312 research outputs found

    NASA and the challenge of ISDN: The role of satellites in an ISDN world

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    To understand what role satellites may play in Integrated Services Digital Network (ISDN), it is necessary to understand the concept of ISDN, including key organizations involved, the current status of key standards recommendations, and domestic and international progress implementation of ISDN. Each of these areas are explained. A summary of the technical performance criteria for ISDN, current standards for satellites in ISDN, key players in the ISDN environment, and what steps can be taken to encourage application of satellites in ISDN are also covered

    On the proposed integrated services digital network

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    The ultimate aim of this dissertation is neither to increase the state of the art in networking technology nor to predict the future structure of telecommunications networks. It is an attempt to raise the awareness of both the author and the reader as to the evolutionary forces driving vast changes in the telecommunications field. The impact of these changes will significantly alter the way we live and conduct business in the Information Age. For those involved with the communications field, the ability to make sound business decisions will require an in-depth knowledge of the technology and services that compose ISDN. Therefore this paper will explore the motivating forces, the potential services, and the technical components in the emerging Integrated Services Digital Network (ISDN). My interest in data communications was kindled at RIT and has continued in my work, both as a systems programmer in the telecommunications division at the Travelers Insurance Company and as a printing systems analyst for Xerox Corporation. This thesis has helped me answer both personal and professional questions about the future of telecommunications and to share this information with others

    Application of Asynchronous Transfer Mode (Atm) technology to Picture Archiving and Communication Systems (Pacs): A survey

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    Broadband Integrated Services Digital Network (R-ISDN) provides a range of narrowband and broad-band services for voice, video, and multimedia. Asynchronous Transfer Mode (ATM) has been selected by the standards bodies as the transfer mode for implementing B-ISDN; The ability to digitize images has lead to the prospect of reducing the physical space requirements, material costs, and manual labor of traditional film handling tasks in hospitals. The system which handles the acquisition, storage, and transmission of medical images is called a Picture Archiving and Communication System (PACS). The transmission system will directly impact the speed of image transfer. Today the most common transmission means used by acquisition and display station products is Ethernet. However, when considering network media, it is important to consider what the long term needs will be. Although ATM is a new standard, it is showing signs of becoming the next logical step to meet the needs of high speed networks; This thesis is a survey on ATM, and PACS. All the concepts involved in developing a PACS are presented in an orderly manner. It presents the recent developments in ATM, its applicability to PACS and the issues to be resolved for realising an ATM-based complete PACS. This work will be useful in providing the latest information, for any future research on ATM-based networks, and PACS

    Performance evaluation of currently available VLSI implementations satisfying U-interface requirements for an ISDN in South Africa.

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    A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering.This project report examines the performance of three VLSI U-interface implementations satisfying the requirements of Basic Access on an ISDN. The systems evaluated are the Intel 89120,Siemens PEB2090 and STC DSP144, operating on 2BIQ, MMS4J and SU32 line codes respectively. Before evaluating the three abovementioned systems, a review of the underlying principles of U-interface technology is presented. Included in the review are aspects of transmission line theory, line coding, echo-cancellation, decision feedback equalisation, and pulse density modulation. The functional specifications of the three systems are then presented followed by a practical evaluation of each system. As an aid to testing the transmission systems, an evaluation board has been designed and built. The latter provides the necessary functionality to correctly activate each system, as well as the appropriate interfacing requirements for the error-rate tester. The U-interface transmission systems are evaluated on a number of test-loops, comprising sections of cable varying in length and gauge. Additionally, impairments are injected into data-carrying cables, in order to test the performance of each system in the presence of noise. The results of each test are recorded and analysed. Finally, a recommendation is made in favour of the 2BIQ U-interface. It is shown to offer superior transmission performance, at the expense of a slightly higher transmit-power level.Andrew Chakane 201
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