Note: Descriptions are shown in the official language in which they were submitted.
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CARD CALLIN~ TELEPHONE SYSTEM
Background of the Invention
The present invention relates to a card
telephone calling system and, more particularly, to one in
which the calling cards are provided with built-in
information to adapt them to specific functions.
In the typical card telephone calling system,
information is transferred from the card, usually for
control purposes, to the telephone in which the card is
inserted, but there is little information transferred from
the telephone back to the card because there has not been
known a way to do this reliably. This has restricted the
functions for which a card may be used.
The present invention relates to a card calling
telephone system in which information is transferred both
from and to the card.
It would be desirable to use a calling card in
the following ways if each could be readily done. It would
be desirable if the card would permit a call to be made
without the need for any cash transfer at the time but with
a minimum need for extraneous record keeping or follow-up
billing. This can be accomplished if there is provided a
card in which there is built in a certain calling capacity
for which the owner has previously paid, and which capacity
is automatically reduced by an appropriate amount as the
card is used. Moreover, the calling capacity of the card
should be readily reinstatable without the need for
replacing the card.
Additionally, an ideal calling card system ~ould
provide for the rapid-call feature in which -the subscriber
stores in the card a group of telephone numbers frequently
called from which a particular one can be easily selected
for use in making a call automatically. Mor~over, the
subscriber should have the ability to change this
information at will with a minimum of inconvenience.
While the desirability of these functions has
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probably been generally recognized, systems including them
are not presently available. The present invention is
believed to present a novel system which is capable of
such functions involving the bilateral transfer oE
information between the telephone and the card.
the Invention
A card calling system in accordance with the
present invention is characterized by the use of optical
signals both for transferring information from the card to
the telephone for transferring information from the
telephone back to the card, and for powering the card.
In particular, it includes a card which is
provided with photosensitive means adapted to be
illuminated with light from the telephone. Such light is
used both to power the electronics on the card and to
transfer information in the form of optical pulses from the
telephone to the card. Additionally, the card includes
provision for generating appropriate light pulses when
information is to be transferred from the card to the
telephone. Conversely, in such a system, the telephone is
provided with photosensitive means for receiving the
optical pulses generated by the card for transferring
information to the telephone and light source means for
illuminating the card appropriately when information is
being transferred to the card and for powering the card.
The card further includes the necessary
electronics including, for example, a nonvolatile
semiconductor memory in which is stored the information
necessary for the functions expected of it and which can be
programmed by information supplied by optical pulses from
the telephone. Typically, the memory is adapted to store a
list oE numbers frequently called, which list is under the
control of the subscriber by way of the keypad of the
telephone. ~dditionally, in the same or another memory
there can be stored information as to the amount of credit
remaining on the card, which information is adjustable
under control of signals supplied by the telephone.
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In accordance with an aspect of the invention
there is provided a card calling telephone system including
a calllng card and a telephone in which the calling card is
to be inserted for making calls characterized in that the
calling card comprises photovoltaic means adapted to be
illuminated with light from said telephone for powering
the card, photosensitive means adapted to be illuminated
with optical pulses from said telephone for transEerring
signal informa-tion fxom the telephone to the card, optical
means for providing optical pulses for transferring signal
informa-tion from the card to the telephone, and circuit
means powered by the photovoltaic means for processing
signal information from the photosensitive means and
developing signal in:Eormation for the optical means, and
the telephone comprises means for illuminating the photo-
voltaic means with light, means for illuminating the photo-
sensitive means with optical pulses including signal
information, photosensitive means adapted to be illuminated
by the optical pulses Erom the optical means in the card,
and circuit means for processing signal information from
the photosenstive means in the telephone and developing
signal information for transfer by the optical means in
the telephone.
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Brief Descriptio,n of the Drawing
The lnvention will be discussed in ~ore detail in
connection with the accompanyiny drawing in which:
FIGS. 1 and 2 illustrate a card and a telephone,
respectively, in which the various functional elements,
important to the invention, are shown in block diagram
form.
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In FIG. 1, there is shown schematically a credit
card of the kind contemplated for the practice of the
inven-tion. It comprises a fairly rigid thin plastic
sheet 11 on which the various elements would be supported.
Since the card should be of a size convenient for carrying
in a wallet, the sheet would be of corresponding size,
typically about two inches by three inches. Mounted on one
portion of the sheet is the photovoltaic element 12 which
typically comprises several silicon photovoltaic cells
serially connected, so that when illuminated there is
developed a voltage clearly ade~uate to power the circuitry
included on the card. Mounted on another portion of the
sheet is a display 13, advantageously a liquid crystal
display. Its basic function is to provide the optical
pulses used to transfer information from the card to the
telephone. Advantageously, these pulses are binary for
increased reliability. The information transferred can be
of a variety of kinds. One kind can be the number being
called when such number is developed from a list of numbers
stored in a memory on the card. For such applications, it
may be desirable to transmit a plurality of binary digits
in parallel, for example eight, to represent a pair of
numbers, to increase the speed of transfer. For such a
case, the display should include eight discrete elements,
one for each of the eight possible pulses.
The display advantageously also should be
adaptable upon command to display, for the benefit of the
subscriber, in numerical form, the amount of credit still
unused on the card. Such a command would be an appropriate
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keying of the keypad of the telephone or of a keypad on the
card.
Mounted on another portion of the sheet is a
nonvolatile electrically programmable and erasable
semiconductor memory 14 (E2PROM) in which there can be
programmed initially the amount oE credit bought for the
card, which amount can be adjusted by subse~uently erasing
some of the information in accordance with credit used up
in making a call. ~dditionally, there can be provision
for restoring credit when this is desired. The
modification of the inEormation in the memory is
controlled by optical signals supplied by the telephone to
the card. Mounted on another portion of the sheet is
another E2PROM memory 15 in which there is stored a group
of telephone numbers frequently called, with provision for
entering and changing these numbers under control of the
subscriber by appropriately keying the keypad of the
telephone. Of course, memories 14 and 15 can be integrated
into a sin~le memory. Mounted on another portion of the
sheet is a microprocessor chip 16 used for controlling the
various elements described or achieving the functions
desired. Also depicted is a photodiode 17 which is used to
collect the light pulses supplied by the telephone to
provide control information to the card. Alterna-tively
photovoltaic element 12 could be adapted to serve this
role, as discussed hereinafter~ Also distributed on the
sheet, properly located and interconnected, are any other
circuit elements (not shown) needed to effect the desired
control functions and not conveniently included in the
microprocessor chip 16. The interconnecting wiring needed
also has not been shown.
It will, of course, be appreciated that separate
chips may be unnecessary for each o the functional
elements described and that two or more may be incorporated
into a common chip. For example, it should be feasible to
incorporate the microprocessor, memory, and photovoltaic as
separate portions of a sin~le monolithic silicon chip.
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The circui-t elements and wiriny advantageously
are covered by a protective covering, transparent as needed
to permit the passage of the useful light to and from the
photosensitive and display portions.
An important advantage of the system of the
invention is the absence of need for any critical direct
electrical connection between the card and the telephone
Eor the basic functions described. By such absence and by
the use only of optical pulses for communication between
the card and telephone, the reliability of the system can
be greatly increased.
In FIG. 2, there are shown the basic elements
needed in the telephone in which the credit card is
inserted to e-ffect a credit card call in accordance with
the invention. It includes a first light source 21 that
would provlde the illumination on the photovoltaic
element 12 used to power the card. It may also include a
second light source 22 which can be used to supply control
pulses to photodiode 17, or alternatively the photovoltaic
element 12 if that element is used in a dual role. In this
case, the function of light source 22 may be achieved by
appropriately modulating the light source 21, in accordance
with the desired signal information, and recovering such
information by demodulation fro~ the voltage developed by
element 12.
The telephone also lncludes photos~nsitive
means 33 adapted to recover the optical pulses generated
by the display 13 of the card. The photosensitive means
should be adapted to complement the display included on
the card. For example, if for communicating with the
telephone the card is designed to display eight binary
digits simultaneously in parallel, the means 23
advantageously comp~ises an array of eight photodiodes, one
for each of the light positions of the display.
Additionally, the telephone includes the various
control circuits, designated simply by box 24, which would
be used in conjunction with elements 21, 22 and 23, and the
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card to achieve the various functions described.
Since it i5 believed well within the skill of a
worker in the telephone art to design the appropriate
control circuitry, both o~ the telephone and of the card,
and since the specific form oE control circuitry employed
is not a part oE this invention, no specific form is being
shown.
However, the circuits are intended to act in the
following fashion.
To initiate a call, the subscriber would first
insert the card, of the kind described, in a telephone of
the kind described. Typically, such telephones would be
located at airports or other locations where credit card
calling is prevalent and being encouraged~ The subscriber
would then key in an appropriate code on the telephone's
ke~pad. This would actuate the telephone and cause it to
power the card by appropriatel~ illuminating its
photovoltaic source. The telephone would then interrogate
the card by appropriate light pulses supplied to the card's
photodiode and the card would supply information about
itself to the telephone by way of optical pulses generated
by its display. This information typically would include
the amount of credit remaining on the card and, probably
also an identification of the subscriber. Then by
manipulating appropriately the keypad, the subscriber could
either enter the number to be called directly or else
select a number from the list stored in the card's ~emory.
The telephone would then connect the subscriber to the
called party and the call would proceed. The telephone
would be monitoring the cost of the call continuously. I~
the card's credit approached exhaustion, as an optional
feature the telephone might initiate so~e warning signal to
the subscriber. At the completion of the call, the
telephone would calculate the cost of the call~ and
transfer cost information to the card as a series o~
optical pulses which would be recovered by photodiode on
the card. The resulting electrical signal would be
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processed by the microprocessor on the card and the latter
would develop an electrical signal which would be supplied
to the mernory on the card to adjust the amount of credit
remaining on the cardO Thereafter, the card could be
released for removal. Provision can also be made so that,
beEore complete release, the subscriber could, by an
appropriate keypad entry, arrange to have the amount of the
remaining balance shown on the card's display. Various
alternatives are available for handling any charges in
iO excess of the credit on the card.
Various other functions could obviously be
performed by coaction of the card and telephone. For
example, for changing numbers stored in the card's memory,
an appropriate entry into the telephone's keypad could
result in optical pulses to the card to erase numbers
previously stored and to substitute new ones~
