Line control of switched network data sets

• US 4,488,002 A
• Filed: 12/21/1981
• Issued: 12/11/1984
• Est. Priority Date: 12/21/1981
• Status: Expired due to Term

• Current Assignee: Bell Telephone Laboratories, Inc. (Nokia Corporation)
• Original Assignee: AT&T, Inc.
• Inventors: Seibel, Richard R.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/333,038
• Time in Patent Office: 1,086 Days
• Field of Search: 179/2 DP, 179/2 C, 375/7, 375/8, 370/76
• US Class Current: 379/93.26
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors

Abstract

Each station of a switched telephone network voiceband data communication system includes a data set and a telephone set. The data set includes primary signal processing circuitry which performs the real-time signal processing of the data set under the control of a microprocessor-based primary controller. The latter also controls connection of the data set and telephone set to, and disconnection of same from, the telephone line. A portion of the frequency spectrum of the telephone line is allocated to a secondary channel over which a secondary controller within each data set communicates test, health and other information to a counterpart within the other data set. Line functions, such as the switching of a station into and out of the data state, talk state and disconnect state, are not executed at least until a line control message indicative of the line function in question has been communicated to the data set within the other station via the secondary channel. This allows appropriate steps to be taken at one or both stations to avoid such potential problems as the non-disconnection of unattended telephones and the premature re-enabling of disabled echo suppressors.

Claims

1. A data set adapted for use in conjunction with a telephone set which has a talk button and a data button, said data set comprising

data communication means for transmitting voiceband data signals to, and receiving voiceband data signals from, a second data set over a voiceband telephone line,

means operative when said talk button is operated for connecting said telephone set to said line and for thereafter connecting said data communications means to said line in response to operation of said data button, said

line control means operative when said data communications means is connected to said line and said talk button is thereafter operated for transmitting to said second data set over said line a line control signal indicative of the operation of said talk button and for reconnecting said telephone set to said line no sooner than at a time subsequent to the transmission of said line control signal.

7. The invention of claims 1, 3 or 5 wherein said data communication means is adapted to transmit and receive said voiceband data signals over said line via a first data communication channel and wherein said line control means is adapted to transmit said line control signal over said line via a second data communication channel.

8. The invention of claim 7 wherein said first and second channels comprise respective portions of the frequency spectrum of said line.

2. A data set adapted for use in conjunction with a telephone set which has a talk button and a data button, said data set comprising

data communication means for transmitting voiceband data signals to, and receiving voiceband data signals from, a second data set over a voiceband telephone line,

means operative when said talk button is operated for connecting said telephone set to said line and for thereafter connecting said data communication means to said line in response to operation to said data button, and

line control means operative when said data communication means is connected to said line and said talk button is thereafter operated for transmitting to said second data set over said line a first line control signal indicative of the operation of said talk button and for reconnecting said telephone set to said line no sooner than at a time subsequent to receipt from said second data set over said line of a second line control signal indicative to said data set that said first line control signal was received by said second data set.

9. The invention of claims 2, 4 or 6 wherein said data communication means is adapted to transmit and receive said voiceband data signals over said line via a first data communication channel and wherein said line control means is adapated to transmit said first and second line control signals over said line via a second data communication channel.

10. The invention of claim 9 wherein said first and second channels comprise respective portions of the frequency spectrum of said line.

3. A data set adapted for use in conjunction with a telephone set, said data set comprising

data communication means for transmitting voiceband data signals to, and receiving voiceband data signals from, a second data set over a voiceband telephone line,

means operative when the switch hook of said telephone set is in a first position for connecting a selected one of said data communication means and said telephone set to said line, and

line control means operative when said telephone set is connected to said line and said switch hook is subsequently switched to a second position for transmitting over said line to said second data set a line control signal indicative to said second data set that it is desired to disconnect said telephone set from said line and for disconnecting said telephone set from said line no sooner than at a time subsequent to the transmission of said line control signal.

4. A data set adapted for use in conjunction with a telephone set, said data set comprising

data communication means for transmitting voiceband data signals to, and receiving voiceband data signals from, a second data set over a voiceband telephone line,

means operative when the switch hook of said telephone set is in a first position for connecting a selected one of said data communication means and said telephone set to said line, and

line control means operative when said telephone set is connected to said line and said switch hook is subsequently switched to a second position for transmitting over said line to said second data set a first line control signal indicative to said second data set that it is desired to disconnected said telephone set from said line and for thereafter disconnecting said telephone set from said line in response to a second line control signal subsequently received from said second data set over said line, said second line control signal being indicative to said first data set that said first line control signal was received by said second data set.

5. A data set adapted for use in conjunction with a telephone set and a data source, said data set comprising

data communication means for transmitting to a second data set over a voiceband telephone line voiceband data signals respresenting data provided by said data source and for receiving voiceband data signals from said second data set over said line, said data communication means and said telephone set being selectively connectable to said line,

means for receiving from said source a control signal having first and second values, said first value indicating that said data communication means can be connected to said line and said second value indicating that it should not be connected to said line, and

line control means operative in response to the switching of said control signal from said first value to said second value and operative when said data communication means is connected to said line for transmitting over said line to said second data set a line control signal indicative of said switching and for disconnecting said data communication means from said line no sooner than at a time subsequent to the transmission of said line control signal.

6. A data set adapted for use in conjunction with a telephone set and a data source, said data set comprising

data communication means for transmitting to a second data set over a voiceband telephone line voiceband data signals representing data provided by said data source and for receiving voiceband data signals from said second data set over said line, said data communication means and said telephone set being selectively connectable to said line,

means for receiving from said source a control signal having first and second values, said first value indicating that said data communication means can be connected to said line and said second value indicating that it should not be connected to said line, and

line control means operative in response to the switching of said control signal from said first value to said second value and operative when said data communication means is connected to said line for transmitting over said line to said second data set a first line control signal indicative of said switching and for disconnecting said data communication means from said line in response to a second line control signal subsequently received from said second data set over said line, said second line control signal being indicative to said first data set that said first line control signal was received by said second data set.

11. A method for use in a data set adapted for use in conjunction with a telephone set which has a talk button and a data button, said data set comprising data communication means for transmitting voiceband data signals to, and receiving voiceband data signals from, a second data set over a voiceband telephone line, and means operative when said talk button is operated for connecting said telephone set to said line and for thereafter connecting said data communication means to said line in response to operation of said data button, said method comprising the steps of

transmitting to said second data set over said line, when said data communication means is connected to said line and said talk button is thereafter operated, a line control signal indicative of the operation of said talk button, and

reconnecting said telephone set to said line no sooner than at a time subsequent to the transmission of said line control signal.

12. A method for use in a data set adapted for use in conjunction with a telephone set which has a talk button and a data button, said data set comprising data communication means for transmitting voiceband data signals to, and receiving voiceband data signals from, a second data set over a voiceband telephone line, and means operative when said talk button is operated for connecting said telephone set to said line and for thereafter connecting said data communication means to said line in response to operation of said data button, said method comprising the steps of

transmitting to said second data set over said line, when said data communication means is connected to said line and said talk button is thereafter operated, a first line control signal indicative of the operation of said talk button, and

reconnecting said telephone set to said line no sooner than at a time subsequent to receipt from said second data set over said line of a second line control signal indicative to said data set that said first line control signal was received by said second data set.

13. A method for use in a data set adapted for use in conjunction with a telephone set, said data set comprising data communication means for transmitting voiceband data signals to, and receiving voiceband data signals from, a second data set over a voiceband telephone line, and means operative when the switch hook of said telephone set is in a first position for connecting a selected one of said data communication means and said telephone set to said line, said method comprising the steps of

transmitting over said line to said second data set when said telephone set is connected to said line and said switch hook is subsequently switched to a second position a line control signal indicative to said second data set that it is desired to disconnect said telephone set from said line, and

disconnecting said telephone set from said line no sooner than at a time subsequent to the transmission of said line control signal.

14. A method for use in a data set adapted for use in conjunction with a telephone set, said data set comprising data communication means for transmitting voiceband data signals to, and receiving voiceband data signals from, a second data set over a voiceband telephone line, and means operative when the switch hook of said telephone set is in a first position for connecting a selected one of said data communication means and said telephone set to said line, said method comprising the steps of

transmitting over said line to said second data set when said telephone set is connected to said line and said switch hook is subsequently switched to a second position a first line control signal indicative to said second data set that it is desired to disconnect said telephone set from said line, and

thereafter disconnecting said telephone set from said line in response to a second line control signal subsequently received from said second data set over said line, said second line control signal being indicative to said first data set that said first line control signal was received by said second data set.

15. A method for use in a data set adapted for use in conjunction with a telephone set and a data source, said data set comprising data communication means for transmitting to a second data set over a voiceband telephone line voiceband data signals representing data provided by said data source and for receiving voiceband data signals from said second data set over said line, said data communication means and said telephone set being selectively connectable to said line, and means for receiving from said source a control signal having first and second values, said first value indicating that said data communication means can be connected to said line and said second value indicating that it should not be connected to said line, said method comprising the steps of

transmitting over said line to said second data set in response to the switching of said control signal from said first value to said second value and when said data communication means is connected to said line a line control signal indicative of said switching, and

disconnecting said data communication means from said line no sooner than at a time subsequent to the transmission of said line control signal.

16. A method for use in a data set adapted for use in conjunction with a telephone set and a data source, said data set comprising data communication means for transmitting to a second data set over a voiceband telephone line voiceband data signals representing data provided by said data source and for receiving voiceband data signals from said second data set over said line, said data communication means and said telephone set being selectively connectable to said line, and means for receiving from said source a control signal having first and second values, said first value indicating that said data communication means can be connected to said line and said second value indicating that it should not be connected to said line, said method comprising the steps of

transmitting over said line to said second data set in response to the switching of said control signal from said first value to said second value and when said data communication means is connected to said line a first line control signal indicative of said switching, and

disconnecting said data communication means from said line in response to a second line control signal subsequently received from said second data set over said line, said second line control signal being indicative to said first data set that said first line control signal was received by said second data set.