GB2381993A - Central computer and remote terminal - Google Patents
Central computer and remote terminal Download PDFInfo
- Publication number
- GB2381993A GB2381993A GB0126834A GB0126834A GB2381993A GB 2381993 A GB2381993 A GB 2381993A GB 0126834 A GB0126834 A GB 0126834A GB 0126834 A GB0126834 A GB 0126834A GB 2381993 A GB2381993 A GB 2381993A
- Authority
- GB
- United Kingdom
- Prior art keywords
- central computer
- modem
- terminal
- call
- service provider
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/2854—Wide area networks, e.g. public data networks
- H04L12/2856—Access arrangements, e.g. Internet access
- H04L12/2869—Operational details of access network equipments
- H04L12/287—Remote access server, e.g. BRAS
- H04L12/2872—Termination of subscriber connections
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Telephonic Communication Services (AREA)
Abstract
A computer network comprises a central computer (1) and a plurality of remote terminals (5-1 to 5-n) connected to a web site hosted by the central computer (1) via the internet (4). In order to cause a selected terminal (5-1 to 5-n) to connect to the web site, the central computer (1) is arranged to initiate a call to a telephone number of a modem (21) in the terminal (5-1 to 5-n). The modem (21) is arranged, on detection of the calling tone of the incoming call initiated by the central computer (1), to initiate a procedure. This procedure causes an outgoing telephone call to be made to a local internet service provider (6-1 to 6-n) subsequent to termination of the incoming call. On connection to the local internet service provider (6-1 to 6-n) the terminal (5-1 to 5-n) generates and transmits the internet address of the web site on the central computer (1) to connect the terminal (5-1 to 5-n) to the web site.
Description
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Central Computer and Remote Terminal The invention relates to a method of causing a remote terminal to connect to a central computer using the internet. The invention further relates to a computer network comprising a central computer and a plurality of remote terminal connected to a website hosted by the central computer via the internet. The invention still further relates to a terminal for connection for a website hosted by a central computer.
Systems comprising a central computer and a plurality of outstations which are in communication with the central computer by means of the public switched telephone network are well known. Generally the central computer polls the outstations and they respond over a telephone line. This telephone line may be either a private line which is permanently connected between the central computer and each of the outstations or may make use of the public switched telephone network. A problem which occurs in systems of this type is that the cost of telephone calls can be significant, particularly when the outstations are located in a different country from the central station which will entail the use of international telephone calls. In our concurrently filed application, (reference 43022), it is proposed to overcome the problem of the expense of using the public switched telephone network to interconnect the central computer and the remote terminal by using the internet at the connecting data service.
Thus, the central computer is connected via a local internet service provider to the internet and each of the remote terminals are connected via local internet service providers to the internet. In this way, the cost of the calls is limited to the cost of connection between the central computer and a local internet service provider and
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between the remote terminals and their respective local internet service providers. In this way expensive national or international call rates are not incurred.
Such a system is ideally applied to a situation where the remote terminals are merely monitoring devices and do not receive any data from the central computer, since while the central computer is permanently connected to the internet and can receive data from the remote terminals at any time, the remote terminals are only connected to the internet when they wish to send data back to the central computer. Such connection can occur at fixed intervals or when specific events which are monitored occur. This means that the remote outstation will have an indeterminate before communication is established between it and the central computer and thus the central computer is unable to update control data within the remote terminal immediately it has the need to do so but has to wait for this indeterminate time before it is possible to send new commands to the remote terminal.
The invention provides a method of causing a remote terminal to connect to a central computer using the internet comprising the steps of; providing the terminal with a modem connected to a telephone network, causing, under the control of the central computer, the number of the modem to be called, causing the modem on detection of ringing tone to dial the number of a local internet service provider, and causing the modem to input the internet address of the central computer once connection to the local internet service provider has been established.
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By using this method the central computer can cause the telephone number of the remote terminal to be called in order to provoke the remote terminal into connecting to the internet to enable the transfer of data in either direction via the network. The central computer merely has to initiate a short telephone call to the modem, which can be done at low cost even if an international connection is required. The connection only has to last for a sufficiently long time to enable the terminal to detect that the central computer has initiated a call, as this amounts to a wake up call to the remote terminal that instructs it to connect to the central computer via the local internet service provider and the internet.
The remote terminal may be arranged to answer and terminate the call before dialling the local internet service provider. This may be necessary in some jurisdictions where the public switched telephone network operator has rules which prevent instructions being passed via the telephone network without a connection being established. This is because the telephone network operator will not receive any revenue unless the call is actually established. The call can, however, still be made at minimal cost since the connection only needs to be made for a short period before being terminated.
The invention further provides a computer network comprising a central computer and a plurality of remote terminals connected to a website hosted by the central computer via the internet, wherein in order to cause a selected terminal to connect to the website, the central computer is arranged to initiate a call a telephone number of a modem in the terminal, the modem is arranged on detection of the calling tone of the incoming call initiated by the central computer to initiate a procedure
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to cause an outgoing telephone call to be made to a local internet service provider subsequent to the termination of the incoming call, and on connection to the local internet service provider, to generate and transmit the internet address of the website on the central computer to connect the terminal to the website.
The control computer may include dialling means for dialling the telephone number of the modem in the terminal. Alternatively, the central computer, in order to initiate a call, may trigger an external device to dial the telephone number of the modem in the terminal.
The invention still further provides a terminal for connection to a website hosted by a central computer, the terminal comprising a modem, the modem including a calling tone detector, means responsive to an output of the calling tone detector for causing the modem to initiate a call to a local internet service provider and for detecting connection thereto, and means for causing the modem to transmit the address of the website hosted by the central computer when connection to the local internet service provider has been established.
The above and other features and advantages of the invention will be apparent from the following description, by way of example, of an embodiment of the invention with reference to the accompanying drawings, in which: Figure 1 shows in block schematic form a computer network according to the invention, Figure 2 shows in block schematic form a remote terminal for use in a computer system as shown in Figure 1, and Figure 3 is a flow diagram illustrating the steps in a
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method according to the invention for causing a remote terminal to connect to the central computer.
The computer network shown in Figure 1 comprises a central computer 1 which is connected to the public switched telephone network 2 using a modem 10. The central computer 1 is also connected to the internet 4. The central computer 1 may instead of being directly connected to the internet 4 be connected via a local internet service provider (ISP) either by means of a direct connection to the ISP or via the public switched telephone network. A plurality of remote terminals 5-1 to 5-n are connected to the public switched telephone network 2 and can communicate with the internet 4 via respective local internet service providers 6-1 to 6-n. In this way connection between the central computer 1 and the remote terminals 5-1 to 5-n is by means of the public switched telephone network to a local internet service provider and thence via the internet 4. It should be noted that the term public switched telephone network encompasses not only the traditional wired network but also cellular and satellite networks over which a public service is offered.
Consequently, call costs are minimised as each of the terminals need only to make local telephone calls to the internet service providers even if the remote terminals and the central computer are located much further apart.
They could even be in different countries. Clearly, if some of the remote terminals 5-1 to 5-n are located in close proximity to each other they may use a common local internet service provider and as a result there may not be as many local internet service providers as there are remote terminals. In addition, if the central computer 1 is connected to the internet 4 via a local ISP it may connect to its local internet service provider 3 via a private line rather than using the public switched
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telephone network since the central computer will be connected to the internet service provider either permanently or for major portions of the day. Under these circumstances a physical or virtual private line may be economical.
As described so far, the network will work satisfactorily provided that the remote terminals know when to connect to the central computer 1. However, it is not possible for the central computer 1 to initiate a communication between itself and the remote terminals since the remote terminals are only connected to the internet for short periods of time, which may be at regular intervals or may also include times when the remote terminal has some data to transmit to the central computer with some urgency. If, however, the central computer wishes to initiate a transmission to one or more of the remote terminals, it can only do so when the remote terminals are connected to the internet. In order to enable the central computer to communicate with any of the remote terminal on demand, the system includes provision for the central computer to initiate a call to the telephone number of the remote terminal. The terminal includes a modem that is arranged to detect that the central computer has called the remote terminal. The central computer 1 may either include an autodialer which is operated whenever the central computer wishes to communicate with a particular terminal or may trigger an external device, possibly another computer, to make the call, which may be made over any suitable network and not only the public switched telephone network.
Figure 2 shows in block schematic form the construction of the remote terminals 5-1 to 5-n. They have an input 20 which is connected to the public switched telephone network 2. The input 20 is connected to a modem 21 which
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in turn is connected to a microprocessor 22. The modem 21 will recognise and react to the standard call tone produced by the telephone network when the central computer 1 initiates a call through the public switched telephone network. When it receives the call tone it will send a signal to the microprocessor 22. This signal will start a routine in the microprocessor 22 that will cause the modem 21 to dial the number of the local internet service provider, after a delay to allow the call from the central computer 1 to clear. Once the connection between the remote terminal 5 and the corresponding local internet service provider 6 has been made, the microprocessor 22 will cause the modem 21 to transmit data via the internet 4 to the address of the website hosted by the central computer. Thus connection will be made via the internet between the remote terminal 5 and the central computer 1.
Once this connection has been made the central computer 1 may send control data over the internet 4 to the remote terminal 5. This data will be processed by the microprocessor 22 and may either be placed in a read write memory 23, for example as updated set points for comparison with inputs received from sensors via an input interface 24. Alternatively or in addition the data may represent control signals for plant to which the remote terminal 5 is connected via an output interface 25.
Clearly if the remote terminal performs a purely monitoring function the output interface 25 may be omitted as it is only required if the central computer 1 is not configured to control any of the functions of equipment where the remote terminal is situated.
The microprocessor routine which causes the modem 21 to dial the number of the local internet service provider may be initiated either by means of an output from the modem
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21 and implemented in software within the microprocessor 22 or may use a hardware call tone detector 26. The hardware call tone detector 26 may produce an output which is fed to the microprocessor 22 to cause the modem 21 to generate the local internet service provider telephone number or may produce an output directly to the modem to cause the modem to generate the local internet service provider telephone number.
Figure 3 is a flow diagram illustrating a method according to the invention for communicating between a central computer and a remote terminal in a system as shown in Figures 1 and 2. The process starts by the central computer 1 initiating a call to the remote terminal 5 over the public switched telephone network 2 using the modem 10 or a similar device controlled directly by the computer 1 as shown in step 31. Alternatively the call may be initiated by a modem or equivalent dialling device connected to a separate computer which is also connected to the internet and which receives commands to initiate dialling from the central computer 1 via the internet as direct data connection or by e-mail messaging. Step 32 illustrates the remote terminal modem 21 detecting the call tone. Step 33 illustrates the modem 21 setting an output to the microprocessor 22 to initiate a call routine. The call routine initiated in step 34 causes the microprocessor 22 to instruct the modem 21 to call a local internet service provider 6. In this step 34 the microprocessor inserts a time delay to enable the call from the central computer to clear before the modem 21 attempts to call the local internet service provider 5.
Once the local internet service provider 5 has been contacted in step 35 the microprocessor 22 instructs the modem 21 to transmit the website address of the website hosted by the central computer 1. It then checks in step
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36 that connection has been established between the remote terminal 5 and the website.
Once connection has been established, the central computer 1, in step 37, transmits control or other data to the remote terminal 5. This control or other data may be stored in the read write memory 23 in the remote terminal 5 or may be passed through the output interface 25 in the remote terminal 5 to plant or machinery which is controlled by the remote terminal 5. When the central computer 1 has transmitted the control data to the remote terminal it then, in step 38, transmits a terminate call instruction to the remote terminal 5 and the remote terminal 5 in step 39 disconnects itself from the local internet service provider 6. The connection may also be established to enable the central computer 1 to receive data from the remote terminal. Accordingly steps 38 and 39 may be delayed to enable the transmission of data from the remote terminal to the central computer.
In a refinement to the method between steps 33 and 34 the microprocessor 22 may insert a step 40 in which it instructs the modem 21 to answer the call from the central computer 1 and then after a preset delay, in step 41, the microprocessor 22 instructs the modem 21 to terminate the call. This refinement may be necessary in some jurisdictions as the local telephone network operator may require that no equipment is connected to its network which does not answer calls. Clearly revenue to the network operator only accrues when calls have been connected and the transmittal of information without actual connection will deprive the local network operator of revenue. As a result, in some jurisdictions, the network operator is entitled to object to equipment being
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attached to the public switched telephone network which does not answer calls which are directed to it.
It is possible for the central computer to initiate a connection with many remote terminals using a single telephone line since the wake up call is short. The many remote terminals can make simultaneous connection with the central computer using a suitable packet switched network such as the internet.
Thus, the present invention enables a remote terminal connected by a telephone to a local internet service provider to be triggered to originate a call on demand from a central computer by using the telephone calling tone as detected from a modem within the remote terminal.
In this way a short telephone call initiated by the central computer to any remote terminal will cause it to connect to a website hosted by the central computer using a local internet service provider and the internet. In this way a comparatively inexpensive solution to the transfer of data between a central computer and remote outstations can be implemented. The transmission of data takes place over the internet and between the remote terminals and local internet service providers with connection to the internet service provider being by means of the internet. Thus, when the central computer and remote terminals are located in different countries, only a short international telephone call is required from the central computer to each remote terminal and the transfer of data utilises connections between the terminal and local internet service providers. As a result the necessity for international calls over the public switched telephone network to transfer data between the central computer and the remote terminals is eliminated. Further the central computer is enabled to initiate data transfer
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between itself and the remote terminals without the remote terminal needing to be permanently connected to the internet.
Various causes may arise for the central computer to wish to communicate with a remote terminal. Some examples are: 1) a predetermined time has elapsed since the remote terminal last originated a call, 2) a change of configuration or output data is detected at the control computer, 3) a manual request is originated by an authorised user is received over the internet by the central computer website via a web browser or e-mail messaging, 4) an electronic request is originated by another internet connected computer.
It will be appreciated that the foregoing is merely a list of examples and is not exhaustive.
Claims (14)
1. A method of causing a remote terminal to connect to a central computer using the internet comprising the steps of; providing the terminal with a modem connected to a telephone network, causing, under the control of the central computer, the number of the modem to be called, causing the modem, on detection of ringing tone, to call the number of a local internet service provider, and causing the modem to input the internet address of the central computer once connection to the local internet service provider has been established.
2. A method as claimed in Claim 1 in which the modem waits for a preset time interval before calling the internet service provider.
3. A method as claimed in Claim 1 or Claim 2 in which the modem is arranged to answer and terminate the call before calling the internet service provider.
4. A method of causing a remote terminal to connect to a central computer substantially as described herein with reference to the accompanying drawings.
5. A computer network comprising a central computer and a plurality of remote terminals connected to a web site hosted by the central computer via the internet wherein, in order to cause a selected terminal to connect to the web site the central computer is arranged to initiate a call to a telephone number of a modem in the terminal, the modem is arranged, on detection of the calling tone of the incoming call initiated by the central
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computer, to initiate a procedure to cause an outgoing telephone call to be made to a local internet service provider subsequent to termination of the incoming call, and on connection to the local internet service provider to generate and transmit the internet address of the web site on the central computer to connect the terminal to the web site.
6. A computer network as claimed in Claim 5 in which the modem is arranged on reception of the calling tone to answer the call, the central computer or the modem is arranged to terminate the call after a preset interval, and the modem is arranged to call the local internet service provider after a preset interval subsequent to termination of the call from the central computer.
7. A computer network as claimed in claim 5 or claim 6 in which the central computer includes dialling means for dialling the telephone number of the modem in the terminal.
8. A computer network as claimed in claim 5 or claim 6 in which the central computer, in order to initiate a call, triggers an external device to dial the telephone number of the modem in the terminal.
9. A computer network substantially as described herein with reference to the accompanying drawings.
10. A terminal for connection to a web site hosted by a central computer, the terminal comprising a modem, the modem including a calling tone detector, means responsive to an output of the calling tone detector for causing the modem to initiate a call to a local internet service provider and for detecting connection thereto, and means
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for causing the modem to transmit the address of a web site on the central computer when connection to the local internet service provider has been established.
11. A terminal as claimed in Claim 10 in which the terminal further comprises means for establishing connection on reception of the calling tone for a preset time interval.
12. A terminal as claimed in Claim 11 in which the terminal further comprises means for terminating the call after a preset time interval.
13. A terminal as claimed in any of Claims 10 to 12 further comprising a delay arrangement for delaying the initiation of the call to the local internet service provider for a preset time interval after termination of the call from the central computer.
14. A terminal for connection to a web site hosted by a central computer, the terminal being substantially as described herein with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0126834A GB2381993A (en) | 2001-11-08 | 2001-11-08 | Central computer and remote terminal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0126834A GB2381993A (en) | 2001-11-08 | 2001-11-08 | Central computer and remote terminal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0126834D0 GB0126834D0 (en) | 2002-01-02 |
| GB2381993A true GB2381993A (en) | 2003-05-14 |
Family
ID=9925396
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0126834A Withdrawn GB2381993A (en) | 2001-11-08 | 2001-11-08 | Central computer and remote terminal |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2381993A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5809118A (en) * | 1996-05-30 | 1998-09-15 | Softell | System and method for triggering actions at a host computer by telephone |
| WO1999022576A2 (en) * | 1997-11-05 | 1999-05-14 | Telia Ab (Publ) | Procedure and arrangement for delivery of e-mail to modem-connected user |
| WO1999035805A1 (en) * | 1998-01-09 | 1999-07-15 | Farzad Mobin | Pseudo dedicated line remote information delivery system |
| EP1089493A2 (en) * | 1999-10-01 | 2001-04-04 | General Electric Company | Internet based remote diagnostic system |
-
2001
- 2001-11-08 GB GB0126834A patent/GB2381993A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5809118A (en) * | 1996-05-30 | 1998-09-15 | Softell | System and method for triggering actions at a host computer by telephone |
| WO1999022576A2 (en) * | 1997-11-05 | 1999-05-14 | Telia Ab (Publ) | Procedure and arrangement for delivery of e-mail to modem-connected user |
| WO1999035805A1 (en) * | 1998-01-09 | 1999-07-15 | Farzad Mobin | Pseudo dedicated line remote information delivery system |
| EP1089493A2 (en) * | 1999-10-01 | 2001-04-04 | General Electric Company | Internet based remote diagnostic system |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0126834D0 (en) | 2002-01-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |