GB2078465A

GB2078465A - Data retrieval apparatus

Info

Publication number: GB2078465A
Application number: GB8116172A
Authority: GB
Original assignee: General Electric Co PLC
Current assignee: General Electric Co PLC
Priority date: 1980-06-13
Filing date: 1981-05-27
Publication date: 1982-01-06
Also published as: GB2078465B

Abstract

A data terminal is used to collect information field on respective pages of a number of remotely located data banks each accessible through the public telephone network. The terminal is arranged to set up a call through the telephone network to a first data bank, the number of which is hold in an internal store of the terminal. The terminal receives from the first data bank data comprising a list of the respective telephone numbers of each data bank from which the user may receive the information. The terminal is then arranged to set up respective calls to each of the data banks the telephone numbers of which have been received and to receive from each one any data to be recorded at the terminal. <IMAGE>

Description

SPECIFICATION Data retrieval apparatus The present invention relates to data retrieval apparatus and is more particularly concerned with such apparatus of the kind in which the information to be retrieved is signalled from a remote location in response to a request for that information being signalled by the apparatus to the remote location.

Apparatus for use at a terminal station of a view-data system, for example the PRESTEL system operated by the British Post Office, is display apparatus of the kind specified and the invention is more particularly, but not exclusively, concerned with terminal apparatus for such a system.

Several computer based systems such as the PRESTEL system which may be accessed via the public telephone network are now in service. Several of these systems include a data storage facility known as a "response frame".

Information providers, that is those who provide data pages to the computer system for access either by authorised persons or for general access, require feed-back information from those who access their data pages. For example a manufacturer may have an information page briefly describing his products and prices and inviting the information user to request a brochure or a call by a representative. If the information user requires a brochure he may operate one or more of a number of manually operable keys at his data terminal and the system will store user's name and address in the information provider's response frame.

An information provider, such as the manufacturer above, may be an information provider on several computer systems. Thus each system including a response frame must be accessed periodically by the information provider and the information contained in the response frames retrieved.

If the information provider is a manufacturer then the response frames could be retrieved from the computer systems in each area by a sales representative.

Retrieving the information from the response frames of several computer systems is a time consuming business. Each system must be individually dialled-up with the possibility of misdialling or failure through exchange equipment faults or congestion. The page number of the response frame specific to the particular system must then be transmitted and the page accessed regardless of whether there are any messages to be retrieved.

If the information provider wishes to change the systems to be accessed-for example when the information provider commences use of a new computer system or ceases to be an information provider of one of the systems previously subscribed to such a change must be notified to the user responsible for retrieving the response frames.

It is an object of the present invention to provide electronic apparatus of the kind specified in which at least some of the aforementioned disadvantages are substantially overcome.

According to one aspect of the present invention data retrieval apparatus comprises means to record information received over a line from a remote location, signalling means to transmit to line signals characterising a telephone number of a required data bank, and a store to store data relating to a plurality of telephone numbers each of which is the respective telephone number of a respective remotely located data bank accessible from a telephone type network, the signalling means being arranged to transmit in turn each telephone number stored by the store, the apparatus being arranged on completion of signalling of each telephone number to receive signals from the respective remotely located bank, said signals received either indicating that no data is to be received by the apparatus or chracterising information to be recorded by the apparatus, the apparatus being further arranged to provide a record of the information (if any) which is received and on completion of receipt of the signals from the respective data bank to repeat the process in respect of each telephone number held by the data store.

According to a second aspect of the present invention data retrieval apparatus comprises means to record information received over a line from a remote location, signalling means to transmit to line signals characterising telephone numbers, a first store arranged to store data characterising the telephone number of a remote data bank and a second store arranged to store data received over a line from the first remote data bank, said received data characterising the respective telephone numbers of a plurality of remote data banks, the apparatus being arranged to cause the signalling means to transmit to line the telephone number stored by said first data store, to receive from the first data bank the signals characterising the respective telephone numbers of the remote data banks, to store said telephone numbers in said second store and on completion of receipt of said signals to initiate transmission to line of signals characterising the first telephone number stored in the second data store, the apparatus being further arranged on completion of sending said telephone number to receive signals from the respective data bank, said received signals either indicating that no data is to be received by the apparatus or characterising information to be recorded by the apparatus, the apparatus also being arranged to provide a record of the information (if any) which is received over the line and on completion of receipt of signals from the respective remote data bank to repeat the process in each telephone number held by said second store.

Preferably the means to record information received over the line is a printer which may include fast storage means arranged to store the signals received from the remote data bank at a first baud rate to enable the apparatus to continue signalling the next telephone number to line whilst hard copy is printed at a second slower baud rate.

Apparatus in accordance with either aspect of the present ivention may be arranged to identify calls to stored telephone numbers which have not been responded to by the remote data bank and to make a further attempt to call the or each of such telephone numbers on compeletion of calling each of the stored telephone numbers.

The apparatus may also be arranged to make a predetermined number of attempts to call the or each failed telephone number and if none of the predetermined number of attempts receives a correct response to provide a record of the or each failed telephone number.

Sending of the first telephone number held in the store may be initiated by means of a manually operable key or the apparatus may be arranged to complete its cycle of operation at periodic intervals.

Apparatus in accordance with the present invention will now be described with reference to the accompanying drawings of which Figure 1 is a block schematic diagram of the apparatus, Figure 2 shows how Figs 3, 4, 5 and 6 should be fitted together, Figures 3, 4, 5 and 6, when connected together as shown in Fig. 2, show a flow chart for the programme of the apparatus of Fig. 1, Figure 7 shows a part of the flow chart of Figs 3, 4, 5 and 6 in greater detail, Figure 8 shows how Figs. 9 10 and 1 1 should be fitted together; and Figures 9, 10 and ii, when connected together as shown in Fig. 8, show another part of the flow chart of Figs 3, 4, 5 and 6 in greater detail.

Referring to Fig. 1 the apparatus comprises a visual display unit 1 arranged to display information received over a telephone line 2 under control of a microprocessor 3 which has an associated programme store 8 and an associated data store 9. The microprocessor 3 also accesses a local printer store 4 which is connected to a printer 5 by way of an interface 6.

To permit a user of the apparatus to initiate particular functions or to enter parameters into the data store a keyboard 7 is provided.

It will be appreciated that the apparatus may be of the kind described in our copending United Kingdom Patent application number 7942912 with the programme store being a plug-in read only memory unit.

The operation of the apparatus of Fig. 1 will now be described with reference to the accompanying flow charts. In order that the operation may be more readily understood reference numerals in brackets, thus (101) indicate the point in the programme flow chart which has been reached at each described step.

When a user of the apparatus wishes to accept information from response frames of computer systems to which he has access he operates a manually operable key of the key- board 7.

The microprocessor 3 detects the operation of the key and seizes the line 2 to a public telephone exchange (not shown). Under control of the programme held in the programme memory 8 the microprocessor 3 causes loop disconnect signals to be sent (109) to the line 2 characterising the telephone number of a remote data bank (not shown) which number may be permanently programmed (103) in the programme store or may be held in the data store 9. If the number is held in the data store 9, it may be changed as required by operation of keys of the keyboard 7.

On completion of sending the telephone number the microprocessor 3 awaits receipt of a carrier signal from the remote data bank before transmitting the identity of the terminal which is permanently stored in the terminal.

When the identity of the terminal is received by the remote data bank, the data bank responds by sending its own opening announcement (111) and awaits a page request from the terminal.

The microprocessor 3 transmits a page number to the remote data bank which identifies a data page holding a list of telephone numbers and, if required, a respective page number associated with each of the telephone numbers in the list.

The remote data bank transmits the data page requested to the terminal apparatus which stores the list in a telephone number store 10. (113-119).

The microprocessor 3 now causes the line 2 to be released.

It will be appreciated that if the carrier signal is not received within a predetermined period, say twenty seconds, of completion of dialling the microprocessor 3 causes the line 2 to be released and makes a further attempt to establish a connection to the remote data bank.

Should the apparatus fail to obtain connection to the remote data bank within a predetermined number of attempts (106), say four, it is arranged to cause an appropriate message (108) to be printed (132) on the printer 5.

Having received and stored the list of tele phone numbers and page numbers from the remote data bank (120) the microprocessor 3 causes the line 2 to be seized again. Signals characterising the first telephone number held in the telephone number store 10 which is the telephone number of a respective remote data bank are now sent (129) to the telephone exchange (not shown) by way of the line 2.

On receipt of the carrier signal (130) from the respective remote data bank the microprocessor 3 sends the terminal identity, receives the opening announcement from the respective data bank and sends the respective page number (305, 306) to the remote data bank.

The "collect response frames" function 134 is shown in greater detail in Figs. 9, 10 and 11 and is fully described hereinafter.

The remote data bank responds by sending either data indicating no messages received (314, 317, 320), in which case the microprocessor 3 releases the line 2 and proceeds with a call to the next telephone number in the list held in the telephone number store 10, or data representing a message or messages held in the requested page (312, 313, 315).

If data representing a message is received the microprocessor 3 causes this to be stored (324 et seq) at the baud speed at which it is received in the local store 4.

Having stored the message (136) in the local store 4 the microprocessor 3 causes the line 2 to be cleared (138) and then reseized before initiating transmission of signals characterising the second telephone number (1 25) held in the list in the telephone number store 10 which number is the telephone number of a respective remote data bank.

The data held by the local store 4 is printed out in hard copy form by the printer 5 at the baud rate of the printer whilst the apparatus continues setting up of calls.

When a call to a remote data bank has been successfully set up and the required data page has been received the respective telephone number is erased (140) from the telephone number store 10 by the microprocessor 3.

The "delete telephone number" function 140 is shown in detail in Fig. 7.

If such a fixed list is included then the microprocessor 3 must be arranged to introduce a data marker if a call fails rather than to erase successfully called numbers.

Parameters such as the number of repeat attempts made prior to determine call failure may also be altered by means of the keyboard 7.

The local store 4, the programme store 8, the data store 9 and the telephone number store 10 may be included in an internal random-access-memory (RAM) of the microprocessor 3.

It will also be realised that where the list is retrieved from a first remote data bank the numbers held therein may be altered by the information provider without further action being required by those needing access to each of the remote data banks.

In order that the "collect response frames" function 134 may be more readily understood it is necessary to appreciate the layout of data received from a typical data bank. With this understanding, the programme may be modified to accommodate the kind of data received from any data bank.

Therefore, referring to Figs. 9, 10 and 11, when connection to the data bank is achieved and has been acknowledged it is necessary to send to the data bank a "page request" instruction. In the United Kingdom "Prestel" system this instruction is either *930 96 96 or *931 96 96 for collecting respectively received response frames or stored response frames. The request page data may be permanently stored in the data store of the microprocessor 3 and is sent to the data bank one character at a time (305-307).

On receipt of a request page instruction the data bank sends one complete page of data (if any such data is avialable) the last line of which reads "KEY *930 96 96 FOR NEXT PAGE. If no data page is available the data bank is arranged to send a page of spaces with the exception of the last line which reads "NO FURTHER PAGES".

This information when received is stored in a screen memory of the microprocessor 3 and is displayed on the display device 1 which may be a visual display unit or a television set.

The programme scans the last line of data stored in the screen memory after first eliminating any initial space or control character which may have been received (31 0-31 1) to determine whether the last line of the data received commences with the word "KEY" (312, 313) orthe word "NO" (314, 317).

If neither of these responses is received the apparatus is arranged to make further applications to the data bank for a correct response up to a predetermined number of attempts (302). Should all applications be unsuccessful the programme returns to the main programme with an error code (303).

If data has been successfully transferred then it must be transferred from the screen memory to the local store 4 for subsequent printing by the printer 5. The content of the screen memory will be displayed by the display device 1 under control of a cursor and the transfer of data from the screen memory to the local store (4) is best carried out when the cursor is at its home position in the screen memory. The apparatus is arranged to wait for the cursor to return to its home position (319) or for a predetermined period (323) if the cursor fails to return to its home position. To guard against accidental corruption of the data held in the screen memory the output interface to the display device (1) is then turned off (324).The instruction line "KEY *930 96 96 FOR NEXT PAGE" is deleted (326) to prevent this being printed by the line printer 5.

To ensure that the printer 5 does not overprint previously displayed data the codes for "Carriage Return" and "Line Feed" (328) are now inserted in the next positions in the local store 4. After a "carriage return" instruction sixteen "nulls" (329) are inserted to ensure that the carriage of the printer 5 is at its home position.

The characters held in the screen memory are now transferred one at a time into the local store (4). As line printers and teletypes are not generally able to reproduce the graphics data which may be sent from the data bank a check is made on all received characters and graphics data received from the data bank is replaced by an asterisk (*) (347) in the local store for subsequent printing. It is here noted that certain characters of the ASCII code in which data is transferred from the data bank have the same meaning in both graphics and alpha-numeric modes. In particular space characters (343) and upper case (capital) alphabet characters (345) are still printed in the graphics mode.

Control characters (change code and the like) are eliminated from the text string (336) and are replaced by a space in the output (346).

When all the characters of a received page have been transferred from the screen memory to the local store 4 the screen output interface is restarted (335) and an instruction is sent to the data bank (337) to indicate that the particular page of data has been transferred and may be erased or overwritten in the data bank. Subsequent pages of data are transferred in similar manner until a "NO FURTHER PAGES" instruction appears in the last line of the screen memory (314, 317) when the apparatus returns to the main programme with a successful transfer acheived code (320).

Claims

1. Data retrieval apparatus comprising means to record information received over a line from a remote location, signalling means to transmit to line signals characterising a telephone number of a required data bank, and a store to store data relating to a plurality of telephone numbers each of which is the respective telephone number of a respective remotely located data bank accessible from a telephone type network, the signalling means being arranged to transmit in turn each telephone number stored by the store, the apparatus being arranged on completion of signalling of each telephone number to receive signals from the respective remotely located data bank, the received signals wither indicating that no data is to be received by the apparatus or characterising information to be recorded by the apparatus, the apparatus also being arranged to provide a record of information received (if any) and on completion of receipt of the signals from the respective remotely located data bank to repeat the ploc- ess in respect of each telephone number held by the data store.

2. Data retrieval apparatus having means to record information received over a line from a remote location, signalling means to transmit to line signals characterising telephone numbers a first store arranged to store data characterising the telephone number of a first.

remote data bank, a second store arranged to store data received over a line from the first remote data bank, said received data charactersing the respective telephone numbers of a plurality of remote data banks, the apparatus being arranged to cause the signalling means to transmit to line the telephone number stored by said first data store, to receive from the first data bank signals characterising the respective telephone numbers of a plurality of remote data banks and to store the telephone numbers received in the second store and, on completion of receipt of signals from the first remote data bank to initiate transmission to line of signals characterising the first telephone number stored in the second store, the apparatus also being arranged on completion of sending said telephone number from the second data store to receive signals from a respective remote data bank, the received signals either indicating that no data is to be received by the apparatus or characterising information to be recorded by the apparatus, the apparatus also being arranged to provide a record of the information (if any) which is received over the line and on completion of receipt of signals from the respective remote data bank to repeat the process for each telephone number held by said second store.

3. Data retrieval apparatus according to Claim 1 or Claim 2 wherein the means to record information received has an associated store to enable signals received over the line to be stored at a first baud rate and to be recorded at a second, slower baud rate.

4. Data retrieval apparatus according to any preceding claim wherein the means to record information is a printer.

5. Data retrieval apparatus according to any preceding claim which is also arranged to identify telephone numbers which have not been responded to by the respective remote data bank and on completion of calling each telephone number to which a call is to be made is arranged to make a further attempt to call the or each such telephone number.

6. Data retrieval apparatus according to Claim 5 wherein the apparatus is arranged, after making a predetermined number of attempts to call the or each telephone number without receiving a correct response, to record the or each such telephone number on the recording means.

7. Data retrieval apparatus according to any preceding claim wherein sending of the first telephone number is initiated by a user of the apparatus by means of a manually operable key.

8. Data retrieval apparatus according to any one of Claims 1 to 6 wherein a call to the first telephone number is initiated by the apparatus at periodic intervals.

9. Data retrieval apparatus substantially as hereinbefore described with reference to the accompanying drawings.