JPH0323733A - Outgoing/incoming call system for isdn - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a call origination/termination method, and more specifically, a method for determining a calling terminal in terminal-to-terminal communication via an integrated services digital network (ISDN). Regarding.

[Prior art]

Conventionally, in a communication system consisting of a plurality of public networks (for example, a public telephone network, a public facsimile network, a public line switched network, etc.) and terminals that communicate via the public networks, one of the methods for reducing communication charges for the terminals has been proposed. As a first step, when setting up a communication path between the terminals, the calling terminal selects the network from among multiple public networks that provides the lowest communication charges between the terminals, depending on the communication conditions between the terminals. LCR (Least Cost)
Routing). An example of LCR is described, for example, in JP-A-62-30452.

On the other hand, integrated service digital networks (
ISDN) has multiple information channels (Bch) and at least one control channel (Dch) and is based on the International Telegraph and Telephone Consultative Committee (CCITT) Recommendation I. 430, I. 43
1.I. 440, I. 441, I. 450, I. 451
As shown in the record, a control channel (Dch) can be provided to terminals connected to ISDN, and each terminal sends a call setup message (SETUP) in the Dch call setup procedure described above.
, alert message (ALERT), response message (C
ONN), disconnection message (DISC), release message (REL), release complete message (REL C)
OMP) can be used to transfer information between users that is not related to the network.

FIG. 2 is a diagram showing the configuration of a communication system using ISDN 50, in which terminal equipment 1i10A and IOB are connected to ISDN 50 via network termination devices (NT) 20A and 20B, respectively. The ISDN 50 includes exchange termination equipment (ET) 51A, 51B connected to the network termination equipment, circuit switching equipment (CS) 52A, 52B, and a packet handler (P).
H) 53A. 53B, the operator IA or 1B gives instructions to the terminal 10A or IOH by inputting commands and obtains messages from the terminal.

By the way, according to the conventional communication system, establishment of a call with a partner terminal is performed as follows based on a call setup establishment request from an operator from one terminal.

Figure 35 shows conventional call setup/release messages between terminals.
This is a diagram showing a sequence, in which, for example, the operator IA on the terminal A side requests the terminal 10A (calling terminal) to set up a call (step S50), and based on the call setting request, the calling terminal connects to ISDN. Make a call (S51), ISDN5
0 sends a call setup acceptance message to the calling terminal as a response to the call setup message (S 5 2).
. Further, the engineering SDN calls the terminal 10B (called terminal) based on the request from the calling terminal (853).
. The called terminal 10B that received the call setting message transmits a response to the above-mentioned SDN (S54). I received the response
The SDN 50 sends a response confirmation to the called terminal (857
) and sends a response to the calling terminal (S55).

To the calling terminal Jtl 0 operator IA which received the response. The call setting confirmation is notified (8 5 6), and the called terminal 10B notifies the operator IB of the call setting (858).
, As a result, a call between the terminals is established and the notification becomes possible (860). The call is released according to steps 861-69.

[Problem to be solved by the invention]

For example, when a terminal in Japan and a terminal in the United States communicate with each other via a public switched network, there is a time difference between Japan and the United States, so when it is daytime in Japan, it is nighttime in the United States. Therefore, if you make a call from a device in the United States to a device in Japan at night, you can use nighttime discount rates to communicate at a low cost.
Conventional LCR did not take this point into consideration.

That is, in the conventional LCR system, it was not possible to select the calling side (call setting side) terminal in order to reduce communication charges in communication between terminals via a public network.

On the other hand, even in communication systems using ISDN, so far, terminals with lower communication charges (e.g., terminals that can use night-time discount charges) have shifted from terminals with higher communication charges (for example, terminals with night-time discount charges). By making a call to the terminal (for which the fee is not available), the above ISDN
There is no such thing that takes into account the reduction of communication charges between terminals connected to the above ISDN.
There was a problem in that it was not possible to reduce communication charges for terminals communicating via N.

An object of the present invention is to provide a communication system consisting of an ISDN and terminals that communicate via the ISDN, from a terminal with a lower communication charge (for example, a terminal that can use night rIfJm discount charges) to a terminal with a higher communication charge. [To solve the problem] Means] In order to achieve the above object, the present invention provides an ISDN and
In a communication system consisting of terminals that communicate via the above-mentioned ISDN, when a call is established on a control channel (Dch), a calling terminal sets a "call request request" in the user/user information request of a call setup message (SETUP). and makes a call to the called terminal. ``The called terminal that has received the outgoing call request will first reject the call before establishing the call, and conversely, the called terminal will establish a call to the calling terminal. do.

In this case, in order for the called terminal to re-call only under specific conditions, the calling terminal should add other half-hanging information to the call setup message in addition to the call request request. Based on the above judgment information, the called terminal either establishes the call, or rejects the call and sends a new call from the called terminal to the calling terminal.

[Effect]

According to the present invention, when a calling terminal requests a call request to a called terminal, the called terminal sends a call request to the called terminal without establishing the call. , the calling terminal can avoid paying charges. In addition, if r condition information is added to the call setup message in addition to "call request request," the called terminal can determine whether or not to accept the call request based on the above condition information. Inform the other party of the communication charges for setting up the call, and the called party compares the above communication charges with the communication charges for setting up the call, and accepts the call request if it is determined to be cheaper. For example, communication between terminals can be performed at low cost. Additionally, if a "closed area identifier" is added to the call setup message so that the called terminal only accepts outgoing calls with a specific closed area identifier, terminals belonging to a specific group specified by the closed area identifier in advance can be used. Communication can be carried out at low cost.

According to one embodiment of the present invention, a calling terminal sets "call request request" in the user information of a call setup message and calls two called terminals.

The called terminal that has received the call request request J rejects the call, sets r call request request in the user information of the call setup message, and then sends the call to the third terminal (which communicates with the calling terminal). (desired terminal).

The third terminal that has received the "outgoing call request" temporarily rejects the call and sets up a call to the calling terminal. In this way, even if the user does not know the ISDN number of the third terminal, it is possible to communicate with the third terminal by knowing only the ISDN number of the called terminal.

〔Example〕

The details of the present invention will be explained below with reference to the drawings. (1)
The system configuration in FIG. 3 shows the terminal device 10 (10A, I
This is a diagram of the structure of OB). Each terminal is an operator (OP)
1 via the keyboard 11, and notifies the operator of the message via the CRT display 12. In addition, an ISDN adapter (hereinafter referred to as ISA
) 18 and a subscriber line LINE, it is connected to a network terminal (NT) 20.

CPU 15, keyboard board 11, CRT display 12, floppy disk driver 13,
The ROM 16, RAM 17, and ISA 18 are connected via a bus 19, respectively. FIG. 4 shows the memory structure of the ROM 16.

In FIG. 4, the memory has a program area 16', a supervisor program area 20, an ISA control program area 21 for controlling ISA, and a Dch call control program area 22 for controlling calls between terminals. ,
Bah call control program area 23 for controlling calls on information channels, resource management program area 24 for managing resources such as call numbers, and upper layer control process area 25
It becomes more.

Further, the ISA control program area 21 includes an ISA state control program area 21A, a physical link control program area 21B . Dch data link control program area 21C. Bch data link control program area 21D
It consists of more. FIG. 5 shows the memory structure of the RAM 17.

The RAM 17 consists of a control information area 31 and a data area 32, and the control information area 31 is . A call number management information area 33 for managing the call number of a Dch call, a closed area identifier information area 34 for managing a closed area identifier for making a closed area connection,
Called number management information area 35 for managing the called number when a call is received, transfer number information area 47 for obtaining a forwarding destination terminal number based on the ISDN number of the calling terminal when a call is received, and based on the called number and call setup time. A communication charge information management area 36 that manages communication charges between terminals, a communication charge number management information area 37 that manages the terminal number of the other party to whom communication charges are to be paid at the time of a call, and a number management information area 37 to which the communication charge is to be paid when a call is received; , a communication fee-bearable party number management area 38 for determining whether or not to bear the communication fee for the call, an ISA management table area 39 for managing the ISA, and a physical link control table area for controlling the physical link. 40. D for controlling the Dch data link
ch data ring control table area 43, Bch data link control table area 44 for controlling Bah data links, Dch control table area 45 for controlling Dch calls, Bah call control table area 46 for controlling Bch calls. have.

Further, the data area 32 has a transmitting/receiving buffer area 48 for transmitting and receiving data.

From FIG. 6 to FIG. 16, the call number management information table (FIG. 6) in the call number management information area 33, the closed area identifier information table (FIG. 7) in the closed area identifier information area 34, and the called number The called number management information table (FIG. 8) in the management information area 35, the communication charge information table (FIG. 9) in the communication charge information area 35, and the communication charge bearer number in the communication charge bearer number management information area 37. Management information table (Figure 10), communication chargeable party number management area 3
8, the communication fee-bearable party number information table (first
1), the forwarding number information table in the forwarding destination number information 47 (Fig. 12). ISA management table (Figure 13), Dch physical link control table 41 and Bch physical link control table 42 in the physical link control table area 40
(p 1 4 Figures (A) to (B)) % Dch data link control table (Figure 15 (A), Bah data link control table (Figure 15 (B)), Dch call control table (Figure 16 ( A)), Bch call control table (FIG. 16(B)).

FIG. 17 shows an interface of a Dch call control processing unit (Dch call control program 22) that controls calls of the terminal 10. The Dch call control processing 22 has an interface with the operator 1, the resource management section 24, and the ISA 21, as shown in the figure.

FIG. 18 shows the interface of the Dch protocol control unit 54 that controls the Dch calls of the line exchange in the ISDN 50. The Dch protocol control unit 54 has an interface with a Dch call control processing unit 55, a resource management unit 56, and a DCH SA 57.

Figure 19 shows the format of messages between the terminal and the network, and Figure (
A. 'I is a call setup message, Figure CB) is a call setup acceptance message, Figure (c) is a response message, Figure CD) is a disconnection message, Figure (E) is a release message, Figure (F)
is the release completion message. Here, in order to facilitate understanding of the present invention, the conventional terminal-to-terminal call setup procedure when using circuit switching in the communication system shown in FIG.
The message sequence shown in the figure, the call control procedure of the calling side terminal shown in Fig. 36, the call control procedure of the called side terminal shown in Fig. 37, and the SDL of the Dch protocol control section of the calling side network shown in Fig. 39. 40 and an SDL diagram of the Dch protocol control unit of the receiving side network shown in FIG. Furthermore, the third
8(A) to (H) show the meanings of the symbols used in the SDL description of FIGS. 36 and 37, and similarly, FIGS. The meanings of the symbols in SDL in Figure 40 are shown. According to the conventional system, as shown in FIG.
The Dch call control processing unit 22 of A is in an empty state (step 30
0), when a call setup request is received from the operator, (30
2), Call number management information table (308). Dch protocol control unit 5 on the calling terminal side of ISDN 50
4, as shown in FIG. 39, is in the idle state (400) and upon receiving the call setup message (406). The call setting is notified to the DcnQ control processing unit 55 (404). The call state is entered (406).

When the Dch protocol control unit 54 on the calling terminal side of the ISDN 50 receives a call setting acceptance request from the Dah call control processing unit 55 (408), it transmits the call setting acceptance to the calling terminal 10A (410). ．． The call is accepted (4)
1 2).

Calling terminal 1. As shown in No. 361, when the Dch call control processing unit 22 of the OA receives the call setting acceptance in the calling state (310). The system enters a call acceptance state (312). On the other hand, when the Dch protocol control unit 54 on the called terminal side of the ISDN 50 receives a call setup request from the Dch call control processing unit 55 in the idle state (450), as shown in FIG. (4.52) - called terminal]. A call is made to the OB with a call setup message (454), and the call is received (45).
6).

As shown in FIG. 87, when the Dch call control processing unit 22 of the called terminal 10B receives a call setup message from the ISDN 50 in the idle state (300) (332). A response is sent to ISDN (334) to indicate acceptance of the call.
). It becomes a response state (3 3 6).

Dch protocol control unit 5 on the called terminal side of ISDN 50
4 is the incoming call state (4 5 6) as shown in Fig. 40.
When a response message is received from the terminal (458), D
Notify the channel call control processing unit 55 of call setting confirmation (460)
, becomes responsive (462).

Upon receiving the response confirmation request from the Dch call control processing unit 55 (464), the Dch protocol control unit 54 on the called terminal side of the ISDN transmits a response confirmation message to the called terminal 10B (466), and enters the communication status. Becomes (470).

The Dch call control processing unit 22 of the called terminal 10B is an ISDN
When the response confirmation message is received from 50 (338).
The call setup is notified to the operator IB (340), and the communication status is entered (345).

Next, as shown in FIG. 39, when the Dch protocol control unit 54 on the calling terminal side of the ISDN 50 receives call setup confirmation from the Dch call control processing 55 (414), it sends a response message to the calling terminal 10A. Send (416). The communication state becomes d (420). ．． As shown in FIG. 36, the Dch call control processing 22 of the calling terminal 10A receives a response message from the ISDN 50 (314). Operator Air A is notified of the call setup confirmation (316) and the communication status (
1) First Embodiment FIG. 1 is a message sequence showing a call control procedure according to a first embodiment of the present invention in the above communication system. In this embodiment, the calling terminal 10A sets a calling request request in the user information of the call setting message, makes a call to the called terminal, and the called terminal 10B receives the calling terminal request. However, the call is once rejected and a new call is established to the calling terminal 10A. This allows the calling terminal to request the called terminal to make a call. In FIG. 1, the operator IA requests the terminal 10A (calling terminal) to make a call request (step S1), and the calling terminal sets the call request request in the user information of the call setup message. Make a call to IsDN50 (S2)
．． Upon receiving the call setup message, the ISDN 50 transmits a call setup acceptance message to the calling terminal 10A (S3).
, sends a call setup message to the terminal 10B (called terminal) (84). In this case, ISDN is 10B
accepts the call trust request unconditionally, sets call request acceptance in the release completion message, and temporarily rejects the call (S5)
．． ISDN 50, which has received the release completion notification, transmits release completion (call request acceptance) to the calling terminal (S6). The calling terminal 10A, which has received the release completion (call request acceptance), notifies the operator IA of the call request acceptance (S7). Upon completion of the release, the called terminal 10B, which has notified the calling end station that the call request has been accepted, secures a new call and makes a call to the ISDN 50 (Sa). The ISDN 50 transmits a call setup acceptance message to the called terminal 10A (S9), and transmits a call setup message to the calling terminal 10A (810). The calling terminal 10A that received the call setup message sends a response to the above ISD.
N (S11). The ISDN 50 transmits a response confirmation to the calling terminal 10A (S12). Called terminal 1 responds
0B (S13). The above-mentioned calling terminal that receives the response confirmation notifies the operator IA of call setup (confirmation of calling request)
(S 1 5). On the other hand, the called terminal 10B that received the response also notifies the operator IB of a call setup notification (confirmation of the calling request) (S14).

Next, the details of the embodiment of the above construction are shown in the SIDL diagram of the Dch call control processing section 22 of the terminal shown in FIG. 20 and the second construction drawing, and the Dch protocol control section of the ISDN shown in FIG. 39 and FIG. 40. This will be explained with reference to the SDL diagram of No. 54.

In FIG. 20, the Dch of the calling terminal (terminal A) IOA
The call control processing unit 22 is in an empty state (100) when the operator L
When a call setup request is received from A (102), an unused call number is selected from the call number management information table 33 shown in FIG. 6 (104). A calling request request 67B is set in the user information 67 of the call setting message shown in FIG. 19(A), and a call is made to the ISDN 50 (108) - the calling state is entered (110). Next, the Dch on the ISDN calling terminal 10A side in FIG.
As shown in FIG. 39, when the protocol processing unit 54 receives the 2 call setup message in the empty state (4 0 0), the protocol processing unit 54
02), notifies the Dch call control processing 55 of the call setup (4)
04). The system enters a calling state (406). still. ISDN50
notifies the called terminal of the user-to-user information in the call setup message without checking it.

As shown in FIG. 39, the Dch protocol processor 54 on the calling terminal 10A side of the ISDN 50 processes
When a call setting acceptance request is received from the call control processing 55 (408
). A call setup acceptance message is sent to the calling terminal 10, A (410), and the call acceptance state is entered (41'2). As shown in FIG. 20, when the Dch call control processing unit 22 of the calling terminal 10A receives the call setup acceptance message in the calling state (112). The call receiving state is entered (120).

The Dch protocol processing unit 54 on the called terminal (terminal 10B) side of the ISDN 50 is in an empty state (
When a call setup request is received from the ISDN Dch call control processing unit 55 at step 100) (452), a call is made to the called terminal 10B with a call setup (outgoing request request) message (454),
The call enters the incoming state (456). Note that the Dch protocol control unit 54 adds the user-to-user information of the call setup message from the calling terminal 10A as is to the call setup message for the called terminal 10B.

As shown in FIG. 21, when the Dch call control processing unit 22 of the called terminal 10B receives a call setup (call request) message from the ISDN 50 in the idle state 200 (202),
Issues release completion (call request accepted) (2 1 0), releases call once (2 1 2), and transitions to idle state (2 1 0).
20).

The called terminal 10B sets a call request acceptance 67E in the user/user information 67 of the release completion message shown in FIG. 19(F) to indicate that the call request has been accepted to the calling terminal 10A. There is.

Next, the Dch protocol control unit 54 on the called terminal 10B side of the ISDN 50 controls the call receiving state
When the release completion (outgoing request accepted) is received at 56 (4 8
0), and notifies the Dch call control processing unit 55 of the release confirmation (
482), becomes empty (484). In addition, ISDN50
The user information of the release completion message of the called terminal 10B is not checked, and the calling terminal ↓OA is sent as is.
take over.

Next, as shown in FIG. 39, when the Dch protocol control 54 of the calling terminal 10A of the ISDN 50 receives a release notification from the Dch call control processing 55 (430), the Dch protocol control 54 of the calling terminal 10A informs the calling terminal 10A of the release completion (calling request). Reception) Send a message (432). It becomes empty (434). As shown in FIG. 20, when the Dch call control processing unit 22 of the calling terminal 10A receives a release completion (calling request accepted) message from the ISDN 50 (122). Operator I
A is notified of acceptance of the outgoing call request (124), the call is released (126), and the call becomes idle (130).

In order to accept the call request, the called terminal 10B, which has once released the call, selects a new call number as shown in FIG. 21 (222). The call request confirmation 67B is set in the user information 67 of the call setup message shown in FIG. 9(A), and the call setup (call request confirmation) is requested from the ISDN (
4). The call state is entered (230).

As shown in FIG. 39, when the Dch protocol processing unit 54 on the called terminal 10B side of the ISDN 50 receives the call setup message in the idle state 400 (402). The call setting is notified to the Dch call control processing unit 55 (404), and the call origination state is entered (406).

Further, upon receiving a call setup acceptance request from the ISDN Dch call control processing section 55 (408), the Dch protocol processing unit 55 on the ISDN called terminal 10B side sends a call setup acceptance message to the said ISDN called terminal 10B. Shi (410)
, the call acceptance state is entered (412).

As shown in FIG. 21, when the Dch call control processing unit 22 of the called terminal 10B receives the call setup acceptance message in the calling state 230 (232). The call is accepted (240
).

On the other hand, as shown in FIG. 40, when the Dch protocol control unit 54 of the ISDN 50 (7) calling terminal 10A receives a call setup request from the Dch call control processing unit 55 in the idle state 450 (452). A call is made to the calling terminal 10A with a call setup (call request confirmation) message (454), and the call is received (
456).

The Dch call control processing unit 22 of the calling terminal 10A is the 20th
As shown in the figure, when a call setup (call request confirmation) message is received from the ISDN 50 in the empty state 130 (132),
A response message is sent to I to indicate that the call has been accepted.
Send to SDN (134) and enter response state (140)
.

Next, as shown in FIG. 40, the Dch protocol control unit 54 on the ISDN calling terminal 10A side displays
When the response is received (458), the Dch call control processing unit 5
5 to confirm the call setup (460), and enters the response state (
462). Further, when the Dch protocol control unit 54 of the ISDN calling terminal 10A receives a response confirmation request from the Dch call control processing unit 55 (464), it transmits a response confirmation message to the calling terminal 10A (466), and enters a communicating state. becomes (
4 7 0).

The Dch call control processing unit 22 of the calling terminal 10A is ISDN5
When the response confirmation message is received from 0 (142), the operator 1A is notified of the call setting (call request confirmation) (14
4). It enters a communicating state (150). On the other hand, as shown in FIG. 39, when the Dch protocol control unit 54 on the called terminal 10B side of the ISDN 50 receives call setting confirmation from the Dch call control processing 55 (414), it sends a response to the called terminal 10B. (416), and becomes in communication status (420). Further, as shown in FIG. 21, when the Dch call control processing unit 22 of the called terminal 10B receives a response from the ISDN (242), it notifies the operator 1B of call setting (call request notification) (244). The state is in communication (
250).

Through the above procedure, the call request from the calling terminal to the called terminal is completed, and a call between the terminals is established.

According to this embodiment, the calling terminal can request the called terminal to make a call without once establishing a call.

Therefore, the calling terminal does not need to establish a call to the called terminal to request a call, and use the call to request the call. Therefore, the calling terminal, to the called terminal,
There is no need to establish a call to request an outgoing call and pay communication charges associated with establishing the call.

Furthermore, since the called terminal accepts the call request request from the calling terminal, the calling terminal does not have to bear any communication charges after the call is established.

(3) Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. 22 to 25. In the second embodiment, the control channel Dch)
When establishing a call, the calling terminal sets "rclosed area identifier" in the user information field of the call setup message and requests a call request from the called terminal, and the called terminal receives the call request. is characterized in that it checks the above-mentioned "r closed area identifier" and accepts only call request requests from calling terminals having a specific "closed area identifier".

Hereinafter, differences from the first embodiment will be mainly explained.

FIGS. 22 and 23 show a message sequence when a call is requested from the terminal 10A to the IOB in the second @ system.

In FIG. 22, when setting up a call, the terminal 10A (calling terminal) includes a calling request request 67B and a closed area identifier 67A indicating the closed area of the terminal in the user information 67 of the call setting message shown in FIG. 19(A). settings and makes a call to ISDN 50 (S2').

The ISDN 50 inherits the user-to-user information 67 of the call setting message from the calling terminal 10A as it is and makes a call to the called terminal 10B (S4').

The called terminal 10B determines whether the closed area identifier 67A of the received call setting message matches a predetermined closed area identifier stored in the called terminal itself, and if it matches, accepts the call request. , processing steps 85 to S15 in this case
is the same as in the first embodiment.

If the closed area identifier does not match the predetermined closed area identifier, as shown in FIG. 23, the called terminal 10B rejects the call request in the user/user information 67 of the release completion message shown in FIG. 19 (CF). A code 67E is set and sent to ISDN 50 (S 1 6). The release completion message is sent from the ISDN 50 to the calling terminal (IOA) (S17), and the calling terminal 10A notifies the operator IA of the rejection of the calling request (8 1 8).

FIGS. 24 and 25 are SDL diagrams showing the call setting procedure executed by the Dch call control processing unit 22 in the calling terminal 10A and the called terminal 10B, respectively. Figure 24 SDL
The difference between this figure and the SDL diagram of FIG. 20 (first embodiment) is that closed area identifier selection processing 105 and release completion (call rejection) reception processing 160 to 166 are added.

The Dch call control processing unit 22 of the calling terminal 10A has an empty status of $1.
When a call setup request is received from operator LA at 00 (10
2) Select an unused call number from the call number management information table 33 shown in FIG. 6 (104), and select the closed area identifier 34 corresponding to the called terminal from the closed area identifier information table 34 shown in FIG.
Select B (l O 5). Next, a calling request request 67B and a closed area identifier 67A are set in the user-to-user information 67 of the call setting message shown in FIG. 19, similar to the ISD embodiment. However, when the Dch control processing 22 of the calling terminal 10A receives a release completion (rejecting the calling request) message from the engineering SDN 50 in the call accepting state 120 (160)
．． Notify the operator IA of the rejection of the call request (162),
The call is released (164) and becomes idle (166).

DCh call control process 22 of the called terminal 10B shown in FIG.
206 is added to the SDL diagram of . The called terminal 10B is in the idle state 200 and the I
When receiving a call setup (outgoing call request, closed area identifier) message from the SDN (202'), it is determined whether the closed area identifier matches the closed area identifier stored in itself (203').
), if it is 1 m, the call request is accepted by release completion (call request acceptance) (210). If the idle area identifiers do not match, a release completion (call request rejected) message is sent (204). Once the call is released (205), the state changes to the idle state (206).

Note that since the ISDN 50 inherits the user-to-user information without checking, even if the contents of the user-to-user information are different, the ISDN 50 takes over the user-to-user information without checking. The processing content of the DN is the same as in the first embodiment.

According to this embodiment, when a call is set up, the called terminal is a predetermined closed user.・Since it is possible to reject call requests from terminals outside the group, it is useful for protecting the confidentiality between users and group terminals inadvertently.

(4) Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIGS. 26 to 29. In this example, the control channel (Dc
h) When establishing a call, the calling terminal receives the above-mentioned "call request request" if the user/user information terminal in the call setup message is not answered, and establishes a call from the called terminal to the above-mentioned calling terminal. It is characterized by what it did.

FIGS. 26 and 27 show a message sequence when a call is requested from the terminal 10A to the terminal 10B in the communication system shown in FIG. The difference from the message sequence of the first embodiment explained in FIG.
A calls the called terminal after setting the outgoing request and the communication fee in the call setup message, and the called terminal 10
B compares the communication charges between the terminals, and if the communication charge of the calling terminal is higher than the communication charge of the called terminal, the called terminal rejects the call and sends a new call to the calling terminal. A call is set up, and if the communication charge of the calling terminal is less than the communication charge of the called terminal, the called terminal accepts the call.

In the message sequence shown in FIG. 26, the calling terminal 10A sends a call request request 67 to the user information 67 of the call setting message shown in FIG.
Set the communication charge of 67C for B and the calling terminal, and
50 (S2'). The ISDN 50 inherits the user-to-user information 67 of the call setting message from the calling terminal 10A as it is and makes a call to the called terminal 10B (S4'). The called terminal 10B compares the communication charge indicated by the call setting message with the communication charge on its own terminal side, and if the communication charge of the calling terminal is equal to or higher than the communication charge of the called terminal, it accepts the call request.

If the communication charge of the calling terminal is less than the communication charge of the called terminal, as shown in Fig. 27, a call request rejection 67D is set in the user/user information 67 of the response message shown in Fig. 19 (Q). Then, the calling terminal 10A is notified of the rejection of the call request (S16'S17'). The call is established without being rejected (S19). The calling terminal 10A and the called terminal 10B notify their respective operators of call setup notification (call request rejection) (818
', S20).

FIGS. 28 and 29 are SDL diagrams showing the call setting procedure carried out by the Dch call control processing units 22 of the calling terminal 10A and the called terminal 10B, respectively, in this embodiment.

Hereinafter, differences from the first embodiment described in FIGS. 20 and 21 will be described.

In FIG. 28, when the Dch call control processing unit 22 of the calling terminal 10A receives a call setting request from the operator IA in an empty state 100 (102), it selects an unused call number from the call number management information table 33 shown in FIG. Select the call number (104
). Also, with reference to the communication charge information table 36 shown in FIG. A call is made to the ISDN 50 by setting a calling request request 67B and a communication fee 670 in the user information 67 of the call setting message shown in FIG.
8') and enters the calling state (1 1 0).

Further, the Dch call control processing unit 22 of the calling terminal 10A
Upon receiving a response (call request rejection) message from the SDN 50 (170), it notifies the operator 1A of a call setup notification (call request rejection) (172), and enters a communicating state (1
50).

On the other hand, as shown in FIG. 29, when the called terminal 10B receives a call setup (call request, communication fee) message from the ISDN in the idle state 200 (202'), the called terminal 10B
Compare the communication charge of 0A and the communication charge of the called terminal (204
), if the communication charge estimate of the calling terminal is greater than or equal to the communication charge of the called terminal, a release completion (call request accepted) is sent (2 1
0), accepts a call request.

If the communication charge of the calling terminal 10A is less than the communication charge of the called terminal 10B, the call is established (207) with a response (rejection of the call request) message, and the operator is notified of the call setup (rejection of the call request). ) (208), and transitions to the communicating state (250).

Note that since ISDN 50 inherits user-to-user information without checking, the processing content of ISDN is the same as in the first embodiment even if the contents of user-to-user information are different. According to this embodiment, when communicating between terminals, a call can be made from the terminal with the lowest communication charge, so the communication charge between the terminals can be reliably reduced.

(5) FIG. 4 Embodiment Next, a fourth embodiment of the present invention will be described with reference to FIGS. 30 to 32.

In this embodiment, the calling terminal requests the called terminal to bear the communication charges, and the called terminal checks the ISDN number of the calling terminal and determines whether or not to bear the charges. ing. Therefore, in this embodiment, when the called terminal pays the communication fee, the message sequence is the same as that shown in FIG. 1, and when the called terminal refuses to pay the communication fee, the message sequence is as shown in FIG. It can be distinguished from the forward first embodiment in that 816 to 818 are added.

FIG. 31 and FIG. 32 are SDL diagrams showing the call setup procedure executed by the Dch call control processing units of the calling terminal 10A and the called terminal 10B, respectively.

In FIG. 31, when the Dch call control processing unit 22 of the calling terminal 10A receives a call setting request from the operator IA in the idle state 100 (102), the Dch call control processing unit 22 of the calling terminal 10A selects an unused call from the call number management information table shown in FIG. Select the telephone number 33A (104), and select the called party number (destination ISDN number) 37A that will bear the communication charges from the information table of numbers to which the communication charges will be borne (1 0 7).
). Next, these data are set as a calling request request 67B in the user information 67 of the call setting message shown in FIG. 19(A), and a call is made to the ISDN 50 (108
). A call is placed (1 1 0).

The Dch call control unit 22 of the calling terminal 10A is an ISDN5
Upon receiving a release completion (outgoing request rejection) message from 0 (160), the operator IA is notified of the outgoing request rejection (162). Releases the call (164) and becomes idle (1
66).

On the other hand, as shown in FIG. 32, when the called terminal 10B receives a call setup (outgoing call request) message from the ISDN in the idle state 200 (202), the called terminal 10B receives the call destination number information table for which communication charges can be paid as shown in FIG. 38 as the calling number (the other IS
DN number) and determines whether or not the calling terminal can bear the communication charges (203'). If it is possible to bear the burden, the call request is accepted upon release completion (call request accepted) (2 1 0). On the other hand, if you cannot bear the burden, send a release completion (call request rejected) message (20
4) and releases the call (205). Transition to empty state (
206).

Incidentally, since the ISDN takes over the user-to-user information without checking, even if the contents of the user-to-user information are different, the processing contents of the ISDN are the same as in the first embodiment. According to this embodiment, using ISDN circuit switching,
When communicating between terminals, communication charges for the terminals can be unified.

(6) Fifth Embodiment Next, a fifth embodiment of the present invention will be described with reference to FIGS. 33 and 34. This embodiment differs from other embodiments in that the called terminal that receives the call request requests the third terminal to make the call, and the third terminal establishes the call to the calling terminal. That is, in this embodiment, when setting up a call on a control channel (Dch), the calling terminal sets a "call request request" in the user information of the call setting message and calls the called terminal, "
The called terminal that received the "call request request" once rejects the call, newly sets "call request request" in the user information of the setting message, and communicates with the third terminal (calling terminal). The third terminal that receives the "call request request" temporarily rejects the call and establishes a new call to the calling terminal. FIG. 33 is a conceptual diagram of the above-mentioned call transfer.

For example, when the terminal 10B receives a call request from the calling terminal 10A, the called terminal 10B once rejects the call between the calling terminal and the called terminal, and the called terminal 10B , sets the calling request request 67B in the user information 67 of the call setting message, transfers the calling request to the third terminal (terminal that wishes to communicate with the calling terminal) IOC, and sends the calling request to the third terminal ↓OC. However, once the call between the called terminal 10B and the third terminal is rejected, a new call is established between the third terminal 10C and the calling terminal 10A.

FIG. 34 shows the message sequence of the fifth embodiment. In the figure, the calling terminal 10A requests the called terminal 10B to make a call request (S2) in accordance with the operator IA's request (S1). The above-mentioned called terminal 1 that received the above-mentioned call request
0B once rejects the call between the calling terminal 10A and the called terminal 10B (85-S7). The message sequence up to this point is the same as in the first embodiment.

Next, the called terminal OB that rejected the call transfers the call to the third terminal 10.
To transfer the call to C, search based on the SDN number (destination ISDN number) shown in Fig. 12, select transfer destination ISDN number 47B, and make a call to the third terminal (822 to S
24). The third terminal 10C is the called terminal 10B.
and the third terminal 10C is temporarily rejected (
S 2 5 , 826).

Next, the third terminal 10C establishes a call to the calling terminal 10A (88-S13).

These message sequences 88-S13 are
This procedure is similar to the call setting procedure from the called terminal to the calling terminal in the embodiment. After the call is established, the calling terminal 10A and the third terminal 10
C notifies each operator of call setup (confirmation of call request) (S14, S15).

Incidentally, since the ISDN takes over the user-to-user information without checking, even if the contents of the user-to-user information are different, the processing contents of the ISDN are the same as in the first embodiment.

According to this embodiment, the called terminal transfers the calling terminal's call request request to the third terminal, and the third terminal that has received the call request request makes the call to the calling terminal. Establish.
Therefore, the calling terminal uses the ISDN of the third terminal.
Even if you do not know the number, if you know the ISDN number of the called terminal, you can communicate with the third terminal. Although the embodiments of the present invention have been described above, the features of each of the embodiments described above may be combined with other embodiments. [Effects of the present invention] As explained above, in the present invention, the control channel (Dc
In the call setup procedure h), the calling terminal sets "call request", "closed connection", or "communication fee" in the user information of the call setup message, and requests the called terminal to make a call. Depending on the conditions, the called terminal that has received the "outgoing request request" may either reject the call and establish a new call to the calling terminal, or, depending on the conditions, may accept the "outgoing request request" The called terminal accepts the call, or the called terminal that has received the "call request request" transfers the call request request to a third terminal,
The third terminal that received the call request request sets up a call to the calling terminal. Therefore, according to the present invention, it is not necessary for the calling terminal to establish a call to the called terminal in order to request a call, and to request the call using the call. Therefore, the calling terminal
There is no need to establish a call to the called terminal in order to request an outgoing call, and to bear communication charges associated with establishing the call. Furthermore, when setting up a call, if the called terminal rejects calls from outside the closed user group, it will not be possible to accidentally establish a call with a terminal outside the closed user group, and the confidentiality between the terminals can be protected. Furthermore, when communicating between terminals, calls can be made from the terminal with the lowest communication charges, which reduces communication charges between terminals, and only the terminal that pays the communication charges can establish a call, reducing the burden of communication charges between terminals. You can unify the source. Further, the called terminal transfers the calling terminal's call request request to the third terminal, and the third terminal receives the call request request.
If the terminal establishes a call to the calling terminal,
Even if the calling terminal does not know the ISDN number of the third terminal, it can communicate with the third terminal if it knows the ISDN number of the called terminal.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the message sequence of the first embodiment of the present invention, FIG. 2 is an overall configuration diagram showing an example of a communication system using ISDN, and FIG. 3 is a diagram showing the equipment configuration of the terminal 10. Figure 4 shows the ROM
FIG. 5 is a diagram showing the memory configuration of the RAM 16, and FIG. 6 is a diagram showing the memory configuration of the RAM 16.
3, FIG. 7 is a diagram showing the closed area identifier information table 34, FIG. 8 is a diagram showing the called party number management information table 35,
9 is a diagram showing the communication charge information table 36, FIG. 10 is a diagram showing the communication charge burden destination number information table 37, and FIG. 11 is a diagram showing the communication charge burden destination number information table 3.
8, FIG. 12 shows the forwarding number information table 47, FIG. 13 shows the ISA management information table 39, and FIG. 14 shows (A) and (B), respectively. 15 is a diagram showing the physical link control tables 41.42 for Dch and Bch, and FIG. 15 is a diagram showing the data ring control tables 43.44 for Dch and Bch, respectively.
) are the Dch and Bch call control tables 45.
46, FIG. 17 is a diagram showing the logical interface of the Dch call control processing section of the terminal, FIG. 18 is a diagram showing the logical interface of the Dch protocol control section of the network, and FIG. 19 (A) to (F ) are diagrams showing message formats for call setup, call setup acceptance, response, disconnection, release, and release completion, respectively. FIGS. FIG. 22 and FIG. 23 are diagrams showing a message sequence in the second embodiment of the present invention, and FIGS. 24 and 25 are diagrams showing the second embodiment of the present invention, respectively. 26 and 27 are diagrams showing the message sequence in the third embodiment of the present invention, and FIGS. 28 and 29 are diagrams showing the call control procedure of the calling terminal and the called terminal, respectively. FIG. 30 is a diagram showing the call control procedure of the calling terminal and called terminal in the third embodiment, and FIG. 30 is a diagram showing the message sequence in the fourth embodiment of the present invention. FIGS. 31 and 32 are respectively A diagram showing the call control procedure and sequence of the calling terminal and the called terminal in the fourth embodiment, FIG. 35 is a diagram showing the conventional call setup and release message sequence, FIGS. 36 and 37 Figure 38 shows the SDL used in Figures 36 and 37 above, respectively.
Figures 39 and 40 are explanatory diagrams of symbols, and Figures 39 and 40 are diagrams showing call control procedures executed by the Dch protocol control units on the originating and terminating sides in tIsDN, respectively. SD used in Figure 40
It is an explanatory diagram of the L symbol. Explanation of symbols LA, IB; operator of terminal device FIG. 33 is a conceptual diagram for explaining the fifth embodiment of the present invention; FIG. 34 is a message 41A in the fifth embodiment;
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Claims (1)

[Claims] 1. An integrated services digital network (ISDN) having a plurality of information channels (Bch) and at least one control channel (Dch), and a plurality of terminals connected to the ISDN, which perform circuit switching procedures. In a communication system that communicates between terminals by using Dch, when a control channel (Dch) call is established, the calling terminal sets a "call request request" in the user information of the call setup message and sends it to the called terminal. Make a call and
An ISDN call originating/receiving system characterized in that the called terminal that receives the "call request request" once rejects the call and establishes a new call to the calling terminal. 2. In the ISDN call origination/reception system according to claim 1,
When establishing a call on the control channel (Dch), the calling terminal enters a "call request request" in the user information of the call setup message.
and a "closed area identifier" and make a call to the called terminal, and upon receiving the "call request request" and the "closed area identifier," the called terminal receives a call from a calling terminal other than the specific "closed area identifier". IS characterized by rejecting "call request request"
DN call origination/reception method. 3. In the ISDN call originating/receiving system according to claim 1,
When establishing a call on the control channel (Dch), the calling terminal enters a "call request request" in the user information of the call setup message.
The called terminal sets a "communication charge" and makes a call to the called terminal, and receives the "call request request" and the "communication charge".
Comparing the above "communication charge" with the "communication charge" of the above called terminal, if the "communication charge" of the above called terminal is lower, the above called terminal that received the above "call request request" An ISDN call originating/terminating system, characterized in that a call is established from the called terminal to the calling terminal. 4. In the ISDN call origination/reception system as set forth in claim 1,
When setting up a call on a control channel (Dch), the calling terminal enters "Call request request" in the user information of the call setting message.
, make a call to the terminal that will pay the communication charges, and select "
An ISDN call originating/receiving system characterized in that the terminal that receives a "call request request" temporarily rejects the call and establishes a new call to the calling terminal. 5. In the ISDN call origination/reception system according to claim 1,
When setting up a call on a control channel (Dch), the calling terminal enters "Call request request" in the user information of the call setting message.
is set, the called terminal makes a call to the called terminal, and upon receiving the "call request request", the called terminal rejects the call and makes a new call.
Set a "call request request" in the user information of the call setup message, make a call to the third terminal (the terminal that wishes to communicate with the calling terminal), and receive the "call request request". The IS characterized in that the third terminal once rejects the call and establishes a new call to the calling terminal.
DN call origination/reception method.