JP3216828B2 - Transmission control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to 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 a private line is in a busy state. The present invention relates to an outgoing call control method for bypassing outgoing calls to a public network.

[0002]

2. Description of the Related Art Conventionally, in a private branch exchange system in which two PBXs are connected to each other by a dedicated line and a public network, if all the dedicated lines cannot be used due to busy or the like, a detour to the public network is performed to pass through the public network. A method for transmitting a call to a target PBX is known.

[0003] In this system, a dedicated PB in which a dedicated line is accommodated.
The station line subscriber number of X is registered in advance, and if a dedicated line cannot be used at the time of making a call, the station line connected to the public network is automatically captured and the station line subscriber number of the registered partner PBX is registered. Is to be transmitted in accordance with

[0004]

However, in the conventional transmission control system, the transmission condition of the dedicated line is generally specified directly by the caller without the intervention of an operator or the like. In order to achieve the same function as a dedicated line by connecting to a public network without using a dedicated line when the connection is made using the dedicated line, there are the following problems.

(1) It is necessary to register a subscriber line number corresponding to a dedicated line number. For this reason, on the transmitting station side, a huge amount of memory is required for storing a subscriber number corresponding to the dedicated line number. You need something.

(2) At the receiving station, at least one
Contracts for one or more dial-in office lines are required, and further contracts for a plurality of dial-in numbers are required, resulting in a large economic burden.

The present invention is to solve such a conventional problem. The present invention is not limited to the memory capacity, the operating conditions of the office line, and is not limited by the economy, so that the public can be transmitted by the same operation as when transmitting to a dedicated line. It is an object of the present invention to provide a transmission control method capable of detouring to a network.

[0008]

In order to achieve the above object, a transmission control system according to the present invention comprises a terminal accommodated in an exchange,
Terminals accommodated in other exchanges should be leased lines and ISDN public
Switching system with outgoing call control function connected via network
A transmitter control system for beam, when transmitting via the dedicated line, during busy all the leased line is originating switch is connected to a dedicated line transmission of the calling terminal to the ISDN public network By diverting to an ISDN central office trunk to capture a trunk that meets the detour conditions,
And send the necessary tone to the calling terminal
And, and the destination subscriber number registered as the called party number information in the call setting message, and determines the terminating switch, the terminating call setup message that registered the extension number of the destination subaddress via the control channel of the ISDN public network Notifying the exchange, the terminating exchange extracts the extension number in response to the arrival of the call setup message to the ISDN central office trunk, and establishes a communication path between the receiving terminal corresponding to the extension number and the calling terminal. It is characterized by forming.

[0009]

According to the present invention, when a call cannot be sent to the destination exchange while the leased line is all busy, the bypass condition when the dedicated line trunk is busy is the ISDN public network, and the destination exchange is also switched to the IDN.
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. The trunk can be seized, and the destination exchange can be determined in advance by the subscriber number of the ISDN public network accommodated in the destination exchange. Also, when the central control unit in the exchange recognizes that it is a bypass call when dialing the special line transmission special number,
The next operation to be performed can be connected by exactly the same operation as when an outgoing call is made to a dedicated line, ie, 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, and shows an example of a private branch exchange (hereinafter referred to as a PBX).

In FIG. 1, reference numeral 100 denotes a communication path switch of a first PBX, and reference numeral 120 denotes a communication path switch of a second PBX connected to the first PBX via a dedicated line and an ISDN public network. Reference numerals 101 and 121 denote line circuit controllers connected to the communication path switches 100 and 120, respectively.
Reference numeral 21 is for notifying the central control units 107 and 127 of information such as the calling of the extension terminals 102 and 122 and disconnection of the dial, and for controlling the extension terminals 102 and 122 in accordance with instructions from the central control units 107 and 127. Of the control information in the line circuit control devices 101 and 121 to control the extension terminals 102 and 121.

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

The central control bus 106,
The respective central control units 107, 127 via 126
This is a storage device that exchanges data with the PBX and stores the processing status of PBX extension data, station data, and control data.
Reference numeral 109 denotes an input / output interface trunk connected to the central control bus 106, which exchanges data between the external input / output device 110 used for registering the above-mentioned extension data and station data and the central control device 107.

FIG. 2 shows that when all leased lines are busy,
This is an example of a case where a call is transmitted from the first PBX to the second PBX of the other party by bypassing the public network.

From the extension terminal 102 accommodated in the first PBX, the corresponding second terminal
When calling a PBX extension terminal, the first P
The extension terminal 102 on the BX side dials the station number and extension number of the second PBX, and thereby the extension terminal 10 of the first PBX.
2 is connected to the extension terminal 122 of the second PBX.
In addition, when the dedicated line is busy, a call is normally automatically bypassed to the public network, and a call is made to a specific destination of the corresponding second PBX. It is common to transfer and connect to. Therefore, in FIG. 2, the specific destination is the central office relay station accommodated in the second PBX, and the transfer destination is the extension terminal 122 in the second PBX.

In such a detour method, the caller can finally connect to the other party to which the caller wants to connect, but the condition that a third party intervenes is required. different. In addition, as a method of connecting without the intervention of a third party, the operating conditions of a detour target station line accommodated at the receiving station side are determined by a direct in-dial method (hereinafter, referred to as a DID method) or a dial-in method (hereinafter, referred to as a DI method). There is a method of directly designating a partner to call.

In the DID system, since the extension on the receiving side is designated by a PB signal, the sender is a terminal capable of transmitting the PB signal, and it is premised that the network is in a call state in order to pass the PB signal. . As a result, in the DID system, when a call arrives at the opposite party, the incoming call becomes a chargeable call. For example, when the designated extension is busy, there is a problem that the designated extension cannot be called directly.

In the DI system, unlike the DID system, a call is not charged until the call is formed. However, 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 receiving station and a program for executing the control.

Therefore, in the present embodiment, by accommodating an ISDN central office trunk having a control channel and a communication channel, the extension of the correspondent PBX corresponding to the operation of the exclusive line transmission can be performed without the intervention of a third party. Be able to call.

Hereinafter, the operation of this embodiment will be described.

FIG. 3 shows an example of the contents of a "call setup" message to be notified to the other party when making a call to the ISDN public network. In the ISDN interface, circuit switching is performed by using a signal defined by a name called a message type, separately from signals corresponding to various signals used in a normal analog network. The various messages are composed of a combination of a plurality of information elements, and among the information elements of the "call setting" message, a plurality of elements including the called number and called sub-address number used in the present embodiment are represented by one.
One message is composed.

FIG. 4 shows an example of the contents of a "disconnect" message notified when a communication partner disconnects a call during communication via the ISDN public network. The "disconnection" message is also composed of a combination of a plurality of information elements like the "call setting" message, and the information element of the "disconnection" message includes the disconnection reason information used in the present embodiment. I have.

FIG. 5 shows an example of the structure of the subscriber number registration data, which includes called number information required when the dedicated line is busy and the PBX is activated when the dedicated line is transmitted. . The start condition referred to here is a dial start condition after a dedicated line is captured, and includes a timing method for dialing after a predetermined standby time has elapsed, a second dial tone method 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
In the case where 2 makes a dedicated line call, the extension terminal 102 first dials a special number for making a call to the dedicated line.
As a result, the dial information is stored in the line circuit controller 1.
01 is recognized by the control unit mounted on the control unit 01, and further notified to the central control unit 107 by the line circuit control unit 101. The central control unit 107 starts a program described for analyzing the dial information based on the notified dial information. As a result, when it is recognized that the content of the dial is a special line transmission special number, a program described for performing the exclusive line transmission is started next.

Hereinafter, an outline of the processing of the procedure for the exclusive line transmission will be described with reference to the flowchart shown in FIG.

In step S1, whether or not there is a dedicated line that can be transmitted is checked. The transmission condition is that the transmission is a dedicated line, and the empty / occupied state of the corresponding trunk is checked. The process proceeds to the processing step. If the capture is impossible in the closed state, the process proceeds to step S2. In step S2, since the bypass condition is registered in advance as the ISDN public network, the use state of the bypass target trunk 103 is checked, and if the bypass trunk condition is unusable, the process proceeds to a processing step of determining the restriction condition. I do. If the detour trunk is empty and a call can be made, the target trunk 103 is captured.

Next, in step S3, a pre-process for alternate transmission is executed. In this step S3, a leased line activation condition is extracted from the information shown in FIG. 5, and control necessary for the originating extension terminal 102 when the leased line is activated is executed.
As an example, if the activation condition of the dedicated line transmission is the 2nd dial tone system, a pseudo tone equivalent to the dial tone heard from the corresponding PBX is output to the tone generator 111.
Extension terminal 10 via the line circuit controller 101
2 is sent. As a result, for the caller, the same environment as that of the leased line call, that is, the pseudo tone is the second P
It is possible to provide an environment as if emitted from the BX.

In the next step S4, the detour subscriber number shown in FIG.
It is stored in the called number area in the “call setting” 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 transmitted from the control unit mounted on the line circuit controller 101 to the first PB.
The central control unit 107 in X is notified of the extension number by a program described to extract the extension number. This extension number information is stored in the ISDN office trunk 10
No. 3 is stored in an internal arrival address area of the "call setting" message on the RAM. In step S6, a program described to perform office line transmission transmits a "call setting" message to the control channel (D channel) of the ISDN office line trunk 103, and the extension call control via the office line is executed. Is done.

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

Next, an outline at the time of the above-mentioned incoming call on a local line will be described with reference to a flowchart shown in FIG. When receiving a local line,
The destination subaddress information specified on the calling side is notified through the control channel (D channel) of the ISDN central office trunk 123, and the information content is defined to correspond to the extension number of the second PBX. The device 127 extracts the number from the destination subaddress information and activates a program described to extract the extension. If it is determined in the next step S12 that the designated extension is in a callable state, the central control unit 127 activates a program described for calling the extension, and the control unit of the line circuit control device 121 The call information is notified to the user. Thereby, the second PBX
Of the extension terminal 122 performs an incoming call display. Then extension terminal 1
22 responds, the line circuit controller 121
, The response information is notified to the central control device 127, and the "response" information is notified to the central control device 107 in the first PBX via the ISDN local line trunk 123. As a result, a call between the extension terminal 102 on the first PBX side and the extension terminal 122 on the second PBX side is formed.

If it is determined in step S12 that the designated extension cannot be called, the process proceeds to step S13, in which the call disabling reason is developed into the "disconnection" message reason information for the first PBX on the calling side. 2PBX I
A disconnect message is transmitted to the control channel (D channel) of the SDN central office trunk 123.

FIG. 8 is a flow chart showing the processing of the second PBX when the second PBX on the transmitting side receives a "disconnection" message in the case of an extension prohibition condition in step S12 of FIG.

At step S21 in FIG. 8, it is determined whether or not the disconnection is normal, and the "disconnection" message notified via the ISDN central office trunk 103 is notified to the central control unit 107 in the first PBX. As a result, the central control unit 107 starts a program described for extracting the reason information in the “disconnection” message, and analyzes the reason for disconnection. If the disconnection reason is normal disconnection, a program described to make the calling extension terminal 102 hear a busy tone is started. If it is determined in step S21 that the disconnection reason is other than the normal disconnection, the process proceeds to step S2.
2 and the central control unit 107 is operated by the talkie trunk 111 in which guidance suitable for the disconnection reason is incorporated in advance.
Executes a program described for making a talkie connection to the originating extension terminal 102, whereby the originating extension terminal 102 recognizes the extension state of the corresponding partner PBX by voice guidance.

As described above, according to the present embodiment, in a private branch exchange system accommodating a dedicated line, even if all the dedicated lines are busy, the ISDN office line trunk having the control channel and the communication channel is provided. Can be connected to the designated extension terminal with the same operation as when sending to a dedicated line even in a connection via the public network, This has the effect that the reason for the connection failure can be recognized by voice guidance.

[0036]

As is apparent from the above embodiment, the present invention accommodates an ISDN central office trunk having a control channel and a communication channel in a system equipped with a dedicated line trunk, so that the system can be operated through a third party. This has the effect that the extension of the corresponding partner PBX can be called without being aware of the detour to the office line by the same operation as the dedicated line transmission.

Further, in the present invention, as is clear from the above, if the office line is contracted as ISDN, not only the operation of the office line but also the operation of the exclusive line becomes possible, and the operation is compared with the DID system and the DI system. In this case, there is little restriction in operation, and it is economically advantageous. Furthermore, there is an effect that the state in another PBX can be grasped by voice guidance by effectively using the D channel information.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram showing an example of a case where a call is made to a partner PBX by bypassing the public network when all dedicated lines are busy, according to the embodiment;

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

FIG. 4 is an explanatory diagram illustrating an example of a disconnection message in the embodiment.

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

FIG. 6 is a flowchart illustrating a processing procedure in the central control device when a dedicated line is detoured in the present embodiment.

FIG. 7 is a flowchart showing a processing procedure in the central control device at the time of incoming of a line in this embodiment.

FIG. 8 is a flowchart illustrating a processing procedure when disconnection information is received from a station line in the present embodiment.

[Explanation of symbols]

 100, 120 Line switch 102, 121 Line circuit controller 102, 122 Extension terminal 103, 123 ISDN central line trunk 104, 124 Dedicated line trunk 105 Talk trunk 106, 126 Central control bus 107, 127 Central controller 108, 128 Storage Device 109 I / O interface trunk 110 External I / O device 111 Tone generator

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04M 3/00 H04M 3/16-3/20 H04M 3/38-3/58 H04M 7/00-7 / 16

Claims (1)

(57) [Claims] 1. An originating control system for an exchange system having an originating control function for connecting a terminal accommodated in an exchange and a terminal accommodated in another exchange via a dedicated line and an ISDN public network. When all of the leased lines are busy, the calling exchange switches the leased line transmission of the calling terminal to the ISDN central office trunk connected to the ISDN public network, and When a matching trunk is captured ,
Then, the activation condition of the leased line is extracted and
Necessary tones are sent out in a simulated manner, and incoming calls are made using the called party number registered as called number information in the call setup message.
In addition to determining the local exchange, the call setup message in which the extension number is registered as the destination subaddress is notified to the destination exchange through the control channel of the ISDN public network, and the destination exchange receives the call setup message to the ISDN central office trunk. A call path between the receiving terminal corresponding to the extension number and the calling terminal.