JPH04219040A - Call connection system in isdn - Google Patents

Abstract

PURPOSE:To find out a communication capability of an opposite terminal equipment in a short time when a terminal equipment having plural sets of communication capabilities makes communication with an opposite terminal equipment whose communication capability is not clear with respect to the call connection system of the terminal equipment having plural sets of communication capabilities in an ISDN. CONSTITUTION:A terminal equipment having plural sets of communication capabilities for ISDN is provided with a connection generating means 1 making connection processing, a call information storage means 2 storing a call message corresponding to each communication capability, a call message transmission means 3 sending the plural call messages to a network sequentially when the connection processing means implements a call not designating the communication capability of the communication opposite terminal equipment, a reply monitor means 4 informing identification information of a replied call message to the connection processing means and the call information storage means when reply information is sent from the opposite terminal equipment with respect to plural set messages and a call message cancel processing means 5 implementing the cancel processing other call message than that having the reply information to the network.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a call connection system in an ISDN when a plurality of terminals connected to an ISDN and having communication capabilities communicate with a partner terminal whose communication capabilities are unknown.

[0002] In recent years, ISDN (Integrated Service Digital Network) is becoming popular, but in ISDN, voice,
Communication using various media such as facsimile (FAX) and data is possible, and the communication method can be selected from circuit switching and packet switching using the B channel on the I interface, or packet switching using the D channel. , it has become possible to perform a variety of communications.

[0003] Along with this, the terminals (TE) connected to the S/T point interfaces also have multiple communication capabilities, and are now capable of supporting various communication services. ISD
The communication capability parameters in N include "Transfer Capability (BC)" which indicates the basic communication capability, and "Low Layer Consistency (LL)" which indicates the communication capability of layers 1 to 3 of the communication protocol.
C)" and "Higher Layer Compatibility (HLC)" which indicates the communication capability of layers 4 to 7, and the terminal has the communication capability of a combination of these.

[0004] However, as the communication capabilities of terminals become more diverse, when communicating between terminals, it is sometimes unclear what kind of communication capabilities the other terminal has, and when making a call, It is essential to check the communication capabilities of the other party's terminal.

[0005]

2. Description of the Related Art FIG. 8 shows a configuration diagram of the prior art, showing the configuration of a call-related portion of a terminal having multiple communication capabilities and connected to an ISDN via an S/T point interface.

When the terminal in FIG. 8 communicates with another terminal (not shown), the user of the terminal (hereinafter referred to as the calling party) uses the connection processing unit 31 from an input device (not shown) or an external circuit.
Make a call request via . At this time, if it is unclear what kind of communication capabilities the other party's terminal has, it is necessary to confirm the communication capabilities of the other party's terminal when making a call.
If the communication capability of the other party's terminal has been confirmed in advance by telephone or the like, the communication capability of the other party's terminal is input to the connection processing section 31 together with the connection information for the other party's terminal. As a result, the connection processing section 31 sends a calling message corresponding to the communication capability of the input partner terminal to the IS from the calling message sending section 33.
Send it to the other party's terminal via the DN. In this case, since the communication capabilities match those of the other terminal, response information is returned to the response monitoring section 34 via the network, and the response monitoring section 35 notifies the connection processing section 31 of completion of the connection. As a result, the connection processing section 31
transmits communication information data and the like from a communication information storage unit (not shown) via the communication control unit 37 to the other party's terminal via the network.

On the other hand, if the communication capability of the other party's terminal is unknown, for example in the case of FAX communication, if it is unknown whether the other party's terminal is a G3 or G4 machine, the call is first made assuming that it is a G4 machine. A message is sent, and if response information is not returned within a certain period of time, the connection is temporarily cut off and the call message is sent again as a G3 device. In this way, in the conventional technology, the calling terminal sequentially sends out calling messages using various combinations of the multiple communication capabilities of its own terminal to find the communication capability that matches the other party's terminal. It takes time and effort.

[0008]

[Problem to be solved by the invention] When communicating between ISDN terminals, if the communication capability of the other terminal is unknown,
In conventional technology, it is necessary to confirm in advance what kind of communication capabilities the other party's terminal has by means such as a telephone, or to repeatedly make calls based on various combinations of communication capabilities of the own terminal to establish communication that matches the other party's terminal. Because we need to discover our abilities,
It required a lot of time and effort. Especially in the latter method,
It takes at least several seconds for a single call to determine that the communication capabilities of the other party's device do not match, and in the case of a mismatch, time is added to set up a message that corresponds to the communication capabilities of the next candidate. Therefore, it has the disadvantage that it takes a lot of time to find a communication capability that is suitable for the other party's terminal.

Furthermore, even if call connection is completed and communication can be started, synchronization with the other party's terminal may not be achieved due to a mismatch in detailed conditions such as a mismatch in parity. In such a case, the call connection becomes wasteful, and it becomes clear that communication is impossible after the start of communication, resulting in unnecessary communication costs.

[0010] The present invention makes it possible, when a terminal having a plurality of communication capabilities communicates with a partner terminal whose communication capabilities are unknown, to find a communication capability suitable for the partner terminal in a short time and perform the communication. purpose.

[0011]

[Means for Solving the Problems] FIG. 1 is a diagram illustrating the principle of the present invention (claim 1), and FIG. 2 is a diagram illustrating another principle of the present invention (claims 2 to 4).

[0012] In Figs. 1 and 2, the same target parts are indicated by the same symbols, and 1, 1a, 1b and 1c are terminals that have multiple communication capabilities and are connected to ISDN via an S/T point interface. , to the other party's terminal (
(not shown); 2 is a calling message storage means that stores in advance a calling message corresponding to each of the plurality of communication capabilities; 3 is the connection processing means 1, 1a, 1b or 1c, when receiving a call request that does not specify the communication capability of a communicating party terminal, transmitting a call message for sequentially transmitting a plurality of call messages stored in the call message storage means 2 to the network; When the means 4 receives response information sent via the network from the other party's terminal in response to one of the plurality of transmitted calling messages, the means 4 determines that the connection is complete and the identification information of the responded calling message is connected to the connection. Processing means 1, 1a, 1b
or 1c and response monitoring means for notifying the calling message storage means 2; and 5, when receiving notification of response information from the response monitoring means 4,
This is a calling message canceling means that accesses the network and cancels calling messages other than calling messages for which there is response information.

Reference numeral 6a denotes a plurality of outgoing calls stored in the outgoing call message storage means 2, when the calling message transmitting means 3 receives a calling request that does not specify the communication capability of the communication partner terminal from the connection processing means 1a. When messages are sent sequentially to the network, if response information is not received from the other party's terminal within a predetermined time and no response information is obtained even after making a specified number of re-calls, the Connection restriction terminal storage means 7 records that a call request that does not specify communication capability is invalid for the other party terminal under the control of the processing means 2; communication control means for controlling communication with the terminal, 6
In b, when it is found that synchronization between the terminals cannot be achieved after the connection processing means 2 terminates the calling connection specifying the communication capability of the communication partner terminal and the communication control means 7 starts communication.
Connection restriction terminal storage means 6 for storing, under the control of the connection processing means 1b, that communication using the call message used in the call origination is not possible with respect to the partner terminal;
When the connection processing means 1c ends a calling connection that does not specify the communication capability of the communication partner terminal and starts communication by the communication control means 7, when it is found that the terminals cannot be synchronized, the connection processing means 1c is a connection restriction terminal storage means for recording that communication based on a call request that does not specify a communication capability is not possible with respect to the other party's terminal. Note that 1a, 1b and 1c are shown in the same location using the same name "connection processing means", and 6a, 6b and 6
c are shown in the same location using the same name "Connection restriction terminal storage means".

[0014]

[Operation] Figure 1 has multiple communication capabilities, and is compatible with ISDN.
2 shows the configuration of a call-related portion of a terminal connected by a /T point interface.

When the terminal in FIG. 1 communicates with another terminal (not shown), the user of the terminal (hereinafter referred to as the calling party) communicates with the connection processing unit 1 from an input device or an external circuit (not shown). to request a call. At this time, if it is unclear what kind of communication capability the other party's terminal has, the connection processing means 1 issues a call request to the calling message transmitting means 3 without specifying the communication capability of the other party's terminal.

The calling information storage means 2 stores in advance a calling message corresponding to each of the plurality of communication capabilities of the terminal shown in FIG. A plurality of call messages stored in the call information storage means 2 are sequentially transmitted to the network. In this case, multiple call messages are sent to the network in sequence without checking whether response information is returned from the network or the other party's terminal in response to one call message.

[0017] When the other party's terminal finds one of the plurality of call messages that it receives that is compatible with its own communication capability, it sends response information via the network. When the response monitoring means 4 receives this response information, it notifies the connection processing means 1 and the call information storage means 2 that the connection has been completed and the identification information of the answered call message.

When the calling message cancellation processing means 5 receives the reception notification of the response information from the response monitoring means 4, it accesses the calling message storage means 2 and deletes the calling message other than the calling message for which the response information was included. Confirm and cancel the request to the network.

Further, upon receiving the notification of connection completion, the connection processing means 1 operates a communication control means (not shown) and starts transmitting communication information such as data to the partner terminal. As described above, in Figure 1, calling messages corresponding to multiple communication capabilities are sent out in succession, and the communication capability of the other party's terminal is confirmed without sequentially checking whether or not the other party's terminal responds to each message. It becomes possible to check the communication capability of the other party's terminal based on the time.

Similar to FIG. 1, FIG. 2 also shows the configuration of the call-related portion of a terminal that has multiple communication capabilities and is connected to the ISDN via an S/T point interface, but there are some changes to FIG. is added.

The operation of claim 2 will be explained below with reference to FIG. When the connection processing means 1a issues a call request to the calling message transmitting means 3 without specifying the communication capability of the communication partner terminal, the calling message transmitting means 3 transmits the plurality of communications stored in the calling information storage means 2. Sequentially transmits call messages corresponding to the capabilities to the network. However, there may be cases where the other party's terminal does not respond to the multiple call messages sent. In this case, re-calling is performed a preset number of times, such as by sending a calling message again, but in the end, response information is often not obtained.

[0022] When it is confirmed by the response monitoring means 4 that no response information is obtained, the connection processing means 1a does not allow communication even if it makes a call request without specifying the identification information of the partner terminal and the communication capability to the terminal. The fact that it is not possible is stored in the connection restriction terminal storage means 6a.

Thereafter, when the connection processing means 1a receives a call request, it accesses the connection regulation terminal storage means 6a before making the call request to the call message transmission means 3, and specifies the communication capability of the other party's terminal. If it is confirmed that connection is not possible due to a call request that is not made, the caller is notified to that effect and the process is terminated without performing call processing.

[0024] Therefore, an invalid connection process is not performed for a terminal with which communication is not possible, and the call connection process is made more efficient. Next, the effect of claim 3 will be explained using the same FIG.

In this case, the calling party knows in advance the communication capability of the other party's terminal, and the connection processing means 1b requests the calling message transmitting means 3 to make a call by specifying the communication capability of the other party's terminal. The calling message transmitting means 3 sends the corresponding calling message to the other party's terminal directly or via the calling message storage means 2 according to the specification from the connection processing means 1b, but since the communication capabilities are compatible, the response information is not received. can get.

[0026] As a result, the connection processing means 1b operates the communication control means 7 to start communication, but some incompatibilities may occur during the data exchange process, making communication impossible. In this case, the connection processing means 1b receives information from the communication control means 7, and stores in the connection restriction terminal storage means 6b that it is not possible to communicate with the other terminal due to the specified communication capability.

[0027] Thereafter, if there is a call request specifying the same communication capability to the same destination terminal, the connection processing means 1b
As in claim 2, the caller is notified of the inability to communicate and no call processing is performed.

Next, regarding the effect of claim 3, FIG.
Explain using. When the connection processing means 1c issues a call request to the calling message transmitting means 3 without specifying the communication capability of the communication partner terminal, the calling message transmitting means 3 stores the call message in the calling message storage means 2, as in FIG. A plurality of calling messages are sequentially sent to the network, and when response information is obtained for one of them, the connection processing means 1c
The connection operation is terminated by notifying the user that the connection has been completed.

However, as described above, after data communication is started using the communication control means 7, a mismatch may occur and communication may become impossible. In this case, even if there is a calling message whose communication capability is more suitable than the first calling message for which response information was returned, the other party's terminal sends the calling message in the order stored in the calling message storage means 2. is sent, so response information will be returned to the first matching calling message.

Therefore, if a calling connection is terminated without specifying the communication capability and communication is found to be impossible after starting communication, the connection processing means 1c does not specify the communication capability for the other party's terminal. The fact that the call request is inappropriate is stored in the connection restriction terminal storage means 6b. Thereafter, such call requests will be regulated in the same manner as above.

As described above, according to the present invention, it is possible to confirm in a short time the communication capability of a partner terminal whose communication capability is unknown, and also to prevent calls that cannot be communicated due to inappropriate specification of communication capability. It becomes possible to regulate requests in advance.

[0032]

[Embodiment] FIG. 3 is a block diagram of an embodiment of the present invention, FIG. 4 is a signal sequence diagram of an embodiment of the present invention, FIG. 5 is a flowchart of call setting processing of an embodiment of the present invention, and FIG. FIG. 7 is a flowchart of a response waiting process according to an embodiment of the present invention. FIG. 7 is a configuration diagram of a call information table according to an embodiment of the present invention.

Reference numeral 10 in FIG. 3 is a mail storage and distribution device of the mail communication system, which has a plurality of communication capabilities, and has ISDN
An example of a terminal connected by an S/T point interface is shown as one that includes all the principles of FIGS. 1 and 2.

Reference numerals 11 to 19 are each part constituting the mail storage and distribution device 10, and 11 is the connection processing means 1 of FIGS. 1 and 2.
, 1a, 1b, and 1c and a mail communication processing function; 12 is a calling information storage unit that stores information including calling messages corresponding to a plurality of communication capabilities; and 13 is a calling message. 14 is a response monitoring unit; 15 is a calling message cancellation processing unit; 16 is a connection regulation table having the functions of the connection regulation terminal storage means 6a, 6b, and 6c in FIG. 2; 17 is a communication control unit; 18 is an external a transmission request reception unit that accepts email transmission requests;
Reference numeral 19 represents a communication data storage unit that stores mail communication data, and reference numeral 20 represents a line support unit that serves as an interface with ISDN.

[0035] Also, 21 is ISDN (network), 22 to 2
5 is a terminal, and here terminal 22 (hereinafter referred to as terminal A) is a transmission request source terminal, for example, a communication terminal, terminal 23
(Terminal B) is a destination terminal, for example, a G4 FAX that uses ISDN B channel packet exchange, terminal 24,
25 (Terminals C and D) are G4FAX that uses B channel circuit switching, and G3F that uses channel circuit switching.
It is any terminal such as AX.

First, terminal A connects to the mail storage and distribution device 10 in order to transmit data or FAX mail to terminal B. The email to be sent is stored in advance in the email storage and distribution device 1.
However, when transmitting from terminal A, the data to be transmitted via the line support unit 20 and the transmission request receiving unit 18, the destination, etc. Information necessary for communication is temporarily stored in the communication data storage section 19.

At this time, the destination (telephone number) for terminal B has been sent from terminal A to the mail storage and distribution device 10, but if information regarding the communication capability of terminal B has not been sent, the transmission request is not accepted. The mail communication connection processing section 11, which has received the transmission request from the section 18, makes a call request to the calling message transmitting section 13 under an "arbitrary" condition, for example, without specifying the communication capability. Upon receiving the request, the calling message transmitting section 13 reads out the calling message to be transmitted from the calling information storage section 12.

FIG. 7 shows an example of the structure of the calling information table stored in the calling information storage section 12. In this table, as common information, for example, the number of calling information ( In this example, the processing status indicating whether the entire call information table is in a completed state or an uncompleted state is stored in the B section. After that, n pieces of call information are stored, and each call information stores information from items C to F.

Section C is the call information number (sometimes referred to as call number), and Section D is the individual processing status, that is, whether the call message has not been sent or if the call setup has not yet been accepted from the network after sending. A state in which no message has been received (unprocessed), a state in which a call setup acceptance message has been received from the network and is waiting for a response from the other party's terminal (response waiting), and a state in which no information has been sent from the network or the other party's terminal. Either the state in which the call was made again because there was no connection (recalling), or the state in which the process was completed either by receiving response information from the other party's terminal and completing the connection, or by being rejected by the network or the other party's terminal (processing completed). is memorized.

[0040] Section E specifies a set value for the number of times (r times in this example) to re-call when information is not returned from the network or the other party's terminal within a predetermined time. Section F is the content of the calling message sent to the other party's terminal, and the contents differ depending on the communication capability, so the contents of Section F from calling information (1) to calling information (N) are all different. There is.

The calling message transmitting unit 13 sequentially sends the calling messages in section F from the calling information (1) in the calling information table to the ISDN 21 (hereinafter referred to as network) via the line handling unit 20. , the network sends this to the destination terminal B.

FIG. 4 shows the main signals transmitted and received between the mail storage and distribution device 10, the network, and terminal B. There are two types of calling messages (indicated by call number 1 and call number 2). ) is shown.

The calling message transmitter 13 first sends a call setup message (SETUP) to the network in order to transmit the calling message for call number 1 from the calling information storage unit 12 (
(See Figure 4-a). When the network accepts this and starts processing, it returns a call setup acceptance message (CALLPROC) (FIG. 4-b). As shown in Figure 4, the individual processing status of call information (1) is "until CALLPROC is received.
However, upon receiving CALLPROC, the calling message storage means 1 sets "waiting for response" in the individual processing status section of the calling information (1) in FIG. 7. (Hereinafter, the explanation of setting the call information table to the individual processing state will be omitted.)
The network sends SETUP with call number 1 to terminal B (Figure 4
c), the call message transmitter 13 transmits SETUP for the next call number 2 without waiting for return information such as a response to call number 1 from terminal B, and receives CALLPROC from the network.
(Figure 4-d, e), the network also sets SE for call number 2.
Send TUP to terminal B (FIG. 4-f).

[0044] If the content of the calling message sent by call number 2 matches the communication capability of terminal B, terminal B sends a response message (CONN) to the network, and the network sends a response confirmation message (CONNACK). ) to terminal B (
In addition to (g, h) in FIG. 4, the response information for call number 2 is notified to the mail storage and distribution device 10 by CONN (
Figure 4-i).

The response information is received by the response monitoring section 14, and the response monitoring section 14 notifies the mail communication connection processing section 11 that the connection has been completed. At this stage, "processing completed" is stored in the individual processing status section of the call information (1) in the call information table of FIG.

The response monitoring section 14 also notifies the calling message cancellation processing section 15 that there is a response to the call number 2, which causes the calling message cancellation processing section 15 to access the calling information storage section 12. and call number 1 is waiting for a response.
The information for canceling the calling message is sent to the network (the above is not shown in FIG. 4).

If rejection information is received from the network or the other party's terminal B in the above process, the process can be terminated without using the calling message cancellation processing unit 15, but as shown in FIG.
An example of this is shown. That is, terminal B sends a release completion message (RELCOMP) to the network that refuses to connect to call number 1 due to a mismatch in communication capabilities (Figure 4-j), and upon receiving this, the network stores and delivers the mail. Device 1
A release completion message (RELCOMP) is returned to call number 1, and the processing for call number 1 is completed (FIG. 4-k).

For data communication, the mail communication connection processing section 11 receives the response information of call number 2 and starts the communication control section 17.
The data stored in the communication data storage unit 19 is transmitted to terminal B via the network (FIG. 4-m).

Note that in FIG. 4, a specific arrangement sequence is shown for ease of explanation, but since two call settings are actually performed in parallel, the order of the sequence may be reversed from that in FIG. 4. is possible.

Although FIGS. 5 and 6 are flowcharts showing the above operations, a brief explanation will be provided to avoid duplication. Note that S1 to S31 are symbols indicating each step. First, the flow of call setting processing will be explained with reference to FIG. The call message transmitter 13 includes a call information counter N,
A calling information number counter I and a re-calling number counter R (both not shown) are provided, and the initial setting is N.
is the number n of outgoing messages to send (in the example above, n=
2) Set I to the number of the call information to be read out (initially 1, that is, call number 1), and R to set the number of re-calls r (S1).

[0051] When the calling message transmitting section 13 receives the calling request from the mail communication connection processing section 11, it reads out the calling information (1) as described above (S2) and transmits SETUP to the network (S4).

In S5, a timer for monitoring message reception from the network (not shown in FIG. 3) is set in the calling message transmitting section 13, and in S6 and S7, an event of receiving a message from the network or occurrence of a timeout is waited for. If a timeout occurs, the SETUP is sent to the network again at a fixed time interval in S10 (S10, S11→S4).
).

If a message is received from the network in S6, it is determined in S8 whether the received message is CALLPROC. If it is not CALLPROC, send SETUP again at a certain time interval (S10, S11 → S4
). In the case of CALLPROC, call information (I) is sent in S9.
"Waiting for response" is set to "waiting for response" and response waiting processing is started. The subsequent response waiting processing will be explained with reference to FIG.

[0054] When the call number 1 enters the state of waiting for a response in S9, the response waiting process is activated and proceeds to S1.
Proceed to step 3, add 1 to counter I (specify call number 2),
Call setup for call number 2 is started. That is, if the number of call information does not exceed n, the process returns to S2 and performs the same call setting process as described above for call number 2 (S13-S14→S2). Note that if I>n in S14, call setting is performed again from call number 1 (S15→S2).

[0055] If the conditions are not met in S3, the process proceeds to S12, but if the processing status of the common information is not completed, the process moves to the call setting process for the next call number (S13), and if the process is completed, the process proceeds to S12. Call setup ends.

Next, the flow of response waiting processing will be explained with reference to FIG. The response waiting process is activated when there is a call waiting for the first response in FIG.
~S24). If RELCO is sent from the network while waiting for a response.
Upon receiving the MP, the response monitoring unit 14 stores the calling information storage unit 1.
2, check the call number that received the RELCOMP, and set "Recall" in the individual processing status of the calling information (I) so that the recall process is performed by subtracting 1 from the number of recalls R ( S21→S25-S28).

When the number of re-calls R reaches the set value r for the number of re-calls, R≦0 in S27, the process advances to S29, and processing is completed for this call number. N at S30
If >1, it means that the call setting process has been completed for all call numbers, so the process of S31 is performed and the process is completed in a state where connection is not possible.

FIG. 3 includes the functions of claims 2 to 4 shown in FIG. 2, but since these are the same as those already explained in the operation of the present invention, their explanation will be omitted.

Although the embodiment of the present invention has been described above with reference to FIGS. 2 to 7, FIGS. 2 to 7 merely show one embodiment of the present invention. It is obvious that the configuration of the terminal, the configuration of the calling information table, the sequence, and the flowchart are not limited to those illustrated. For example, it is clear that the effects of the present invention will not change even if the respective components are merged or separated in FIG. 3. In addition, the flowcharts in FIGS. 5 and 6 only show the basic flow, and the conditions and timing of re-calling,
Even if the timing of transmitting the calling message is other than that shown in the figure, the effects of the present invention do not change.

[0060]

[Effects of the Invention] As explained above, according to the present invention,
When a terminal that has multiple communication capabilities and is connected to an ISDN via an S/T point interface communicates with a partner terminal whose communication capabilities are unknown, it becomes possible to discover the communication capabilities of the partner terminal in a short time, and Since it becomes possible to restrict in advance call requests that cannot be communicated due to inappropriate specification of communication capability, this greatly contributes to improving the efficiency of call connection in ISDN.

[Brief explanation of the drawing]

[Figure 1] Diagram explaining the principle of the present invention (1)

[Figure 2] Diagram explaining the principle of the present invention (2)

[Figure 3] Configuration diagram of an embodiment of the present invention

[Figure 4] Example signal sequence diagram of the present invention

[Figure 5]
Example call setup process flowchart of the present invention

[Figure 6]
Flowchart of response waiting process according to an embodiment of the present invention

[Figure 7
] Embodiment of the present invention Calling embodiment table configuration diagram

[Figure 8
] Configuration diagram of conventional technology

[Explanation of symbols]

1 Connection processing means 2 Calling conventional technology storage means 3. Call message transmission sending means 4 Response monitoring means 5 Call message cancellation processing means 6 Connection restriction terminal storage means 7 Communication control means

Claims (4)

[Claims] Claim 1: Has multiple communication capabilities, and has ISDN and S
In a terminal connected via the /T point interface, connection processing means (1) performs connection processing with a partner terminal via the network, and a call message corresponding to each of the plurality of communication capabilities is transmitted. Pre-stored call information storage means (2), and when a call request that does not specify the communication capability of the communication partner terminal is received from the connection processing means (1), it is stored in the call information storage means (2). calling message transmitting means (3) for sequentially transmitting a plurality of calling messages transmitted to the network; and response information sent from a partner terminal via the network in response to one of the plurality of transmitted calling messages. response monitoring means (4) for notifying the connection processing means (1) and the calling information storage means (2) of the completion of the connection and the identification information of the answered calling message.
), and upon receiving a notification of receipt of response information from the response monitoring means (4), the calling message storage means (2)
A calling message cancellation processing means (5) is provided for accessing the network and canceling calling messages other than calling messages for which there is response information to the network, and continuously sending calling messages corresponding to multiple communication capabilities. A call connection method in ISDN, which is characterized by confirming the communication capability of the other party's terminal in a short period of time by transmitting the following information. 2. A plurality of calling message transmitting means (3) which have received a calling request that does not specify the communication capability of the communication partner terminal from the connection processing means (1a) are stored in the calling information storage means (2). If no response information is obtained under predetermined conditions when calling messages are sent to the network one after another, the connection processing means (1a) controls a calling message that does not specify communication capability for the other party's terminal. Connection restriction terminal storage means (in which it is recorded that the call request is invalid)
6a), where the connection processing means (1a) accesses the connection restriction terminal storage means (6a) at the time of a call connection, thereby making it invalid to make a call request that does not specify communication capability. I according to claim 1, characterized in that it is possible to avoid invalid calling connections by identifying
Call connection method in SDN. 3. Communication control means (7) in which the connection processing means (1b) controls communication with the other party terminal after the calling connection is terminated; and the connection processing means (1b) controls the communication capability of the communication partner terminal. Terminates the calling connection that specified the communication control means (
When it is found that the terminals cannot be synchronized after starting the communication according to 7), the connection processing means (1b) controls the communication to the other party terminal using the calling message used when making the call. connection control terminal storage means (6b) for storing information indicating that the connection is disabled;
b) at the time of outgoing call connection, the connection regulation terminal storage means (6b)
), it is possible to identify a partner terminal with which communication is impossible based on a call request specifying a communication capability, and to avoid an invalid call connection. Call connection method in ISDN. Claim 4: After the connection processing means (1c) terminates a call connection that does not specify the communication capability of the communication partner terminal, and after the communication control means (7) starts communication, it is found that synchronization between the terminals cannot be achieved. When the connection processing means (1c)
connection restriction terminal storage means (6c) for storing that communication is not possible in response to a call request that does not specify communication capability to the other party's terminal under the control of the connection processing means (6c);
When 1c) makes a call connection, the connection regulation terminal storage means (6
c) by accessing, identifying a partner terminal with which communication is impossible due to a call request that does not specify communication capabilities;
4. The call connection system in ISDN according to claim 3, characterized in that it is possible to avoid invalid call connections.