JPH07143118A - Isdn terminal adaptor - Google Patents

Abstract

PURPOSE:To provide an ISDN terminal adaptor selecting line exchange and packet exchange so as to reduce the communication cost. CONSTITUTION:A data quantity detection circuit 15 detects an average communication data quantity between an interface section 11 and a changeover circuit 12 and informs the detected quantity to a control section 17. An operation display section 16 inputs a data quantity setting value to the control section. The control section compares a received average communication data quantity with the data quantity setting value to select either of the line exchange and the packet exchange. The control section controls an ISDN communication section 13, a synchronization PAD section 14, and the changeover circuit 12 to change over the line exchange into the packet exchange or vice versa.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ISDN terminal adapter, and more particularly to an ISDN terminal adapter having a circuit switching interface and a packet switching interface.

[0002]

2. Description of the Related Art A conventional ISDN terminal adapter is
It has one of a circuit switching interface and a packet switching interface. Also, an IS having a circuit switching interface and a packet switching interface
Some DN terminal adapters are set to use one of the interfaces at the time of connection.

A terminal adapter capable of handling both circuit-switched calls and packet-switched calls from a terminal device is disclosed in JP-A-1-240047.

[0004]

In the data communication using the ISDN network, it is desirable that the line communication and the packet communication can be appropriately selected. That is, in the ISDN terminal adapter, it is desired that the circuit switching interface and the packet switching interface can be selectively used as appropriate.

However, the conventional ISDN terminal adapter has a problem that only one of the circuit switching interface and the packet switching interface can be used.

Further, even with an ISDN terminal adapter having a circuit switching interface and a packet switching interface, it takes time and labor to switch the circuit switching interface and the packet switching interface. Therefore, the circuit switching interface and the packet switching interface are required. There is a problem that it is not realistic to use different interfaces as needed.

Further, in the terminal adapter capable of both circuit switching and packet switching according to the call,
Since the communication form is determined by the call, once one of the communication forms is established, there is a problem that the other communication form cannot be changed in the middle.

According to the present invention, in order to reduce communication cost, an ISDN terminal capable of automatically using a circuit switching interface and a packet switching interface so as to select an optimum communication network even during communication. The purpose is to provide an adapter.

[0009]

According to the present invention, an interface unit connected to a terminal device, an ISDN communication unit having a circuit switching interface and a packet switching interface and connected to an I interface DSU, and the packet switching are provided. A synchronous PAD unit connected to the interface for converting a synchronous protocol signal into a packet signal and vice versa; and a switching circuit for selectively connecting the interface unit to either the circuit switching interface or the synchronous PAD unit. A data amount detection circuit connected to the interface unit for measuring the data amount of a synchronization protocol signal, an input unit for inputting a data amount set value from the outside, the switching circuit, the ISDN communication unit, the synchronization PA.
The switching circuit, the ISDN communication unit, and the synchronization PA are connected to the D unit, the data amount detection circuit, and the input unit, and are based on the data amount and the data amount set value.
IS having a control section for controlling the D section
A DN terminal adapter is obtained.

Further, according to the present invention, the I interface D is provided with an interface unit connected to the terminal device, a circuit switching interface and a packet switching interface.
An ISDN communication unit connected to the SU, a synchronous PAD unit connected to the packet switching interface for converting a synchronous protocol signal to a packet signal and vice versa, and the interface unit for the circuit switching interface and the synchronous PAD unit. A switching circuit selectively connected to any one of the two, an input unit for inputting a set time from the outside, the switching circuit, the ISDN communication unit, and the synchronous PA.
An ISDN terminal adapter is obtained, which is connected to the D section and the input section, and has a control section that controls the switching circuit, the ISDN communication section, and the synchronous PAD section based on the set time. .

[0011]

The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an ISDN terminal according to an embodiment of the present invention. The ISDN terminal adapter 10 of this embodiment includes a terminal device 20 and an I interface DSU 30.
Used to connect between and.

The ISDN terminal adapter 10 includes an interface section 11, a switching circuit 12, and an ISDN communication section 1.
3, synchronous PAD unit 14, data amount detection circuit 15, operation
The display unit 16 and the control unit 17 are included.

The interface section 11 includes an interface compliant with CCITT Recommendation V24 / V28 and is connected to the terminal device 20. Further, the interface section 11 is connected to the switching circuit 12.

The switching circuit 12 connects the interface unit 11 and the circuit switching interface 18 of the ISDN communication unit 13 or connects the interface unit 11 and the synchronous PAD unit 14 in accordance with a control signal from the control unit 17.

The ISDN communication section 13 is a circuit switching interface 18 for controlling communication using the ISDN circuit switching network.
And the packet switching interface 19 for performing communication control using the ISDN packet switching network, and are connected to the I interface DSU.

The synchronous PAD unit 14 converts the synchronous protocol signal input from the interface unit 11 via the switching circuit 12 into a PAD signal and outputs it to the packet switching interface unit 19. Further, the packet signal input from the packet switching interface unit 19 is converted into a synchronous protocol signal and output to the switching circuit 12. This synchronous PA
The D unit 14 is compatible with synchronization protocols such as SDLC, HDLC, and BSC, and is set to support any synchronization protocol.

The data amount detection circuit 15 includes SDLC, HD
It can support synchronization protocols such as LC and BSC, detects the amount of data according to one of the synchronization protocols by setting, and outputs it to the control unit 17. The setting of the data charge detection circuit 15 needs to match the setting of the synchronous PAD unit 14. The detection method of the data detection amount of the data amount detection circuit 15 is a unit time by detecting the start flag and the end flag of the frame and the transmission sequence number N (S) for the SDLC and HDLC synchronization protocols. Calculate the average data amount. In addition, for the BSC synchronization protocol, the data transmission control codes STX (start of text), ETX (end of text), ACK0 (acknowledgement (0)), ACK1 in the information message.
(Affirmative response) and NACK (negative response) are detected to detect the average data amount per unit time.

The operation / display unit 16 gives the set value data necessary for the control unit 17 to control the switching circuit 12, the synchronous PAD unit 14 and the ISCN communication unit by an external input. This set value data includes a threshold value and a reservation time required for switching between circuit switching and packet switching. In addition, the operation / display unit 16 includes a control unit 17
Receives data from and displays the operating status of this ISDN terminal adapter.

The control unit 17 controls the switching circuit 12, the synchronous PAD unit 14, and the ISCN communication unit 13 based on the detected data amount from the data amount detection circuit 15 and the set value data from the operation / display unit 16. Control. More specifically, the selection of a line based on the threshold value or the reservation time, the communication control of the ISDN communication unit 13, the line switching control for the partner device, and the line switching control of the own device are performed.

Next, the operation of this embodiment will be described with reference to FIGS. In the following description, as shown in FIG.
ISDN terminal adapters 10a and 10 of this embodiment
b is connected between the terminal device 20 and the CPU 21 and the I interface DSCs 30a and 30b, respectively. The I interfaces DSCs 30a and 30b are IS
It is connected to the DN circuit switching network 22 and the ISDN packet switching network to form an ISDN network.

First, the switching operation of circuit switching / packet switching based on the amount of communication data will be described. In the system as shown in FIG. 2, communication is usually performed by packet switching in order to suppress communication costs. That is, ISDN
Switching circuit 12 for the terminal adapters 10a and 10b
Connects the interface unit 11 and the synchronous PAD unit 14.

During the communication between the terminal device 20 and the CPU 21, the data amount detection circuit 15 of either the ISDN terminal adapter 10a or the ISDN terminal adapter 10b monitors (detects) the communication data amount. To do. This is, for example, the terminal device 20 and the CPU
IS connected to the device on the side that started communication
The DN terminal adapter 10 is used. Here, the ISDN terminal adapter 10a connected to the terminal device 20 is used.
Will monitor the communication data.

The data amount detection circuit 15 of the ISDN terminal adapter 10a notifies the control unit 17 of a predetermined average communication data amount per unit time. Control unit 17
, A threshold value input from the operation / display unit 16 is set in advance, and this threshold value is compared with the average communication data amount from the data detection circuit 15. When the average communication data amount is less than or equal to the threshold value, the control unit 17 does nothing and continues the data communication by packet switching as it is. On the other hand, when the average communication data amount exceeds the threshold value, the control unit 17
The circuit switching interface unit 18 is controlled to establish a circuit switching link. When the circuit switching link is established, the control unit 17 instructs the ISDN terminal adapter 10b via the circuit switching interface unit 18 and the circuit switching network 22 to switch from packet switching to circuit switching.

The ISDN terminal adapter 10b is I
When the switching instruction is received from the SDN terminal adapter 10a, the switching operation is performed and the switching completion response is output via the packet switching network 23 as described later. This switching completion response is input to the control unit 17 via the packet switching interface unit 19 of the ISDN terminal adapter 10a.

When the control section 17 receives the switching completion response from the ISDN terminal adapter 10b, the switching circuit 1
Then, the interface section 11 and the circuit switching interface 18 are connected. After that, the terminal device 20 and C
Communication with the PU 21 is performed via the ISDN circuit switching network 22.

While communication is being performed by circuit switching,
The data amount detection circuit 15 of the ISDN terminal adapter 10a continues to monitor the data amount. The control unit 17 establishes a packet switching link to the packet switching interface unit 19 when the average communication data amount per unit time from the data amount detection circuit 15 becomes smaller than a preset threshold value. Control.

When the packet switching link is established, the control unit 17 instructs the ISDN terminal adapter 10b to switch from circuit switching to packet switching via the packet switching interface unit 18 and the packet switching network 23. To do.

After performing the switching operation, the ISDN terminal adapter 10b sends a switching completion response to the circuit switching network 22. This switching completion response is input to the ISDN terminal adapter 10a and sent to the control unit 17 via the circuit switching interface unit 18 of the ISDN communication unit 13.
When the control unit 17 confirms the switching completion response, the switching circuit 1
Then, the interface section 11 and the synchronous PAD section 14 are connected. After that, communication is performed between the terminal device 20 and the CPU 21 via the ISDN packet switching network 23.

Next, the switching operation of the ISDN terminal adapter 10b which has received the switching instruction will be described. ISDN terminal adapter 1 for packet switching communication
The circuit switching interface 0b is 18 and the circuit switching network 2
When the call originating from the ISDN terminal adapter 10a is confirmed via 2, the incoming call state is established and a circuit-switched link is established.

Next, the ISDN terminal adapter 10
The switching instruction sent from a through the circuit switching network 22 is input to the control unit 17 through the circuit switching interface 18. Upon confirming the switching instruction, the control unit 17 switches the switching circuit 12 and connects the interface unit 11 and the circuit switching interface 18. And the control unit 1
7 transmits a switching completion response to the ISDN terminal adapter 10a via the packet switching interface unit 19 and the packet switching network 23. Finally, the control unit 17 includes the synchronous PAD unit 14 and the packet switching interface unit 19
Stop the operation of. After that, the terminal device 20 and the CPU 21
And the communication are performed via the ISDN circuit switching network 23.

When the ISDN terminal adapter 10b performing the circuit switching communication receives the switching instruction, the switching is performed by the same operation as described above.

Further, the disconnection of communication is performed in the same manner as in the conventional case in both packet switching and circuit switching. For example, in the ISDN terminal adapter 10a, a disconnection instruction is issued from the operation / display unit 16, and the control unit 17 causes the IS
The current interface unit of the DN communication unit 13 is controlled to execute the disconnection operation. ISDN terminal adapter 1
0b confirms disconnection of the ISDN terminal adapter 10a and executes disconnection operation.

Next, with reference to FIGS. 1 and 2, the switching operation of circuit switching / packet switching depending on the switching reservation time will be described. Here again, it is assumed that the system shown in FIG. 2 is communicating by packet switching. In the present embodiment, the data amount detection circuit 15 of the ISDN terminal adapter 10 is not necessary, so that its operation is stopped by the control unit 17.

In advance, the ISDN terminal adapter 10a
The scheduled switching time input from the operation / display unit 16 is set in one of the control units 17 of 10 and 10b. Here, it is assumed that the scheduled switching time (time or elapsed time) is set in the control unit 17 of the ISDN terminal adapter 10a.

The control unit 17 of the ISDN terminal adapter 10a has a timer, and when the preset switching time from packet switching to circuit switching comes, it controls the circuit switching interface unit 18 to link the circuit switching link. Establish. When the circuit switching link is established, the control unit 17 instructs the ISDN terminal adapter 10b via the circuit switching interface unit 18 and the circuit switching network 22 to switch from packet switching to circuit switching.

The ISDN terminal adapter 10b is I
When receiving the switching instruction from the SDN terminal adapter 10a, the switching operation is performed and the switching completion response is output via the packet switching network 23. This switching completion response is an ISDN
It is input to the control unit 17 via the packet switching interface unit 19 of the terminal adapter 10a.

When the controller 17 confirms the switching completion response from the ISDN terminal adapter 10b, the switching circuit 1
Then, the interface section 11 and the circuit switching interface 18 are connected. After that, the terminal device 20 and C
Communication with the PU 21 is performed via the ISDN circuit switching network 22.

At the scheduled switching time from circuit switching to packet switching, the control unit 17 controls the packet switching interface unit 19 to establish a packet switching link.

When the packet switching link is established, the control unit 17 instructs the ISDN terminal adapter 10b to switch from circuit switching to packet switching via the packet switching interface unit 18 and the packet switching network 23. To do.

After performing the switching operation, the ISDN terminal adapter 10b sends a switching completion response to the circuit switching network 22. This switching completion response is input to the ISDN terminal adapter 10a and sent to the control unit 17 via the circuit switching interface unit 18 of the ISDN communication unit 13.
When the control unit 17 confirms the switching completion response, the switching circuit 1
Then, the interface section 11 and the synchronous PAD section 14 are connected. After that, communication is performed between the terminal device 20 and the CPU 21 via the ISDN packet switching network 23.

On the other hand, ISDN terminal adapter 10b
The ISDN terminal adapter 10b has a circuit switching interface 18 and an ISDN via the circuit switching network 22.
When the call originating from the terminal adapter 10a is confirmed, the call enters the incoming state and the circuit switching link is established.

Next, the ISDN terminal adapter 10
The switching instruction sent from a through the circuit switching network 22 is input to the control unit 17 through the circuit switching interface 18. Upon confirming the switching instruction, the control unit 17 switches the switching circuit 12 and connects the interface unit 11 and the circuit switching interface 18. And the control unit 1
7 transmits a switching completion response to the ISDN terminal adapter 10a via the packet switching interface unit 19 and the packet switching network 23. Finally, the control unit 17 includes the synchronous PAD unit 14 and the packet switching interface unit 19
Stop the operation of. After that, the terminal device 20 and the CPU 21
And the communication are performed via the ISDN circuit switching network 23.

Also, ISDN which is performing circuit switching communication
When the terminal adapter 10b receives a switching instruction from the ISDN terminal adapter 10a, switching is performed by the same operation as above.

Further, the disconnection of communication is performed in the same manner as in the conventional case in both packet switching and circuit switching. For example, in the ISDN terminal adapter 10a, a disconnection instruction is issued from the operation / display unit 16, and the control unit 17 causes the IS
The current interface unit of the DN communication unit 13 is controlled to execute the disconnection operation. ISDN terminal adapter 1
0b confirms disconnection of the ISDN terminal adapter 10a and executes disconnection operation.

[0045]

According to the present invention, the switching circuit controlled by the control unit switches between the circuit switching and the packet switching, so that the network can be switched in a short time without human intervention. .

Further, since the data detection circuit detects the communication data amount and switches the circuit switching and the packet switching depending on the detected communication data amount, the optimum network should be selected according to the data amount. Therefore, the communication cost can be reduced. Similarly, since the circuit switching and the packet switching are switched according to the communication time, the optimum network can be selected according to the data amount, and the communication cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of an ISDN terminal adapter according to an embodiment of the present invention.

FIG. 2 is a block diagram of a communication system using the ISDN terminal adapter of FIG.

[Explanation of symbols]

 10 ISDN terminal adapter 10a, 10b ISDN terminal adapter 11 interface unit 12 switching circuit 13 ISDN communication unit 14 synchronization PAD unit 15 data amount detection circuit 16 operation / display unit 17 control unit 18 circuit switching interface 19 packet switching interface 20 terminal device 21 CPU 30 I interface DSU 30a, 30b I interface DSU

Claims (2)

[Claims] 1. An IS including an interface unit connected to a terminal device, a circuit switching interface and a packet switching interface and connected to an I interface DSU.
A DN communication unit, a synchronous PAD unit connected to the packet switching interface for converting a synchronous protocol signal into a packet signal and vice versa, and the interface unit as either the circuit switching interface or the synchronous PAD unit. A switching circuit that is selectively connected, a data amount detection circuit that is connected to the interface unit and measures the data amount of the synchronization protocol signal, an input unit that inputs a data amount set value from the outside, the switching circuit, and the ISDN.
The switching unit, the ISDN communication unit, and the synchronous PAD unit are connected to the communication unit, the synchronous PAD unit, the data amount detection circuit, and the input unit, and are based on the data amount and the data amount set value. An ISDN terminal adapter having a control unit for controlling. 2. An IS including an interface unit connected to a terminal device, a circuit switching interface and a packet switching interface and connected to an I interface DSU.
A DN communication unit, a synchronous PAD unit connected to the packet switching interface for converting a synchronous protocol signal into a packet signal and vice versa, and the interface unit as either the circuit switching interface or the synchronous PAD unit. A switching circuit that is selectively connected, an input unit that inputs a set time from the outside, the switching circuit, and the I
The SDN communication unit, the synchronous PAD unit, and the input unit are connected to each other, and the switching circuit and the I circuit are connected based on the set time.
An ISDN terminal adapter having an SDN communication unit and a control unit for controlling the synchronous PAD unit.