JP2567878B2 - Relay line connection control method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a trunk line call connection control method suitable for call connection control between two private branch exchanges via an ISDN switching network.

[Prior Art] In recent years, it has become possible to perform normal voice telephone communication by compressing it to a communication speed of 8 to 32 kbps by improving digital signal technology. In addition, in communication between data terminals,
Communication speeds around kbps are the mainstream. On the other hand, IS
Since the smallest exchange unit in the DN exchange network is the 64 kbps information channel, it is useless for telephone and data communication.

By the way, in Japanese Patent Laid-Open No. 61-61543, a switch
In an interface that accommodates a voice terminal and a data terminal in a subscriber line at the same time, a method has been proposed in which a voice call and a data call are simultaneously multiplexed at 64 kbps and an information channel is effectively used. Further, as a channel effective use method in a digital leased line, as described in Japanese Patent Application No. 61-23706, there is a method in which the compression / expansion side of each time slot can be dynamically controlled between opposite exchanges. Proposed.

[Problems to be Solved by the Invention] However, in the case of the former publication, since a device connected to a subscriber line performs demultiplexing processing, individual switching connection cannot be performed for each call, and therefore, it is caused by multiplexing. There is a problem that the effective use of the line is limited to the case where a terminal connected to one subscriber line multiplexes a plurality of calls to 64 kbps and communicates with another similar subscriber line connection terminal.

Further, in the case of the latter publication, there is a disadvantage that the applicable interface is limited to a dedicated line or a dedicated network to which a special communication protocol is applied.

The object of the present invention is to enable private branch exchanges to be exchanged between ISDN exchange networks.
This is to provide a trunk line call connection control method that enables effective use of information channels by realizing a bearer speed call connection control procedure not provided by the ISDN switching network.

[Means for Solving the Problems] The object is to set any one of the plurality of information channels after the call of the plurality of information channels is established between the two private branch exchanges by the signal channel. As a dedicated control channel between two private branch exchanges, a data link between the two private branch exchanges is established on the dedicated control channel, and information channel division / merge designation for the remaining information channels is performed by message communication on the data link. This is achieved by performing connection control of the bearer speed call according to the above-mentioned information channel division / merging designation, which cannot be provided from the ISDN switching network, on the remaining information channel.

[Operation] A call using a plurality of information channels via the ISDN switching network by a signaling channel between two private branch exchanges having a connection function with the ISDN switching network and having a call connection control procedure using a plurality of information channels After setting, the specific information channel is connected to the layer 2 control section by controlling the information channel exchange switch by the central control section. In addition, the central control unit has 2 on the specific information channel.
A data link between the private branch exchanges is established, but when a call is made from the extension terminal to the opposite exchange-extension terminal, the call at the transfer rate of the extension terminal is connected to the remaining information channels by message communication on the data link. It is designed to work. This allows 64 private branch exchanges between two private branch exchanges.
Information channels of kbps unit can be divided or merged to control connection of calls having an optimum communication speed, and the information channels can be effectively used.

[Examples] The present invention will be described below with reference to Figs.

First, the relay system according to the present invention will be described.
The figure shows the connection concept.

As shown in the figure, the private branch exchanges 1-a and 1-b are primary group speed interfaces (channel structure: 23B (B: information channel) + 1D).
(D: signal channel) 2 is connected to the ISDN switching network, and accommodates an extension terminal 5 capable of 32 kbps compression communication, and switch control in units of 32 kbps is possible. The primary group speed interface 2 also comprises a signal channel 3 for call control and the like and an information channel 4 serving as a communication path between users.

Now, in this example, a state in which two calls of 32 kbps are simultaneously set on one information channel between two private branch exchanges is conceptually shown. The signaling channel 3 controls the connection of the plural information channels 4a and 4b between the two private branch exchanges 1-a and 1-b, while the (specific) information channel 4a is set to the plural information channels 4a and 4b. After the information channel 4
It is designed to perform call control on b. That is, the information channel 4a functions as a dedicated control channel between the two private branch exchanges 1-a and 1-b. This channel
Since the message on 4a is transparently transferred to the opposite private branch exchange in the ISDN exchange network, two private branch exchanges 1-a, 1-
It is possible to provide information fields specific to b.
The multiple connection of the 32 kbps call to the information channel 4b in this example is realized by providing the demultiplexing function in the private branch exchanges 1-a and 1-b and by designating the dedicated information field. .

Next, the private branch exchanges 1-a and 1-b according to the present invention will be described with reference to FIG. 2. First, the station line corresponding unit 6 accommodating the primary group speed interface 2 is a layer 2 control unit 7 and a signal channel layer 2 Control unit 8, information channel switch 9, demultiplexer 10 and 64kbps / 32kbps demultiplexer 1
It is composed of 1. Of these, the demultiplexer 10 has a function of buffering the data of the signal channel and the information channel received from the line in bytes and separating them as a serial continuous signal of 64 kbps, and transmitting the signal from the exchange side to the line at a predetermined timing. Have. Further, the layer 2 control unit 7 and the signal channel layer 2 control unit 8 implement a data link procedure (LAPD) for performing error-free data transfer with the opposite layer 2 control unit, but both hardware configurations are the same. Well this is currently 1 chip LS
It is realized in I. By the way, since the LAPD procedure differs between the network mode and the user mode in the field specification of the transmission / reception frame, when performing communication between two private branch exchanges using the layer 2 control unit 7, one is used in the network mode and the other is used in the user mode. There is a need to.

Further, in the information channel exchange switch 9, the information channel 4b
Is exchange-connected as it is at 64 kbps, which can be integrated with the exchange switch 13 described later. 64 more
In the kbps / 32kbps demultiplexer 11, the 64kbps channel is
It is designed to be divided into 2 kbps units and, conversely, to be multiplexed.

The configuration of the office line corresponding unit 6 is as described above, but the central control unit 12 which is a component other than this implements ISDN interface layer 3 processing, performs hardware control of switches and the like, and selects the selector 15 Specifies whether to transmit a 64 kbps signal transmitted (received) by the extension terminal 5 transparently or to compress (decompress) it to 32 kbps via the 64 kbps / 32 kbps speed conversion unit 14, and further, the exchange switch 13
In 32 kbps and 64 kbps unit switching connection has been made.

Here, the call control will be described. Private branch exchange 1-
A uses a call attribute parameter arranged in advance with the private branch exchange 1-b at a time of heavy traffic and sets up a call consisting of a plurality of information channels 4a and 4b according to the ISDN procedure. After that, both private branch exchanges 1-a , 1-b, under the control of the central control unit 12, the specific information channel 4a is connected to the layer 2 control unit 7 through the information channel exchange switch 9 to establish a data link in which one is in the network mode and the other is in the user mode. It is like this. The connection between the layer 2 control unit 7 and the information channel 4a is realized by switching the receiving side and the transmitting side of the transmission / reception serial port of the layer 2 control unit 7 to the information channel receiving side and the transmitting side. In addition,
The method of designating the specific information channel 4a and the method of designating the network mode and the user mode between both private branch exchanges may be a method that is fixed in advance or a method that is specified by the connection procedure on the signal channel 3.

Now, when a call is made from the terminal 5 which is compressed to 32 kbps and is capable of communication to the extension private branch exchange terminal, the central control unit 12 which receives the call information from the extension corresponding signal channel layer 2 control unit 8
Is 32kbps with the opposite private branch exchange using specific information channel 4a.
Make a call connection that specifies a subchannel. FIGS. 3 (a) and 3 (b) show an example of the information channel division designation method. In this example, 64 kbps is divided into two by four time slots, which are defined as subchannels 1 and 2, respectively. Information channel 4
At the time of call setup on a, the information channel number and subchannel number are specified in the 2-byte field of the call connection message.

If the call connection conditions are satisfied in the above procedure, the central control unit
A switch 12 switches the selector 15 to the 64 kbps / 32 kbps speed conversion unit 14 side and controls the exchange switch 13 and the information channel exchange switch 9 to connect the communication path.

As described above, since two calls can be set up on one 64 kbps information channel between private branch exchanges, efficient use of the channel can be achieved, and the signaling channel can reduce messages for call connection. Therefore, the communication capacity of the signal channel packet is improved.

It is easily conceivable to multiplex 8 kbps and 16 kbps calls to the information channel in the same manner as this embodiment, and the extension side
When the 32 kbps information channel division use (4 calls can be set for 2B) is realized, the compression (expansion) function by the 64 kbps / 32 kbps speed conversion unit 14 and the selector 15 becomes unnecessary. Further, even when communication is made between an extension terminal of 64 kbps × n kbps such as 192 kbps and an extension terminal of the opposite private branch exchange, the exchange switch 13 may be adapted to 64 kbps × n, and may be operated in reverse to the information channel demultiplexing unit 11. This enables connection control of calls at bearer speeds that cannot be controlled directly in ISDN switching networks.

[Effects of the Invention] As described above, according to the present invention, it becomes possible to connect a call at a bearer speed, which cannot be exchange-connected in an ISDN switching network, between two private branch exchanges via the ISDN switching network, and to connect a line There is an effect that economic efficiency can be achieved by effective use.

[Brief description of drawings]

FIG. 1 is a diagram showing a connection concept of a relay system according to the present invention,
FIG. 2 is a diagram showing a block configuration of an example of a private branch exchange according to the present invention, and FIGS. 3 (a) and 3 (b) are diagrams showing an example of an information channel division designation method. 1 (1-a, 1-b) ... Private branch exchange, 2 ... Primary rate interface, 3 ... Signal channel, 4a ... Specific information channel, 4b ... Information channel, 5 ... Extension terminal, 6 ...
... Station line corresponding part, 7 ... Layer 2 control part, 8 ... Signal channel layer 2 control part, 9 ... Information channel exchange switch, 12 ... Central control part, 13 ... 32kbps / 64kbps exchange switch, 14 ... … 64kbps / 32kbps speed converter.

Claims (1)

(57) [Claims] 1. A trunk line call connection control method when two private branch exchanges are interconnected by a plurality of information channels via an ISDN switching network, each having a call connection control procedure using a plurality of information channels. After a call of a plurality of information channels is set up between two private branch exchanges by a signaling channel, one of the plurality of information channels is used as a dedicated control channel between the two private branch exchanges,
The data link between the two private branch exchanges is established on the dedicated control channel, and the information channel division / merging designation for the remaining information channel is performed by the message communication on the data link. Then, a trunk line call connection control method in which connection control of a bearer speed call according to the above-mentioned information channel division / merge specification is performed, which cannot be provided from the ISDN switching network.