JP2748055B2 - External line transmission method and digital exchange using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external line transmission system in a digital exchange having a digital terminal in an extension and a digital exchange using the same.

[0002]

2. Description of the Related Art A conventional analog exchange connected to an analog public network transmits a call to an external line in the following procedure.

[0003] An operator of a terminal dials a special number indicating a request to make a call to an outside line. This special number is, for example, “0”. Thereby, the dial information is transmitted from the terminal to the exchange. When the exchange recognizes that the number indicates a call request to an outside line by analyzing the number included in the dial information, the exchange performs an outside line capture process and establishes a call path between the vacant outside line and the terminal. Set. As a result, the dial tone is transmitted from the public network to the terminal. The operator of the terminal can know from the dial tone that calling to an outside line is possible. Then, when the operator of the terminal dials the called number, a call is made to an outside line.

On the other hand, ISDN (Integrated Services Di
gital Network).
For example, transmission to an outside line is performed according to the procedure shown in FIG.

[0005] An operator of the ISDN terminal 10 inputs a special number "0" and a called number. As a result, ISDN
The terminal 10 sends a call setup (SETUP) message including the special number “0” and the called number to the ISDN exchange 20. The call setup message is a message sent to start call setup at the time of calling, and includes a protocol identifier information element, a call number information element, a message type information element, a called number information element, and the like. The special number “0” and the called number are included in the called number information element in the call setup message. The called number information element is used to specify a communication partner.

[0006] The ISDN exchange 20 is connected to the ISDN terminal 10.
When a call setup message is received from the ISDN, a call setup message including the called number is sent to the ISDN public network 30. Also,
The ISDN exchange 20 sends a call setup acceptance (CALL PROCEEDING) message to the ISDN terminal 10. The call setting acceptance message is a message indicating that the requested call setting has been started. In addition, IS
A call setting acceptance message is transmitted from the DN public network 30 to the ISDN exchange 20.

Thereafter, the ISDN public network 30 sends the ISDN
A paging (ALERTING) message is transmitted to the exchange 20, and a paging message is transmitted from the ISDN exchange 20 to the ISDN terminal 10. The call message is a message indicating that the called terminal is being called. Thereafter, a response (CONNECT) message is transmitted from the ISDN public network 30 to the ISDN exchange 20, and furthermore, the ISDN exchange 20
A response message is transmitted to N terminal 10. The response message is a message indicating that the operator on the receiving side has accepted the call.

In this way, the ISDN exchange 20 makes a call from the ISDN terminal 10 to an outside line.

When transmitting the additional information from the ISDN terminal 10 to the ISDN public network 30, the additional information (IN
(FORMATION) message is transmitted. The additional information message includes a protocol identifier information element, a call number information element, a message type information element, a keypad facility information element, and the like. The keypad facility information element is used to carry dialing information set by the keypad of the ISDN terminal.

This additional information message can be transmitted at any time. Using the additional information message, additional services such as a call waiting function, a transfer during communication function, a three-way call function, and a call transfer function can be received.

[0011]

As described above, the ISD
In a conventional ISDN exchange 20 accommodating N terminals 10,
After the operator of the ISDN terminal 10 finishes inputting all called numbers, a call is made to an outside line. This method is called a preset method.

As described above, since the transmission is performed by the preset method, the operator of the ISDN terminal 10 cannot perform the transmission in the same procedure as that in the analog public network. Therefore, the operator of the ISDN terminal 10
Only after inputting all called numbers including a special number that indicates a call to an outside line at the beginning, it is impossible to know whether or not a call to an outside line is possible.

An object of the present invention is to provide an external line transmission system and a digital exchange which can perform transmission to an external line in a digital communication network in the same procedure as an analog communication network.

[0014]

According to the outside line transmission method of the digital exchange according to the present invention, a call is transmitted to an outside line in the following procedure. After receiving from the terminal a call setup message including a predetermined number for requesting outgoing calls,
The call setting message is stored and an outside line is captured. Based on the processing result, it notifies the terminal whether or not it is possible to make a call to an outside line. When the additional information message including the called number is received from the terminal, a call is made to an outside line based on the stored call setup message and the called number included in the additional information message.

[0015] A digital exchange according to the present invention includes a means for receiving a call setup message including a predetermined number for requesting a call to an outside line from a terminal, a means for storing a call setup message, and a call setup message. Means for performing outside line capturing processing in response to The digital exchange further includes means for notifying the terminal whether or not transmission to an outside line is possible based on the result of the acquisition processing, and additional information message including a called number from the terminal when the transmission to the outside line is possible. Means for receiving, and means for making a call to an outside line based on the stored call setup message and the called number included in the received additional information message.

[0016]

According to the outside line transmission system and the digital exchange according to the present invention, when the operator of the terminal inputs a predetermined number, a call setting message including the number is transmitted from the terminal to the digital exchange. The digital exchange stores the call setup message and performs a process of capturing an outside line, and notifies the terminal whether or not transmission to the outside line is possible based on the processing result. Thereby, the operator of the terminal can know whether or not a call to an outside line is possible.

When the terminal operator inputs the called number, the terminal transmits an additional information message including the called number to the digital exchange. As a result, the digital exchange makes a call to an external line based on the stored call setup message and the called number included in the additional information message.

As described above, in the outside line transmission system and the digital exchange according to the present invention, a predetermined number is transmitted from the terminal to the digital exchange using the call setup message, and the call is terminated when the outside line can be transmitted. The number is transmitted from the terminal to the digital exchange using an additional information message. Therefore, in a digital communication network, an operator of a terminal can make an outgoing call to an outside line in the same procedure as the outside line sending method in an analog communication network.

[0019]

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

FIG. 1 is a block diagram showing the configuration of an ISDN switching system using an outside line transmission system according to one embodiment of the present invention, and FIG. 2 is a sequence diagram for explaining the outside line transmission system of the embodiment. It is.

In FIG. 1, a plurality of ISDN terminals 1 are connected to an ISDN exchange 2 via a bus L1. The ISDN exchange 2 is connected to the ISDN exchange 2 via the line L2.
It is connected to the DN public network 3. Bus L1 includes, for example, two information channels for transferring user information such as voice information, and a signal channel for mainly transferring control signal information. The information channel is called a B channel, and the signal channel is called a D channel. Similarly,
Line L2 also includes, for example, two information channels and one signal channel.

The ISDN terminal 1 includes an input / output device 11, a control device 12, a storage device 13, and an interface 14. The input / output device 11 inputs dial information such as a special number and a called number given by the operator and other various information to the storage device 13 via the control device 12. Further, the input / output device 11 outputs various information provided from the bus L1 via the interface 14. The storage device 13 stores an operation program of the control device 12 and temporarily stores various information input by the input / output device 11 and various information input via the interface 14.
The control device 12 creates various messages based on the various information stored in the storage device 13 and sends them to the bus L1 via the interface 14.

The ISDN exchange 2 includes an extension interface 21, a switch 22, an external interface 23, a control device 24, and a storage device 25. The extension interface 21 is connected to the bus L1, and the outside interface 23 is connected to the line L2. A switch 22 is connected between the extension interface 21 and the external interface 23.

The storage device 25 stores an operation program of the control device 24, various information provided through the extension interface 21 and the external line interface 2.
3 is temporarily stored. The control device 24 creates various messages based on the various information stored in the storage device 25 and sends them to the bus L1 via the extension interface 21 or to the line L2 via the outside interface 23. . The control device 24 further controls the connection of the switch 22.

Next, an external line transmission system according to this embodiment will be described with reference to the sequence diagram of FIG. 2 and the flowcharts of FIGS. 3 and 4.

The operator of the ISDN terminal 1 that makes a call to an outside line inputs a special number (for example, "0") indicating a request for making a call to the outside line into the ISDN terminal 1 (step S1 in FIG. 3). Thereby, the ISDN terminal 1 creates a call setup message including the special number “0” and sends it to the ISDN exchange 2 via the D channel (step S
2). This special number “0” is included in the called number information element in the call setup message.

The ISDN exchange 2 receives the call setup message from the ISDN terminal 1 (step S1 in FIG. 4).
1) By analyzing the called number information element, it recognizes that the number indicates a request for outgoing call (step S12). As a result, the ISDN exchange 2
The call setup message is stored in the storage device 25 (step S13), and a call setup acceptance message is sent to the ISDN terminal 1 via the D channel (step S3 in FIG. 3 and step S14 in FIG. 4). In addition, ISD
The N exchange 2 performs an outside line acquisition process (step S15 in FIG. 4).

When a free outside line can be secured (step S16), the ISDN exchange 2 sends a response message to the ISDN terminal 1 via the D channel and also sends a dial tone on the B channel (FIG. 9). Step S4 of Step 3 and Step S17 of FIG. 4). As a result, the ISDN terminal 1 enters a communication state (step S5 in FIG. 3), and the operator of the ISDN terminal 1 is notified that the outside line has been secured.

On the other hand, when the free outside line cannot be secured (step S16 in FIG. 4), the ISDN exchange 2 sends a busy tone on the B channel instead of sending a dial tone on the B channel (step S16). S18). Thereby, the operator of the ISDN terminal 1 is notified that a call cannot be made to an outside line.

IS who knew that a free outside line could be secured
The operator of the DN terminal 1 inputs a called number to the ISDN terminal 1 (step S6 in FIG. 3). Thereby, the ISDN terminal 1 creates an additional information message including the called number and sends it to the ISDN exchange 2 (step S7). This called number is included in the keypad facility information element in the additional information message.

The ISDN exchange 2 receives the additional information message from the ISDN terminal 1 (step S in FIG. 4).
19), a call setup message is created based on the called number in the received additional information message and the information in the call setup message stored in the storage device 13, and sent to the ISDN public network 3 (step S20). . Thereby, IS
A call setup acceptance message is transmitted from the DN public network 3 to the ISDN exchange 2, and thereafter, the ISDN
A call message is transmitted to N exchange 2 (step S
21). Further, a response message is transmitted from the ISDN public network 3 to the ISDN exchange 2 (step S22).
As a result, the call processing is performed by the ISDN exchange 2. (Step S23).

The service type is voice service or 3.
In the case of the 1 kHz audio service, a ringback tone is transmitted from the ISDN public network 3 to the B channel after a call message is transmitted from the ISDN public network 3. The ringback tone is transmitted to the ISDN terminal 1 via the ISDN exchange 2. As a result, IS
The operator of the DN terminal 1 can know that communication with the terminal on the receiving side is enabled. Thereafter, when a response message is transmitted from the ISDN public network 3, the ISDN terminal 1 enters a communication state. In this way, the transmission from the ISDN terminal 1 to the outside line is performed.

The sequence of the message after the call setup acceptance message is transmitted from the ISDN public network 3 is as follows:
It is not limited to the sequence shown in FIG.

The dial tone is provided only in the voice service and the 3.1 kHz audio service, and is not provided in other services. For example,
If the ISDN terminal 1 is a personal computer, no dial tone is provided.

Further, the special number is not limited to "0", and various numbers can be set as special numbers.

[0036]

As described above, according to the present invention, an operator of a terminal can know whether or not a call to an outside line is possible only by inputting a predetermined number. Transmission to an external line can be performed in the same procedure as the external line transmission method in the network. Therefore,
It is possible to maintain the commonality of the procedure for transmitting an external line between the analog exchange and the digital exchange.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an ISDN switching system using an outside line transmission system according to an embodiment of the present invention.

FIG. 2 is a sequence diagram for explaining an outside line transmission method according to the embodiment.

FIG. 3 is a flowchart for explaining processing of an ISDN terminal;

FIG. 4 is a flowchart for explaining processing of the ISDN exchange;

FIG. 5 is a sequence diagram for explaining an outside line transmission method in a conventional ISDN exchange.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ISDN terminal 2 ISDN exchange 3 ISDN public network 21 extension interface 22 switch 23 external interface 24 control device 25 storage device L1 bus L2 line In each figure, the same code | symbol shows the same or corresponding part.

Claims (2)

(57) [Claims] 1. An external line transmission system for a digital exchange disposed between a digital communication network, which is an extension, to which a plurality of terminals are connected, and a line of a digital public network, which is an external line, for requesting transmission to an external line. After the digital exchange receives a call setting message including a called number information element including a predetermined number from any of the terminals, the digital exchange stores the call setting message and performs an outside line capturing process. Notifying the terminal whether or not outgoing calls are possible based on the processing result, and when the digital exchange receives from the terminal an additional information message including a keypad facility information element including a called number A new call setup message based on the stored call setup message and the called number included in the additional information message. An outside line transmission method, wherein the outgoing line is transmitted from the terminal to an outside line by generating and transmitting the generated signal to the digital public network and connecting the digital public network to the terminal. 2. A digital exchange installed between a digital communication network, which is an extension, to which a plurality of terminals are connected, and a line of a digital public network, which is an external line, wherein a digital exchange for requesting a call to an external line is provided. Means for receiving a call setup message including a called number information element including a predetermined number from any of the terminals; means for storing the received call setup message; and capturing an outside line in response to the call setup message. Means for performing processing; means for notifying the terminal whether or not transmission to an outside line is possible based on the result of the capturing means; and a keypad including a called number from the terminal when transmission to an outside line is possible. Means for receiving an additional information message including a facility information element, based on the stored call setup message and the called number included in the received additional information message. Means for generating a new call setup message and transmitting the generated message to the digital public network, and connecting the digital public network with the terminal to make a call from the terminal to an outside line. switch.