Data communication apparatus having communication-mode changeover function and method of data communication between data communication stations having the same

A data communication apparatus for a first data communication station connectable to a second data communication station with a plurality of modes served by an ISDN network, comprising:

• data communication control means for performing data communication in a selected one of said plurality of modes;
• notifying means for notifying the second data communication station whether a changeover from said selected one of said modes to another mode is enabled or disabled, in response to an inquiry from the second station;
• and
• changeover means for controlling said data communication control means so as to changeover from said selected one of said modes to said another mode without breaking continuity of the data communication in case that said notifying means notify an affirmative

The data communication apparatus for a first data communication station connectable to a second data communication station with a plurality of modes served by a ISDN network, comprising:

• data communication control means for performing data communication in a selected one of said plurality of modes;
• inquiring means for inquiring of the second station subjected to the data communication whether a changeover from said selected one of said modes to another mode can be performed in response to a changeover request of the first station;
• and
• changeover means for controlling said data communication control means so as to changeover from said selected one of said modes to said another mode without breaking continuity of the data communication in response to an affirmative response from the second data communication station;
• wherein said data communication control means comprises a plurality of inputting means provided in association with said plurality of modes, a receiving buffer for storing therein received data from one of said plurality of inputting means, a plurality of outputting means provided in association with said plurality of modes, and a transmitting buffer for storing therein data to be transmitted to one of said plurality of outputting means, said changeover means synchronously selects said one inputting means and said one outputting means.

The data communication apparatus for a first data communication station connectable to a second data communication station with a plurality of modes served by an ISDN network, comprising:

• data communication control means for performing data communication in a selected one of said plurality of modes;
• notifying means for notifying the second data communication station whether a changeover from said selected one of said modes to another mode is enabled or disabled, in response to an inquiry from the second station;
• and
• changeover means for controlling said data communication control means so as to changeover from said selected one of said modes to said another mode without breaking continuity of the data communication in case that said notifying means notify an affirmative response;
• wherein said data communication control means comprises a plurality of inputting means provided in association with said plurality of modes, a receiving buffer for storing therein received data from one of said plurality of inputting means, a plurality of outputting means provided in association with said plurality of modes, and a transmitting buffer for storing therein data to be transmitted to one of said plurality of outputting means, said changeover means synchronously selects said one inputting means to said one outputting means.

The data communication apparatus for a first data communication station connectable to a second data communication station with a plurality of modes served by a ISDN network, comprising:

• data communication control means for performing data communication in a selected one of said plurality of modes;
• inquiring means for inquiring of the second station subjected to the data communication whether a changeover from said selected one of said modes to another mode can be performed in response to a changeover request of the first station;
• and
• changeover means for controlling said data communication control means so as to changeover from said selected one of said modes to said another mode without breaking continuity of the data communication in response to an affirmative response from the second data communication station;
• wherein said changeover means serves to stop data from being transmitted to the second station at a time when said changeover request is made, and to resume the transmission of data from a time when said changeover has been completed or when a negative response is received from the second station.

The data communication apparatus for a first data communication station connectable to a second data communication station with a plurality of modes served by a ISDN network, comprising:

• data communication control means for performing data communication in a selected one of said plurality of modes;
• inquiring means for inquiring of the second station subjected to the data communication whether a changeover from said selected one of said modes to another mode can be performed in response to a changeover request of the first station;
• and
• changeover means for controlling said data communication control means so as to changeover from said selected one of said modes to said another mode without breaking continuity of the data communication in response to an affirmative response from the second data communication station;
• wherein said changeover means is activated in such a manner that when the changeover is made from said selected one of said modes, the data communication between the two stations is continued in said another mode, and when undelivered data to the second station are present at the time of the changeover, said undelivered data are transmitted to the second data communication station in said selected one of said modes in parallel with said another mode.

The data communication apparatus for a first data communication station connectable to a second data communication station with a plurality of modes served by a ISDN network, comprising:

• data communication control means for performing data communication in a selected one of said plurality of modes;
• inquiring means for inquiring of the second station subjected to the data communication whether a changeover from said selected one of said modes to another mode can be performed in response to a changeover request of the first station;
• changeover means for controlling said data communication control means so as to changeover from said selected one of said modes to said another mode without breaking continuity of the data communication in response to an affirmative response from the second data communication station;
• and
• means for calculating a time at which a charge for use of a public line shall increase from a date of the data communication and an address of the second data communication station, in case that the data communication is performed in a line switching mode as said selected one of said modes, and wherein said changeover means is so activated that the data communication is continuously made in said line switching mode up to said calculated time, without regard to the time of occurrence of said changeover request.

A method of data communication linked between first and second data communication stations with an ISDN network in a plurality of kinds of modes, comprising the steps of:

• transmitting a changeover inquiry command to the second data communication station from the first data communication station for inquiring of the second data communication station whether a changeover of one of said modes to another of said modes is enabled, when a request of the changeover is made in the first data communication station;
• setting a second data communication call with said another of said modes in addition to an existing first data communication call with said one of said modes;
• transmitting a permission command to the first data communication station from the second data communication station in response to said changeover inquiry command, in case that said changeover is enabled;
• transmitting a reject command to the first data communication station from the second data communication station in response to said changeover inquiry command, in case that said changeover is disabled;
• starting the data communication with said second data communication call when the first data communication station accepts said permission command;
• and
• continuing the data communication with said first data communication call when the first data communication station accepts said reject command.

A method of data communication linked between first and second data communication stations with an ISDN network in a plurality of kinds of modes, comprising the steps of:

• transmitting a changeover inquiry command to the second data communication station from the first data communication station for inquiring of the second data communication station whether a changeover of one of said modes to another of said modes is enabled, when a request of the changeover is made in the first data communication station;
• setting a second data communication call with said another of said modes in addition to an existing first data communication call with said one of said modes;
• transmitting a permission command to the first data communication station from the second data communication station in response to said changeover inquiry command, in case that said changeover is enabled;
• transmitting a reject command to the first data communication station from the second data communication station in response to said changeover inquiry command, in case that said changeover is disabled;
• starting the data communication with said second data communication call when the first data communication station accepts said permission command;
• continuing the data communication with said first data communication call when the first data communication station accepts said reject command;
• and
• stopping the data communication with said first data communication call when said first data communication station accepts aid permission command, and cancelling the data communication with said second data communication call when said first data communication accepts said reject command.

A method of data communication linked between first and second data communication stations with an ISDN network in a plurality of kinds of modes, comprising the steps of:

• transmitting a changeover inquiry command to the second data communication station from the first data communication station for inquiring of the second data communication station whether a changeover of one of said modes to another of said modes is enabled, when a request of the changeover is made in the first data communication station;
• setting a second data communication call with said another of said modes in addition to an existing first data communication call with said one of said modes;
• transmitting a permission command to the first data communication station from the second data communication station in response to said changeover inquiry command, in case that said changeover is enabled;
• transmitting a reject command to the first data communication station from the second data communication station in response to said changeover inquiry command, in case that said changeover is disabled;
• starting the data communication with said second data communication call when the first data communication station accepts said permission command;
• continuing the data communication with said first data communication call when the first data communication station accepts said reject command;
• and
• transmitting said changeover inquiry command to the second data communication station from the first data communication station again when the first data communication station accepts said reject command.

A method of data communication linked between first and second data communication stations with an ISDN network in a plurality of kinds of modes, comprising the steps of:

• transmitting a changeover inquiry command to the second data communication station from the first data communication station for inquiring of the second data communication station whether a changeover of one of said modes to another of said modes is enabled, when a request of the changeover is made in the first data communication station;
• setting a second data communication call with said another of said modes in addition to an existing first data communication call with said one of said modes;
• transmitting a permission command to the first data communication station from the second data communication station in response to said changeover inquiry command, in case that said changeover is enabled;
• transmitting a reject command to the first data communication station from the second data communication station in response to said changeover inquiry command, in case that said changeover is disabled;
• starting the data communication with said second data communication call when the first data communication station accepts said permission command;
• and
• continuing the data communication with said first data communication call when the first data communication station accepts said reject command;
• wherein said changeover inquiry command, said accept command and said reject command are incorporated into user to user information elements in call control primitives.