Telephone system

• US 5,303,239 A
• Filed: 03/26/1991
• Issued: 04/12/1994
• Est. Priority Date: 03/26/1990
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Aoki, Takashi, Sano, Yoshikazu
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): HOM, SHICK C
• Application Number:
  US07/674,952
• Time in Patent Office: 1,113 Days
• Field of Search: 370/94.2, 370/94.3, 370/95.3, 370/110.1, 370/95.1, 370/58.2, 370/77, 379/88, 379/219
• US Class Current: 370/410
• CPC Class Codes: H04M 9/008 Multiplex systems
• CPC Class Codes: H04Q 11/04 for time-division multiplexing H04Q11/0001 takes precedence
• CPC Class Codes: Y10S 370/904 Integrated Services Digital Network, ISDN

Abstract

The telephone system comprises a central or key service unit 1, data terminal units 5₁ to 5_n, and data set circuits of data terminal interface units 27₁ to 27_n for communications between the central unit 1 and the data terminal units 5₁ to 5_n, respectively. The central unit 1 includes a time switch 17 for executing exchange service and a control unit 19 for controlling the time switch 17. Each interface unit 27₁ to 27_n is connected to the time switch 17for communication of communication-data and connected to the control unit 19 for communication of control-data. Each interface unit 27₁ to 27_n enables and disables communication of communication-data between each data terminal 5₁ to 5_n and the time switch 17 in response to predetermined control commands received from each data terminal unit 5₁ to 5_n.

Claims

1. A telephone system, comprising:

central means having

exchange means for executing exchange service, and

exchange control means for controlling said exchange means; and

interface means

connected to said exchange means for communication of communication-data therewith,

connected to said exchange control means for communication of control-data therewith, and

connected to a data terminal unit for providing an interface for communication of said communication-data between said central means and said data terminal unit;

said interface means enabling and disabling said communication of said communication-data between said central means and said data terminal unit in response to predetermined control commands included in a data stream received from said data terminal unit, and

said interface means enabling and disabling said communication of said communication-data independently of operations of said exchange means in said central means, wherein said interface means

transmits first control data to said exchange control means in response to a first control command from said data terminal unit indicative of a data communication start,

transmits second control data to said exchange control means in response to a second control command from said data terminal unit indicative of a data communication end,

disables said communication of communication-data between said central means and said data terminal unit in response to a third control command from said data terminal unit indicative of a data communication interrupt, and

enables said communication of communication-data between said central means and said data terminal unit in response to a fourth control command from said data terminal unit indicative of a data communication restart; and

said exchange control means controlling said exchange means so that communication of communication-data between said data terminal unit and another selected data terminal unit is maintained from a time when said first control data is received from said interface means to a time when said second control data is received from said interface means.

2. The telephone system of claim 1, wherein:

said interface means and said central means are connected to each other via a signal line including a first time-division channel through which said communication-data are transmitted and a second time-division channel through which said control-data are transmitted; and

said interface means enables and disables said communication of communication-data between said central means and said data terminal unit by connecting and disconnecting said data terminal unit and said first time-division channel.

3. The telephone system of claim 2, further comprising:

an extension telephone set connected to said central means via said signal line;

said signal line further comprising a third time-division channel for said extension telephone set to communicate speech-data with said exchange means;

said extension telephone set communicating control-data for call processing with said exchange control means via said second channel.

4. A telephone system, comprising:

a data terminal unit;

exchange means, in a central unit, for executing exchange service;

exchange control means, in said central unit, for controlling said exchange means; and

an interface unit for providing an interface for communication of communication-data between said data terminal unit and said exchange means;

said interface unit enabling and disabling said communication of said communication-data between said exchange means and said data terminal unit in response to predetermined control commands included in a data stream received from said data terminal unit, wherein said interface unit

transmits first control data to said exchange control means in response to a first control command from said data terminal unit indicative of a data communication start,

transmits second control data to said exchange control means in response to a second control command from said data terminal unit indicative of a data communication end,

disables said communication of communication-data between said central unit and said data terminal unit in response to a third control command from said data terminal unit indicative of a data communication interrupt, and

enables said communication of communication-data between said central unit and said data terminal unit in response to a fourth control command from said data terminal unit indicative of a data communication restart; and

said exchange control means controlling said exchange means so that communication of communication-data between said data terminal unit and another selected data terminal unit is maintained from a time when said first control data is received from said interface unit to a time when said second control data is received from said interface unit.