GB2035638A - Improvements in or relating to a computer terminal - Google Patents

Abstract

A control system for a terminal adapted to display information stored in a computer ensures that only certain restricted information is displayed on the terminal. Means are provided in the terminal for monitoring the page numbers of pages of information supplied from the computer to the terminal or requested by the terminal. The monitored page numbers are compared with signals stored in a memory, and as a consequence of this comparison the information is displayed or blocked. Thus only permissible pages of information may be displayed on the terminal. <IMAGE>

Description

SPECIFICATION Improvements in or relating to a display device The present invention relates to a display device and, more particularly, relates to a display device adapted to display information contained within a computer.

At the present time, in this country, the Post Office are proposing to operate a computer in which persons or companies may store information. It is proposed that persons or companies interested in receiving the stored information may obtain computer terminals, and when they wish to extract information from the computer, they may use a conventional telephone dial or similar dialling equipment to dial the number of the computer to establish contact between the computer and the terminal, and may then have access to various "pages" of information stored within the computer. It is envisaged that the computer terminal will be connected to the computer through the normal Post Office telephone lines.

A charge will, of course, be rendered for this service, a portion of the charge comprising the normal telephone charges for the establishment of communication between the computer output terminal and the computer, this charge being dependent upon the distance between the terminal and the computer, and the time of day, and the duration of the connection. However, a further charge will be rendered for each page of information displayed on the terminal. This charge will vary from page to page, some pages of information having a very low charge, and other pages of information having a relatively high charge.

Persons or companies storing information within the computer will, of course, be reimbursed by the Post Office with regard to the number of times pages of information that they have stored within the computer are transmitted for display to the various terminals, the reimbursement depending upon the price charged by the Post Office to the users of the terminals.

It is envisaged that the pages of information stored by a particular person or company within the computer will each be identified by a serial number, and the opening digits of that serial number, for example the first three digits, will be the same for all pages of information stored by apy particular company or persons storing information within the computer.

It is envisaged that there will be many ocassions when a computer terminal is only to be utilised to provide access to certain predetermined pages of information stored within the computer. For example an airline may find it economically attractive to provide appropriate computer terminals in Airport, the terminals being available for free use by members of the public. Members of the public will then be able to connect the terminal with the computer either by operating a dial or by initiating the action of an automatic dialling apparatus by pressing an appropriate button, for example.The airline would store, within the computer, pages of information concerning the time table of the airline and information concerning any delays or the like, the intention being that members of the public would be able to utilise the terminal to obtain the information that they desire concerning the time of arrival or departure of any particular flight. It is to be appreciated, of course, that if such a computer terminal is to be installed it is important that members of the public can only use the terminal to have access to the pages of information stored within the main computer by the airline in question, since otherwise members of the public may utilise the terminal to obtain access to other information contained within the computer, and the charge for a member of the public viewing all these pages of information would have to be carried by the airline.Thus, if such a computer terminal is to be provided it is important that safe-guards are provided to ensure that the computer terminal will only be able to have access to predetermined pages of information.

The present invention seeks to provide an appropriate control system for such a terminal.

According to this invention there is provided a control system for a terminal adapted to display information stored in a computer, said system comprising means for monitoring or generated by the computer identifying information that is about to supply the signals generated to summons information from the computer means for comparing the thus monitored signals with corresponding signals stored in a memory and means, responsive to said comparison, for allowing or preventing the said generated signals from being transmitted to the computer.

Preferably only the opening digits of any number generated by the computer to identify information that is about to supply are monitored, these opening digits being compared with preselected opening digits stored within the memory.

Advantageously the memory stores "allowable" opening digits, and thus if the opening digits generated compare directly with a set of opening digits stored within the memory, the generated signal is allowed to be transmitted to the computer to summons the appropriate information to the terminal. Of course, if the opening digits do not correspond with the predetermined "allowable" opening digits stored within such a memory information is not displayed.

Advantageously means are provided for reading the page number present on each frame of information supplied by the computer, means are provided for comparing the page number thus read with predetermined numbers stored in the memory, and means are provided to prevent the page being displayed if the page number is of a predetermined group of page numbers.

Preferably the memory may contain the page numbers of allowable pages, or at least the opening digits of page numbers of allowable pages. The page number, or opening digits of the page number, of any page supplied to the terminal are read as the corresponding signals are received or while the signals are processed before the page is displayed, and the read number is compared with the numbers stored in the memory and if the page number, or opening digits of the page number, correspond with any entry within the memory the page is permitted to be displayed, whereas if the page number, or opening digits of the page number does not compare with digits stored within the memory the page is not permitted to be displayed.

Again the memory may alternatively contain the page number, or opening digits of the page number, of disallowed pages of information.

Advantageously means may be provided for displaying a message on a screen of the terminal if the page is prevented from being displayed inviting the operator of the device to re-operate the key pad or like device.

In order that the invention may be more readily understood and so that further features thereof may be appreciated the invention will now be described by way of example with reference to the accompanying drawings which is a block diagram of part of an apparatus in accordance with the invention.

When a computer terminal associated with the Post Office computer is utilised, initially a primary index is consulted to provide information concerning the various types of information stored within the computer, and the person using the terminal must punch an appropriate number of digits on a key pad to select which general type of information is to be displayed upon the screen of the terminal. Subsequently a more detailed index appears and by pressing a "star" key and one or more digits a further yet more detailed index of the information required, will appear. In many cases when a page of information appears the person using the apparatus is allowed to select alternative pages of information or more detailed pages of information by again pressing the "star" key and an appropriate number of digits. This method of operation generally is called "treeing".

An alternative method of operation is to punch the entire digit address of a particular page of information that is of interest to the customer.

The initial digits punched during either of the above operations identify the "entry point" or the point at which the initial access is made to the various pages of information stored within the computer. This "entry point" identifies the company or person whose information stored within the computer is to be displayed to the person using the computer terminal.

In the Post Office "View Data" system it is proposed that the number of each page will be shown in the top line of page, and it is proposed, at the present time that the page number will be shown at the left hand side of the line, that is to say the opening characters of the line.

In a display device in accordance with the present invention input signals received from the Post Office computer are initially present on lead 1 which is connected to a micro processor 2. The micro processor is a "6802" and this type of micro process including a portion of working memory. The micro processor 2 is connected by a data bus 3 and by an address bus 4 to a programme store 5, the programme store being a "2716". An extension of data bus 6 and an extension of the address bus 7 connect the micro processor 2 and the programme memory 5 to a page store memory 8, the page store memory comprising two "2114" devices. An output 9 from the micro processor 2 leads to the visual display unit of the display device in accordance with the present invention.

The programme memory 216 contains a programme which effecitvely controls the overall operation of the display device, including the steps of establishing communication with the Post Office computer when a coin is inserted into the apparatus and including the control of the display device so that the display device displays the various symbols represented by the signals provided to the device by the Post Office computer.

However, the programme also includes portions which relate to the reading of the page number and assessing if the page is to be allowed or dis-allowed and which relate to the reading of the price of a page of information and substracting this price from a credit register, the credit register storing information relating to the total credit of any customer utilising the display device at any particular instant in time.

The appropriate portion of the programme that is blown into the programme memory 5 is set out in Table 1.

When a person using the display device calls for a page of information to be displayed signals representative of the page of information are supplied to the micro processor 2 through the input lead 1. The signals are stored in the page store memory 8. Whilst the initial signals are being stored the screen of the display device is blanked. The opening portion of the programme set out in table 1 relates to the checking of the page number of a page that is to be displayed against page numbers stored in a memory. If the page number of the page that has been called for by the person operating the device corresponds with the page number of a dis-allowed page as stored in the memory, then the page is not displayed.However, if the page called for is not a page whose number is stored in the memory and also is not a page that is provied with a "cursor on" signal, that is to say a response frame, then the frame is to be displayed and so it is then necessary to ascertain the price of the page to enable that price to be subtracted from the price stored in the credit register.

Turning to Table lit can be seen that the opening steps of the portion of the programme given in the table relate to the location of a control character which signifies the initiation of a signal representative of a page of information and also relates to the assessing of the arrival of signals representative of the first line of a page of information. This information is stored in a temporary memory and, turning to step zero 223 it can be seen that the address that the page number is assessed, and then in step zero 228 the programme jumps to a sub routine which checks the page number.Once the page number has been checked the page number is compared with the list of dis-allowed pages and if the page is not allowed the programme jumps as at step zero 231 to an abort position in which a frame is displayed on the screen of the visual display unit inviting the operator of the unit to select a fresh page of information to view.

It is to be appreciated that whilst the information relating to the first line of the page to be displayed is being stored in the temporary memory the apparatus is blanked and so no information is present on the screen. Thus, if a dis-allowed page is called for no part of the dis-allowed page will be displayed.

Whilst the invention has been described with reference to an embodiment in which the digits representative of the page number being supplied by the computer to the display terminal are stored in a memory and are compared with digits (or opening sequencies of digits) representative of allowable (or dis-allowable) pages which are stored in a second memory it is to be appreciated that in a modified embodiment of the invention signals generated by the key pad may be monitored, these signals being stored in a temporary memory and being compared with further signals stored in the memory representative of allowable (or dis-allowable) pages. If the signals generated by the key pad are found to be representative of a disallowable page then means may be provided to prevent such signals being transmitted to the computer.

Whilst the apparatus has been described with particular reference to the GPO "View Data", computer system it is to be appreciated that apparatus in accordance with the present invention may be utilised in many different situations. For example, company may store information within its own "in house" computer and various members of the staff of the company may be provided with computer terminals to enable those members of staff of the company to have access to information contained within the computer.

Some pages of information stored within the computer may be confidential to only one department within the company. For example, pages of information containing the personal details of the employees of the company and including details of their salaries, should only be available to the Personnel Department.

Similarly, pages of information relating to the precise financial situation of the company should be available only to the Accounts Department. Various other pages of information should only be available to a restricted number of employees of the company. It will be appreciated that in such a situation a number of terminals in accordance with the present invention may be provided, the "allowable" page numbers shown in the memory or memories associated with each terminal being dependent upon the person who is to operate the terminal. In this way, the precise nature of the pages of information that can be displayed at each terminal are regulated, and in this way a computer can be utilised to store confidential information without fear of that confidential information passing into the wrong hands.

The invention may, of course, find many other applications.

TABLE 1 0187 *Subroutine to output char to screen* 0188 F92081 20 VDU1 CMPA #t20 IS IT A CO NTROL CHAR? 0189 F922 24 11 BHS PRCHAR 0190 F924 CE FC 09 LDX &num;TABLE START OF CONTROL CHAR TABLE 0191 F927A1 00 MATCH CMPA 0,X 0192 F9292722 BEQ FOUND CHAR FOUND 0193 F92B08 INX 0194 F92C08 INX 0195 F92D08 INX TRYNEXTCHAR 0196 F92E8CFC2D CPX #TABEND+3 ENDOFTABLE? 0197 F931 26 F4 BNE MATCH 0198 F933 86 3F LDA A &num;;? 0199 F935DE06 PRCHAR LDX DISPT NOTCONTROLCHAR 0200 F937 6D 00 TST 0,X 0201 F939 9A 04 DRA A FORFLG SET BIT 7 IF IN FOREIGN CHAR TABLE I (CONT) 0202 F93B 94 05 AND A ESCFLG SUPPRESS BIT 6 IF CONTROL CODE 0203 F93D A7 00 STA A 0,X AND STORE IT 0204 F93F 86 FF LDA A ##FF 0205 F941 97 05 STA A ESCFLG RESET ESC FLAG 0206 F943 7F 00 04 CLR FORFLG 0207 F9469607 LDAA DISPT+1 0208 F948 BD FA 56 JSR INCDIS INC DISPLAY POINTER 0209 F94B 20 06 BRA VDU2 0210 F94DEEO1 FOUND LDX 1,X GET ADDR OF SUBROUTINE 0211 F94F 96 07 LDA A DISPT+1 0212 F951 ADOO JSR OX GO THERE 0213 F953DEO6 VDU2 LDX DISPT GETCURSORADDRESS 0214 F955 8C DO 40 CPX #SCNST+940 HAVE WE FINISHED TOP LINE? 0215 F958 27 OE BEQ CHKNO IF SO, GO TO ROUTINE FOR CHECKING PAGE NO AND SUBTRACTING FRAME COST FROM CREDIT 0216 F95A8C DO 67 CPX ##DO67 0217 F95D 26 03 BNE NXSC 0218 F95F7EF9E8 JMP SYNC 0219 F962 8C D5 D4 NXSC CPX &num;POSCN-1 0220 F965 27 7D BEQ CLTFLG 0221 F967 39 RTS 0222 *ROUTINE TO CHECK PAGE NO AND DEBIT CREDIT* 0223 F968 CE DO 19 CHKNO LDX &num;PAGEND GET ADDRESS OF PAGE NO.

ON SCREEN 0224 F96BDF13 STX XTEMP1 PUT IT IN TEMPORARY STORE 0225 F96D CE FD 88 LDX #LIST GET ADDRESS OF LIST OF DISALLOWED TABLE I (CONT) PAGE NOs 0226 F978 DF 17 STX XTENP3 STORE IT 0227 F972 OE CL1 ENABLE INTERRUPTS 0228 F973 BD FD 4A JSR SEARCH JUMP TO SUBROUTINE WHICH CHECKS PAGE NO. AGAIN ST THOSE IN LIST 0229 F976 OF SEl DISABLE INTERRUPTS 0230 F977 24 03 BCC ABNDT ON RETURN FROM SUBROUTINE, CARRY FL AG SE1 MEANS PAGE NO.MRS FOUND IN LIST 0231 F979 7E FA 15 JMP ABORT PAGE NOT ALLOWED 0232 *PAGE WAS NOT FOUND IN LIST, SO GET PRICE INFORMATION 0233 F97C B6 DO 27 ABNDT LDA A two27 0234 F97F 81 70 CMPA ##70 CHECK FOR SMALL P 0275 F981 26 53 BNE VDU4 IF NOT SMALL P, FORGET IT 0236 F983 7D 00 20 TST DEBFLG CHECK IF WE HAVE ALREADY DEDUCTED THIS FRAME COST 0237 F986 26 4E BNE VDU4 IF SO, RETURN 0238 F988 7D 00 22 TST REDFLG CHECK IF REDO KEY HAS BEEN PRESSED 0239 F98B 26 45 BNE VDU42 IF SO, RETURN 0240 IF WE GET TO HERE IT IS O.K. TO CHARGE FOR THIS FRAME* 0241 F98D B6 DO 24 LDA A PRICE GET FIRST CHARACTER OF PRICE FIELD 0242 F99081 20 CMPA #$20 IS IT A SPACE? 0243 F992 27 OC BEQ NODP IF SO, BRANCH TO XXp ROUTINE 0244 *ROUTINE FOR X Xp FORMAT* 0245 F994 97 1E STA A UNIT1 IF NOT, STORE IN TEMP STORE FOR PENCE 0246 F996 B6 DO 26 LDA A PRICE+2 THEN GET CHARACTER FROM TENTHS OF TABLE I (CONT) PENCE POSITION 0247 F999 97 1 D STA A TENTH AND STORE IT 0248 F99B 7F 00 1F CLR TEN 1 AND CLEAR TEMP STORE FOR TENS OF PENCE 0249 F99E 20 00 BRA VDU41 0250 *ROUTINE FOR XXp FORMAT* 0251 F9AOB6DO25 NODP LDAA PRICE +1 GET TENS OF PENCE CHARACTER 0252 F9A3971F STAA TEN1 STORE IT 0253 F9A5 B6 DO 26 LDA A PRICE+2 GET CHARACTER FROM PENCE FIELD 0254 F9A8971E STAA UNIT1 AND STORE IT 0255 F9AA 7F 00 1D CLR TENTH CLEAR TEMP STORE FOR TENTHS OF PENCE 0256 F9AD OC VDU41 CLC 0257 *THIS NEXT SECTION SUBTRACTS THE AMOUNTS IN TEMPORARY STORE AGE FROM THE CREDIT REMAINING* 0258 F9AE 96 19 LDAA TENTH GET TENTHS FROM ACTUAL CREDIT STORE E 0259 F9B0 D6 1D LDA B TENTH GET TENTHS FROM TEMP STORE 0260 F9B2FD7B JSR DECUSB JUMP TO ROUTINE FOR DECIMAL SUBTRACTION 0261 F9B59719 STAA TENTH STORE RESULT IN ACTUAL CREDIT REGISTER 0262 F9B7 96 1A LDA A UNIT 0263 F9B9D6lE LDA B UNIT1 DITTO FOR UNITS 0264 F9BB C9 00 ADO B #O TAKING ACCOUNT OF BORROW 0265 F9BD BD FD 78 JSR DECSUB 0266 F9CO 97 1A STA UNIT 0267 F9C2961B LDA A TEN 0268 F9C4D61F LDA B TEN1 DITTO FOR TENS 0269 F9C6 C9 00 ADC B #O 0270 F9C8 BD FD 7B JSR DECSUB TABLE I (CONT) 0271 F9CB 97 1 B STA A TEN 0272 F9CD 2403 BCC VDU42 0273 F9CF7A00 1C DEC POUND DECREMENTPOUNDS REGISTER IF BORRO GENERATED FROM TENS SUBTRACTION 0274 F902 8601 VDU42 LDA A i 0275 F9D4 9720 STA A DEBFLG SET FLAG TO SHOW WE HAVE DONE THIS FRAME 0276 F906 7F C4 01 VDU4 CLR TEXT REMOVE SCREEN BLANKING 0277 F909 7F 00 22 CLR REDFLG CLEAR FLAG WHICH IS SET WHEN REDO KEY IS PRESSED 0278 F9DCDE06 LDX DISPT

Claims (8)

1. A control system for a terminal adapted to display information stored in a computer, said system comprising means for monitoring or generated by the computer identifying information that it is about to supply the signals generated to summons information from the computer means for comparing the thus monitored signals with corresponding signals stored in a memory and means, responsive to said comparison, for allowing or preventing the said generated signals from being transmitted to the computer.

2. A system according to claim 1 wherein only the opening digits of any number generated by the computer to identify information that is about to supply are monitored, these opening digits being compared with preselected opening digits stored within the memory.

3. A control system according to claim 2 wherein the memory stores "allowable" opening digits, and thus if the opening digits generated compare directly with a set of opening digits stored within thememory, the generated signal is allowed to be transmitted to the computer to summons the appropriate information to the terminal.

4. A system according to any one of the preceding claims wherein means are provided for reading the page number present on each frame of information supplied by the computer, means are provided for comparing the page number thus read with predetermined numbers stored in the memory, and means are provided to prevent the page being displayed if the page number is of a predetermined group of page numbers.

5. A system according to claim 4wherein the memory contains the page numbers of "allowable" pages, or at least the opening digits of page numbers of allowable pages.

6. A system according to any one of the preceding claims wherein means are provided for displaying a message on a screen of the terminal if a page is prevented from being displayed inviting re-operation of the key pad or like device.

7. A control system for a terminal adapted to display information stored in a computer substantially as herein described with reference to the accompanying drawings.

8. Any novel feature or combination of features disclosed herein.