open systems interconnection (OSI) standards. Matching communications protocols while searching all possible configurations is notoriously slow even on a computer. We show how the search speed can be significantly improved by using expert system knowledge compilation, a computer-aided software engineering (CASE) technique. ALCA is based on a centrally updated knowledge base of various local area networking products and their interconnect possibilities. ALCA also allows querying to find out protocol interfaces supported by a particular product/service. Finally, it includes a graphic user interface and context-sensitive menus to reduce user information load. ALCA is intended to be used by the field personnel involved in pre-sales support, by the data communication product managers, and as an educational tool for novice communication product managers.     

Communications Systems Driven by Software Agent Technology

The application of software agent technology to the management of communications' infrastructures is a challenging domain as it requires management on different time scales and has many interacting components. This paper looks at the potential benefits that may be gained from the application of agent technology to communications systems and surveys recent developments. Recent work using distributed network management by adopting co-operating and self-interested agent models of collaboration are described. The paper provides an introduction to the authors' perceptions of agent technology, followed by a discussion of some issues that need to be addressed for agent technology to be of practical use in the communications domain. Following sections describe how agent technology has been used for network management, legacy telecommunications systems, and telecommunications integration. The authors discuss how the emerging standards for agent technology can be used in an applied situation of providing a virtual private network and mobile agent technology used for fully distributed network control.     

用公共信道信令提升ISDN通信性能的分析

综合业务数字网(ISDN)是综合数字网的延伸,它打破了传统电话网和数据网之间的界限,扩展了网络业务的使用类型和范围。本文指出了传统的通信网的随路信令不能控制和处理ISDN多种数据业务的原因,并从ISDN用户接口部分(U-NI)和网络接口部分(NNI)的LAPD和SS7(ISUP)信令的工作原理出发,使用七号信令分析软件分析了这两种公共信道信令(共路信令)控制ISDN业务传送的过程,得出了运用这两种共路信令是支持和提升ISDN通信性能的必然趋势的结论。     

ITU-T standardization activities for interactive multimedia communications on packet-based networks: H.323 and related recommendations

The Telecommunication Sector of the International Telecommunication Union (ITU-T) has developed a series of recommendations together comprising the H.323 system that provides for multimedia communications in packet-based (inter)networks. This series of recommendations describe the types and functions of H.323 terminals and other H.323 devices as well as their interactions. The H.323 series of recommendations includes audio, video and data streams, but an H.323 system minimally requires only an audio stream to be supported. Motivated by straightforward interoperability with the ISDN and PSTN networks and a variety of other protocols, the recommendation H.323 has been accepted as being the standard for IP telephony, developed by the ITU-T and broadly backed by the industry—which is also adopted by both the Voice over IP (VoIP) forum and the European Telecommunication Standards Institute (ETSI). This paper presents an overview of the H.323 system architecture with all its functional components and protocols and points out all the related specifications.