JPH09149149A - ISDN terminal communication control system - Google Patents

Abstract

(57) An object of the present invention is to enable extension communication between terminal devices without going through an ISDN network and to enable extension communication of two or more ISDN terminal devices. D channel detection control circuit 2 of DSU 12
Reference numeral 1 detects an extension request and a normal activation request D channel control signal from the terminal devices 15 to 18, and when the extension request is detected, the transmission line 3 and the reception line 4 are connected so as to be folded back as they are. The terminal device 16 that has issued the extension request
After detecting the extension enable signal from U12, the code of the terminal device 15 of the communication destination is output. The other terminal device 15 is
The receiving circuit 52 outputs the received code and channel information to the channel switching circuit 55 and the code comparison circuit 53,
When the received code and the code of the own terminal device are compared and when they match, communication is performed using the channel designated by the channel switching circuit 55. By dividing the B channel into halves for transmission and reception, extension communication between two or more terminal devices becomes possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention enables extension communication without passing through an ISDN network in communication between ISDN terminal devices connected to an ISDN network through a network terminating device (hereinafter abbreviated as DSU). ISDN terminal communication control system.

[0002]

2. Description of the Related Art FIG. 5 shows a schematic block diagram of a conventional ISDN terminal communication control system.

Referring to FIG. 5, an ISDN terminal communication control system includes an ISDN network 1, a DSU 2 and terminal devices 5, 6,
7, the ISDN network 1 is connected to the DSU 2 by the basic interface of 2B + D, and the transmission line 3
Terminal devices 5, 6, and 7 are connected to the S-point interface composed of the receiving line 4.

When communication is performed between the terminal devices 5 and 6,
Instead of directly using the S-point interface, communication is performed via the ISDN network.

For example, as shown in FIG. 6, a communication request INFO1 (+ 0, -0,1,1,1,1,1) is sent from the terminal device 5.
1, 1) to DSU2 via the D channel. D
Upon detecting INFO1, SU2 transmits INFO2 to terminal device 5, and in response to this, terminal device 5 causes DSU2
INFO3 (communication signal) to the DSU2
Transmits INFO4 (normal signal) to the terminal device 5. As a result, the start-up is completed for the first time, and the ISDN network is connected. Next, the terminal device 5 recognizes the code of the terminal device 6 and sends it to the ISDN exchange by using the D channel, and the exchange side recognizes the code of the terminal device 6 and calls the terminal device 6 by using the D channel to make a call. Start.

The definition of INFO is shown in FIG. Further, in the current ISDN network, when the terminal devices 5 and 6 are communicating, since the B1 and B2 channels are occupied, the third terminal device 7 cannot communicate.

[0007]

However, in the conventional ISDN terminal communication control system as described above, the IS
There is a problem that communication cannot be performed between the terminal devices without passing through the DN network, communication cost for using the ISDN network is high, and communication cannot be performed by two or more ISDN terminal devices.

The present invention solves the above problems and enables extension communication between terminal devices without passing through an ISDN network and extension communication of two or more ISDN terminal devices. It is an object of the present invention to provide an ISDN terminal communication control system.

[0009]

In order to solve the above-mentioned problems, according to the present invention, a network terminating device detects an extension request and a D channel control signal which is a normal activation request from an ISDN terminal device, and detects the extension request. Each ISDN terminal device has a code recording circuit for recording its own code, and a D channel detection control circuit for controlling the transmission line and the reception line to connect so that the transmission line and the reception line are folded back as they are. A code comparison circuit that compares a code received from the other party with its own code, a channel switching circuit that controls a transmission channel and a reception channel, and outputs the received code and channel information to the code comparison circuit and the channel switching circuit. And a code and data indicating the ISDN terminal device of the communication destination that is to be transmitted to the transmission channel on the transmission line. It is made and a signal circuit.

This enables extension communication between terminal devices without going through the ISDN network and communication between two or more ISDN terminal devices.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is a plurality of ISDN terminals connected to a network terminating device connected to an ISDN network through an S point interface consisting of a transmission line and a reception line. An ISDN terminal communication control system for performing communication between devices, wherein the network terminating device is the ISD
N: A D channel control signal which is an extension request and a normal activation request from the terminal device is detected, and when the extension request is detected, the transmission line and the reception line are controlled to connect the transmission line and the reception line so that they are folded back as they are. Each ISDN terminal device includes a channel detection control circuit, and each ISDN terminal device records a code of itself, a code comparison circuit that compares a code received from the other party with its own code, and a transmission channel and a reception channel. A channel switching circuit to control,
A receiving circuit for outputting the received code and channel information to the code comparing circuit and the channel switching circuit; and a transmitting circuit for transmitting the code and data indicating the ISDN terminal device of the communication destination to the transmission channel on the transmission line. The ISDN terminal device that requested the extension
After detecting the extension communication enable signal from the network terminating device, the code of the ISDN terminal device of the communication destination is output. Then, the ISDN terminal device on the partner side outputs the received code and channel information to the channel switching circuit and the code comparison circuit in the receiving circuit, compares the received code with the code of the own terminal device, and detects a match, Communication is performed using the channel designated by the channel switching circuit. Also, by dividing the B channel in half and transmitting and receiving,
Enables extension communication between one or more terminal devices.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 1 is a block diagram showing a schematic configuration of an ISDN terminal communication control system in an embodiment of the present invention.

In FIG. 1, the ISDN terminal communication control system comprises an ISDN network 1, a DSU 12 and a terminal device 15,
16 and 17, the DSN 12 is connected to the ISDN network 1 by a basic interface of 2B + D, and the terminal devices 15, 16, 17, and 18 are connected to the S point interface including the transmission line 3 and the reception line 4. Has been done.

The DSU 12 includes a D channel detection control circuit 21 which detects the D channel control signal and controls the transmission line 3 and the reception line 4.

The terminal device 15 includes a code recording circuit 54 for recording its own code, a code comparison circuit 53 for comparing the received code with its own code, and a channel switching circuit 55 for controlling the transmission channel and the reception channel. , A receiving circuit 52 for outputting the received code and channel information to the code comparing circuit 53 and the channel switching circuit 55.
And a transmission circuit 51 for transmitting the code and data indicating the ISDN terminal device of the communication destination to the transmission channel on the transmission line 3.

The terminal devices 16, 17, and 18 are terminal devices 15.
Since it has the same configuration as the above, the description of the configuration is omitted.

Next, the operation of this embodiment configured as described above will be described with reference to FIG.

When the terminal device 15 communicates with the terminal device 16, the extension request INFO1 '(IN
Signals other than FO1, such as +0, -0, 1, 1, 1,
+0,1,1) is transmitted to the DSU 12 via the transmission circuit 51 using the D channel. Then, D of DSU12
In the channel detection control circuit 21, INFO1 ′ is a normal activation request (INFO1 = + 0, −0, 1, 1, 1, 1,
1,1) or an extension request (INFO1 '= + 0,-
0,1,1,1, + 0,1,1), and if it is an extension request, the transmission line 3 and the reception line connected to the DSU 12 are connected so as to be folded back, and INFO4 ′
(Extension enabled signal which is a synchronization frame including general data in B, D and D echo channels) is output.

Note that the INFO2 issues a command to the DSU to output INFO2 to the DSU so that the INFO2 does not malfunction when a plurality of ISDN terminal devices make activation requests at the same time. In response to this, INFO3 is returned. ing. However, in the present embodiment, since the transmission line and the reception line are connected so as to be folded back after the INFO1 ′ is input, the INFO2 and the INFO3 are not particularly necessary.

Next, the receiving circuit 52 of the terminal device 15 is set to IN.
After recognizing FO4 ', the code of the terminal device 16 and the channel information are output to the D channel. In the terminal device 16,
The code and channel information is read from the receiving circuit, the code information is output to the code comparing circuit, and the channel information is output to the channel switching circuit. The code comparison circuit compares the received code with the code of the terminal device 16 itself recorded in the code recording circuit, and when the code of the terminal device 16 matches, instructs the transmission circuit to match the code. Further, in the channel switching circuit of the terminal device 16,
The transmitter circuit of the terminal device 16 is instructed to transmit on a channel that is not used on the B1 or B2 channel. In this transmission circuit, communication is started between the terminal device 15 and the terminal device 16 using the channel determined by the instruction of the code comparison circuit and the channel switching circuit.

As a result, as shown in FIG. 3, the transmission line 3
The terminal device 16 uses the B1 channel above and the terminal device 15 uses the B2 channel for transmission, respectively, and B1 on the reception line 4 is used.
The channel is the terminal device 15 and the B2 channel is the terminal device 1
The communication between the terminal device 15 and the terminal device 16 is performed by each of them being used by 6 for reception.

When a call is being made between the terminal device 15 and the terminal device 16, the receiving circuit of the third terminal device 17 is B.
No communication request is made because the 1 and B2 channels are monitored and recognized as being in use. That is, communication is not possible.

In addition, when the terminal devices 15 and 16 are in a call,
When the DN network side makes a communication request, the D channel detection control circuit 21 of the DSU 12 controls the DSU so that the DSU does not respond to the ISDN network. In the ISDN network, it judges that there is no response and stops the communication request.

Next, a case where communication is performed by two or more ISDN terminal devices will be described. In the configuration of FIG. 1, when the terminal device 15 communicates with the terminal device 16, the extension request INFO1 ″ (for example, +0, −
0, 1, 1, 1, 1, +0, 1) is transmitted to the DSU 12 via the transmission circuit 51 using the D channel. Then, the D channel detection control circuit 21 of the DSU 12
FO1 ′ is a normal activation request (INFO1 = + 0, −0,
1,1,1,1,1,1,1) or extension request (INF
O1 '= + 0, -0,1,1,1, + 0,1,1 or INFO1 "= + 0, -0,1,1,1,1, + 0,
If it is 1) and it is an extension request INFO1 ″, the transmission line 3 and the reception line connected to the DSU 12 are connected so as to be folded back as they are, and INFO4 ″ is output.

Next, the receiving circuit 52 of the terminal device 15 is set to IN.
After recognizing FO4 ", the code and channel information of the terminal device 16 are output to the D channel.
The code and channel information is read from the receiving circuit, the code information is output to the code comparing circuit, and the channel information is output to the channel switching circuit. The code comparison circuit compares the received code with the code of the terminal device 16 itself recorded in the code recording circuit, and when the code of the terminal device 16 matches, instructs the transmission circuit to match the code. Further, in the channel switching circuit of the terminal device 16,
The transmission circuit of the terminal device 16 is instructed to transmit the B channels to the unused channels divided into two. In this transmission circuit, communication is started between the terminal device 15 and the terminal device 16 using the channel determined by the instruction of the code comparison circuit and the channel switching circuit.

As a result, as shown in FIG. 4, the transmission line 3
The upper B1 channel (64 kbps) to B11 (32 kb)
ps) and B12 (32 kbps).
Is used by the terminal device 16 for transmission, and the B2 channel (64 kbps) on the receiving line 4 is set to B21 (32 kbps) and B2.
2 (32 kbps) and divide this B21 into the terminal device 1
6 is used for reception, and B11 on the reception line 4 is used by the terminal device 15
Is used for reception and B21 on the transmission line 3 is used for transmission by the terminal device 15 to perform communication.

If the terminal device 17 issues an extension request INFO1 "while the terminal device 15 and the terminal device 16 are in a call, the D channel detection control circuit 21 of the DSU 12 outputs INF.
After recognizing that it is O1 ″, INFO4 ″ is output. Next, the receiving circuit of the terminal device 17 outputs the code of the terminal device 18 to the D channel after recognizing the INFO4 ″. The terminal device 18 reads the code and the channel information from the receiving circuit and reads the code information. 18
Of the channel information to the terminal device 1
8 to the channel switching circuit. In this code comparison circuit, the received code is compared with the code of the terminal device 18 itself recorded in the code recording circuit, and when the code matches the code of the terminal device 18, the transmission circuit is instructed to match the code. Further, the channel switching circuit of the terminal device 18 gives an instruction to the transmission circuit of the terminal device 18 so as to recognize the unused channel and transmit to the unused channel. In this transmission circuit, communication is started using the channel determined by the instructions of the code comparison circuit and the channel switching circuit.

As a result, as shown in FIG. 4, the transmission line 3
Communication is performed by using B12 above for the terminal device 18 and B22 for the terminal device 17 for transmission, B12 on the receiving line 4 for the terminal device 17 and B22 for the reception device 18, respectively. Extension communication can be performed with four terminal devices.

When the terminal device 17 (or the terminal device 18) issues the extension request INFO1 'or the activation request INFO1 while the terminal device 15 and the terminal device 16 are in a call, the D channel detection control circuit 21 of the DSU 12 At INF
When it recognizes that a signal other than O1 ”is input,
Since NFO4 "is not output to the terminal device 17 (or the terminal device 18), the terminal device 17 (or the terminal device 1)
8) stops the communication request.

In addition, when the terminal devices 15 and 16 are in a call,
When the DN network side makes a communication request, the D channel detection control circuit 21 of the DSU 12 controls the DSU so that the DSU does not respond to the ISDN network. In the ISDN network, it judges that there is no response and stops the communication request.

According to this embodiment, the ISDN
The extension call between the terminal devices can be performed without going through the ISDN network, and the communication cost can be reduced. In addition, extension communication is possible between two or more terminal devices.

[0032]

As described above, according to the present invention, ISDN
Without using the network, S between the network terminating equipment and the ISDN terminal equipment
An extension call between terminal devices can be performed using the point interface, and the communication cost can be reduced. Further, by dividing the B channel into two and performing communication, there is an effect that extension communication can be performed between two or more terminal devices.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an ISDN terminal communication control system according to an embodiment of the present invention.

FIG. 2 is a sequence diagram showing a communication procedure in the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an example of a signal channel according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing another example of a signal channel according to the embodiment of the present invention.

FIG. 5 is a block diagram showing a schematic configuration of a conventional ISDN terminal communication control system.

FIG. 6 is a sequence diagram showing a communication procedure of a conventional example.

FIG. 7 is a diagram showing the definition of INFO.

[Explanation of symbols]

 1 ISDN network 3 transmission line 4 reception line 12 DSU 15, 16, 17, 18 terminal device 21 D channel detection control circuit 51 transmission circuit 52 reception circuit 53 code comparison circuit 54 code recording circuit 55 channel switching circuit

Claims (1)

[Claims] 1. An ISD for performing communication between a plurality of ISDN terminal devices connected to a network terminating device connected to an ISDN network via an S-point interface consisting of a transmission line and a reception line.
In the N terminal communication control system, the network terminating device detects a D channel control signal which is an extension request and a normal activation request from the ISDN terminal device, and when the extension request is detected, the transmission line and the reception line are connected. The ISDN terminal device is provided with a D channel detection control circuit that controls and connects the transmission line and the reception line so as to fold back as they are. A code comparison circuit that compares a code, a channel switching circuit that controls a transmission channel and a reception channel, a reception circuit that outputs the received code and channel information to the code comparison circuit and the channel switching circuit,
An ISDN terminal communication control system, comprising: a transmission circuit for transmitting a code and data indicating an ISDN terminal device of a communication destination to a transmission channel on the transmission line.