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Claims  |
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What is claimed is:
1. A digital information storage, retrieval and display system comprising:
a central computer means in which plural blocks of information are stored
at respectively corresponding locations, each of which locations is
designated by a predetermined address therein by means of which a block
can be selected, each of said blocks comprising a first portion containing
information for display and a second portion containing information not
for display but including the complete address for each of plural other
blocks of information;
plural remote terminal means, each including (a) modem means for effecting
input/output digital data communication with said central computer means
via the telephone lines of a telephone network, (b) local memory for
locally storing digital data representing at least the first portion of
the selected block of information received via said modem means from the
central computer, (c) display means for visually displaying such a locally
stored first portion of a block of information and (d) key pad means
connected to communicate data to at least said modem means for manual
entry of keyed digital data; and
further memory means being provided as a part of said central computer
means for receiving and storing said second portion of the block of
information selected by a particular terminal means in response to the
selection of the block and when its respective first portion is
transmitted to that terminal means for display, said central computer
means utilizing keyed digital data from that particular terminal means of
less extent than any one of said complete addresses for another block of
information but nevertheless uniquely indicative of one of the complete
addresses contained in said portion of the block of information which
contains the first portion then being displayed by that particular
terminal means for selectively accessing the part of said further memory
means associated with that particular terminal means and for supplying the
complete address of the next block of information which is to be retrieved
for that particular terminal means and utilized for display purposes at
that terminal means.
2. A system as in claim 1 wherein the second part of a block of information
includes a representation of the monetary charge to be made in respect of
supplying such information for display from the central computer means
which also includes means for accumulating charges derived from the second
parts of such supplied blocks and for associating the charges with the
terminal apparatus to which the first parts of such blocks were
transmitted.
3. A digital information storage, retrieval and display system comprising:
a central computer means in which plural blocks of information are stored
at respectively corresponding locations each of which locations is
designated by a predetermined address therein by means of which a block
can be selected, each of said blocks comprising a first portion containing
information for display and a second portion containing information not
for display but including the complete address for each of plural other
blocks of information;
plural remote terminal means, each including (a) modem means for effecting
input/output digital data communication with said central computer means
via the telephone lines of a telephone network, (b) local memory means for
locally storing digital data representing at least the first portion of
the selected block of information received via said modem means from the
central computer and for processing digital data, (c) display means for
visually displaying such a locally stored first portion of a block of
information and (d) keypad means connected to communicate data to at least
said local memory means for manual entry of keyed digital data; and
further memory means being provided as a part of said local memory means at
each of said remote terminal means for receiving and storing said second
portion of the selected block of information in response to the selection
of the block and when its respective first portion is transmitted thereto,
said local memory means utilizing keyed digital data of less extent than
any one of said complete addresses for another block of information but
nevertheless uniquely indicative of one of the complete addresses
contained in said second portion of the block of information which
contains the first portion then being displayed for selectively accessing
said further memory means and for supplying data to be transmitted by said
modem means and indicative of the complete address of the next block of
information which is to be retrieved and utilized for display purposes.
4. A system as in claim 3 wherein the second part of a block of information
includes a representation of the monetary charge to be made in respect of
supplying such information for display from the central computer means
which also includes means for accumulating charges derived from the second
parts of such supplied blocks and for associating the charges with the
terminal apparatus to which the first parts of such blocks were
transmitted.
5. A terminal apparatus for use in a digital information storage, retrieval
and display system having a central computer and a plurality of remote
terminal apparatuses providing access via telephone lines to information
stored in the central computer as plural blocks of information, each said
block of information being stored at a respectively corresponding location
designated by a predetermined unique address by means of which single
address that complete block of information can be selected, each of said
blocks comprising a first portion containing information for display at a
remote terminal apparatus and a second portion containing information not
for display but including the complete address for each of plural other
stored blocks of information, said terminal apparatus comprising:
(a) modem means for effecting input/output digital data communications with
said central computer via the telephone lines of a telephone network,
(b) local memory means linked to said modem means for locally storing
digital data representing at least the first portion of the selected block
of information received via said modem means from the central computer,
(c) display means coupled to said local memory means for visually
displaying such a locally stored first portion of a block of information,
(d) keypad means coupled to at least one of said modem means and said local
memory means for manual entry of keyed digital data,
(e) further memory means for receiving and storing said second portion of a
selected block of information when its respective first portion is
transmitted for display to the terminal means, and
(f) means coupled to said further memory means and to said keypad means for
addressing such second portion stored in said further memory means using
keypad digital data of less extent than any one of said complete addresses
for another block of information to address a portion of the further
memory means and cause a read-out portion of the further memory means to
supply the complete address of the next block of information which is to
be retrieved and utilized for display purposes, the thus obtained complete
address being transmissible via the modem means to said central computer.
6. A terminal apparatus as in claim 5 including means responsive to
information stored in the further memory means for modifying signals
derived from the keypad means to produce the signals to be transmitted by
the modem to a telephone line.
7. A terminal apparatus as in claim 5 including logic means responsive to
data entered through the keypad means and the second portion then stored
in the further memory means, the logic means having an output connected to
the local memory means which logic and local memory means jointly cause
the generation of a display dependent (a) on the data entered through the
keypad means and (b) on the second portion then stored in the further
memory means. |
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Claims  |
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Description  |
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BRIEF SUMMARY OF THE INVENTION
This invention relates to an information handling system in which
information is derived from a computer at a remote point and transmitted
via the public telephone network to terminal apparatus. The invention also
includes the terminal apparatus itself.
It has been proposed to provide for domestic and/or business consumers a
simplified form of computer terminal by means of which information stored
in a computer can be obtained from it via the public telephone network.
The form of the terminal is different from a conventional computer
terminal, both in the simplicity of its operation and in the form of its
display. The display is of the form of a page of data and is reproduced on
a cathode-ray tube screen which may be part of a domestic television
receiver or may be a special purpose apparatus for this function. Instead
of a cathode-ray tube screen, a special purpose alphanumeric display may
be used. Initially the data is displayed on the screen in the form of a
sequence of progressively more detailed indices by means of which an
operator is enabled to key-in to a key pad provided for the terminal
numbers identifying a particular page of information which he requires.
Since the system is to be operated by unskilled operators it is important
that the key required be of self-evident nature and inevitably this will
restrict the nature of facilities which the computer can provide. One such
system is known by the name VIEWDATA, and in which the information
provided by the computer is identified by a page number and when this page
is keyed the whole of the data contained in that page is transmitted in
coded form to the terminal where it is stored and displayed continnously,
until the next page is received or the terminal switched off.
Difficulties arise in such a system, however, because of the need to ensure
the simplicity of operation of the terminal, bearing in mind the
likelihood that the significance of particular keying inputs may need to
be varied in dependence on the data being displayed.
It is an object of the present invention to alleviate the above difficulty.
According to one aspect of the present invention there is provided an
information handling system in which information is transmitted to a
terminal apparatus from a computer via a telephone line, the information
being transmitted to the terminal apparatus in packets, each of which is
displayed by the terminal apparatus as a page consisting of a plurality of
parallel lines of alphanumeric characters and/or graphical data, the
terminal apparatus including means for transmitting signals to the
computer via the telephone line indicating which packet or packets of
information are to be transmitted by the computer, wherein information is
stored by the computer in blocks each of which contains a first part
consisting of the packet of information in the form of coded groups of
digits representing the characters or graphical data forming the page to
be displayed and a second part containing in coded form details relating
to the page of information which are not displayed, means being provided
for storing the second part of a block when the first part is transmitted
to the terminal apparatus.
The details relating to the page of information may be retained in the
computer, for example, in a special register provided for the purpose, so
that inputs from the terminal apparatus can be used to select items from
among the details as information or instruction data for the computer. If
the system forms part of a public telephone network, it is necessary to
provide a way of charging a subscriber's account for the block or blocks
of information transmitted to his terminal equipment. It is envisaged that
certain information may be provided at very low cost or possibly free,
whereas other information such as, for example, latest stock market prices
may be relatively expensive. In such a system the second part of a block
may include an indication of the charging rate for information supplied in
the first part, so that the computer and/or the terminal can be arranged
to record the cost of the information extracted to be charged against the
subscriber's account.
The second part of a block may include software, that is programming
information, for simplifying entries to be made by an operator on the
basis of the information displayed to him by the terminal apparatus. For
example, the page of information displayed may be an index or part of an
index, and to simplify keying each item of the index displayed may be
indicated by a single digit. When the digit against a desired item is
keyed it may be used to select full addressing information from the second
part of the block, which full information is transmitted to the computer
to enable the selection of the desired item. The second parts of the
blocks of information may alternatively be transmitted to the terminal
apparatus and stored in a special register there.
According to a second aspect of the invention there is provided a terminal
apparatus for an information handling system in which information is
transmitted from a computer to the terminal apparatus via a telephone
line, the information being transmitted to the terminal apparatus in
blocks each of which is displayable by the terminal apparatus as a page
consisting of a plurality of lines of alphanumeric characters and/or
graphical data, the apparatus including means for receiving blocks of
information signals from a telephone line, storage means for storing a
block of information signals, means for repeatedly reading at least part
of the storage means, means for converting signals repeatedly read from
the storage means into video signals, means for producing a prolonged
visible display in response to the video signals, and means for
transmitting signals to a telephone line indicating to a computer which
block or blocks of information are to be transmitted, wherein the storage
means has a first part for storing coded groups of digits representing
alphanumeric characters or graphical data forming the page of information
to be displayed, and a second part for storing the remainder of the block
of information representing details relating to the page of information to
be displayed.
The terminal apparatus may include data entry means, such as a manual
keyboard, and means responsive to information stored in the second part of
the storage means for modifying signals from the data entry means before
they are applied to the transmitting means. Alternatively or additionally
signals read from the second part of the storage means may be selectively,
in response to the data entry means, transmitted to the telephone line for
addressing other blocks of information stored in the computer.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be fully understood and readily carried
into effect it will now be described with reference to the accompanying
drawings, of which:
FIG. 1 shows in block diagrammatic form one example of a system according
to the invention;
FIG. 2 is a diagram showing a block of information; and
FIG. 3 shows another system according to the invention.
DETAILED DESCRIPTION
The system shown in FIG. 1 has a computer 1 connected by a telephone line 2
to terminal apparatus which forms the remainder of the figure. The line 2
would of course include the telephone exchange equipment normally in a
public telephone system, but this is not shown to avoid complicating the
figure. The terminal apparatus has a changeover switch 3 connected to the
telephone line 2 which enables a telephone apparatus 4 to be connected to
the line 2 when the terminal is not in use. Isolation and protection
circuits 5 connect a modem 6 to the switch 3. Alternatively, the switch 3
and the circuits 5 may be replaced by an acoustic coupler for connecting
the modem 6 to the telephone apparatus 4. The demodulated signals from
modem 6 are applied to a memory A, reference 7, which is controlled by a
memory control unit 8 repeatedly to produce coded output signals which are
applied to a read only memory 9 which operates as a character generator to
provide video signals for a display device 10 shown as including a
cathode-ray tube. The memory control unit 8, the ROM 9 and the display
device 10 are synchronised in their operation by a display control unit
11.
Inputs from an operator to the terminal apparatus are entered by means of a
key pad 12 which is connected to a signal generator 13 producing signals
which after modulation in the modem 6 are transmitted via the isolation
and protection circuits 5 and the switch 3 to the line 2, and through that
line to the computer 1.
FIG. 2 is a diagram illustrating a block or "page" of information such as
would be transmitted from the computer 1 to the terminal. The page
consists of two parts, the first part being displayed information in
response to which the display device 10 is operated, and the second part
is hidden information which is related to the displayed information and
may be used in various ways as described below. The displayed information
consists of 960 bytes, each of eight bits, and may, for example, represent
24 lines each of 40 characters forming an alphanumeric display. The hidden
information consists of 64 bytes, each of eight bits.
In the operation of the system shown, when a block of which is to be
displayed is transmitted by the computer 1 to the terminal and routed to
the memory A. The second part of the selected block is transferred to
special memory B included in the computer 1 and associated with the input
channel of the computer to which the terminal is connected. The memory
control unit 8 repeatedly reads memory A which produces an eight-bit
parallel output which is applied to the ROM 9. Each eight-bit parallel
output from the memory A represents either an alphanumeric character or an
element of a graphical display, using, for example, an ASCII code. The
timing of the reading of information from the memory A is controlled by
the memory control unit 8 and is synchronised with the scanning of the
display device 10 and the operation of the ROM 9 by signals applied to the
unit 8 from the display control unit 11, which times the operation of the
ROM 9 and the scanning of the device 10, so that the information is
displayed by the device 10 in the appropriate page format.
If the information displayed is an index, then it is anticipated that the
operator will operate one of the keys of pad 12 to indicate which item of
the displayed index he wishes to receive. The complete reference (i.e.
address) of the index items could be displayed on the screen and the
operator could be required to press a number of keys on the pad 12 to
select a particular item. However, it would be simpler for the operator if
the items of the index displayed were simply numbered, say, from 1 to 9 so
that all the operator had to do was to press a single key on the pad 12 to
select a particular item. This could be achieved by applying a signal from
the pad 12 to the computer 1 for selecting an address in the memory B, for
transfer of the full address of the particular item selected to circuit 21
of the computer. Any calculation or logical operations required could
either be performed by the computer itself or in a special logic unit
provided for the purpose.
It will be appreciated that the second part of each block could have other
uses, both for influencing the nature of the display produced and to
reduce the complexity of keying required to communicate with the computer
1. For example, the display could be of a game to be played by the
operator and the reaction of the computer 1 to any particular key input
would depend on the data displayed to the operator which represents the
current state of the game. Information could be stored in the memory B to
interpret the keying on the basis of the displayed information to feed a
corresponding signal to the computer to enable it to respond to the
operator's "move".
An alternative to the embodiment described above is shown in FIG. 3 in
which the memory B together with associated address and input and output
circuitry is located in the terminal instead of in the computer. This
means that the second parts of the blocks of information must be
transmitted to the terminals when selected, and that the terminal must
have means for selecting signals from the memory B for transmission to the
computer when information stored in the memory B is to be employed. This
alternative embodiment would have an advantage if the displayed
information were in the form of questions, for example, of an educational
programme, because the answers could be stored in the memory B and they
could be compared with answers provided by the user and entered through
the keyboard without the need for further communication with the computer
1.
In FIG. 3 components corresponding to those of FIG. 1 have the same
reference numerals as in that figure. In FIG. 3, the terminal includes
memory B 14 which is connected to receive memory control signals from the
memory control unit 8 through a line 15, and produces output signals which
are applied to memory B LOGIC unit 16 to which signals from the key pad 12
are also applied. Lines 17 and 18 convey output signals from the logic
unit 16 to the memory A 7 and the signal generator 13 respectively.
Information to be stored in the memory B 14 is applied to it from the
modem 6 via a line 19. Output signals from the key pad 12 are also applied
to the memory control unit 8 along a line 20.
Insofar as the operation of FIG. 3 is the same as that of FIG. 1 it will
not be further described. When a block of information is received from the
computer 1, the first part is stored in memory A 7 and the second part in
memory B 14 under the control of memory control unit 8. If the information
stored in the memory B is used to augment or modify address data from the
key pad 12, the pressing of a key of the pad 12 at this time causes the
unit 8 to select the appropriate information from the memory B 8 and apply
it to the logic unit 16 where it is combined with the data from the key
pad and the full address transmitted via line 18, the signal generator 13,
and the modem 6 to the computer 1.
Where an entry on the key pad 12 is in answer to a question, the entry is
compared with the correct answer from the memory B in the logic unit 16
and the appropriate response applied via the line 17 to the memory A for
display.
Although the invention has been described with reference to a specific
embodiment it will be appreciated that modifications can be made to the
system described without departing from the invention. In particular, the
numbers of digits making up each part of a block of information may differ
from those described. The memory B may be duplicated, with one memory B
located in the computer 1 and the other in the terminal.
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Description  |
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