GB2255877A - Communications link carrying interface configuration signal - Google Patents

Communications link carrying interface configuration signal Download PDF

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Publication number
GB2255877A
GB2255877A GB9110715A GB9110715A GB2255877A GB 2255877 A GB2255877 A GB 2255877A GB 9110715 A GB9110715 A GB 9110715A GB 9110715 A GB9110715 A GB 9110715A GB 2255877 A GB2255877 A GB 2255877A
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United Kingdom
Prior art keywords
interface
terminal
modem
interface configuration
configuration signal
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.)
Granted
Application number
GB9110715A
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GB9110715D0 (en
GB2255877B (en
Inventor
Alan Douglas Clark
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DOWTY COMMUNICATIONS Ltd
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DOWTY COMMUNICATIONS Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by DOWTY COMMUNICATIONS Ltd filed Critical DOWTY COMMUNICATIONS Ltd
Priority to GB9110715A priority Critical patent/GB2255877B/en
Publication of GB9110715D0 publication Critical patent/GB9110715D0/en
Publication of GB2255877A publication Critical patent/GB2255877A/en
Application granted granted Critical
Publication of GB2255877B publication Critical patent/GB2255877B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
    • H04M11/06—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/40—Network security protocols

Abstract

A communications link is set up between two terminals (1, 2), e.g. computers, via a pair of data communications devices (3, 4), e.g. modems, by one device (4) responding to a communications request signal by sending to the other device (3) an interface configuration signal corresponding to the configuration of the interface between it (4) and the terminal (2) to which it is connected, and the other device (3) responding to the interface configuration signal from the one device (4) by configuring the interface between it (3) and the terminal (1) to which it is connected so that it is compatible with the interface configuration between the device (4) and the terminal (2) to which it is connected. This removes the need for the user to configure his terminal/device interface himself in communicating with a remote terminal. The communication request signal typically originates with the user at their terminal (1) and either the interface between the remote device (4) and terminal (2) is configured to match the interface between the user's terminal (1) and device (3), or vice versa. The data communications devices may be modems or other devices used for asynchronous communication. The interface configuration signal may comprise data format, flow control information and required terminal type. <IMAGE>

Description

COMMUNICATIONS LINK Technical Field This invention relates to a method and apparatus for setting up a communications link between two terminals via a pair of data communications devices such as modems.
A pair of modems is commonly used for communicating data between computers, for example, between a personal computer and a computer supporting-an information service. Data is commonly transferred in an asynchronous (i.e.
start-stop) format from the computer to the modem, the format for a serial interface typically conforming to the CCITT recommendation V.14.
Also, a flow control scheme is implemented to turn on and off the flow of data between the computer and modem to ensure that data is transferred at a rate compatible with both modems and which does not cause data buffers in the modems to overflow.
In order that the two computers can communicate successfully, it is necessary that the interface between each computer and its corresponding modem should match. Normally this is achieved by the user configuring the interface between his computer and modem to match the configuration of the interface between the remote computer and modem. Thus the user has to know the configuration of the interface between the remote computer and modem before they can configure the interface between their own computer and modem.
This can be confusing for a non-technical user and renders the use of modems unnecessarily complex.
The two modems employ a protocol in communicating with one another, and it is known to arrange for one modem to automatically reconfigure the other modem to ensure that both are compatible in their operation. However, if the configuration of the interface between each computer and its modem are different to one another, only the user can correct this by reconfiguring the interface between their computer and modem.
Disclosure of the Invention An object of the present invention is to provide improved modems with remove the need for the user to configure their own computer/modem interface as a preliminary step to communicating with a remote computer.
According to the invention, a method of setting up a communications link between two terminals via a pair of data communications devices such as modems comprises one device responding to a communications request signal by sending to the other device an interface configuration signal corresponding to the configuration of the interface between it and the terminal to which it is connected, and the other device responding to the interface configuration signal from the one device by configuring the interface between it and the terminal to which it is connected so that it is compatible with the interface configuration between the other device and the terminal to which it is connected.
The communication request signal typically originates with a user at their terminal and either causes the corresponding data communication device (for example, a modem) to send the interface configuration signal to a remote data communication device (for example, another modem) connected to a remote terminal with which the user wishes to communicate, or is transmitted via the user's modem to the remote modem and causes the remote modem to send the interface configuration signal back to the user's modem. Thus, either the interface between the remote modem and terminal is configured to match the interface between the user's terminal and modem, or the interface between the user's terminal and modem is configured to match the interface between the remote modem and terminal.
The data communication device responds to the interface configuration signal by passing a corresponding interface configuration signal to the terminal to which it is connected. The terminal then either directly controls reconfiguration of the device before reconfiguring itself, or simply initiates reconfiguration of the device before it reconfigures itself. In the latter case, the device reconfigures itself using the interface configuration signal it has received.
Apparatus according to the invention comprises a pair of data communications devices, one being adapted to send the interface configuration signal, and the other being adapted to be reconfigured in response to the interface configuration signal. Each device may be unique and different to the other, or both devices may be similar and have the ability to reconfigure the other device or be reconfigured by the other device.
The data communications devices may be modems or any other devices used for asynchronous communications such as X25 PADs, LAN terminal servers and statistical multiplexers.
Description of the Drawings The invention will now be described by way of example with reference to the accompanying drawing of a block diagram of data communications apparatus according to the invention.
Mode of Carrying Out the Invention In the illustrated data communications apparatus, a first data terminal 1 such as a personal computer, is used to access a second data terminal 2 such as a remote computer supporting a database.
The two computers 1, 2 are connected via a communications link comprising a pair of modems 3, 4 and a dial-up telephone connection 5 between them. One modem 3 is connected via ports 6 to the personal computer 1, and the other modem 4 is connected via ports 7 to the remote computer 2.
The remote computer 2 and the corresponding remote modem 4 are each configured in a predetermined manner to transfer data therebetween in an asynchronous format on ports 7. The format used typically conforms to the CCITT recommendation V.14 and comprises a start bit, a predefined number of data bits, a parity bit for error detection, one or more stop bits, and an indication of the data transfer rate. In addition, a flow control scheme is implemented to turn on and off the flow of data between the computer and modem, the scheme used being any one of a number of known schemes such as X on/X off flow control or RTS/CTS flow control or pass through flow control.
If the personal computer 1 is to access the remote computer 2 successfully, then the personal computer 1 and corresponding modem 3 must be configured in a similar manner to the remote computer 2 and modem 4 in order that data is transferred in a compatible manner at both ends of the communications link. That is, the configuration of the interfaces between each computer and modem must be compatible. This has been achieved in known systems by the user of the personal computer 1 configuring the interface with the modem 3 so as to match the configuration of the interface between the remote computer 2 and modem 4. However, the user has to first know the configuration of the remote interface.According to the present invention, this is made unnecessary by arranging that the personal computer 1 and modem 3 are configured automatically to match the configuration of the interface between the remote computer 2 and modem 4 when dialling in to the latter.
This is achieved by holding information of the interface configuration between the remote computer 2 and modem 4 in a store 8 in the modem 4. When the user operates the personal computer 1 and modem 3 to establish a telephone line to the remote modem 4, the remote modem 4 answers the call and sends an answer tone back to the modem 3.
The modems then agree a modulation scheme, for example, by using the automode procedure of CCITT, and an error control protocol, preferably using the ODP/ADP sequence of CCITT recommendation V.42.
The modems then agree the protocol optimir and parameter values needed for correct interworking, preferably using the V.42 LAPM XID procedure. In particular, the remote modem 4 sends back to the modem 3 an interface configuration signal incorporating the information in store 8. On receiving the interface configuration signal, the modem 3 passes the configuration information to the personal computer 1 using a readable string such as CONFIG 7EI, or a concise encoding, or interface lines such as pins of the V.24/RS 232 interface. The personal computer 1 then makes use of this information to reconfigure the interface between it and the modem 2 to match that of the interface configuration between the remote computer 2 and modem 4.The personal computer may directly control configuration of the modem 3 before reconfiguring itself, or alternatively, it may simply initiate reconfiguration of the modem 3 by an appropriate signal before reconfiguring itself. In the latter case, the modem 3 is able to reconfigure itself using the interface configuration signal that it receives.
As well as storing the data format and flow control information in store 8, other information useful in ensuring computer compatibility such as required terminal type, may be stored in store 8.
In an alternative embodiment of the invention, it may be the user 5 modem 3 which incorporates the store 8 to store information of the configuration of the interface between the personal computer 1 and modem 3, and the modem 3 may generate the interface configuration signal which it passes to the remote modem 4 in the process of accessing the remote computer 2. The modem 4 and computer 2 then respond to this signal like the personal computer 1 and modem 3 in the illustrated example, to reconfigure the interface therebetween to match that of the interface configuration between the personal computer 1 and modem 3.

Claims (8)

1. Data communication apparatus comprising a pair of data communication devices adapted to form a communication link between two terminals, one device being adapted to respond to a communication request signal by sending to the other device an interface configuration signal corresponding to the configuration of the interface between it and the terminal to which it is connected, and the other device being adapted to respond to such an interface configuration signal received from the one device by configuring the interface between it and the terminal to which it is connected so that it is compatible with the interface configuration between the other device and the terminal to which it is connected.
2. Apparatus as claimed in claim 1 in which said one device is adapted to respond to a communication request signal from the terminal to which it is connected.
3. Apparatus as claimed in claim 1 in which said one device is adapted to respond to a communication request signal from the other device and sends back to the other device the interface configuration signal.
4. Apparatus as claimed in any one of the preceding claims in which said other device sends a corresponding interface configuration signal to the terminal to which it is connected so that the terminal can configure the interface between it and said other device.
5. Apparatus as claimed in claim 4 in which said other device is adapted to be configured by the terminal to which it is connected.
6. Apparatus as claimed in any one of claims 1 to 4 in which said other device is configured by said interface configuration signal.
7. Data communication apparatus comprising a pair of data communication devices adapted to form a communication link between two terminals, each device being adapted to respond to a communication request signal by sending to the other device an interface configuration signal corresponding to the configuration of the interface between it and the terminal to which it is connected, and being further adapted to respond to such an interface configuration signal received from the other device by configuring the interface between it and the terminal to which it is connected so that it is compatible with the interface configuration between the other device and the terminal to which it is connected.
8. A method of setting up a communications link between two terminals via a pair of data communication devices comprising one device responding to a communication request signal by sending to the other device an interface configuration signal corresponding to the configuration of the interface between it and the terminal to which it is connected, and the other device responding to the interface configuration signal from the one device by configuring the interface between it and the terminal to which it is connected so that it is compatible with the interface configuration between the other device and the terminal to which it is connected.
GB9110715A 1991-05-17 1991-05-17 Communications link Expired - Fee Related GB2255877B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9110715A GB2255877B (en) 1991-05-17 1991-05-17 Communications link

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9110715A GB2255877B (en) 1991-05-17 1991-05-17 Communications link

Publications (3)

Publication Number Publication Date
GB9110715D0 GB9110715D0 (en) 1991-07-10
GB2255877A true GB2255877A (en) 1992-11-18
GB2255877B GB2255877B (en) 1995-07-12

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2289186A (en) * 1994-04-05 1995-11-08 Ibm Collaborative working method and system
US5572674A (en) * 1993-01-07 1996-11-05 Bmc Software, Inc. Method of dynamically adjusting SNA network control program parameters
US5630170A (en) * 1994-10-12 1997-05-13 Kabushiki Kaisha Sega Enterprises System and method for determining peripheral's communication mode over row of pins disposed in a socket connector
US5634074A (en) * 1993-05-07 1997-05-27 Apple Computer, Inc. Serial I/O device identifies itself to a computer through a serial interface during power on reset then it is being configured by the computer
GB2311389A (en) * 1996-03-18 1997-09-24 Ibm Software installation in data processing network.
GB2330926A (en) * 1997-11-03 1999-05-05 Tdk Grey Cell Limited Connecting a device and a computer
WO2000028335A2 (en) * 1998-11-09 2000-05-18 Sipex Corporation Connection detection circuit apparatus and method
EP1209853A1 (en) * 2000-11-28 2002-05-29 Telogy Networks Inc. Modem transmission over packet networks
US7213138B2 (en) * 1997-02-14 2007-05-01 Canon Kabushiki Kaisha Data transmission apparatus, system and method, and image processing apparatus
US7401213B2 (en) 1997-02-14 2008-07-15 Canon Kabushiki Kaisha Data communication apparatus and method of a device that supports plural communication methods

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4215243A (en) * 1978-11-17 1980-07-29 Racal-Vadic Inc. Automatic modem identification system
US4358825A (en) * 1978-06-30 1982-11-09 Motorola, Inc. Control circuitry for data transfer in an advanced data link controller
US4581484A (en) * 1982-09-29 1986-04-08 Oclc Online Computer Library Center Incorporated Audio-enhanced videotex system
EP0292691A2 (en) * 1987-05-26 1988-11-30 Hayes Microcomputer Products, Inc. Fast turnaround protocol for use with a high speed half duplex modem

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4358825A (en) * 1978-06-30 1982-11-09 Motorola, Inc. Control circuitry for data transfer in an advanced data link controller
US4215243A (en) * 1978-11-17 1980-07-29 Racal-Vadic Inc. Automatic modem identification system
US4581484A (en) * 1982-09-29 1986-04-08 Oclc Online Computer Library Center Incorporated Audio-enhanced videotex system
EP0292691A2 (en) * 1987-05-26 1988-11-30 Hayes Microcomputer Products, Inc. Fast turnaround protocol for use with a high speed half duplex modem

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5572674A (en) * 1993-01-07 1996-11-05 Bmc Software, Inc. Method of dynamically adjusting SNA network control program parameters
US5634074A (en) * 1993-05-07 1997-05-27 Apple Computer, Inc. Serial I/O device identifies itself to a computer through a serial interface during power on reset then it is being configured by the computer
GB2289186A (en) * 1994-04-05 1995-11-08 Ibm Collaborative working method and system
US5630170A (en) * 1994-10-12 1997-05-13 Kabushiki Kaisha Sega Enterprises System and method for determining peripheral's communication mode over row of pins disposed in a socket connector
GB2311389A (en) * 1996-03-18 1997-09-24 Ibm Software installation in data processing network.
GB2311389B (en) * 1996-03-18 2000-06-07 Ibm Software installation in data processing network
US7213138B2 (en) * 1997-02-14 2007-05-01 Canon Kabushiki Kaisha Data transmission apparatus, system and method, and image processing apparatus
US7430660B2 (en) 1997-02-14 2008-09-30 Canon Kabushiki Kaisha Data transmission apparatus, system and method, and image processing apparatus
US7401213B2 (en) 1997-02-14 2008-07-15 Canon Kabushiki Kaisha Data communication apparatus and method of a device that supports plural communication methods
GB2330926A (en) * 1997-11-03 1999-05-05 Tdk Grey Cell Limited Connecting a device and a computer
WO2000028335A2 (en) * 1998-11-09 2000-05-18 Sipex Corporation Connection detection circuit apparatus and method
US6378026B1 (en) 1998-11-09 2002-04-23 Sipex Corporation Connection detection circuit and method
WO2000028335A3 (en) * 1998-11-09 2000-12-07 Sipex Corp Connection detection circuit apparatus and method
US7042833B1 (en) 2000-11-28 2006-05-09 Texas Instruments Incorporated Modem transmission over packet networks
EP1209853A1 (en) * 2000-11-28 2002-05-29 Telogy Networks Inc. Modem transmission over packet networks

Also Published As

Publication number Publication date
GB9110715D0 (en) 1991-07-10
GB2255877B (en) 1995-07-12

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Legal Events

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732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19990517