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Electronic Frontier Foundation page 1
INNOVATIVE SERVICES DELIVERED NOW:
ISDN Applications at Home, School, the Workplace
and Beyond
Introduction
Since October, 1991, the Electronic Frontier Foundation has been
advocating a practical, incremental approach to modernizing the
telecommunications infrastructure. Calling for an “open platform” for
innovation in telecommunications modelled on the success of the
personal computer in the 1980s, EFF has sought to develop a
consensus for the widespread deployment of the “Integrated Services
Digital Network” (ISDN).1 ISDN Open Platform service will enable
personal and small group communication for residential, non-profit
and small business users.
ISDN enables the telephone network, which was built for traditional
voice calls, to carry far more information at higher speeds and
without the errors of the traditional analog system.2 As a result,
ISDN can deliver a wide range of desirable applications in education,
healthcare, telecommuting, videoconferencing and multimedia, and
home energy management. In light of this substantially increased
functionality, EFF believes that ISDN can be the telecommunications
analogue to the Apple II or early IBM PC: a widely available,
reasonably priced open platform that offers a critical mass of
features and thus enables the development of scores of new
applications.
EFF has collected information and analyses to test the Open Platform
proposal.3 We believe that evidence supports our position that ISDN
can be tariffed affordably enough to position it as a “mass market”
service.4 Based on public commitments made by the Regional Bell
Operating Companies (RBOCs), nearly 60% of telephone access lines
nationwide will be served by the necessary digital infrastructure for
ISDN by the end of 1994.5 Knowledgeable executives from the
telecommunications and computer industries have publicly
expressed support for the ISDN-based “Open Platform” approach to
network modernization.6 And consumer groups, which have
traditionally opposed telecommunications modernization efforts,
support this “narrowband” approach because it allows those who
want enhanced functions to get them at a reasonable price, without
burdening other ratepayers with the costs of unwanted services.
However, the potential of ISDN remains unclear to many observers
because they are unaware of what services can be provided over it.
Indeed, despite the fact that ISDN has been under development since
1968, applications have been slow to develop. In the U.S., this was
exacerbated by the divestiture of the Bell Operating Companies from
AT&T, which created seven large local service providers, the RBOCs,
in place of a centrally coordinated, vertically integrated, monopoly
provider. Although every RBOC (and many non-Bell companies)
offered ISDN on a limited basis in a handful of areas starting in the
mid- to late 1980s, any one company’s ISDN could not connect to or
interoperate with any other company’s version of the service. As a
result, the growth of applications was stymied by the lack of
standard protocols and the resulting small markets. In a classic
“chicken and egg” conundrum, the service languished because
potential subscribers could not identify useful applications, and
applications developers saw little opportunity in ISDN because the
market was not yet in place. And just as few would be likely to
subscribe to “550MHz of analog signal transport over coaxial cable” in
the absence of cable program services such as HBO or CNN, ISDN has
had few takers in the absence of identifiable applications that can be
delivered through this technology.
Nevertheless, ISDN-based services have been created and are being
offered today. Through trials by US providers, the extensive
deployment of ISDN in other countries (most notably, France, Japan,
Singapore, and, to a lesser extent, the U.K.), and a developing interest
in related technologies for use in private networks or over leased
lines, a variety of applications can be identified that take advantage
of the digital bandwidth that ISDN makes possible.
EFF believes that many of the functions most often described by
proponents of advanced telecommunications networks can be
delivered over ISDN lines.7 The following report identifies a handful
of representative examples of what is being done today with the
bandwidth and functionality that ISDN offers. It makes no claim to
be a definitive listing of all those services currently available over
ISDN. Instead, the paper will focus on selected applications in those
areas most often discussed by proponents of infrastructure
modernization: telecommuting, health care, distance learning, video
conferencing, etc.8 While ISDN can not offer all those services
foreseen in the broadband networks of the future (e.g., high
definition television, high-speed packet switching, or high resolution
interactive multimedia), many services can be provided today over
the narrowband facilities that ISDN offers.9
Finally, despite the many working applications described below, EFF
expects that the most exciting and innovative applications remain to
be developed. Just as the existence of the Apple II and the PC led to
the independent development of applications the hardware
manufacturers and the public never imagined, EFF believes that
widespread availability of ISDN as an open platform will create a
fertile market that entrepreneurs will rush to seed with new
applications.10 The independently developed application that creates
a whole new genre or market — the “Pagemaker” or “Lotus 1-2-3” of
telecommunications — will not appear until the platform is available.
The Changing Context for Applications
The perceived desirability of ISDN is growing because the
technological and social context for evaluating it has rapidly evolved.
Perhaps most dramatically, the widespread availability of PCs has
created an installed base of devices through which users can realize
and enjoy many of ISDN’s benefits. Moreover, computing technology
is becoming faster, cheaper, and more powerful, while many people
are becoming accustomed to increasingly sophisticated computers
and telephones in their offices or at home. These two trends — more
powerful and inexpensive computing tools and assimilation of
increasing levels of computer technology in daily life — are creating a
new interest in ISDN.
A. Technology Gains Deliver More Power to Users
There is no set of applications that inhere in ISDN. ISDN merely
offers transmission capacity of a specified type, with a standard set
of call control and capacity-management functions. The uses to
which that managed capacity can be put are constantly expanding
due to three inter-related trends: 1) dramatic gains in computer
processing power; 2) rapidly falling costs for equivalent computer
functions; and 3) substantial advances in compression, which allow
an ever-greater amount of information to be squeezed through the
same line. As a result, new services are being developed that push
the envelope of what can be done with ISDN’s 144,000 bps of digital
capacity.
Both research and anecdotal evidence suggest these trends toward
greater efficiency and creative use of bandwidth will continue, so
that cost-effective means for delivering applications heretofore
thought to be “impossible” over ISDN will continue to be found.
For example, a recent analysis of computer performance per $1000
spent, based on desktop and laptop computers from 1983-1991,
found that every year the same $1000 will purchase 47% more CPU
capacity than the year before, 52.4% more memory capacity (RAM),
and 115.2% more disk capacity. These trends are projected to
continue.11 A similar study of larger computer systems supports the
finding.12 Thus, through steady gains in computing efficiency, speed,
power and memory, the amount of computing intelligence available
to the end-user is both growing and becoming more affordable.13
The increased efficiency of computer components and their falling
costs have clearly discernible effects on what can be done with ISDN.
In 1992, Dr. Robert Lucky, then the Executive Director of AT&T Bell
Laboratories’ Communications Sciences Research Division, noted that
video-windows on PCs over ISDN is emerging now because of the
development of cheap bandwidth, significant improvements in video
compression and the recent availability of low-cost video
equipment.14 Executives at the British subsidiary of PictureTel, a
leading U.S. manufacturer of videoconferencing equipment, estimate
that prices for comparable videoconferencing services are cut in half
every two years.15
B. A Revolution of Rising Expectations
The other significant trend that shapes the context for applications is
the growing use of and familiarity with increasingly powerful
personal computers and on-line information services in businesses,
schools and homes. The percentage of U.S. households with a PC has
grown by 10 percentage points every five years since 1980, when
they first became widely available;16 over 25% of all homes and
small businesses now have them, as do half of all medium-sized
businesses and almost all large businesses.17 According to a recent
estimate, the dial-up modem business is currently growing by 25% a
year,18 which suggests a fast growing demand for on-line services
and computer-based communication over the public network. The
use of electronic mail is now widespread among Fortune 2000 firms,
and by 1990, there were an estimated 12 million users of these
services in the U.S. The Internet, an international network of
networks connecting academics, government workers, employees in
the commercial sector and others, is estimated to be adding hosts at
the rate of 15% per month.19
More and more people have come to depend on file servers,
networked applications over local area networks (LANs), voice mail,
and even videoconferencing at their offices or in their professional
lives. Today, more than 30% of all PCs are equipped with
communications capabilities, and the majority of business computers
are already attached to networks.20 Sales of U.S. office system LANs
have grown from approximately 12,000 units in 1990 to almost
35,000 projected for 1992; shipments of routers, LAN interface cards
and servers have similarly taken off since 1990.21 Recent forecasts
predict that well over half of all PCs in the U.S. will be attached to
LANs by 1995.22 The growing need to connect these LANs has
stimulated interest in cost-effective networking options, especially
those available through the public switched network.23
Finally, with graphical user interfaces (GUIs) becoming increasingly
common, as Apple’s Macintosh is joined by Microsoft’s Windows and
IBM’s OS/2, bandwidth demands are growing to perform the same
functions. These GUIs make greater information demands with their
full color images, multi-fonted text, and more complex output, such
as desktop publishing documents. As a result, traditional
applications like electronic mail, as well as newer applications, such
as screen sharing, will require a step up in bandwidth simply to stay
the same from the user’s perspective.
Applications in Education/Distance Learning
Distance learning refers to “the linking of a teacher and students in
several geographic locations via technology that allows for
interaction.”24 It was initially designed to extend educational
resources into geographically remote or rural areas, but interest has
grown in using the technology to share scarce resources in urban
areas as well as to meet the needs of students who cannot reach
traditional classrooms. Researchers have concluded that distance
learning facilities overcome more than simply distance. According to
a recent study, the top three reasons that students report enrolling in
television-based distance learning courses at the college level are
time constraints, work responsibilities, and family responsibilities.25
The prohibitive costs associated with many distance learning
programs have kept these benefits from reaching a wider public,
however.26 Distance learning programs are usually based on
instructional programming delivered by satellite or through an
Instructional Television Fixed Service (ITFS) network. Both methods
require expensive equipment at the school and in the delivery
system, and both allow for only limited interaction between teacher
and student or among students.
Recent efforts to conduct distance learning over ISDN have been
successful. According to a recent report, “ISDN offers students and
teachers in distance learning programs an interactivity level not
available in ITFS or satellite programs without adding to the cost of
the program.”27 For these and other reasons, the researchers
concluded that:
“ISDN has proved extremely efficient and effective
technology for on-demand delivery of educational
services to any region offering digitally switched phone
service.”28
The following examples suggest that ISDN is a viable, effective
technology for distance learning, with shared workscreens, video-
conferencing, and access to off-site resources in many settings.
• California State University, Chico, in partnership with AT&T
and Pacific Bell, has completed two successful trials of ISDN as
a delivery system for distance learning. In May, 1992, ISDN
was used to link fifth-grade classes in three elementary schools
in the Chico area. During the trial, students shared slide show
presentations and participated in conference calls that included
video, data, and image transmissions. Through this system,
students and teachers were able to engage in real-time,
interactive, two-way audio and video communication, view a
laserdisc video clip display, and send and annotate graphic
images or text.29
• Appalachian State University, AT&T Network Systems, and
Southern Bell have built an ISDN-based distance learning
network that delivers interactive voice, data and video to three
North Carolina schools. The 10-year project, called “Impact
North Carolina: 21st Century Education,” was touted as “one of
the first in the nation to deliver interactive video instruction
through existing copper phone lines.”30 The system transmits
interactive voice, data and video at 112,000 bps to two
elementary schools and one high school in Watauga County.
The Impact North Carolina system will give K-12 students
access to remote lecturers, university libraries, and other
distant resources, and will also be used to improve teacher
training, student teacher supervision, and continuing education
at Reich College of Education, a major regional center for
educating teachers.31
• Project Homeroom, an initiative “designed to improve student
thinking, learning and computing skills,”32 is a partnership
among six Chicago area schools, Ameritech, IBM, Illinois Bell,
Prodigy, AT&T Network Systems, Central Telephone Co., and
Eicon Technology Corp. Over 550 students are participating in
the project, which uses PCs, multimedia software with CD-ROM,
video, voice and text features, and on-line services over phone
lines supplied by Illinois Bell. Students access on-line
homework correction, instruction and tutoring, and computer
communication with teachers, among other features. Seventy-
six of the participating students from Stagg High School in Palos
Hills, Ill., use the system over ISDN. ISDN allows these students
to exchange text, pictures and calculations up to 8 times faster
than other students. Initial observations indicate that the
homes outfitted with ISDN links are on line four times more
than those with analog phone service.33
• In Nashville, Tennessee, students at Carter Lawrence Middle
School and Meigs Magnet Middle School can work together and
with the Learning Technology Center at Vanderbilt University
over ISDN. The pilot project, a joint effort of South Central Bell,
Northern Telecom, Vanderbilt and the Tennessee Public Service
Commission, uses voice, video and screen sharing technologies
to enable students to see and talk with other students or with
faculty at Vanderbilt, as well as share documents, graphics and
other information.34
• In the Research Triangle Park area of North Carolina, the North
Carolina State University Center for Communications and Signal
Processing, BellSouth, Southern Bell, GTE, IBM, Northern
Telecom, and the Wake County Public School System are
developing SCHOOLNET, “a project to demonstrate the
enhancement of public education through advanced
telecommunications technologies, specifically ISDN.”35 Among
the functions that SCHOOLNET plans to provide are video
learning and distant instruction; electronic access to library
materials; faculty support for exchange of curriculum materials
and teaching aids; and administrative support for scheduling
and staffing purposes.
ISDN could also enhance the availability and value of educational
resources on the horizon. Congress has passed legislation calling for
the creation of a “National Research and Education Network” (NREN),
to link “educational institutions, government, and industry in every
State.”36 Among its purposes, Congress sought “to promote the
inclusion of high-performance computing into educational
institutions at all levels.”37 The investment needed to actually
connect every one of the nation’s 84,500 public schools and 24,000
private schools is far beyond the resources available in the NREN
legislation. If ISDN was widely available, it could substantially
leverage the value of the government’s investment by enabling
schools, especially at the K-12 level, to attach to the NREN and reap
the benefits of this high-performance network.
Applications in Heath Care
Many analysts have suggested that advanced telecommunications
networks can have substantial benefits in improving the delivery
and reducing the cost of health care services.38 While the publicity
often focuses on medical consultation from home and remote
diagnosis, other applications in the health care field include reducing
administrative costs, providing health and medical information to
help people take better care of themselves and make more informed
decisions about their medical needs, providing health care in rural
areas, and enabling doctors to consult with one another.39
Medical images are often especially dense with information, and the
reliability of their transmission is paramount. A typical CT scan
image contains about 5.2 megabits (Mb) of information, while a
digitized X-ray requires 12 Mb of information. While both CT scan
images and X-rays can be sent over phone lines today, the process is
slow: A single CT scan takes 9 minutes, and an X-ray 21 minutes.
Using just one B channel of an ISDN line, those times can be reduced
to 1.4 minutes and 3 minutes, respectively.40 Of course, by
combining the two B channels of an ISDN line, those times can be cut
in half again.
• The U.S. Public Health Service is facilitating the development of
a multimedia telecommunication network for coordinating
community health and human services and promoting shared
group decision making for better case management. The
Community Services Workstation will combine video-
conferencing, document sharing among remote health care and
social service workers, and access to databases with medical
information, local services, and practical information that can
be produced for clients such as maps and mass transit routes.
Based on prototype research completed by Dr. Anthony Gorry
at Baylor University, the workstation now being tested at
Howard University in Washington D.C. is built on PCs connected
via ISDN.41
• In Huntsville, Alabama, BellSouth and the U.S. Army have
created an ISDN lab to develop voice, video and data
applications for the Army, including medical applications. Dr.
Ira Denton, Jr., a neurosurgeon with The Alabama Back
Institute, has demonstrated how ISDN can support remote
consultation during surgery. In this scenario, a remote
specialist, linked with simplex video and full duplex audio,
views the operation through the operating microscope, getting
the same view of the procedure as the surgeon on site. ISDN
also enables post-operative follow-up exams of patients at
remote locations. The exam can be performed by a nurse-
practioner under the remote guidance of the surgeon, who has
full video and audio contact with the exam site.42
• The General Computer Corporation, a company that processes
claims for insurance and state benefit programs from
pharmacies, doctors’ offices and hospitals, recently announced
that it would begin using ISDN for claim processing and
membership verification services in Pennsylvania. ISDN will
significantly reduce transaction time and telecommunications
charges. Currently, a routine authorization from a pharmacy or
doctor’s office takes over 30 seconds; with ISDN, the same
procedure can be cut to under eight seconds. General
Computer projects that over 25 million pharmacy transactions
are carried each year over the public network, and that the
switch to ISDN can cut response times on claims by up to
85%.43
• The U.S. Department of Veteran’s Affairs (VA) Information
System Center at Silver Spring, Maryland, is testing how ISDN
can extend access to the VA’s medical imaging and document
imaging system. The VA’s integrated imaging system stores
medical images, including pathology specimens, X-rays,
cardiology studies, and endoscopy views, in addition to the
text-based patient information system available at all VA
medical centers. The VA is using ISDN, configured to combine
the two B channels for data transfer, to link the VA center at
Silver Spring, the VA medical centers in Washington, D.C., and
Baltimore, Maryland, and the NIST campus in Gaithersburg,
Maryland. According to preliminary reports, the system can
retrieve a 750 kilobyte, 16 bit color image from the image
server over ISDN in 60 seconds.44
• The University of Louisville, the State of Kentucky Cabinet for
Economic Development, and South Central Bell have created the
Telecommunications Research Center (“TRC”) at the University’s
Shelby Campus. The TRC recently demonstrated the
transmission and reception of dental images using
RadioVisioGraphy (“RVG”), a filmless dental x-ray system, over
ISDN connections between the TRC and Washington, D.C. TRC
forecasts uses for remote consultations for diagnosis, referrals,
and second opinions. With ISDN, the images are transferred 30
times faster than if they were carried over conventional analog
lines.45
• The CapMed Systems Corporation of Huntsville, Alabama, has
developed “Orchids,” a multimedia medical information system
that can be used to allow remote physicians to review charts
and scanned images, which, in many cases, have been
determined to be fully adequate for medical decision making
and follow-up to neurosurgical therapies.46
• Siemens Stromberg-Carlson, in partnership with Motorola,
Voxem, Inc., a New Jersey-based software firm, and Ohio Bell,
have demonstrated an ISDN-based system for tracking medical
records and facilitating information flow between a hospital,
doctor’s office and an insurance company. The system scans
and stores patient records, which are then transmitted to the
insurance company’s claims department, where they are
received as graphics files directly into the company’s system
for easy review and tracking.47
• The Regional Medical Center (“RMC”) at Memphis, Tennessee,
completed a successful test of ISDN in a teleradiology network.
The demonstration, held, in part, to test the cost-benefit ratio
of ISDN as compared with other technologies for teleradiology,
connected the RMC Trauma Center, the home of RMC’s Chief of
Radiology, Dr. Robert Gold, and the Memphis Convention Center,
where the results were showcased. According to Dr. Gold, the
simultaneous availability of voice and data offers an important
advantage in many medical consulting scenarios, and the speed
for the image transfer was fully acceptable.48
Telecommuting/Work-at-home:
ISDN as a ‘LAN Extender’
Telecommuting refers to the use of telecommunications links to work
from home. While not a new phenomenon, telecommuting is seen by
many as an application that could be greatly enhanced by ISDN.49
Through faster data communication, sophisticated call routing
services, and integrated voice and data capacity, ISDN has the
potential to enable people working at home to have their calls passed
instantly from the office at the same time they access their office
LAN for file sharing, e-mail, and file retrieval and applications from a
server, with only somewhat slower response than if they were
actually in their office. In fact, independent experts as well as
telecommunication program managers at telephone companies agree
that the bandwidth needs for telecommuting are modest,50 which
suggests that narrowband ISDN is particularly well-suited to these
kinds of applications.
New interest is also being expressed in telecommuting because of its
potential to cut down on vehicular traffic, which would in turn
reduce air pollution, traffic congestion, fuel consumption and loads on
traditional infrastructure such as roads and bridges. Interest is
especially high where employers have to comply with recently
enacted regulations designed to improve air quality and reduce
pollution. Six metropolitan areas in California and 24 areas in 16
other states are subject to such requirements, which have been
issued by Federal, state and regional authorities.51
• Lawrence Livermore National Laboratories has commenced an
active telecommuting program over ISDN. In the trial, a small
group of scientists and engineers, who tend to have substantial
demands for bandwidth, found that 128kbps offered adequate
performance of applications running on Macintoshes, PCs, Sun
workstations, and X Window terminals. Participants reported
that they could do everything they did at the office
successfully from home. The telecommuting program attracted
between 80 and 100 volunteers within the first 60 days of its
announcement, and continues to receive one or two requests
per day.52
• Illinois Bell is experimenting with an ISDN-based work-at-
home program for its customer representatives. According to
the company, the trial will be first to use software that allows
employes to work from home with access to all information
they need to handle customer requests delivered in real time.
Service calls are routed to employees’ home computers by
“PhoneServer” software developed by Unifi Communications.
The software handles all call routing and network monitoring.53
• The University of Cincinnati College of Engineering recently
concluded a very successful telecommuting trial that the school
plans to turn in to a permanent program. From July, 1991,
through December, 1992, engineering students and faculty
used ISDN lines to dial in to the school’s computer system to
gain access to the University network, connect to the Internet,
and run applications under the X Window System, a standard
for displaying graphical information in a distributed system.
According to the Director of College Computing, who
administered the trial, the school feels that an ISDN-based
telecommuting program effectively extends the availability of
its computer labs without adding new equipment, can help
reduce the University’s capital costs, helps the school cope with
space limitations, and offers flexibility for students.54
• Bell Atlantic and Ameritech used Unifi Communications'
PhoneServer and Distributed Call Center software, running on
an IBM PS/2 computer equipped for ISDN, to demonstrate how
ISDN can be used with local and long distance public switched
networks to route calls and link remote locations. In the
demonstration, the software automatically forwarded incoming
‘800’ number calls to Chicago, Hoffman Estates, Illinois, or the
Washington, D.C. area using interexchange carrier facilities,
depending on the time of day and availability of agents. The
software allowed computers in the Washington and Chicago
areas to remain in constant contact over the D channel.
Messages about the status of customer service agents were
forwarded from one computer to another over a combination of
ISDN circuits and local (X.25) and long distance (X.75) packet
data networks, without ever placing an actual call. The Hoffman
Estates computer thus worked as a Distributed Call Center,
forwarding calls from Chicago to Washington when needed.55
Energy Management:
Demand Side Management/Load Shedding/Meter Reading
Basic telemetry — meter reading from a remote location, such as the
utility company offices — has long been recognized as a potential use
for advanced telecommunications systems. Recent innovations allow
telecommunications lines to connect with a home’s major appliances
and utility systems to manage consumption by routing energy
requests through a gateway that only connects to the power supply
during periods when cheaper, off-peak energy is available. By load
shedding, a utility can reduce the load on its plant at key times by
turning off certain key appliances or systems for a short period.
Such systems or appliances include air conditioning systems, heat
pumps, refrigerators, pool heaters, and hot water heaters.
• The town of Floyd, New York, recently began to implement
XanComm’s Utility Control System to combine automatic meter
reading and demand side management into a single system
using ISDN. XanComm's system is a small box that fits into the
basement and is connected to both an ISDN line and the utility
meter. The system passes meter reading data over the D
channel to a PC-based system in town hall.56
• CyberLYNX, an engineering firm focused on home automation
or “Smarthomes,” is developing an ISDN-based gateway system
with Florida Power Corporation, BellSouth and Teletimer
International. The system uses the Consumer Electronics Bus,
or “CEBus,” protocols riding on ISDN to create a communications
link between a home and various outside service providers,
such as electric utilities, to manage energy use and take meter
readings remotely. A working prototype demonstration was
established in mid-1991 at the University of Colorado’s
Telecommunications Laboratory. BellSouth has received
approval for a tariff to offer service on the D channel only,
which would allow subscribers to get the packet channel for
these Smarthome applications without otherwise changing their
telephone service.57
While recent studies have drawn a link between broadband fiber
deployment and energy management,58 the above examples
demonstrate that telecommunications-based energy management
remains a narrowband application. Broadband networks could
certainly perform the same functions, but they are not necessary to
gain these benefits.
Videoconferencing & Video Telephony
Video telephony is both an application in itself and a component of
many other innovative uses of multimedia telecommunications. Due
to great advances in signal processing, even analog telephone lines
can be used today to send and receive slow speed video images.59
ISDN-based video telephony and videoconferencing are now
available and affordable.
Each of the following video-based applications runs over Basic Rate
Interface (“BRI”) ISDN, the standard 2B+D configuration described
above.60 In some of these applications, a video connection at 64k or
128k bps is linked to a wider bandwidth trunk (e.g., a Primary Rate
Interface (“PRI”) connection, which combines 23 B channels and a D
channel at 64k bps), yet the transport to the end-users remains a
BRI connection and is thus of interest to those considering the
functionality of single-line ISDN. Moreover, the large users included
here demonstrate how the availability of BRI connections can
enhance the reach and flexibility of private networks, and allow
travelling employees, contractors, or affiliates to connect to a
corporate network from beyond the normal reach of the network.
That enhanced connectivity suggests a significant additional source of
potential demand for ISDN.
• Northern Telecom, Inc. offers Visit Video, a package that
includes software, camera, and video board for the PC or
Macintosh. When connected to another computer with the Visit
package, the system offers real-time black and white full
motion video, screen sharing, and file transfer capabilities on
screen. The system needs only a single 56kbps digital
connection and conforms to the National ISDN 1 standard.
When used in conjunction with NT’s Visit Voice, the system
allows users to set up a voice connection over a second channel,
as well as perform other functions.61 Visit Video will be sold
for $2,900 to $3,500, depending on network connectivity.
• In France, France Telecom closed down its 2Mbps
videoconferencing network service and replaced it with dial-up
equipment over ISDN service. Subscribers now dial national
and international calls using the French “Numeris” network at
128,000 bps and will be able to participate in multipoint calls
with up to 16 locations.62
• At General Motors’ Troy, Michigan facilities, the car
manufacturer is testing ISDN links to the company’s private
network, the world’s largest. A Sun Workstation running
CAD/CAM design software has been outfitted with a video
camera. The configuration allows users to share screens of
CAD/CAM and whiteboard displays over one B channel and run
desktop videoconferencing on the other B channel. The
company reports that “our LANs and corresponding customer
premises equipment gain significant application/capability
advantages via access to ISDN.”63
• The Jet Propulsion Laboratory in Pasadena, Calif., and the
Lawrence Livermore National Laboratory in Livermore, Calif.,
are each using ISDN for desktop videoconferencing to conduct
business among scientists and engineers between the two sites.
The system also allows screen sharing and file transfer
capabilities during the videoconference. Project managers at
JPL have also been testing the desktop multimedia system
independently.64
• The Naval Air Warfare Center Weapons Division at China Lake,
Calif., the Navy’s largest research and development project, is
using Basic Rate ISDN for desktop video teleconferencing at the
facility, where offices can be as far as 20 miles apart. They
plan to extend the ISDN-based system to create video links to
AT&T Labs in Holmdel, New Jersey, and the National Institute
of Standards and Technology in Maryland.65
• Hitachi America, Ltd. has installed Basic Rate ISDN at many of
its North American locations to enable videoconferencing
between Hitachi locations in the U.S. and for international
meetings with executives in Japan. People involved in the
videoconferences can simultaneously exchange data files and
fax messages over the same lines.66
• West Virginia University in Morgantown, W. Va., and the
University of Cincinnati have established a desktop video
conferencing link between the two campuses, which can be
combined with an ISDN-based desktop conferencing system to
allow collaborative computing projects and full motion video.67
Assorted Other Uses
Public Safety
In Colorado Springs, Colorado, the fire department uses ISDN to
support dispatch assistance for firefighters. In a dramatic
improvement over what they would be able to do with modem-
based access to data over analog phone lines, dispatchers rely on
ISDN’s speed and accuracy to retrieve information about which
trucks to dispatch and information about hazardous materials that
may be near the site of a fire. At the U.S. Army’s Redstone Arsenal
in Huntsville, Alabama, ISDN enables emergency dispatchers to be
fed information automatically relating to incoming emergency calls,
including the location of the calling party and key information linked
to the location, such as the presence of munitions or stored chemicals.
CAD/CAM
Sony Corp. is using international ISDN service to send CAD/CAM data
between its Haneda Technology Center in Tokyo and its Bayonne
factory in France, which produces printed circuit boards. The new
service uses the TCP/IP communications protocol.68 A CAD/CAM
image normally contains 2 megabits of information, which takes an
ordinary phone line 3.4 minutes to transmit. Using one B channel,
the same image can pass in 31.2 seconds.69
High Speed Facsimile
ISDN enables the use of the next generation of fax machines,
classified as G4. G4 machines transmit one standard sheet of paper
over an ISDN line in about three seconds with a resolution of 400 dpi.
(Standard laser printers offer 300 dpi resolution.)
Real Estate
A number of applications have appeared to serve real estate
professionals. In all of them, ISDN’s capacity to simultaneously
transmit data and high-quality graphics in response to a database
search weds the “Multiple Listing Service” with advanced digital
telecommunications. These same systems could also benefit other
businesses with interests in real estate, such as law offices, banks,
mortgage companies, appraisal firms, title search companies, and
home inspection firms.
• In Rochester, Minnesota, U S West Communications and Moore
Data Management Services, a leading provider of Multiple
Listing Services nationwide, are partners in a field trial that
demonstrates multimedia real estate applications that integrate
voice, data, image and text communications. Agents can access
a database of real estate listings and view photographic images
of selected homes. Agents will also be able to create
advertisements and print out images and text of real estate
listings from the multimedia database.70
• AT&T has demonstrated a DigitalRealty Imaging System over
ISDN. Realtors can sit clients in front of a PC and bring up
available houses matching client needs (e.g., price, style,
neighborhood). For each house, as many as 12 color photos can
be displayed, including exteriors, rooms, and backyard. Data
can be sorted by criteria that include price, number of
bedrooms, facade, schools, nearby golf-courses, churches, etc.
With ISDN links, data would be on screen in 5 seconds or less.
Pacific Bell and BellSouth have each demonstrated similar systems,
as well.71
Used Car Sales
Used car dealers in central Tokyo, where real estate is too expensive
to maintain extensive lots of used cars, have installed videotex and
G4 fax systems to retrieve images and text information from
centralized databases over ISDN.
Conclusion
EFF’s vision of ISDN as an “open platform” for innovation rests on
three necessary criteria for the service:
• it must be widely available;
• it must be reasonably affordable, and;
• it must offer a critical mass of features with enough
functionality to serve as a viable platform for applications.
According to Bellcore’s deployment data, ISDN could be widely
available by 1994. Independent experts, as well as the one state
public service commission to consider the issue (the Massachusetts
Department of Public Utilities), have found that single-line
residential ISDN can be priced reasonably. But does ISDN have the
critical mass of features needed to be a platform?
EFF believes the diverse applications described above, across many
fields, demonstrate that ISDN is powerful enough to deliver many of
the services associated with advanced telecommunications networks.
In the long run, ISDN is not a substitute for broadband networks, but
it can deliver a full range of desirable services long before
broadband networks become available.72 Since it can soon be made
widely available at a reasonable cost, ISDN could bring these and
other services to residential users, small businesses, primary and
secondary schools, not-for-profit organizations, social service
agencies and many others well before the end of the decade.
Moreover, with the recent deployment of the National ISDN-1
standard from coast to coast, and the current development of
National ISDN-2 and ISDN-3 standards to ensure and promote
interoperability throughout a national market, there is every reason
to believe that the pool of applications is poised for a burst of rapid
growth. ISDN’s increasing ability to handle video, which is often
regarded as the most desirable application for advanced
telecommunications services,73 secures its position as a valuable
platform for the development of innovative, multimedia applications
for many fields.
Nevertheless, some proponents of infrastructure modernization argue
that we must move immediately to an integrated broadband
network, defined as one with transmission speeds over 45 Mbps, in
order to provide an adequate level of services to the public at large.
Without regard to the many successful applications described above
or the growing number of applications that narrowband networks
seem capable of supporting, three senior-level engineers with
Ameritech noted in 1991, “While [broadband] was previously
thought to be a future residential offering, most industry observers
now agree that [broadband] will be limited to business applications
for the foreseeable future.”74
Of course, such changes in deployment strategy may be premature.
If residential or other smaller users develop near-term needs for
broadband services, the concern would be that commitments to
narrowband technologies would keep the network stuck at a capacity
unable to meet consumers’ demand for bandwidth. Fortunately,
scientists at AT&T’s Bell Labs recently demonstrated that,
technologically, narrowband is not an impediment to broadband.
According to staff in the Loop Systems Planning Department,
“telephone companies can go ahead and install these narrowband
systems with confidence that they aren’t locking themselves out of
providing broadband services later.”75 Laboratory trials
demonstrated broadband service — simultaneous transmission of
high-resolution video, digital audio and data — over a narrowband
network with fiber in the loop engineered for plain old telephone
service.
Thus, ISDN appears well poised to serve as an open platform for
innovation in telecommunications without holding back further
advances. It can meet each of the criteria that made the PC and
Apple II the launch pad for one of the most startling success stories
of the 1980s: the microcomputer revolution that changed the way
computing, offices, and countless consumer products work.
For more information, contact:
Electronic Frontier Foundation
1001 G Street, NW
Suite 950 East
Washington, DC 20001
202-347-5400 tel
202-393-5509 fax
Internet email: eff@eff.org
1 See, generally “The Open Platform: A Proposal by the Electronic Frontier for a National
Telecommunications Infrastructure,” (Cambridge, Mass.: EFF) 1992. See, also, “Testimony
of Mitchell Kapor on behalf of the Electronic Frontier Foundation before the House
Subcommittee on Telecommunications and Finance,” October 24, 1991; “Testimony of
Mitchell Kapor, President, and Jerry Berman, Washington Office Director, Electronic
Frontier Foundation, before the Joint Economic Committee regarding Telecommunications
Infrastructure,” June 12, 1992; John Mintz, “Getting the Lead Out of Copper: Unusual
Coalition Pushes a System to Open Phone Lines for Information Revolution,” Washington
Post, September 13, 1992, p. F1.
2 As its name implies, ISDN is a digital network that enables the integrated or
simultaneous transmission of distinct services, such as voice, data, facsimile, video, or
graphic images, over a single wire. By organizing information in a digital format and
moving the signalling information used to set up and manage a call to a separate channel,
ISDN allows up to 144,000 bits per second (bps) of information — voice, data, or video — to
travel down the twisted pair of copper wire used today for voice telephony. The basic
configuration for ISDN service is to divide the telephone line into two “bearer” or “B”
channels, each of which has an uncompressed capacity of 64,000 bps, and a “D” channel
(“delta” channel), which carries the call management information in bursts of data called
“packets” at up to 16,000 bps. Without ISDN, most users of today’s modems transmit data
at 2,400 bps, although those same wires can carry 9,600 or 14,400 bps of uncompressed
data, and even up to 38,400 bps thanks to compression and other advances in modem
technology. Of course, the same compression that enables standard analog lines to achieve
throughputs of 38,400 bps can be used with ISDN to achieve significantly higher
throughputs. For a useful introduction to ISDN, see, Fred R. Goldstein, ISDN in
Perspective, (Reading, Mass.: Addison-Wesley Publishing Company) 1992.
3 See, for example, Lee Selwyn, “A Migration Plan for Residential ISDN Deployment”
unpublished paper prepared for the Communications Policy Forum (Boston: Economics &
Technology, Inc.), April 20, 1992; Mark Cooper, “Developing the Information Age in the
1990s: A Pragmatic Consumer View,” unpublished paper, (Washington, DC: Consumer
Federation of America), June 8, 1992; Eli Noam, “ISDN in Perspective,” (New York:
Columbia Institute for Tele-Information), 1992; Harry M. Shooshan III, “ISDN and the
Public Switched Network: Building an ‘Open Platform,’” unpublished paper, (Washington
D.C.: National Economic Research Associates) 1992.
4 See, Selwyn, op. cit., Cooper, op. cit.; see also, The Commonwealth of Massachusetts,
Department of Public Utilities, “Investigation by the Department of Public Utilities on its
own motion as to the propriety of the rates and charges set forth in the following tariff:
M.D.P.U. No. 10, Part C - Section 10 - Revision of Table of Contents Page 1; Revision of
Pages 1 through 15, filed with the Department on August 29, 1991 to become effective
September 28, 1991, by New England Telephone and Telegraph Company [ISDN Basic
Service],” D.P.U. 91-63-B, Order dated February 7, 1992; Bruce L. Egan, “Benefits and
Costs of Public Information Networks: The Case for Narrowband ISDN,” Columbia Institute
for Tele-Information Working Paper (New York: Columbia Institute for Tele-Information),
February 1992.
5 See, Bellcore, ISDN Deployment Data, Issue 2, Report SR-NWT-002102, June 1992;
Filings with the FCC; see also, “RHCs and Bellcore Outline ISDN Deployment and Marketing
Plans,” Communications Daily, June 3, 1992, p. 1.
6 See, for example, “Electronic Frontier Foundation Gets Bellcore Endorsement on ISDN”
Communications Daily, July 29, 1992, p. 3 (“Addressing meeting of NARUC
Communications Committee, Irwin Dorros, Bellcore exec. vp for technical services, said he
was in ‘violent agreement’ with program suggested by previous speaker on program, EFF
Pres. Mitchell Kapor.”) Support has also come from top executives at Microsoft, Inc.;
Apple Computer, Inc.; Sun Microsystems, Inc.; and AT&T, among others.
7 In this regard, compare Cooper, op. cit., p. 1: Widely deployed ISDN –– what Cooper calls
the “Widespread Integrated Narrowband Network” or “WINN” –– “would provide 80 percent
of the capabilities of a [ubiquitous broadband network] in the near term at 10 percent of
the cost.”
8 See, for example, Bell Atlantic, Delivering the Promise: A Vision of Tomorrow’s
Communications Consumer (1989); Pacific Telephone, The Intelligent Network Task Force
Report, (October 1987); Holliday, C. and V. Junkman, “The Integrated Broadband Network –
How Will It Evolve,” Telephony, August 12, 1991, p. 28.
9 At the Transcontinental ISDN Project 1992 (“TRIP ‘92”), a national, multivendor
celebration of coast-to-coast ISDN connectivity held in November, 1992, 74 companies
demonstrated 185 ISDN applications at 150 locations across the U.S. and around the world.
For more information about these applications, see, The Enterprise Computing Group, TRIP
‘92 Atlas, (Manhasset, NY: CMP Publications, 1992, hereinafter, TRIP ‘92 Atlas), p. 16 and
passim.
10 Some telecommunications professionals suggest this is one of ISDN’s main, if less
obvious benefits. “Probably one of the most important benefits of ISDN is that the
technology provides a platform that nurtures computer telephony and advances
information systems within small and corporate businesses.” Russell Roy, “ISDN
Applications at Tenneco Gas,” IEEE Communications Magazine, April 1990, p. 30.
11 Marc Rettig, “A Succotash of Projections and Insights,” Communications of the ACM,
May 1992, p. 26, graph, p. 27.
12 “After controlling all factors such as higher MIPS, larger main memory size, and more
I/O channels, computer purchase prices decrease about 23 percent…each year…. The
result of no scale economies agrees with the present trend of decentralized computing
resource allocation. Rapidly increasing telecommunication technology, popularity of end-
user computing, and no gains from scale economies will continue to make decentralizing
computing power an attractive option.” Y.M. Kang, “Computer Hardware Performance:
Production and Cost Function Analyses,” Communications of the ACM, May 1989, pp. 586-
591.
13 In this regard, compare, Martin C.J. Elton, “Forecasting the Demand for New Broadband
Services,” in Integrated Broadband Networks: The Public Policy Issues, Martin C.J. Elton,
ed., (Amsterdam: Elsevier Science Publishers B.V.) 1991, p. 61: “[S]ervice delivery may be
redesigned so as to allow narrowband services to meet a demand that initially seemed to
require broadband service. In future applications, there will be a relationship between
the decentralization of computer memory and processing power, on the one hand, and
requirements for high-speed transmission on the other hand. Trade-offs between using
public broadband networks to access remote supercomputers and very large databases and
investing more in purchasing technology and data will not necessarily favor the former.”
14 Testimony of Dr. Robert Lucky before the Joint Economic Committee of the U.S.
Congress, June 12, 1992.
15 Paul Taylor, “Videoconferencing: An alternative to costly, tiring travel,” Financial
Times, Special section, “Telecommunications in Business,” June 18, 1992, p. 6.
16 Cooper, op. cit., p. 8.
17 Ibid., at 12, cites omitted.
18 Financial Times, Special section, “Telecommunications in Business,” June 18, 1992.
19 A recent review of the growth of hosts (i.e., computers with Internet addresses, each of
which may serve many users in an area or at an institution) from 1979 until early 1992
reveals a monthly growth rate that varies between 7 and 13 percent, with the average
around 12% per month. The current growth rate, however, is higher, and appears to be
15% per month. Email exchange with Anthony M. Rutkowski, Vice-President, The Internet
Society, January, 1993. Compare, also, “Testimony of Douglas E. Van Houweling, Merit
Network, Inc.,” before the U.S. House of Representatives, Subcommittee on Science, March
12, 1992: “traffic on the [U.S.] backbone has grown almost 7,000 percent” since 1988.
20 Sun Microsystems Computer Corporation, ISDN Technology: Technical White Paper,
(Mountain View, Calif.: Sun Microsystems, Inc.), May, 1992, p. 11.
21 Robert Hinden, “Big markets in LANS->big Inter-net->Internet Society: Preliminary
LAN and Workstation/PC Market Data.” Internet Society News, Winter, 1992, p. 5.
22 Ibid., citing Forrester Research, Network Strategy Report: LANs for Free?, November,
1991; Dataquest, Market Statistics: Local Area Networks, May, 1991.
23 See, for example, Stuart Ehrenberg, “National ISDN-1: A Common Ground for Vendors,
Users and Carriers,” Telecommunications, September, 1992, p. 32: “With the extension of
the LAN environment beyond the boundaries of the corporate office, the need for wide area
network (WAN) connectivity alternatives has emerged. This started with large
corporations and has been pushed down to the medium sized business customer. These
user applications have created the need for medium-bandwidth WAN connectivity, for
which ISDN is ideally suited.” (emphasis added)
24 U.S. Congress, Office of Technology Assessment, Linking for Learning: A New Course
for Education, OTA-SET-430 (Washington, DC: U.S. Government Printing Office) November
1989, p. 4.
25 Richard T. Hezel & Peter J. Dirr, “Barriers that lead students to take television-based
college courses.” Tech Trends, Volume 36, Number 1, 1991, pp. 33-35.
26 See, Interact ‘92, The ISDN in Education Primer, (Chico, Calif.: California State
University, Chico) 1992 (hereinafter, “ISDN in Education Primer”).
27 ISDN in Education Primer, p. 15.
28 Ibid.
29 Ibid., pp. 30-36.
30 Telecommunications Reports, May 6, 1991, p. 8, quoted in National
Telecommunications and Information Administration, Telecommunications in the Age of
Information: The NTIA Infrastructure Report, NTIA Special Publication 91-26
(hereinafter, “NTIA Infrastructure Report”), (Washington, DC: U.S. Department of
Commerce) October 1991, p. 56.
31 See, also, TRIP ‘92 Atlas, p. 6-8.
32 “IBM, Ameritech, Local Illinois Schools for ‘Project Homeroom,’” Consumer Information
Appliance, June 1991, p. 5.
33 Testimony of Thomas M. Isaacson, Manager, Network Design and Support, Prodigy
Services Corp., before the Colorado Public Utilities Commission, August 24, 1992.
34 Deborah G. Garrett, “Long-distance learning to debut,” The Tennessean, December 3,
1992, p. 1B; Jeanne Peck, “Teleconferencing expands classroom,” The Nashville Banner,
December 3, 1992, p. D-1; “ISDN links Metro school students,” Vanderbilt Register,
December 7-13, 1992, p. 3.
35 ISDN User Briefs, January 1992, p. 4.
36 “The High-Performance Computing Act of 1991,” Pub. L. 102-194, Sec. 102(a).
37 Ibid., Sec. 3(H).
38 See, for example, Mark K. Schneider, Nancy Mann and Arthur Schiller, “Can
Telecommunications Help Solve America’s Health Care Problems” (Boston: Arthur D.
Little) July 1992, which concludes that widespread use of telecommunications and
information technology applications can reduce the annual cost of health care in the U.S.
by over $36 billion. The study, co-sponsored by Ameritech, Bell Atlantic, BellSouth,
Northern Telecom, NYNEX, Pacific Telesis Group, Southern New England Telephone, and
Southwestern Bell Corporation, found that $28 billion could be saved each year through
management and transport of patient information, while electronic claims processing
could save $6 billion, electronic inventory control $600 million and video conferencing
$200. As one of the study’s co-author’s, Dr. Arthur Schiller, noted at the recent TRIP ‘92
presentation on medical applications, most of these services can be provided effectively
over ISDN. See, also, John Tebes, “Advanced Telecommunications in Health Care: Impact of
the National ISDN Network on Health Care Delivery in the U.S.,” Optiv: The Business
Journal for Open Systems, Fall, 1992, pp. 24-26.
39 See, NTIA Infrastructure Report, pp. 63-73.
40 David C. Churbuck, “The copper wire gets fatter,” Forbes, October 12, 1992, p. 141.
41 “PHS Tests Networked Multimedia for Coordinating Community Services,” Public
Health Reports, March/April 1993.
42 TRIP ‘92 Atlas, p. 6-45.
43 “General Computer Corporation Purchases Bell Atlantic’s Transaction Switching and
Transport Service,” news release of Bell Atlantic Corporation, January 7, 1993.
44 TRIP ‘92 Atlas, p. 6-213.
45 Ibid., p. 6-205.
46 Ibid., p. 6-45.
47 Ibid., pp. 6-178, 6-182
48 Unpublished remarks of Dr. Robert Gold at “Health Care: On the Line,” the TRIP ‘92
Medical Application Conference, November 17, 1992; conversation with Dr. Robert Gold,
January 15, 1993.
49 See, for example, “Testimony of Karen J. Hardie, Ohio Office of the Consumers’
Counsel, on the Ohio Energy Strategy’s Interim Report,” January 22, 1993 (“ISDN has and
will facilitate the ability of a company or government agency to offer telecommuting
programs.”) p. 9.
50 Martha Strizich, “Tandem, Other Users Turn to Telecommuting,” Communications
Week, September 21, 1992, pp. 35, 37.
51 Ibid., p. 35.
52 Telephone interview with Stan Kluz, Lawrence Livermore National Laboratories,
October 2, 1992.
53 Communications Daily, April 29, 1992.
54 Telephone interview with Jack R. Krebs, Director of College Computing, University of
Cincinnati, College of Engineering, January 14, 1993. See, also, TRIP ‘92 Atlas, pp. 6-203,
6-204.
55 TRIP ‘92 Atlas, p. 6-200; see, also, “Bell Atlantic and Ameritech Work with Unifi
Communications to Demonstrate First Distributed Call System Based on ISDN,” PR
Newswire via First! by Individual, Inc., May 12, 1992.
56 “Briefs,” ISDN News, February 26, 1992, p. 5; see also, Michael Pauzer, “A System to
Simplify Utilities Management,” Public Utilities Fortnightly, April 1, 1992.
57 “Florida Power and BellSouth move ahead with CEBus and ISDN,” SMARTHOME News,
May 1992, p. 2; “ISDN-CEBus Residential Gateway Underway with EMMA Technical
Alliance,” SMARTHOME News, August 1991, p. 1.
58 See, for example, Steven R. Rivkin & Jeremy Rosner, Shortcut to the Information
Superhighway: A Progressive Plan to Speed the Telecommunications Revolution
(Washington, D.C.: Progressive Policy Institute), Policy Report No. 15, July 1992.
59 Elliot M. Gold, “Videoconferencing closes in on the desktop,” Networking Management,
January, 1992, pp. 42-46.
60 See footnote 2, above.
61 “Northern Telecom Ships Desktop Videoconferencing Products,” Computerworld, June
18, 1992.
62 “France Telecom to Replace High Bandwidth Videoconferencing Services with
PictureTel Dial-up Technology,” Business Wire via First! by Individual, Inc., July 14,
1992.
63 TRIP ‘92 Atlas, p. 6-83.
64 Ibid., pp. 6-113, 119.
65 Ibid., p. 6-129.
66 Ibid., pp. 6-95, 6-96.
67 Ibid., p. 6-215.
68 Sony Sets Up ISDN Service Linking PCB Factory in France, Comline Telecommunications
Wire via First! by Individual, Inc., July 21, 1992
69 Churbuck, op. cit., p. 141.
70 “U S West, Fujitsu Demonstrate Narrowband ISDN in Real Estate,” ISDN News, February
12, 1992, p. 1
71 See, for example, “BellSouth Demonstrates ISDN Applications with U.S. Army’s
Redstone Arsenal,” ISDN News, February 26, 1992, p. 4.
72 The above list reflects only a small portion of available applications. There are scores
more applications for large and small businesses, including LAN bridging, LAN routing,
ISDN Wide Area Networking, LAN access to frame relay, packages that take advantage of
ISDN’s ability to deliver the incoming caller’s number before the call is completed,
security, voice recognition, etc. The North American ISDN Users’ Forum (“NIUF”) Catalog
of National ISDN Solutions contains 34 applications “recipes” that can be implemented
over basic rate ISDN in the near term, many of which are not discussed here. See, North
American ISDN Users’ Forum, “A Catalog of National ISDN Solutions for Selected NIUF
Applications Catalog,” (Gaithersburg, MD: NIUF) Draft 5, October, 1992.
73 The NIUF, for example, polled its members to determine their applications priorities.
Members ranked video conferencing as the top application priority. Other top vote-getters
were: telecommuting; multipoint screen sharing; variable bandwidth - voice/image; and a
three-way tie for fifth between automatic number identification, remote terminal access to
LAN, and ISDN telephone/workstation integration. See, Robin Rossow, “North American
ISDN Users’ Forum Status Report on National ISDN,” February 26, 1992 (vu-graphs).
74 P. Douglas Lattner, Robert L. Fike, Gary A. Nelson, “Business and Residential Services
for the Evolving Subscriber Loop,” IEEE Communications Magazine, March 1991, p. 112.
75 Peter Bohn, Supervisor, Loop Systems Planning Department, AT&T Bell Labs, ISDN
News, February 12, 1992, p. 5.