For interactive TV (ITV) networks to be universally available
as the Public' s next mass medium, they will require the most
economical telecomputing method from the perspectives of consumers,
operators, and programmers. Only a telecomputer system based
on telephone keypad signalling can meet this criteria for the
successful nationwide deployment and market acceptance of interactive
television networks as the Public's access to the National Information
Infrastructure (NII).
EXECUTIVE SUMMARY
The telecommunications and computing industries
have captured the imaginations of the Public with visions of
an interactive multimedia network future. The leaders in these
converging industries are each championing an interactive network
model that is in the perceived best interest of their particular
industry. However, sooner or later, economic realities, basic
engineering, marketing, and regulatory imperatives will dictate
a telecomputing architecture and approach for the "Public
Network" that is quite different from today's highly publicized
and so-called interactive TV trials. The following are those
imperatives and realities. Only a headend or central office-based
telecomputer system that is independent of the set-top box can
offer... - ever more aesthetically appealing graphics and system
intelligence, - transparent and unobtrusive system maintenance
and upgrades, - an open systems approach; the economics of a
system that can... - be traffic engineered based on customer
demand, - serve all wired and wireless modes of video delivery;
the creative and artistic freedoms of a system... - not restricted
by hardware limitations. All such centralized telecomputer systems
require a network of I/O channels for consumers to send input
signals and receive audiovisual output. Only a telecomputer
system based on the existing public switched telephone networks
(PSTN) and NTSC broadcast video standards will offer... - the
most economic I/O channels to and from consumers that can be
traffic engineered - - the efficiency of I/O channels consistent
with the asymmetrical nature of interactive programming - artistic
freedoms not restricted by bandwidth limitations, memory constraints,
nor audience reach - competition between wired and wireless
modes of interactive TV program delivery - a way to trial broadband
interactive video programs without having to upgrade the distribution
plant for digital video or two-way traffic Although opinions
may differ on ITV network architectures, one point seems to
be generally accepted. That is, consumer friendly ITV networks
will use simple and intuitive graphical user interfaces (GUI).
When ITV programs originate from centrally located computers
and broadcast their GUIs as ordinary TV video channels, we need
only to provide an adequate supply of video channels and a means
for consumers to remotely signal those computers. A touch-tone
phone, as an ITV network's remote signally unit, is all the
Public will need to start interacting. Consumers just call over
the PSTN to an ITV program that converts their DTMF telephone
keypad signals to a directional and triggering signalling protocol
that multimedia computers can understand as point & click
input. Eventually, as cable systems approach video-on-demand
(VOD) capacity, such computer input devices as; joysticks, mice,
and keyboards will also generate DTMF signalling and be equipped
with RJ-11 jacks for the consumers' convenience. It is important
to recognize that VOD means, in ITV terms, Computers-On-Demand!
The TV screen will become the consumers' PC monitor. The bottom
line is that ordinary touchtone phones provide the most immediate
and economical means to bring interactivity to the medium of
broadcast television in a way that will guarantee universal
access to our interactive TV future.
INTRODUCTION
Before 1993, interactive TV was not a very popular industry
topic and anyone championing such an idea, yet alone a particular
network architecture or vision for delivering it, was likely
met with skepticism or worse. In spite of this, a few of us
still felt that an interactive medium, something more than movies-on-demand,
was going to fill in the successive blank in the electronic
media progression; telegraph, telephone, radio, television,
_____________. Whatever this new medium was going to be, one
thing was certain. The telephone, broadcast, computer, and publishing
industries were going to be up to their commercial and technological
necks in it. Now its 1995 and the environment is quite different.
Not only has anybody that's anybody in wide variety of industries
jumped on the interactive multimedia superhighway bandwagon,
but they have also been struck by their own personal visions
of this future. Understandably, these visions are conveniently
or subconsciously biased in favor of the technologies, culture,
and corporate interests of the originating visionary. Unfortunately,
none of these visions take an engineering and commercial approach
that is in the best interest of the Public at large. This paper
approaches interactive television and telecomputing opportunities
from a perspective that views all our existing and converging
telephone, cable, broadcast, and computer networks as one Public
Network. We need to take the macro engineering and artistic
perspectives on this new medium that are free of the biases
imposed by the current industrial paradigm if we are to have
a next generation Public Network as a worthy successor to the
Bell System.
WHAT IS A TELECOMPUTER SYSTEM?
A telecomputer system, in the fuzzy macro context
of the information superhighway or the NII, is that mass media
system that our nation's cable and telephone companies are striving
to create to deliver interactive digital everything to the consuming
Public. It is that underlying hardware infrastructure that will
integrate telecommunications, television, computers, and electronic
publishing into a seamless national multimedia network. There
are two major telecomputer models competing to be this next
generation's predominate Public Network system. The older and
more familiar one is the PC in every home connected to an on-line
network or "PC" model. Although this model was a dismal
failure as a mass medium during the brief videotex era, it has
had a recent resurgence encouraged by flashy multimedia PCs,
GUIs, and the explosive worldwide growth of the Internet. The
champions of this model tend to be the manufacturers and sophisticated
users of advanced PCs, workstations, and high-speed data networking
gear. The essential NII elements that this model brings to a
telecomputer architecture are those that offer the most artistic,
creative, and communication freedoms to users, programmers,
and publishers. The other, getting off to a very dubious start,
is the smart TV set-top box (TSB) interfacing with a video server
or "TSB" telecomputing model. This model is just emerging
due to recent advances in microprocessor, video compression,
and network transmission technologies. The champions of this
model tend to be the manufactures of cable converters, microprocessors,
and mid-range computers in partnership with our cable and telephone
companies. In apparent conflict with the PC model, the essential
NII elements of the TSB network architecture are those necessary
for responsible mass media broadcasting and network operator
control. More important for ITV and the NII, the TSB telecomputer
model recognizes the utility potential of an unlimited number,
preferably in common carrier form, of video channels to the
consumer. These two models expose most of the essential NII
elements perceived as necessary for a successful new mass medium.
Between the two, it is possible to extract the inherent objective
of a telecomputer system. That being, to offer all consumers
the potential and opportunity to access all multimedia publications
over a Public Network in a responsible and socially acceptable
manner. Although each of the incumbent models has technical
and philosophical advantages over the other, neither will pass
the test of being economically feasible as a mass medium for
reasons discussed later. As a result, this paper is introducing
and championing a new telecomputer model that merges the PC
and TSB network models in a way that will permit the emergence
of a new mass medium providing universal access to the NII.
CREATE THE IDEAL PC MODEL AND EXPLODE IT
From the perspective of a new Public Network infrastructure,
the challenge facing our industry is to create a telecomputer
system that can stand the test of time measured in generations
of Americans. Let's start by creating the ideal PC model and
identify it's economic implications for a mass media solution.
The core elements of the PC telecomputer model are the user's
input and output interfaces, the microprocessor and it's memory,
and interfaces to the external world. To understand the paradigm
shift that will occur in order for mass media convergence to
take place, contemplate these core elements individually and
their economic impact on the engineering of a nationwide multimedia
network. For the user's input interface, the PC model provides
the user with a means to send control and input signals to the
computer. The user generates these signals via several familiar
computer input devices. In the mass media environment, however,
it is generally accepted that consumers will be using a hand-held
point & click device with a minimum of push-buttons for
interacting with intuitive GUIs. It is also generally envisioned
over the longer term that as voice recognition technology advances,
these signals will likely include voice input and commands as
a replacement for the qwerty keyboard. As for the economic impact
on ITV; input devices are inexpensive, require little or no
maintenance, and are rarely rendered obsolete. It is on the
output side of the PC model where we are now seeing and hearing
the most change. Virtually the whole essence of multimedia deals
with the presentation of an advanced audiovisual output interface
to the consumer. The technical advances and dropping costs in
computing power has led to the creation of graphics images that
are indistinguishable from photographic ones. As recent high-tech
movies have vividly shown, computer programming is beginning
to look and sound good enough to watch in the theatre and on
TV. It is this potential for attracting an audience that has
Hollywood excited. The added potential for user interaction
and audience participation is what has Siliwood excited. However,
for all the excitement and hype, the given mass media output
interface to the consumer is still only their existing TV screens
and speakers. This remains true even though advances in consumer
electronics may one day lead to an HDTV or other advanced NTSC
standard home theatre system. Regardless, for an ITV approach
based on NTSC broadcast video standards, the output side of
the PC telecomputing model adds no costs over passive TV. At
the center of the PC model is the microprocessor and it's memory.
In the ideal PC model, the consumer will continually need the
latest and fastest microprocessors with an expanding memory.
Closely coupled with the microprocessor are the interfaces to
the external world. First, is the access to external data storage
media such as diskettes and CD-ROMs. The ideal PC model will
also continually need the latest and fastest network interfaces
to access on-line multimedia publications and connect with global
network sources. Of course, in the ideal PC telecomputer model,
there are no incompatibility nor obsolescence issues. Unfortunately,
the potential for such an ideal PC model ever existing in the
real world are nil. As a result, for a mass medium, the economic
impact associated with these portions of the PC telecomputer
model are so enormous they constitute it's fatal flaw. But what
if we "explode" this ideal PC model to distance the
user's input and output interfaces from the computing center
to remote locations? (Refer to Figure 1) We end up with a view
of the ideal PC's elements in a way that reveals the key characteristics
that are of interest to Public Network engineers. The first
characteristic one can see is that the information flow is uni-directional
in nature rather than bi-directional. This is because the user's
interaction with the computer uses separate and very different
channels for input and output. The second characteristic is
the asymmetrical nature of the bandwidth requirements. The user's
input is narrowband in nature. On the other hand, the computer's
audiovisual presentations are broadband in nature. Together,
these characteristics offer an unique opportunity to network
engineers that can view ITV networks as the integration of existing
PSTN and cabled or wireless broadcast television networks. 
To take advantage of this opportunity will require
a paradigm shift in network architecture thinking. Conventionally,
network engineers view the location of the network interface
for the consumer as being between their PC and the external
world. This is inappropriate for a Public Network system where
"the network is the computer". We need to move the
network interface to a point between the computer and the user's
input devices. A telecomputer system has "two" network
interface channels to the consumer. One is the narrowband "input
network" interface channel to the computer and the other
is the broadband "output network" interface channel
to the consumer's TV. When viewed in this way, the computer
in the PC telecomputer model can be centralized within the Public
Network. Once the computer is taken out of the home and centralized,
it is then possible to provide the consumer with economic access
to the ideal PC. Centralizing the ideal PC computer offers enormous
economic benefits to consumers and operators alike. One, consumers
can share these ideal PCs based on traffic engineering rules.
Two, the consumer is now relieved of the headaches and costs
associated with PC maintenance and obsolescence. When centralized,
the operator could then also provide the consumer with economic
and transparent migration paths to more advanced microprocessors,
software, graphics, intelligence, and faster network connections
to the external world when, and only when, necessary or desired.
Most important, by centralizing these ideal PCs, we simplify
the task of network management and improve network reliability
by eliminating the unnecessary complexity of data networking
devices and a PC in every home. On the output side of the centralized
ideal PC, the RGB signals that would normally go to the consumer's
monitor can be converted to the NTSC broadcast video standard.
Doing so offers the operator several network channel options
for delivering the output interface to consumers. The most likely
predominate form of delivery will be as just another CATV cable
channel. But, unlike the existing telecomputing models for interactive
TV, this approach will work as well with the over-the-air, satellite,
wireless, and switched forms of realtime video delivery. By
using the existing NTSC broadcast video standard as the output
interface standard for ITV there will then exist the potential
for multiple ITV network operators competing for their share
of the ITV audience. If the user's input network channels are
equally available, it will then be possible to offer competitive
ITV programming universally. Fortunately, input network channels
to a centralized ideal PC are already available via the copper
pairs of the PSTN. Any back channel or upstream signalling and
voice capability added to the CATV coaxial distribution plant
would be redundant and a totally unnecessary economic burden
on the NII. The existing PSTN is more than adequate to meet
the narrowband bandwidth requirements of input network channels
and is already universally available.
WHAT THEN SHOULD BE THE ROLE OF THE TSB ?
As the most proliferous element of a growing telecomputer
system, the first thing the TV set-top box should not be is
a camouflaged substitute for the consumer's ideal PC. A smart
TSB cannot even come close to meeting the demanding requirements
of the ideal PC. This misguided role for the TSB would add the
largest and most unnecessary economic burden on the NII. Compromises
in smart TSB design, be they in the power of it's processor
or the amount of resident memory, will not lessen the economic
burden. A waste of money is still a waste of money. Smart TSBs,
as the primary focus for ITV applications, are destined to be
failures in a mass media network and public utility environment.
The Public Network will not benefit from an ITV architecture
where a key network element is already obsolete when first deployed.
Another reason the current and conventional TSB telecomputer
model will fail is that it does not deliver a medium that lives
up to the Public's expectations for interactive television.
ITV must be more than selecting a movie, pizza, catalog shopping,
and access to so-called second level gateways to other information
sources. "Interactivity" is much more than just "selectivity".
Interactive television, as a new mass medium, must deliver a
completely new entertainment experience to consumers. Downloading
adolescent arcade games or simple prompts for play-along TV
game shows to the limited memory of smart TSB will just not
cut it in the eyes of a mass market. Consumers are looking for
and have been promised more. However, with the ideal PC, an
embryonic form of the evolving interactive multimedia experience
can be found on CD-ROM publications. Understandably, the inherent
limitations of the TSB telecomputer model used in today's so-called
ITV trials has failed to attract any interest from the artists,
programmers, and creators of this new interactive multimedia
art form. For a mass medium where, as they say, "content
is king", this will not do. The focus of ITV program development
must shift from the TSB to centralized ideal PCs within the
Public Network. In this way, interactive programs developed
for CD-ROM and the ideal PC are easily ported to the ITV platform
as an additional distribution network and ancillary market for
the mutual financial benefit of the parties involved. The TSB
cannot be at the center of ITV, nor should ITV program development
wait for or depend on it. The role for the TV set-top box is,
as always, only as a mass media network broadcast receiver.
Whether a network's broadcast signals reach the consumer directly
from a satellite, CATV headend, over-the-air, or a telco central
office, the TSB's role is still the same, It is a mass media
network, primarily broadband, receiver. The Public Network does,
however, need a next generation model of TSB that better recognizes
a larger role for receivers in the evolving NII for the next
several generation of Americans.

The most important NII element that this new TSB will offer
the evolving Public Network is the potential for a common carrier
form of video distribution. To realize this potential, the TSB
and it's associated broadband distribution networks must support
addressability and approach virtual VOD capacity. (Ref. 1) For
ITV, the TSB is just an addressable broadcast media receiver
presenting NTSC output network channel interfaces to consumers.
However, should a consumer choose to interact with the ITV programming
offered, as previously described, the PSTN already offers back-channel
or upstream input network channels on a common carrier basis.
As a result, the TSB role has no transmission requirements in
the evolving NII. It is still only a mass media broadcast receiver.
OF MICE AND TV REMOTES
In the centralized ideal PC model for ITV, the
computer delivers the audiovisual output interface to consumers
as video signals over ordinary NTSC distribution networks. To
visualize this, just watch any TV news broadcast where high-resolution
graphics constantly appear over the shoulders of newscasters.
What distinguishes ITV from passive TV, however, will be the
opportunity for the consumer to interact with such computer
generated images. Such TV graphics, when generated by an ITV
program, will present the output interface to the consumer.
The central issue for engineers then becomes the input interface
for ITV networks. What is the consumer's point & click remote
signalling unit? Will it be a mouse, a cable TV remote, or something
else? Will the consumer's remote unit require a special data
network device to transmit signalling? In the telecomputer model
championed in this paper, initially, the consumer's point &
click remote signalling unit will be the touchtone phone. Unlike
computer mice and cable TV remotes, the telephone already has
an ubiquitous upstream signalling network in place. This means
the Public Network does not have to bear the economic burden
of upgrading the cable networks for two-way capability in order
to create this new interactive mass medium. The telephone is
also the only potential ITV input device with the inherent capability
to send voice input and commands to centralized computers without
the aid of data network devices. We just need to look at the
telephone's DTMF keypad in a different way. It was, after all,
created to permit caller access to computers.
Point & Click. If any concept can be credited with opening
the world of computers to the masses, it has to be "point
& click" and the intuitive graphical user interface.
Move a pointer on the screen to the desired selection and press
a button. In entertainment software, press certain buttons to
move animated characters to the right or left and others to
trigger actions. Whether one is accessing a kid's game, PC,
workstation, or supercomputers, it doesn't get any simpler than
that. A set of buttons to control directional movement and a
set to trigger actions. Certainly the twelve buttons of the
touchtone phone can do that. We just need to define the DTMF
signalling protocol.
"DTMF-TV", A NEW TELECOMPUTER MODEL
We must evaluate any new mass medium from the
perspective of the consumer. For an interactive one, network
engineers must focus on what buttons those consumers are being
asked to push, how those buttons connect to and signal the network,
and at what costs. Past attempts to create an interactive mass
medium have always run smack into the same "chicken or
the egg" problem. No mass audience, no compelling programming.
No compelling programming, no reason for the mass market to
purchase the necessary hardware and software required to interact
with the computer programming. The "DTMF-TV" telecomputer
model solves this classic dilemma. The mass market of today's
TV audiences does not need any new hardware or software to access
compelling interactive TV programming, just their existing TVs
and touchtone telephones. To create the DTMF-TV telecomputer
model, explode the ideal PC model to centralize the computer
and divide it's I/O channels into separate user interface networks.
For presenting an output interface to the consumer, convert
the computer's RGB signals to the NTSC standard so it can then
be delivered to the masses over any existing video network.
The video network may be a free over-the-air broadcast, premium,
or a pay-per-view (PPV) channel available only to cable subscribers.
With NTSC video as the ITV output standard, it does not matter
what type of video channel as long as the programming is delivered
in realtime. What will matter, since this GUI may be presented
to the regular and passive viewing TV audience, is that the
multimedia programming be compelling enough to create a desire
in the consumer to interact with it. Content is indeed, king.
Assuming that the ITV programming is compelling, the output
interface should indicate to the viewing audience that they
can interact with the program by calling the displayed telephone
number. By calling this number, the user will then be connected
to the DTMF protocol converter sending input and control signals
to the ITV program's computer. (Refer to Figure 2) This may
be an 800, 900, long distance or local number. For most ITV
programs it will likely be a local number since most telcos
do not charge for incoming calls. The audiovisual output interface,
possibly including voice prompts, should also inform the audience
of potential users that the input interface will be their telephone
keypad.
Central to the DTMF-TV telecomputer model is the DTMF protocol
that will represent the user's ITV input interface to the computer.
It is important that this interface be as intuitive to the user
as GUIs strive to be on the output side. In developing this
patented approach to interactive TV (Ref. 2), an analysis of
various point & click devices yielded their common characteristics.
Whether a mouse, joystick, trackball, or game controller; they
all use a dual element set (DES) protocol. Signals are divided
into a set for directional movement and a set for triggering
actions. Considering the computer mouse as the simplest and
most intuitive, it controls the directional movement of a pointer
on the x, y, and diagonal axes and provides for triggering.
Most mice include two, and some include three, buttons for triggering
program actions. Applied to the standard 3 column by 4 row telephone
keypad, the bottom row or "*", "0", and
"#" keys appear to be the most appropriate keys to
mimic the trigger buttons of most computer mice and game controllers.
This leaves the top three rows where the outer ring of eight
keys surrounding the "5" key as the intuitive choice
for directional movement. This is easy to visualize. Looking
at your telephone keypad, the ITV user will press "4"
to move the pointer to the left, "6" to move it to
the right, "2" for up, "8" for down, and
so on. If presented consistently, it should not be difficult
for the public to learn these basics of the DTMF-TV telecomputer
input protocol. Standardized as the PhoneMouse(tm) ITV interface,
the telephone keypad is capable of more complex actions by assigning
special roles to particular keys. By assigning the "5",
"0" and "#" keys to the role of "cyclers",
this ITV interface adds even greater telecomputer functionality.
For example, as the virtual "ALT" button, pressing
the "5" key can instruct the ITV program to cycle
through a list of alternative user control, computer, and network
options. The user's remotely signalled selections from these
alternatives may be represented on the screen as different pointer
icons. Similarly, pressing the "#" and "0"
buttons can remotely signal the ITV computer program to cycle
through the ITV program's menu of main functions and sub functions,
respectively. Other buttons will also have specific roles as
PhoneMouse-based ITV programming develops. The bottom line is,
when viewed in a new and unconventional way, using the telephone
will be the fastest and most economical approach to interactive
television.
CONCLUSIONS
The DTMF-TV telecomputer model offers the most
economical approach to interactive TV. The DTMF-TV telecomputer
model offers an approach that can provide for the most Public
Network competition between ITV programmers; be they RBOCs,
IXCs, MSOs, Broadcasters or other Electronic Publishers. The
DTMF-TV telecomputer model is the only one that can provide
the NII with equitable and affordable universal access to our
evolving interactive multi-Media Information Superhighway. REFERENCES
(1) - THE AWAKENING 2.0 (C) 1991 : The Comments of GNOSTECH
Incorporated to the FCC's Proposed Rulemaking on Video Dialtone
(Common Carrier Docket 87-266) (2) - United States Patent No.
5,236,199 : INTERACTIVE MEDIA SYSTEM AND TELECOMPUTING METHOD
USING TELEPHONE KEYPAD SIGNALLING