North American agreements on ISDN

The work of the North American Integrated Services Digital Network Users Forum (NIUF) is presented, and its relationship to the Accredited Standards Committee T1 and other standards bodies is discussed. The role of the NIUF within the ISDN arena is evident when considering the Federal Information Processing Standard (FIPS) for ISDN and the Transcontinental ISDN Project (TRIP), both of which are described. The relationship of the ISDN FIPS to the Government Open System Interconnection Profile (GOSIP) and the military standard on ISDN are also discussed. A comparison of NIUF agreements/ISDN standards and the Bellcore NI-1 specifications is presented     

ISDN applications: their identification and development

Two efforts that are underway in the telecommunications industry to identify applications that directly relate to end-customer needs and to demonstrate the benefits of these applications are described. They are the North American ISDN Users' Forum (NIUF), sponsored by the National Institute of Standards and Technology, and the TriVista studies, sponsored by AT&T. Three user-initiated applications that have already been approved by the NIUF are described, namely, sales information management, customer service, and telemarketing. A history of the TriVista project is presented, including an overview of its methodologies and its major results to date. Three application areas identified by TriVista that have shown considerable market appeal are discussed in some detail. They are office automation, MIS help desk, and security     

ISDN terminal portability in the RBOC networks

The differences in the initial ISDN switch implementations by different manufacturers are sufficiently profound that ISDN telephones designed for one switch may not be compatible with other manufacturers' switches. In addition, as new features are added to a given switch, older telephones may not be able to use them. The author examines two solutions to these problems: Bellcore-specified ISDN interfaces and programmable terminals. Bellcore-specified ISDN interfaces are desired by the Regional Bell Operating Companies and support considerable portability. Although conformance to Bellcore specifications will produce a high degree of terminal portability, it is unlikely ever to produce full portability and will not produce any portability in 1990. Programmable terminals are shown to offer interesting potentials for portability and extensibility     

Implementation in Japan [ISDN]

INS-Net, Nippon Telegraph and Telephone's (NTT's) commercial integrated services digital network (ISDN) service, is described. There are two types of INS-Net service. INS-Net 64 provides basic rate interface service, and INS-Net 1500 provides primary rate interface service. The implementation of INS-Net and the promotion, application, and penetration of ISDN services are discussed. It is argued that as the number of useful applications grows, the number of subscribers will rise accordingly, particularly among business users. This increased volume of both applications and users will in turn lead to lower ISDN CPE costs, and will make ISDN an indispensable means to business activities in the 1990s     

An ISDN NetworkD-Channel VLSI Architecture

Dchannel processing in an ISDN exchange termination is very expensive using commercially available serial communications devices. This is because semiconductor manufacturers understand ISDN from the perspective of a terminal which is different from that of a network: the former sees oneDchannel, whereas the latter must deal with many. Consequently, commercially available devices are designed to support a small number of channels, whereas exchange terminations must cost-effectively support a large number of channels. This paper describes an innovative VLSI architecture that uses multiplexing to allow many channels to share serial communications circuitry as well as external message buffering. This capability will greatly reduce the hardware cost and complexity ofDchannel processing in ISDN exchange terminations.     

Line codes for digital subscriber lines [ISDN basic access]

The attributes of the several line codes considered for a North American standard for ISDN basic access are compared. Impairments that affect line code performance are examined, and their performance characteristics are discussed. An intuitive explanation of why the code performs as it does is attempted in each case. Some variations of the codes that were considered and that were intended to improve their performance are also discussed. The codes considered are bi-phase, modified duobinary, alternate mark inversion, 3B2T, 2B1Q and 4B3T     

Application profile for ISDN

The authors examine some key data processing applications to be used in conjunction with the voice and facsimile services as a platform for deploying ISDN (integrated services digital network) in North America. Special emphasis is placed on the emerging standards of both Accredited Standards Committees (ACS) T1 and X3 in an attempt to harmonize the computer and telecommunication industries towards providing the user with an integrated platform that is vendor-transparent and ubiquitous. This generic platform, which spans a large spectrum of businesses, is presented as a base context for defining user-specific needs and incubating the applications that directly relate to businesses. Distributed transaction processing, electronic data interchange, information retrieval, electronic mail, and file transfer together with seven supplementary services for voice and G4 facsimile are proposed for ISDN deployment in the marketplace. The authors describe how the relevant standards may be exercised through the various ISDN channels and emphasize the value of the North American ISDN User's Forum for commercializing this platform     

Bell Canada ISDN Trial Plans

After years of work by the CCITT and other standards bodies, the ISDN concept has reached the stage where manufacturers are announcing the availability of ISDN network and terminal products. Bell Canada has responded to this development by planning an extensive ISDN trial program, including access-loop verification, switch hardware and software verification, and, finally, customer market trials. This trial program will permit Bell Canada to refine the technology and services to best meet customer needs. The trial program is only the most recent manifestation of the evolution towards ISDN through digital network modernization. An early move towards digital technology within Bell has already paid substantial dividends in terms of new services and revenues. These services, and the emerging ISDN-based service opportunities, are highlighted in this paper.     

Performance objectives for ISDN's

THE CONCEPT OF the Integrated Services Digital Network (ISDN) and various aspects of its implementation concerning transmission, switching, subscriber interface and signaling are first briefly reviewed. Approaches to the specification of ISDN performance, currently under consideration of the International Telegraph and Telephone Consultative Committee (CCITT) for standardization, are described. A new parameter, percentage Error-Free Blocks (EFB's), is suggested as an additional measure to be specified at different block lengths. The need for more realistic consideration of the impact of burst errors is highlighted and a procedure is outlined using a specific channel model. Also discussed is the effect of delay when satellite channels are revolved. It is suggested that a joint EFB-delay constraint specification might be useful for network routing internal to ISDN.     

Why are ISDN standards important?

The advantages offered by the integrated services digital network (ISDN) to US Department of Defense (DoD) communications in terms of interoperability provides a framework for a discussion of ISDN standards. The standards organizations working on ISDN and network protocol standards are described, and their relationship to each other is delineated. The status of the standards being developed is discussed, and those that would be of special interest to the US DoD are examined     

ISDN: a customer perspective

Early projected benefits of the integrated services digital network (ISDN) are evaluated from a customer premises equipment (CPE) perspective. It is argued that economic conditions continue to affect ISDN investment in the USA. Worldwide customer acceptance of ISDN is contrasted with earlier projections and shown to be running at about 25% of earlier projections. IBM's current ISDN product set is discussed briefly. Even though the rollout of services has not yet achieved expectations, IBM believes the potential for ISDN use by customers is significant     

Current role and future evolution of the ISDN Signaling system inNTT's network

The current role of the integrated services digital network (ISDN) Signaling System is examined, covering general features of the ISDN protocol, functionalities supporting ISDN services, and functionalities supporting existing services. The Signaling System No.7 (SS7) network and its operation are described. The future evolution of the ISDN signaling system is discussed     

Video and image applications on narrowband and broadband isdn

Two major ISDN applications which will undoubtedly affect world-wide telecommunications in the coming decade are discussed. They are: (1) video transmission and (2) image transmission. Brief reviews of videophone chronicle and the current video coding technologies are presented. The application of videophones using p × 64 (CCITT coding algorithm up to 1·5 Mb/s) and the DCT (discrete cosine transform) algorithm for narrowband ISDN are discussed. Broadcast TV quality DS3-45 MB/s video codecs are also briefly discussed as a probable videophone system in the broadband ISDN era. The explosive growth of facsimile services is reviewed, and the progress of image coding technologies and their standards are covered. The prospects of high resolution image transfer systems with ISDN are addressed.     

ISDN protocols for connection control

The technical details of the integrated services digital network (ISDN) access protocols for connection control are described. These protocols are the ISDN physical layer, link layer, and layer 3, which are documented in International Telegraph and Telephone Consultative Committee (CCITT) Recommendations I.430, I.441, and I.451, respectively. Other work that supports or enhances these protocols is described. In particular, the ISDN protocol reference model, how it relates to the open systems interconnection reference model, and CCITT Recommendation Q.932 on service feature control on ISDN are discussed. Possible uses of ISDN, possible evolution paths, and some understanding issues related to ISDN are also described     

Migration to broadband ISDN

The current state of telecommunications in Japan is briefly discussed, with particular reference to broadband services. Experience with the migration from the analog telephone network to the present narrowband integrated services digital networks (ISDN) is described. Three strategies for the transition from narrowband ISDN to broadband ISDN are examined. The market-driven strategy is to replace existing metallic subscriber loops with optical media, wherever possible, even if only narrowband services are required, with the expectation that these subscribers will eventually use broadband services. The service-oriented strategy entails putting into place a flexible and multipurpose platform that would also allow HDTV distribution and bidirectional communications. Early installation of such a platform would allow for the early announcement of broadband services, which would in turn stimulate demand. The benefits and drawbacks of each of these strategies are discussed. The advance-investment strategy is to press ahead with the introduction of optical subscriber loops to accelerate technological innovation, even if the cost is somewhat high. Other issues that are important to the migration of broadband ISDN are noted     

ISDN implementation strategy of the Deutsche Bundespost telekom

The telephone networks operated by the Deutsche Bundespost are described, and its 64-kb/s ISDN pilot project is introduced. Plans for commercial operation are discussed. Marketing principles surrounding the introduction of ISDN services are examined. Conditions of use and charges in ISDN are considered, focusing on the effects on tariffs caused by the transition to ISDN, and the effects of the proposed switch from periodic pulse metering to time-sensitive calculation of charges are discussed     

Error performance in evolving digital networks including ISDNs

Some recent developments on error performance design methodology and the status of international standardization activities on network performance objectives are discussed. The effects of errors in various services and common error performance parameters are outlined, and a fundamental strategy for ISDN (integrated-services digital network) performance design methodology is presented. Error performance under real operating conditions and in-service monitoring of error performance are described. The status of CCITT Recommendations G.821 and M.550 is examined, and the areas that must be addressed by future studies are identified     

Standardization of a multi-configuration medium access protocol for broadband ISDN

This paper examines the current work within various standards bodies to define a multi-configuration medium access control (MAC) protocol for operation between broadband ISDN terminals. To begin, the configurations in which the MAC protocol is expected to operate are introduced. The relation between the MAC protocol and the broadband ISDN resource allocation schemes is then discussed. Several MAC protocol proposals currently being discussed in various standards bodies, each with unique assumptions regarding resource allocation in broadband ISDN, are then described and compared. Finally, areas for future work on this topic are identified.     

An Idea Turns Into Reality--CCITT Activities on the way to ISDN

This paper traces, in broad terms, how the idea of integration of telecommunication services into one network has evolved in the CCITT. A brief overview of existing telecommunication networks is followed by a review of CCITT activities from 1968 to 1980. It had become evident by 1968 that digital technology would not be restricted to transmission only, but would also intrude into switching, signaling, and the terminal field. The CCITT acknowledged this tendency by setting up a Special Study Group entrusted with the study of all questions related to PCM and the coordination of work going on in other Study Groups in the digital field. By 1980 the first ISDN Recommendation (G. 705) was agreed upon, and activities during 1980-1984, when the ISDN took shape, are related in some detail. The structure of the I-Series Recommendations, all relevant to ISDN matters, is described.     

Whatever happened to ISDN?

The integrated services digital network (ISDN) standard was defined in 1972 yet the progress towards its implementation has been very slow and very little is yet on offer to the consumer. The author looks at the vision where the concept of ISDN transforms the telephone network into a transport mechanism for all communications needs. Services offered by ISDN are discussed as are implementation and tariffs