Long-distance Telephone Research Articles

"City Portraits": An Experience in the Interactive Transmission of Imagination

I n French, a parcours (literally, 'itinerary') is a Each language ir model for circulation. It does not have to be actualized, ticular way of pc though it may well be, as a bus route is, many times each day. ordering experi( The telecommunications project, City Portraits [1 ], contains why we accord s at least four interlaced parcours. The first parcours is within tance during this each city: participants armed with cameras tread the streets tual images and of their home towns, translating their trajectories into imtion. ages. The second parcours is the route taken by the pictures The creation , from city to city, following the path mapped out in the ite portrait, gen project's protocol. The third parcours is that of the partici11 points at roug pants and viewers in the exhibition spaces. The last itinerary time, requires r encompasses the project itself, the many routes it could have cerning the possil taken, the one it finally is taking. tronic media: sl City Portraits purposes to explore the workings of our vision (SSTV), cc imagination through the exchange of images. By using facsimile (fax).' traces of a physical, verifiable reality to create cities that are dures require a m unknown to us, we are confronted with our own image-formof the image, wh ing processes. At the same time, the exchange lets us disgin, into signals cover our cities and ourselves through the eyes of others. transmitted by tel Each participant is both tourist and native, both subject and artist must think < object of the project's research. In this fundamental sense, finished product, our work really is about communication, its possibilities and a sense, the final r its limits. in retrospect, as v In order to carry out this exploration, it was necessary for exchanges, this 'v me to set up a network of artists, teachers and students [2]. place or at any The project was conceived not only to bring together people network. from different cultures but also to create new links between Most of us, the members of one culture. Long-distance telephone connecoften, our audiel tions are complemented by the interaction of participants (and the public) within each city. Obviously the world does Karen O'Rourke (artist), I not appear the same when viewed from Brazil as from France de lArt, 162 rue Saint Cha or Hawaii. The reasons for this are not only geopolitical. Received 8 November 19K nposes a parerceiving and ABSTRACT ence. This is pecial imporThe author describes City project to texPortraits, a telecommunications pheiroj toantxproject in which artists, students their translaand teachers from 11 universities

The great blue box phone frauds

The use of an electronic device called the blue box to exploit a loophole in the nation's long-distance telephone network is recounted. To avoid long-distance charges, blue box users first dialed long-distance directory assistance, 800 numbers, or numbers that carried only a small toll charge. After the user dialed his number and was connected to a long-distance trunk, the blue box emitted a 2600 Hz tone, clearing the equipment at the tandem trunk's receiving end and signaling the switching equipment that the call had been completed and the trunk was waiting for a new call. The local central office, however, had not received its call termination signal, so the local central office did not disconnect the caller from the long-distance network. The permanent solution to the blue box problem proved to be common channel interoffice signaling (CCIS), a method rejected in the 1950s as too costly and difficult to implement.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Fault-tolerant systems

Two mishaps early this year forcefully reminded the authors how important computer systems' reliability has become to human well-being in this last decade of the 20th century. In January, large parts of AT&T's long-distance telephone switching networks failed because of a software problem. Then, in February, a 'fly by wire' Airbus A320 aircraft crashed in Bangalore, India. While a definitive cause for the accident has yet to be established (preliminary investigations suggest that the control computers might well have performed to specifications), the fact that the A320 employs a fully electronic cockpit with no mechanical backup for control has raised much speculation about the computers' role in the crash. The authors stress that the basic idea behind building in a fault tolerant capability is to provide the system with extra (redundant) resources. >

The Impact of Alternative Forms of State Regulation of AT&amp;T on Direct-Dial, Long-Distance Telephone Rates

Federal and state regulatory agencies have traditionally used rate-of-return regulation to set profit and rate levels for utilities. A price cap framework, in which the regulatory agency sets a maximum rate below which the regulated utility has pricing flexibility, is possibly a more efficient alternative to rate-of-return regulation. This article presents an econometric analysis that compares AT&T's prices of intrastate, long-distance telephone service in states that allow AT&T pricing flexibility with those in states that do not. The results of this analysis suggest that AT&T's daytime, evening, nighttime, and weekend rates are significantly lower in states that allow pricing flexibility than in states that use rate-of-return regulation.

The Analog Voice Privacy System

The Analog Voice Privacy System (AVPS) is a voice scrambler that permutes individual output samples from a subband coder analysis filterbank. The system has 125! possible permutation keys, giving it the cryptanalytical strength of a digital encryption system. However, it retains the good voice-quality characteristics of analog scramblers. The AVPS has been implemented in a real-time hardware prototype designed for evaluation in telephone environments and works with any modular telephone and standard 120V ac electrical power. The unit contains two circuit boards — one for analog and one for digital processing — that each use four digital signal processors. To date, we have successfully tested it over long-distance telephone connections, several analog and digital PBXs and telephone switches, and a channel simulator. The quality of the decrypted speech is considered very natural, and speaker recognition is retained — a significant advantage over digital vocoders. This paper describes the underlying principles of the AVPS algorithm, its implementation, and laboratory test results.

Literature as Survival: Allende's "The House of the Spirits"

The story began urgently, if unpretentiously, after a long-distance telephone call from Santiago de Chile to Caracas. Isabel Allende's grandfather, in his ninety-ninth year, was about to die. More precisely, he'd decided his time had come. Despite opposing ideologies, their family relationship had been close; and now, although from the remote region he was about to enter she couldn't expect a reply, she sat down to write him a long letter. Her purpose was to keep him living, in conformity with his own idea of immortality. My grandfather theorized that death didn't really exist. Oblivion is what exists, and if one can remember those who die remember them well they'll always be with him and in some way will live on, at least in spirit.' Living was a persistent tradition in Isabel Allende's family on her mother's side, and her late grandmother -the main model for del Valle, Clara la clarividente, in The House of the Spiritshad been practicing since premature death what Grandfather had always preached in life, with her periodic messages and visitations. The letter to Grandfather got longer, and longer. A year later (1982) it had grown to five-hundred pages. It was a diary in retrospect, a family chronicle, an autobiography, a political testimony, a group portrait and contemporary history, a series of experiments with magic. In other words, a novel. Allende was a journalist in search of a complementary medium. Aesthetically, she would now participate in the basic ritual of Latin American literature: a celebration of reality. Ethically, she wanted to bear witness to social injustice, political violence, and repression having been motivated by the betrayal and murder

The Telephone Enterprise: The Evolution of the Bell System’s Horizontal Structure, 1876–1909 by Robert W. Garnet, and: The Anatomy of a Business Strategy: Bell, Western Electric, and the Origins of the American Telephone Industry by George David Smith, and: From Invention to Innovation: Long-Distance Telephone Transmission at the Turn of the Century by Neil H. Wasserman (review)

The Telephone Enterprise: The Evolution of the Bell System’s Horizontal Structure, 1876–1909 by Robert W. Garnet, and: The Anatomy of a Business Strategy: Bell, Western Electric, and the Origins of the American Telephone Industry by George David Smith, and: From Invention to Innovation: Long-Distance Telephone Transmission at the Turn of the Century by Neil H. Wasserman (review)

The Telephone Enterprise: The Evolution of the Bell System's Horizontal Structure, 1876–1909. By Robert W. Garnet. Pp.xix, 210. $22.50. The Anatomy of a Business Strategy: Bell, Western Electric, and the Origins of the American Telephone Industry. By George David Smith. Pp. xxii, 237. $20.00. From Invention to Innovation: Long-Distance Telephone Transmission at the Turn of the Century. By Neil H.

The Telephone Enterprise: The Evolution of the Bell System's Horizontal Structure, 1876–1909. By Robert W. Garnet. Pp.xix, 210. $22.50. <i>The Anatomy of a Business Strategy: Bell, Western Electric, and the Origins of the American Telephone Industry</i>. By George David Smith. Pp. xxii, 237. $20.00. <i>From Invention to Innovation: Long-Distance Telephone Transmission at the Turn of the Century</i>. By Neil H.

The Telephone Enterprise: The Evolution of the Bell System's Horizontal Structure, 1876-1909. Robert W. GarnetThe Anatomy of a Business Strategy: Bell, Western Electric, and the Origins of the American Telephone Industry. George David SmithFrom Invention to Innovation: The Case of Long-Distance Telephone Transmission at the Turn of the Century. Neil H. Wasserman

Previous articleNext article No AccessSpecial Section on History of TechnologyThe Telephone Enterprise: The Evolution of the Bell System's Horizontal Structure, 1876-1909. Robert W. Garnet The Anatomy of a Business Strategy: Bell, Western Electric, and the Origins of the American Telephone Industry. George David Smith From Invention to Innovation: The Case of Long-Distance Telephone Transmission at the Turn of the Century. Neil H. Wasserman David C. MoweryDavid C. Mowery Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Isis Volume 77, Number 3Sep., 1986 Publication of the History of Science Society Article DOIhttps://doi.org/10.1086/354252 Views: 2Total views on this site Copyright 1986 History of Science Society, Inc.PDF download Crossref reports no articles citing this article.

From Invention to Innovation: Long-Distance Telephone Transmission at the Turn of the Century

From Invention to Innovation: Long-Distance Telephone Transmission at the Turn of the Century

Price and Productivity Change Following Deregulation: The US Experience

No real world market is likely to be perfectly contestable, anymore than it is to be perfectly competitive. Yet, like its predecessor, the contestability benchmark proves highly useful as a framework for evaluating policies and outcomes. Under the contestability framework, entry and price regulation is deemed inappropriate in industries which do not have system-wide natural monopoly characteristics. On this criterion, brokerage, airline, trucking, long-distance telephone and terminal equipment should not be regulated. True, these industries may be characterised by some elements of scale economy, such as economies of vehicle size, so that at some level (city-pair routes) only a few firms may serve. But industry performance need not suffer in such an unregulated environment. Impediments to entry and exit, not concentration or scale of operations, may be the primary source of prices that are not welfare optimal. Even in the presence of natural monopoly characteristics, it is important to isolate those markets which are not yet structurally competitive, as in the case of coal shipments over which the railroads are judged to possess 'market dominance' or in local telephone service. It can be argued that the latter should continue to be overseen by regulators while markets which are controlled by competitive forces, deriving from actual or potential competition or taking other indirect but effective forms, should be free from traditional regulation. Thus, unlike privatisation policy in the United Kingdom, described in the companion article by Kay and Thompson (I985), US deregulatory policy can be construed as having a coherent rationale. The nature and extent of deregulation match remarkably well with the policy prescription of the theory. This paper analyses the consequences that have emerged under deregulation in terms of the following behavioural properties predicted by multi-product competition and contestability theory: a variety of products will emerge, each of which will yield zero economic profit; the revenues from any subset of the products must exceed the incremental costs of those products, so that no cross-subsidy can exist; prices for each product will equal or exceed marginal costs; and an equilibrium market structure will minimise costs for the industry (see Baumol

Canadian consumers and telephone pricing: From luxury to necessity and back again?

Changes are being sought in Canada's telecommunications services which would deregulate the industry and result in reduced long-distance telephone rates and increased local charges. This article examines historical data on telephone rates and penetration, and contemporary evidence on the results of telephone industry changes in both Canada and the USA. The authors argue that such changes would benefit business users and harm residential users. They would challenge Canada's long-term commitment to universal telephone services — an ironic development in an information age where access to electronic technology is becoming essential for daily life.

Bypassing is big business for business: Both traditional and unconventional suppliers vie for the corporate dollar

Attention is called to the trend among large corporations to bypass local and long-distance telephone systems by means of dedicated fiber optics, satellites, microwaves, and private telecommunication companies. The factors responsible for this trend, among them the quest for higher reliability, are discussed. Some of the firms that provide these bypass services are then described. The various ways that bypassing can be carried out are surveyed. Attention is then given to the technologies available for bypassing and to the effect that the Integrated Services Digital Network will have on the trend.

Economics and Politics of Deregulation: The Issue of Telephone Access Charges

The Access Charge Plan, a marginal-cost pricing system for long-distance telephone service, was devised by the Federal Communications Commission in 1982 to facilitate the transition from regulated monopoly to competition. In little more than a year after the plan was proposed, as the plan's distributive and competitive impacts were recognized by a host of stakeholders and political interests, a flood of opposition Abstract swamped the initiative. What emerged, although distinctly different from the system that had previously existed, nevertheless continued to reflect some of the objectives of the past regime, including subsidies to residential users and some shelter for AT&T's principal competitors. The strength of the political process that produced these modifications was due in part to elements in the original FCC proposal that were not essential to its central purpose.

The AR6A Single-Sideband Microwave Radio System: System Design and Performance

This paper describes the overall architecture of the first long-distance microwave telephone transmission system to use Single-Sideband Amplitude Modulation in the microwave transmission path. Compared with commonly used frequency modulation systems, the AR6A Single-Sideband Microwave Radio System more than doubles the number of telephone circuits that can be carried per unit of microwave bandwidth. Included in the description are the system design model, performance objectives, and the allocation of performance impairments. Also discussed are the computer-controlled automated maintenance features and the results of laboratory and field tests.

The Bell Telephone Historical Collection and Late Nineteenth-Century Canadian Urban History: A Preliminary Report

En 1878, le premier central téléphonique de l'Empire britannique était inauguré à Hamilton (Ontario). Dès 1891, la compagnie de téléphone Bell du Canada avait mis sur pied un réseau interurbain déplus de 6000 km, y compris une ligne continue le long de l'axe principal du centre du pays, entre Québec et Windsor. La société desservait en 1891 au-delà de 22,000 abonnés par l'intermédiaire déplus de 200 centraux. L'expansion du réseau interurbain fut entravée au début par les maigres ressources financières de la société et le rendement plutôt faible des investissements, imputable au fait que l'ensemble du réseau comptait seulement quelques milliers d'abonnés. En outre, une grande partie des premières immobilisations tomba vite en désuétude par suite des progrès techniques réalisés dans le domaine de la transmission de la voix. Les circuits métalliques en cuivre, vers le milieu des années 1880, commençaient déjà remplacer les câbles de fer des lignes interurbaines. La présente note de recherche décrit la croissance du réseau téléphonique interurbain dans le centre du Canada, ainsi que le modèle d'évolution des centraux téléphoniques, l'adoption du téléphone et la fréquence d'utilisation du système interurbain à l'époque de son implantation. La recherche a été menée sous les auspices de l'Atlas historique du Canada! Historical Atlas of Canada.

Effect of Echo Canceler on Common-Channel Interoffice Signaling Continuity Check

Annoying echoes generated by impedance mismatches can occur in long-distance telephone networks. An echo canceler controls echo by synthesizing an echo replica and subtracting it from the actual echo on the return path. For the echo canceler to work properly, it must be able to distinguish between desired signals and echoes. One instance where this can be difficult is during the common-channel interoffice signaling (CCIS) continuity check between four-wire switching offices. On OCXS trunks the voice and the signaling are routed separately. To ensure a satisfactory transmission path, a voice path continuity check is conducted before call setup. The check is performed on a loop basis by sending a check tone and looping it back at the distant office. Since the echo canceler adaptive filter memorizes information from the last previous call, it may partially cancel the looped-back tone. In this paper we study the effect of the echo canceler adaptive memory on the CCIS continuity check. The analytical and experimental results indicate that the occurrence of continuity check failure caused by the presence of an active echo canceler is so infrequent and insignificant compared to the existing statistics of all other pertinent failure mechanisms. Thus, disabling the echo canceler during the CCIS continuity check is unnecessary.

Satellite communications I: ESA at the crossroads: Projects for the 1980s at the space agency include satellite launches and a space platform

After a decade of national and transnational communications satellite programs, Europe is at the crossroads. It will move in this decade from the preoperational phase to the use of systems responding to its own needs. It is about to become competitive with the United States and Canada in this field. Five flight units of the European Communications Satellite are being built by European industry, with the first to be orbited by an Ariane launcher in October 1981. These satellites are to be used for carrying long-distance telephone traffic within Europe and for a television interchange service. In addition, ESA is committed to launching three maritime communications satellites. This decade will also see the development by European nations of a space platform that could hold a range of payloads for future communications needs.

Adaptive noise spectral shaping and entropy coding in predictive coding of speech

We report on research to code speech at 16 kbit/s with the goal of having the quality of the coded speech be equal to that of the original. Some of the original speech had been corrupted by noise and distortions typical of long-distance telephone lines. The basic structure chosen for our system was adaptive predictive coding. However, the rigorous requirements of this work led to a new outlook on the different aspects of adaptive predictive coding. We have found that the pitch predictor is not cost-effective on balance and may be eliminated. Solutions are presented to deal with the two types of quantization noise: clipping and granular noise. The clipping problem is completely eliminated by allowing the number of quantizer levels to increase indefinitely. An appropriate self-synchronizing variable-length code is proposed to minimize the average data rate; the coding scheme seems to be adequate for all speech and all conditions tested. The granular noise problem is treated by modifying the predictive coding system in a novel manner to include an adaptive noise spectral shaping filter. A design for such a filter is proposed that effectively eliminates the perception of granular noise.

Echo cancellation in the telephone network

Most long-distance telephone connections generate echoes, which must be heavily attenuated in order to obtain satisfactory transmission quality. Voice-actuated switches (echo suppressors) are widely used to eliminate echoes but have an unfortunate tendency also to cut out part of the desired signal from the other end of the line. Because the distortion caused by echo suppressors is particularly noticeable on satellite-routed connections, the advent of telephone communication via satellite, including the recent introduction of satellite circuits into the U.S. domestic network, has motivated the search for a better way to eliminate echoes. The answer may be the echo canceler, an adaptive filter which selectively eliminates echoes. Advanced echo canceler designs have been undergoing field trials in recent years. This article explains why echo cancelers are advantageous and how they work.