JPH0614104A - Call control system - Google Patents

Abstract

PURPOSE:To bypass a call to a public network with a similar operation to the case of a call to a private line without limitation to a memory capacity, an operating condition of a trunk line and economy. CONSTITUTION:In the private branch of exchange system in which an extension terminal equipment 102 accommodated in a 1st PBX and an extension equipment 122 accommodated in a 2nd PBX are connected via exclusive trunks 104, 124, ISDN office line trunks 103, 123 are connected to an exit to an ISDN public network of the 1st PBX and the 2nd PBX and a call from a private line of the extension terminal equipment 102 is bypassed to the ISDN office line trunk 103 when all private lines are busy, and a called PBX is decided by a called subscriber number in a setup message registered in advance. Then the setup message having an extension number registered in advance is informed to the called PBX through a control channel of the ISDN public network and the extension is called to attain the connection to the called terminal equipment 122.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has been newly developed in a private branch exchange system in which two private branch exchanges (hereinafter referred to as PBXs) are connected by a private line public network when all the private lines are busy. The present invention relates to a call origination control method for diverting a call origination to a public network.

[0002]

2. Description of the Related Art Conventionally, in a private branch exchange system in which PBXs of opposite sides are connected to each other by a private line and a public network, when all the private lines cannot be used due to busy or the like, they are routed to the public network to bypass the public network. Then, there is known a method of transmitting to the target PBX.

In this system, the partner PB in which the private line is accommodated
The subscriber line number of X is registered in advance, and if the leased line cannot be used at the time of calling, the station line connected to the public network is automatically captured, and the subscriber line number of the registered PBX is registered. According to the following.

[0004]

However, in the conventional transmission control system, it is general that the calling condition of the leased line directly designates the caller without the intervention of an operator or the like. Therefore, the intervention of a third party is required. There is a problem as described below in order to satisfy the function equivalent to that of the leased line by making a detour to the public network without using the leased line when the connection is made by.

(1) It is necessary to register the subscriber number of the office line corresponding to the leased line number. Therefore, on the transmitting station side, a huge amount of memory is required for storing the subscriber number corresponding to the leased line number. I need something.

(2) At least 1 at the receiving station
It requires a contract for one or more dial-in office lines, and also requires a contract for a plurality of dial-in numbers.

The present invention solves such a conventional problem, and the public operation is performed in the same manner as in the case of transmitting to a dedicated line without being restricted by the memory capacity, the operating condition of the station line, and economically. It is an object of the present invention to provide a transmission control method capable of making a detour to a network.

[0008]

In order to achieve the above object, the call origination control system of the present invention is such that when a call is originated from a calling terminal via a leased line and all the leased lines are busy, , By diverting the leased line transmission of the calling terminal to the ISDN office line trunk connected to the ISDN public network, capturing the trunk that meets the detour condition, and by the callee number registered as callee number information in the call setup message. , The destination exchange is determined, and a call setup message in which the extension number as the destination subaddress is registered is notified to the destination exchange through the control channel of the ISDN public network, and the destination exchange transmits the call setup message to the ISDN trunk line trunk. When the incoming call is received, the extension number is extracted and a call path is formed between the incoming terminal and the outgoing terminal corresponding to the extension number.

[0009]

According to the present invention, when the call cannot be transmitted to the called side exchange while the leased line is busy, the detour condition when the leased line trunk is busy is the ISDN public network and the called side exchange is I
Since the SDN public network is accommodated, the information of the originating exchange can be easily notified to the terminating exchange through the control channel of the ISDN public network, and the ISDN can be selected from the public line when the private line trunk is busy. The trunk can be captured and the destination exchange can be determined by the subscriber number of the ISDN public network that is housed in advance by the destination exchange. Also, when the central control unit in the exchange recognizes that it is a bypass call when dialing the special line calling special number,
The connection can be made by the next operation, which is the same operation as the operation for making a call to the dedicated line, that is, the designation of the extension on the receiving side.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a system configuration according to the transmission control system of the present invention, showing an example of a private branch exchange (hereinafter referred to as PBX).

In FIG. 1, reference numeral 100 is a first PBX speech path switch, and 120 is a partner second PBX speech path switch connected to the first PBX via a leased line and an ISDN public network. Further, 101 and 121 are line circuit control devices connected to the respective communication path switches 100 and 120.
In order to control the extension terminals 102 and 122 by the instructions from the central control devices 107 and 127, the reference numeral 21 notifies the central control devices 107 and 127 of information such as calling and disconnecting dials of the respective extension terminals 102 and 122. The control information of the above is notified to the control unit in the line circuit control devices 101 and 121 to control the extension terminals 102 and 121.

Reference numerals 103 and 123 denote ISDN office line trunks (ITRK) having an interface composed of ISDN call B channel and control D channel. The ISDN office line trunks 103 and 123 are ISDN.
Each call path switch 10 connected via the DN public network
0,120 is connected. 104 and 124 are communication path switches 100 and 120 which are connected via dedicated lines.
Private line trunk (PRV) connected to the exit side of the
Is a talkie trunk connected to the communication path switch 100 and has a built-in voice ROM for message guidance.

Reference numerals 108 and 128 denote central control buses 106 and
Central control units 107, 127 via 126
Is a storage device for exchanging data with each other and storing processing states of extension data, station data, and control data of the PBX.
Reference numeral 109 is an input / output interface trunk connected to the central control bus 106, and exchanges data between the external input / output device 110 used to register the above-mentioned extension data and station data and the central control device 107.

FIG. 2 shows that when all leased lines are busy,
It is an example of a case where the first PBX bypasses the public network and is transmitted to the second PBX of the other party.

From the extension terminal 102 accommodated in the first PBX to the corresponding second via the leased line trunks 104 and 124.
When making a call to an extension terminal of the PBX, it is usually the first P
The extension terminal 102 on the BX side dials the station number and extension number of the second PBX, so that the extension terminal 10 of the first PBX
2 and the extension terminal 122 of the second PBX are connected.
In addition, the connection during full line busy is normally automatically detoured to the public network to make a call to the specified destination of the corresponding second PBX, and the called party responds to this and the caller wishes Is generally transferred to and connected to. Therefore, in FIG. 2, the specific destination is the station repeater accommodated in the second PBX, and the transfer destination is the extension terminal 122 in the second PBX.

In the detour system as described above, the caller can finally connect to the other party to which he / she wants to connect. different. In addition, as a method of connecting without the intervention of a third party, the operating condition of the detour target station line accommodated in the called station side is a direct-in-dial system (hereinafter referred to as DID system) or a dial-in system (hereinafter referred to as DI system). There is a method to specify the other party who wants to call directly.

In the DID method, since the extension of the receiving side is designated by the PB signal, the caller is a terminal capable of transmitting the PB signal, and it is premised that the call state is established between the networks to pass the PB signal. . As a result, in the DID method, when an incoming call is received by the opposite party, the incoming call becomes a charge target call. For example, when the designated extension is busy, the directly designated extension cannot be called up.

Further, in the DI system, unlike the DID system, the call is not charged until the call is formed, but since a contract for a dial-in number is required for each incoming extension terminal, the cost burden is large. Further, the originating PBX requires a memory for storing the subscriber number corresponding to the extension of the terminating station and a program for executing its control.

Therefore, in this embodiment, by accommodating the ISDN office line trunk having the control channel and the communication channel, the extension of the corresponding PBX can be operated by the same operation as the private line transmission without the intervention of a third party. To be able to call.

The operation of this embodiment will be described below.

FIG. 3 shows an example of the contents of the "call setup" message notified to the other party when the call is made to the ISDN public network. In the ISDN interface, in addition to signals corresponding to various signals used in a normal analog network, signals defined by the name of message type are used to execute circuit switching. Each message is composed of a combination of a plurality of information elements. Among the information elements of the "call setup" message, there are a plurality of elements including the called number and called subaddress number used in this embodiment.
One message is composed.

FIG. 4 shows an example of the content of the "disconnect" message notified when the communication partner disconnects the call during communication via the ISDN public network. Like the “call setup” message, the “disconnect” message is also composed of a combination of a plurality of information elements, and the information element of the “disconnect” message includes disconnection reason information used in this embodiment. There is.

FIG. 5 shows an example of the structure of the subscriber number registration data, which includes the called number information required when making a public network detour call during a leased line call, and the PBX activation conditions corresponding to the leased line call. . The activation condition mentioned here is a dial start condition after the leased line is captured, and its contents include a timing system for dialing after a certain waiting time has elapsed, a second dial tone system for dialing after confirming a dial tone, and the like. This information is stored in a specific area in the storage device 108 via the input / output trunk 109 from the external input device 110 shown in FIG.

In FIG. 1, the extension terminal 10 of the first PBX.
When the number 2 makes a call from the leased line, the extension terminal 102 first dials a special number for making a call to the leased line.
As a result, the dial information is transferred to the line circuit control device 1
It is recognized by the control unit mounted on 01 and is further notified to the central control unit 107 by the line circuit control unit 101. Based on the notified dial information, central controller 107 activates a program described to analyze the dial information. As a result, when it is recognized that the content of the dial is the special line transmission special number, the program described for performing the leased line transmission next is activated.

The outline of the procedure of the procedure for the private line transmission will be described below with reference to the flowchart shown in FIG.

In step S1, whether or not there is a leased line that can be transmitted is checked by checking whether the trunk is empty or blocked because the transmission condition is leased line transmission. If there is an empty trunk, the leased line is captured. Shift to the processing step. If it is not possible to capture in the closed state, the process proceeds to step S2. In step S2, since the detour condition is registered in advance as being the ISDN public network, the usage state of the detour target trunk 103 is checked, and if the condition of the detour trunk is unusable, the process proceeds to the processing step of determining the regulation condition. To do. When the detour trunk is empty and can make a call, the target trunk 103 is captured.

Next, in step S3, preprocessing for bypass transmission is executed. In step S3, the leased line activation condition is extracted from the information shown in FIG. 5, and the control required for activating the leased line is executed for the originating extension terminal 102.
As an example, if the activation condition for the leased line transmission is the 2nd dial tone method, a pseudo tone equivalent to the dial tone heard from the corresponding PBX is generated by the tone generator 111.
The extension terminal 10 via the line circuit control device 101.
Send to 2. This gives the caller the same environment as a leased line call, that is, this pseudo tone is the second P
It is possible to provide an environment as if it were emitted from the BX.

In the next step S4, the bypass subscriber number shown in FIG.
It is stored in the called number area in the “call setup” message on M. In the next step S5, the number of the extension terminal 122 of the second PBX dialed by the extension terminal 102 is the first PB from the control unit mounted in the line circuit control device 101.
The central controller 107 in X is notified, and the extension number is grasped by the program described for extracting the extension number. This extension number information is used for ISDN office line trunk 10
No. 3 RAM is stored in the inbound sub address area of the “call setup” message. In step S6, a program written for making an office line call sends a "call setting" message to the control channel (D channel) of the ISDN office line trunk 103 to execute extension call control via the office line. To be done.

The ISDN of the second PBX from the ISDN public network
When there is an incoming call on the central office trunk 123, a "call setup" message is sent from the ISDN public network, and the contents are ISD.
It is stored in the RAM area of the N station trunk. At the same time, the control device of the ISDN office line trunk 123 notifies the central control device 127 of the second PBX of the incoming call information from the ISDN public network.

Next, an outline of the above-mentioned incoming of the central office line will be described with reference to the flowchart shown in FIG. When receiving a line call,
The destination sub-address information designated by the originating side is notified through the control channel (D channel) of the ISDN office line trunk 123, and the information content is defined to correspond to the extension number of the second PBX. Therefore, the central control in step S11. The device 127 extracts the number from the destination sub-address information and activates the program described for extracting the extension. If it is determined in the next step S12 that the designated extension is in a callable state, the central controller 127 activates the program described for calling the extension, and causes the control unit of the line circuit controller 121 to operate. Notify the call information to the user. As a result, the second PBX
The extension terminal 122 displays the incoming call. After that, extension terminal 1
When 22 responds, the line circuit control device 121
The response information is notified to the central control device 127 via the control unit, and the “response” information is notified to the central control device 107 in the first PBX via the ISDN office line trunk 123. As a result, a call is formed between the extension terminal 102 on the first PBX side and the extension terminal 122 on the second PBX side.

When it is determined in step S12 that the designated extension cannot be called, the process proceeds to step S13, in which the reason why the call cannot be made is expanded to the reason information in the "disconnection" type message for the first PBX on the calling side. 2PBX I
A disconnection message is transmitted to the control channel (D channel) of the SDN office line trunk 123.

FIG. 8 is a flow chart showing the process of the second PBX when the second PBX on the calling side receives a "disconnection" type message under the condition that the extension cannot be called in step S12 of FIG.

In step S21 of FIG. 8, it is determined whether the disconnection is normal or not, and the "disconnect" type message notified via the ISDN office line trunk 103 is notified to the central controller 107 in the first PBX. As a result, the central controller 107 activates the program described for extracting the reason information in the "disconnection" system message and analyzes the reason for disconnection. If the reason for disconnection is normal disconnection, the program described in order to make the extension terminal 102 on the calling side listen to the busy tone is started. If it is determined in step S21 that the reason for disconnection is other than normal disconnection, step S2
2, the central control unit 107 is operated by the torch trunk 111 having a built-in guidance corresponding to the reason for disconnection.
Executes the program described for making a talk connection to the extension terminal 102 on the calling side, whereby the extension terminal 102 on the calling side recognizes the extension state of the corresponding partner PBX by voice guidance.

As described above, according to the present embodiment, in the yard filling system accommodating the leased line, even if all the leased lines are busy, the ISDN office line trunk having the control channel and the communication channel is provided. By housing
Even when connecting through a public network, it is possible to connect to the specified extension terminal by the same operation as when calling to a leased line. Furthermore, the reason information when the "disconnect" message is received gives the reason why the connection cannot be made. Has the effect of being able to be recognized by voice guidance.

[0036]

As is apparent from the above embodiment, the present invention allows a third party to intervene by accommodating an ISDN office line trunk having a control channel and a communication channel in a system having a leased line trunk. It is possible to call the extension of the corresponding partner PBX without the need to be aware of the detour to the central office line by an operation equivalent to that of the private line transmission.

Further, in the present invention, as is apparent from the above, if the contracting of the station line as ISDN enables not only the operation of the station line but also the operation of the leased line, it is compared with the DID method and the DI method. In this case, it is less subject to operational restrictions and is economically advantageous. Furthermore, by effectively using the D channel information, the state in another PBX can be grasped by the voice guidance.

[Brief description of drawings]

FIG. 1 is a block diagram of a private branch exchange system to which a call origination control method of the present invention is applied.

FIG. 2 is an explanatory diagram showing an example of a case of making a call to a partner PBX by bypassing a public network during full-line talk of a leased line according to the present embodiment.

FIG. 3 is an explanatory diagram showing an example of a call setting message in the present embodiment.

FIG. 4 is an explanatory diagram showing an example of a disconnection message in this embodiment.

FIG. 5 is a configuration diagram showing an example of subscriber number registration data in the present embodiment.

FIG. 6 is a flowchart showing a processing procedure in the central control device at the time of bypassing the leased line transmission in the present embodiment.

FIG. 7 is a flow chart showing a processing procedure in the central control unit at the time of an incoming call from a central office line in the present embodiment.

FIG. 8 is a flowchart showing a processing procedure when receiving disconnection information from a central line in the present embodiment.

[Explanation of symbols]

 100,120 Speech path switch 102,121 Line circuit control device 102,122 Extension terminal 103,123 ISDN office line trunk 104,124 Leased line trunk 105 Toki trunk 106,126 Central control bus 107,127 Central control device 108,128 Storage Device 109 Input / output interface trunk 110 External input / output device 111 Tone generator

Claims (1)

[Claims] 1. A transmission control method for a switching system having a transmission control function for connecting a terminal accommodated in an exchange and a terminal accommodated in another exchange via a leased line and an ISDN public network, wherein the leased line is used. When all of the leased lines are busy when making a call via the line, the originating exchange detours the leased line originated from the calling terminal to the ISDN central line trunk connected to the ISDN public network, and the detour condition is satisfied. The destination exchange is determined by the called party number registered in the call setup message as the called party number information, and the call setup message in which the extension number as the called party subaddress is registered is controlled by the ISDN public network. Notify the terminating exchange through the channel, and the terminating exchange extracts its extension number upon receipt of the call setup message on the ISDN central line trunk, Outgoing call control method, and forming a speech path between the calling terminal and the called terminal corresponding to the inner line number.