Nicholas I. Benimoff
`Michael J. Burns
`
`Multimedia User Interfaces for
`Telecommunications Products and Services
`
`The emergence of multimedia systems, which incorporate media types such
`as text, graphics, audio, video, and animation, has great potential to change
`how people interact with systems and with each other. As multimedia tech­
`nologies and their applications in telecommunications products and services
`evolve, some critical human factors challenges in designing these systems
`are emerging. This paper describes how the use of new multimedia technol­
`ogies, complemented by the proper application of human factors design prin­
`ciples, can enhance the usability of AT&T products and services. Examples
`of three types of applications — multimedia-based training, multimedia­
`based performance support, and multimedia conferencing — highlight chal­
`lenges specific to the design of multimedia user interfaces.
`
`Introduction
`
`“Multimedia is a major part of
`AT&T’s future, and we will work
`very hard to make that happen. ”1
`—Robert E. Allen, AT&T Chairman
`
`In the past several decades, telecommunica­
`tions and computer technologies have
`expanded at a far greater rate than many
`could have imagined. Evolving telecommuni­
`cations capabilities have led to changes in
`when, where, why, and how people communi­
`cate. Advances in computer capabilities have
`changed many aspects of our work and per­
`sonal lives, and will continue to do so. We are
`on the verge of a revolution in which the
`boundaries of telecommunications, comput­
`ing, publishing, entertainment, consumer
`electronics, and information access are
`becoming blurred. A “mega-industry” is being
`created, driven by the emergence of new
`technologies, the most important of which is
`multimedia.
`Multimedia systems incorporate a
`variety of media types, including voice, image,
`music, text, animation and graphics, real-time
`and stored video, and facsimiles. At least two
`schools of thought exist concerning the
`definition of multimedia systems.2 Some
`believe that the inclusion of multiple media
`
`types is enough to categorize a system as
`“multimedia.” In this paper, however, we are
`referring to multimedia telecommunications
`products and services that combine some or
`all of these media in an interactive computing
`application.
`This paper describes multimedia sys­
`tems in which the user actively controls com­
`munications. Specifically, the level of control
`is critical. Users of multimedia systems
`should be able to do more than start and stop
`an application. Their actions should trigger
`different system responses, based on a host
`of factors (e.g., prior user actions or current
`system context). The information that the sys­
`tem presents, and even the media through
`which it is presented, will be influenced by
`these factors.
`Multimedia technologies and their
`applications in telecommunications products
`and services are just beginning to evolve.
`Clearly, these technologies will change the
`way people interact with computer systems.
`Much as graphical user interfaces revolution­
`ized human-computer interaction in the
`1980s, the maturation of multimedia technolo­
`gies will fundamentally alter human-computer
`interaction paradigms in the 1990s, and
`beyond. There will be more emphasis on
`developing systems with user interfaces that
`are interactive, dynamic, and engaging.
`
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`In addition to changing how people interact with
`computer systems, multimedia technologies may change
`the way people interact with each other. Video telephony
`has already hit the marketplace with products that are
`certain to affect person-to-person communication.3 On a
`grander scale, multimedia conferencing and multimedia
`computer-supported cooperative work (CSCW) systems
`undoubtedly will change many meeting, work group, edu­
`cational, and other communication activities. (See Panel 1
`for definitions of abbreviations, acronyms, and terms.)
`This paper focuses on how new multimedia tech­
`nologies, combined with the proper application of human
`factors design principles, can improve AT&T’s products
`and services. We discuss usability as it applies to
`multimedia-based products and services, and the design
`challenges presented by multimedia technologies. Exam­
`ples are culled from multimedia-based training, perfor­
`mance support, and conferencing.
`
`Multimedia and Usability
`Brian Shackel defines usability as “the capability
`in human functional terms to be used easily (to a speci­
`fied level of subjective assessment) and effectively (to a
`specified level of performance) by the specified range of
`users, given specified training and user support, to fulfill
`the specified range of tasks, within the specified range of
`environmental scenarios.”4 For a system to be usable, its
`users should be able to:
`- Easily learn how to operate the system
`- Efficiently complete the task(s) they are performing
`with the system
`- Interact with the system without making errors
`- Enjoy interacting with the system.
`These goals apply to the user interface for any
`computer-based system, whether or not it employs multi­
`media technologies. We expect that, when used prop­
`erly, multimedia technologies will enhance the usability
`of many products and services. Multimedia systems
`should create an intuitive environment that minimizes
`the effort required to learn and use the system. Some
`studies of interactive multimedia-based training suggest
`that learning occurs faster and that learned material is
`understood better and remembered longer than it is with
`classroom instruction.5
`People process information using their five
`senses, especially sight and hearing for communication
`tasks. Certain types of information are better commu-
`
`Panel 1. Abbreviations, Acronyms, and Terms
`ac — alternating current
`AM — amplitude modulation
`| CAD/CAM — computer-aided design/computer-aided
`manufacturing
`CD — compact disk
`CPS — Concept Presentation System
`CSCW — computer-supported cooperative work
`de — direct current
`EPS — electronic performance support
`FM — frequency modulation
`NOET — AT&T Network Operations Education and
`Training
`NSD — AT&T Network Systems Division
`VCR — video-cassette recorder
`
`nicated through one medium than another. For example,
`full-motion video does a good job of demonstrating com­
`plex mechanical procedures.6 In addition, multimedia­
`based products and services, such as multimedia-based
`CSCW applications, can help workers be more efficient in
`a variety of tasks, including meetings, document prepara­
`tion, physical design, computer-aided design/computer-
`aided manufacturing (CAD/CAM), etc., especially for
`those in widely separated locations.
`Multimedia technologies often enhance usability
`by supporting various input devices (e.g., voice, pens)
`that allow users to interact more naturally with systems.
`Finally, multimedia systems promise to be more engag­
`ing, more fun to use.7 Multimedia presentation can
`increase the expressiveness of, and the audience’s sense
`of involvement with, the information presented.8
`Although multimedia systems may be “richer”
`than their single-media counterparts, they do not neces­
`sarily increase usability. Studies of multimedia telecon­
`ferencing have shown that the usefulness of video
`depends on the specific tasks that users perform during
`the call.9’10 Kraut et al.8 suggest that interaction with or
`through multimedia systems creates a new type of com­
`munication. The most usable multimedia systems are
`those whose user interfaces are designed consistently
`with, and take advantage of, this premise.
`If the benefits of multimedia-based systems are
`to be fully realized, they must be tailored to the needs,
`capabilities, and limitations of users. Some critical chal­
`lenges in building these systems relate to human factors,
`because they have the potential to change the fundamen­
`tal nature of human interaction with systems and with
`other people using these systems. Although multimedia
`technologies clearly offer benefits, a variety of usability
`issues should also be considered.
`Multimedia Products and Services. Analysts in the
`telecommunications industry agree that multimedia
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`Figure 1. Sample
`screen from the
`Advantage™ multi­
`media training sys­
`tem. The presentation
`window, at the left,
`displays photographs,
`graphics, animation,
`and video. The text
`window, at the right,
`presents text that
`complements the
`audio narration. Func­
`tion buttons and
`other controls are at
`the bottom of the
`screen.
`
`capabilities will be a cornerstone of telecommunications
`network and product development in the next decade.11
`AT&T is committed to offering products and services
`that allow people to communicate efficiently and expres­
`sively. An opportunity now exists to provide useful new
`capabilities based on multimedia technologies, such as
`multimedia conferencing; interactive information ser­
`vices; entertainment services; and education, training,
`and performance support.
`For instance, the Rapport multimedia confer­
`encing system,12 developed at AT&T Bell Laboratories,
`allows people in widely separated locations to share
`voice, video, data, and other applications in real-time,
`AT&T is also cooperating with Pacific Bell, California
`State University at Chico, and the Chico public school
`system to offer distance education, which allows students
`to “attend” a course from a remote location using a multi­
`media workstation. Each student can enroll in individually
`paced courses and attend at his or her preferred time and
`place. The NCR 3331 Multimedia Learning Station delivers
`multimedia-based education courses in business, retail,
`and manufacturing environments. The AVP 4000 video­
`
`compression chip set, produced by AT&T Microelectron­
`ics, makes possible reliable and cost-efficient storage and
`transmission of multimedia data. The AT&T/EO Per­
`sonal Communicator 440 allows users to combine
`multiple input (e.g., touch screen, handwriting) and out­
`put media (e.g., audio, text, fax) to perform a wide vari­
`ety of tasks (e.g., record notes, access bank records,
`place a phone call). Even the AT&T VideoPhone 2500,™
`the world’s first color video telephone that operates over
`conventional copper telephone lines, is based on multi­
`media technologies.
`AT&T is incorporating human factors principles
`into its multimedia products and services to ensure their
`usability. The sections that follow focus on examples
`drawn from multimedia-based training, performance sup­
`port, and conferencing. These examples illustrate the
`potential that multimedia technologies have to enhance
`the usability of many existing products and services and to
`engender entirely new classes of products and services.
`Multimedia-based training. Multimedia technologies
`are revolutionizing how training simulations are used.
`Until recently, complex simulations were prohibitively
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`Figure 2. Sample screen from the Rapport multi­
`media conferencing system. Individual atten­
`dees, conference status, and conference con­
`trols are displayed along the top. Two separate,
`shared applications — in this figure, a text
`document and a stored videotape segment —
`are open for all attendees to view and manipu­
`late at their own workstations.
`
`expensive to develop and deliver. In only a few fields,
`such as aviation and nuclear power (where a single mis­
`take in the real world might be catastrophic), has the
`expense of simulations been justified. One of the most
`important benefits of multimedia technologies, therefore,
`is its ability to deliver low-cost, medium-fidelity simula­
`tions on desktop computers. While these desktop simula­
`tions may not be as realistic as a Boeing 747 flight simu­
`lator, they are realistic enough to give students the free­
`dom to experiment and to practice individual steps in a
`sequence repeatedly until they get them right.
`Many jobs performed by AT&T technicians lend
`themselves naturally to training by simulation. For exam­
`ple, small, unattended buildings, called regen huts, are
`located approximately every 30 miles along a lightguide
`route to regenerate the fiber-optic signal. At each regen
`hut, AT&T technicians perform an annual power review
`that involves 23 major steps that must be completed in a
`specific order. Because the power review is performed
`only once a year per regen hut, even experienced techni­
`cians may run into problems. During the procedure, the
`technician must transfer the power in the regen hut from
`normal commercial ac power to backup de power. This
`procedure puts technicians under stress, because a mis­
`take can result in the failure of a segment of the fiber­
`optic network. By practicing with a simulation of the
`
`annual power review before performing it, the technician
`can become familiar with each step in the procedure and
`how these steps fit together.
`The AT&T Network Systems Division/Network
`Operations Education and Training (NSD/NOET) Power
`Technology Institute is producing a hardware and soft­
`ware platform, called the Advantage3“ multimedia train­
`ing system, to develop and deliver multimedia training.
`The first course provides multimedia-based demonstra­
`tions, practice simulations, and tests for the annual
`power review of a regen hut. Figure 1 shows a screen
`from the annual power review course on the Advantage
`multimedia training system. Future Advantage courses
`will teach students about power-related equipment (such
`as batteries, rectifiers, and tools) and other technologies
`(such as alarms, outside plant, and lightguide). Photo­
`graphic images, audio, and animation all play central
`roles in the Advantage instruction and simulations.
`Multimedia-based performance support. Training
`ensures that workers have achieved a minimum level of
`proficiency before attempting to perform a job in the real
`world. But many instructional technologists are adopting
`the view that training alone may not enable workers to
`do their jobs effectively and efficiently. Electronic perfor­
`mance support (EPS) integrates training, documentation,
`and on-line help and delivers it to the worker as needed
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`at the work site. It emphasizes performance, rather than
`learning, and is delivered to the worker with minimal
`interruption of the normal job flow.
`EPS systems do not necessarily include multi­
`media capabilities, but designers are finding that these
`capabilities make their systems more effective. Several
`versions of the Concept Presentation System (CPS),
`developed in AT&T Bell Laboratories, have supported
`technicians who perform network management and pro­
`visioning activities or who diagnose and repair troubles
`in switches.
`CPS functions with applications the worker nor­
`mally uses to do the job. In the 5ESS® switch version, the
`worker can “toggle” to CPS by pressing a single key on
`his or her workstation. The user receives instructions
`from CPS at several different levels, ranging from an over­
`view of the current procedure, through detailed step-by-
`step instructions, to a listing of valid entries for a specific
`field on a recently changed screen in the on-line system.
`CPS presents information using text, graphics, and
`motion video, with accompanying narration. As soon as
`the user gets the information needed from CPS, he or she
`can toggle back to the on-line system, which remains in
`the same state it was in before the user left it to access
`CPS. If more performance support is required later, the
`user can return to CPS.
`Multimedia conferencing. Multimedia conferencing
`systems, an important application of multimedia tech­
`nologies within AT&T, allow individuals at widely sepa­
`rated locations to perform meeting-related tasks and
`other activities as if they were in the same room. They
`can see one another, talk privately with someone, pre­
`sent viewgraphs, share images, write on a blackboard,
`point to items on the blackboard, etc. Figure 2 shows
`a sample screen for one such system — the Rapport
`multimedia conferencing system — developed at AT&T
`Bell Laboratories.
`Multimedia conferencing provides advantages
`over more limited forms of conferencing. For instance,
`by using technologies that enable participants to see and
`hear one another at the same time, and to use network­
`based blackboards and other communication devices,
`multimedia conferences attempt to restore the “natural­
`ness” of in-person communication to individuals commu­
`nicating electronically. Moreover, multimedia conferenc­
`ing can increase the productivity and efficiency of meet­
`ings. Participants have the flexibility to present or manip­
`ulate information using whichever media best suits their
`
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`
`AT&TTECHNICAL JOURNAL • MAY/JUNE 1993
`
`needs. They have access to information sources, such as
`internal corporate databases, external public resources
`like the Library of Congress, and so on. Multimedia­
`based meetings can also produce tangible savings, such
`as the cost and time associated with travel.
`
`Multimedia User Interface Issues
`Designing a successful multimedia user interface
`is a challenging task, because much of what people do
`“naturally” in everyday life — seeing and understanding
`objects and gestures, understanding each other’s speech,
`etc. — is a tremendous challenge for the field of comput­
`ing.13 A good user interface for an interactive application
`must fit the user’s motor skills,14 problem-solving strate­
`gies,15 and cognitive organization.16 User interface
`design for a single-media application is difficult; the pros­
`pect of designing for multiple media and the need to inte­
`grate different types of media make the task of designing
`user interfaces even harder.
`As we discussed earlier, the application of multi­
`media technologies creates exciting opportunities for
`new products and services. But these new opportunities
`also present challenges to the human factors specialist.
`These challenges, listed in Table I, are detailed in the
`sections that follow.
`Appropriate Use of Media. What tasks are best
`served by the various media now at our disposal? What
`are the development and delivery cost tradeoffs of differ­
`ent media types? Can we identify the different types of
`information delivery tasks and communication situations
`and recommend appropriate media?
`User Control over Multimedia Environment. To
`what extent should users be allowed to customize their
`own multimedia environments? During a multimedia
`conference, for example, should users be able to reposi­
`tion windows that display other attendees? If these win­
`dows are moved, will all attendees know to whom each of
`them is speaking?
`Information Navigation. How should information
`be organized in a multimedia system to make it easy to
`use? How can system designers help users find the
`information they need? Do navigation devices used in
`hypertext systems, such as information structure maps,
`guides, default paths, and backtracking, benefit multi­
`media systems?
`Control of Time-Based Information. By what means
`should users control the presentation and flow of time­
`based information in the system? Are user interface
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`Table I. Multimedia User Interface Challenges and Problems
`
`Human factors
`challenges
`
`Appropriate use of media
`
`User control over
`multimedia environment
`
`Information navigation
`
`Control of time-based information
`
`Tools for multimedia authors
`
`Media fidelity
`
`Social psychological and
`human behavioral issues
`User acceptance of
`multimedia-based products
`and services
`
`Typical problem
`
`Which applications require full-motion video,
`still-image graphics, or animation?
`Should users be allowed to customize how
`multimedia objects are arranged on
`their screens?
`Can users access the next piece of
`information in a database?
`Is there a universal set of on-screen
`controls to start, stop, pause, resume,
`replay, etc.?
`How can multimedia authors decrease
`the time it takes to script, edit, and
`integrate media objects for an application?
`What are the minimal audio and video
`requirements for various applications?
`Which characteristics of face-to-face meetings
`should multimedia conferencing include?
`How can non-computer-literate people
`benefit from multimedia products
`and services?
`
`Problem-solving
`strategies
`
`Iterative rapid prototyping
`•
`Usability testing
`
`User-centered design
`•
`Knowledge gathered from
`many disciplines
`
`metaphors, such as compact disk (CD) audio controls or
`video-cassette recorder (VCR) controls, the best ones? Is
`there a “universal” set of controls, or do different tasks
`demand different controls? What tradeoffs in control fea­
`tures are necessary because of functions not supported
`by the current level of multimedia technologies? And
`more generally, in the absence of industry-wide stan­
`dards, how can we create user interfaces that are consis­
`tent in important aspects with others in the industry?
`Tools for Multimedia Authors. What help Can be
`provided to the people who are developing multimedia
`systems? What tools for idea generation and script writ­
`ing can help them be more creative and productive? Are
`there ways to shorten the time required to develop and
`edit media elements (individual graphics files, audio
`files, etc.)? How can media elements be most efficiently
`assembled and integrated into a coherent application?
`Media Fidelity. What types of audio and video
`quality needs do users have, and how do these needs
`change for different applications? Is CD-quality audio
`
`required, or would frequency modulated (FM) quality, or
`even amplitude modulated (AM) quality, suffice? Is full­
`motion video, or even full-screen video, necessary? What
`levels of color rendition, contrast, image resolution, and
`screen refresh rate are necessary? What degree of
`audio-video asynchrony is perceptible, and at what point
`does it hinder usability? If a window in a multimedia con­
`ferencing environment provides person-to-person eye
`contact, how can we ensure that all important nonverbal
`information (e.g., head-shaking, facial expressions, etc.)
`is communicated while using as little screen space as
`possible? How important is full-duplex audio, and how
`does it affect system usability?
`Social Psychological and Human Behavioral Issues.
`How do face-to-face meetings differ from electronically
`mediated ones? What are the important qualities and
`by-products of both face-to-face and electronically medi­
`ated meetings, and how can multimedia conferencing
`systems be designed to maximize their advantages?
`What are the important nonverbal feedback mechanisms
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`people use in conversation? How is the character of a
`meeting affected by its multimedia nature? What assump­
`tions do participants make about what other participants
`are doing and seeing, and what are the effects of these
`assumptions? How can multimedia conferencing improve
`group dynamics and decision-making processes?
`In summary, it is not sufficient merely to provide
`systems with multimedia capabilities. Instead, we must
`understand how and why individuals will be using the
`system, and we must design the user interface accord­
`ingly, with the set of interaction techniques best suited
`to the given media.
`
`Potential Solutions
`As the previous section illustrates, there are
`many user interface design issues that relate specifically
`to multimedia systems. However, the prospects for
`designing usable multimedia systems are not as over­
`whelming as this list might imply. Some of what we know
`about good design for graphical user interfaces can be
`applied to multimedia user interfaces. Information struc­
`ture maps, guides, etc., should help the user navigate
`through information, whether text-based or multimedia
`in nature. Sometimes, design decisions can be modeled
`on well-known user interface metaphors. For example,
`users seem to have little problem learning, understand­
`ing, and controlling on-screen motion video using a
`design that resembles a VCR remote control device.
`We can also use results gathered from well­
`run empirical studies. For instance, increasing the audio
`quality of a multimedia phone call has been shown to
`have a positive effect on users’ perceptions of the call’s
`video.17 Phenomena such as this can be used to formu­
`late design decisions that improve usability while mini­
`mizing resources.
`Solutions for unsolved multimedia user interface
`design issues will come from many sources. Methodolo­
`gies such as iterative rapid prototyping, usability testing,
`and user-centered design that have been proven success­
`ful in systems design will continue to be critically impor­
`tant.18’19 Iterative rapid prototyping refers to building a
`model of the user interface, before formal development
`of the system, that looks and behaves as the system will
`when it is completed. This prototype shows a system’s
`functionality and user interface and is iteratively updated
`to reflect user and project team feedback, new system
`requirements, etc. Usability testing, in a specially
`
`48 AT&TTECHNICALJOURNAL. MAY/JUNE 1993
`
`designed laboratory or, sometimes, at the user’s work
`site, can uncover design flaws that project team mem­
`bers might miss. Based on what is learned during this
`phase, design changes are made in the next iteration of
`the prototype, ensuring that the final system meets user
`needs in an efficient, pleasing manner. Iterative rapid
`prototyping and usability testing, which work hand-in-
`hand to improve the design of any user interface, are
`core methodologies of user-centered design.
`Knowledge gathered from other fields, such
`as cognitive and social psychology, computer science,
`graphic arts, broadcasting, and instructional technology,
`will also help solve future problems in multimedia user
`interface design. Successful multimedia system develop­
`ment requires diversity among project team members.
`The ideal project development team includes members
`who have most, if not all, of these skills.
`
`Conclusions
`In the future, multimedia technologies will affect
`the ways in which people interact with systems and with
`each other. The inevitable development of powerful
`multimedia products and services, and the broadband
`network infrastructure to support them, will make multi­
`media communications as ubiquitous as today’s tele­
`phone or personal computer. John Sculley, Chairman of
`Apple Computer, Inc., foresees a convergence of previ­
`ously diverse industries — computing, consumer elec­
`tronics, communications, broadcasting, and publishing
`— all integrated in hand-held devices that will be ubiqui­
`tous.20 Nicholas Negroponte, founder and director of the
`Media Laboratory at the Massachusetts Institute of
`Technology, envisions a future in which machines will
`see, hear, talk, and, in a sense, think, all to “know” and
`serve their human masters.21 The speed with which this
`future is realized depends on several factors, including
`the continued development of better hardware (e.g.,
`computers, chips, transport equipment) and software
`(e.g., video compression and decompression algorithms,
`development tools). To be successful and ubiquitous,
`however, these products and services must be designed
`to fit users’ needs. How close we come to achieving this
`will directly affect our ability to realize this vision.
`
`Acknowledgments
`We thank Doug Brems, Jim Farber, Bruce Fetz,
`Susan Fussell, Ken Rosen, and Bill Whitten for
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`thoughtful reviews of earlier drafts of this manuscript
`and for valuable discussions on the roles and uses of
`multimedia technologies. We also thank the AT&T
`NSD/NOET Power Technology Institute for permission
`to include a screen from the Advantage multimedia train­
`ing system, shown in Figure 1. Finally, we thank the Inte­
`grated Computer/Communication Systems Research
`Department of AT&T Bell Laboratories for permission to
`include the Rapport multimedia conferencing system
`screen shown in Figure 2.
`
`References
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`January 3,1993, Section 3, p. 6.
`2. T. Nolle, “Choosing a platform for multimedia,” Datapro Multi­
`media Solutions, McGraw Hill, Inc., New York, June 1992, p. 1030.
`3. J. S. Angiolillo, H. E. Blanchard, and E. W. Israelski, “Video Tele­
`phony,” AT&T Technical Journal, Vol. 72, No. 3, May/June 1993,
`pp. 7-20.
`4. B. Shackel, “The concept of usability,” Visual Display Terminals:
`Usability Issues and Health Concerns, J. Bennett et al. (eds.),
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