JP2828070B2 - Digital exchange - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to communication via an ISDN exchange, and more particularly to a digital exchange suitable for performing simultaneous communication between a plurality of subscribers in a network. About. [0002] A conventional loop network system includes:
As realized as one type of LAN (Local Area Network), for example, IEE, Standard 802.5-1985, Token Ring Access
Method and Physical Layer Specifications (IIS Draft Proposal 8802/5) IEEE Std 802.5-1985, Token Ring Acc
ess Method and physical Layer Specifications (ISO D
raft Proposal 8802/5)). [0003] In the prior art, a plurality of terminals are directly coupled by a loop-type transmission line. Therefore, after a transmission line is once installed, when a terminal is added to a network, terminals at both ends are added to the added terminal. It is necessary to provide a transmission path from the terminal, and it is not practical to install a new terminal at a location far away from the existing terminal and accommodate it in the loop network. This is mainly a loop type network in LA
This is why it has been used for N (Local Area Network). In addition, in order to continue the operation of the network when a terminal or a transmission line fails, a double transmission line is provided in advance,
By folding back between the two transmission lines at both ends of the fault,
One loop is constituted by a double transmission line. Therefore,
In order to continue the operation even when a failure occurs at a plurality of places at the same time, the operation must be divided into a plurality of loops, and accordingly, the terminals in the network are also divided into a plurality of groups. [0004] An object of the present invention is to provide an IS
It is an object of the present invention to provide a digital exchange capable of forming a loop network system between a plurality of arbitrary terminals connected to an ISDN exchange network via an exchange function of the DN exchange network. Further, by providing a digital exchange capable of forming a loop network system in an ISDN exchange network as described above, it is possible to perform a broadcast communication between a plurality of terminals (ie, a conference-type communication system). After the loop network system has been configured, and without performing the switching process of the exchange,
An object of the present invention is to enable information transfer between arbitrary terminals in a network to be started in a short time. In order to solve the above-mentioned problems, a digital exchange according to the present invention comprises at least three I-switches.
An SDN terminal is connected by a transmission line having a first information channel for transmitting and receiving digital information, a second information channel, and a control channel for transmitting and receiving control information, and a first information channel between ISDN terminals and a second information channel. A digital exchange for connecting to an information channel, wherein each of a first information channel and a second information channel of each ISDN terminal is a different ISDN terminal different from its own terminal based on control information of a control channel. The exchange operation is performed so as to be connected to. According to the digital exchange of the present invention, between any one of a group of subscriber terminals connected to the ISDN exchange network, each terminal is connected to the digital subscriber line on the digital subscriber line via the exchange.
A loop network system can be configured by connecting one information channel to each of two different terminals, and information can be circulated in the loop network by an information channel return function of the communication control device. Broadcasting the information transmitted from each terminal to other terminals in the network, or communicating between any two terminals in the network by packetizing the information and adding the receiving terminal and calling terminal addresses Becomes possible. FIG. 1 shows an example of the configuration of a loop network system according to the present invention. This loop network system comprises a subscriber terminal 1, a digital subscriber line 2 having a plurality of multiplexed information channels, a digital exchange 3, and an inter-exchange digital trunk line 4. The digital subscriber line 2, the digital exchange 3, A loop network is formed between the subscriber terminals 1 via the digital exchange line 4 between exchanges. In this figure, only six subscriber terminals 1 and three digital exchanges 3 are shown, respectively. However, even if a large number of subscriber terminals 1 and digital exchanges 3 exist, May be present alone. FIG. 2 shows a configuration example of a dual loop network system according to the present invention. The components in this figure are the same as those in FIG. 1, but the subscriber 2 and the trunk line 4 are each duplicated. As shown in the frame structure of the user-network interface in the ISDN basic interface of the CCITT recommendation shown in FIG. 3, the information channel in the digital subscriber line generally comprises a pair of bidirectional channels. The slots can be used to form double loops in opposite directions. Thus, 1) a redundant loop network system including a working loop and a protection loop. 2) When a failure occurs in a subscriber terminal, the subscriber terminals at both ends of the subscriber terminal communicate with the failed subscriber terminal. 3) a loop network system having a loop reorganization function by disconnecting (terminating a call) and communicating and turning back both time slots in a communication channel with a subscriber terminal at the other end 3) Double loop It is possible to realize a multimedia loop network system in which different media such as voice and data are circulated. As shown in FIG. 3, a transmission frame on the ISDN user / network interface is roughly composed of a downstream frame F1 from the network to the terminal and an upstream frame F2 from the terminal to the network. The downstream frame F1 and the upstream frame F2 are composed of 48 bits, and are transmitted repeatedly at a cycle of 250 microseconds. In the case of the basic interface of the present ISDN, there are two information channels. In FIG. 3, each of the information channels is represented by B1 and B2, each of which is continuous by 8 bits. Therefore, the transmission rate of each information channel is 64 Kbit / sec. Normally, in ISDN, when a terminal communicates with two partner terminals, the information channels B1 and B2 in the upper / lower frame are respectively connected to the partner terminals. In the case of this loop network system, the communication control device of the terminal includes: By returning the information channel B1 in the downstream frame F1 to the information channel B2 in the upstream frame F2 and returning the information channel B2 in the downstream frame F1 to the information channel B1 in the upstream frame F2 and communicating, A double loop in the opposite direction can be formed. D in FIG. 3 is a bit for a signal channel (16 Kbit / sec). FIG. 4 shows an example in which a conference telephone system according to the present invention is constructed using one digital exchange and four subscriber terminals. In FIG. 4, a subscriber terminal 1 is connected to an information channel 2 of a digital subscriber 2 from another subscriber terminal 6.
1 through a multiplexing / demultiplexing device 11, and a decoder circuit 12 in a communication control device 19.
After being converted into an analog signal, the echo canceller circuit 13 removes the voice component of the speaker of the own terminal that has returned through the loop from the analog voice signal, and inputs it to the speaker 41 through the amplifier circuit 14. .
On the other hand, the output audio signal of the echo canceller circuit 13 is synthesized by the mixing circuit 16 together with the audio signal input through the microphone 42 and the attenuator circuit 15, and then converted again into a digital audio signal by the coder circuit 17. The information is transmitted to another subscriber terminal 7 via the information channel 22 of the digital subscriber line 2 and the digital exchange 3. Similarly, the subscriber terminal 7 synthesizes its own user's voice with the voice received from the subscriber terminal 1 and
The subscriber terminal 8 synthesizes the voice of the user with the voice received from the subscriber terminal 7 and transmits the synthesized voice to the subscriber terminal 6. The subscriber terminal 6 converts the voice received from the subscriber terminal 6 A conference call is formed by synthesizing the voice of the user and transmitting the synthesized voice to the subscriber terminal 1. The digital subscriber line 2 comprises two information transfer channels 21, 22 and a signal channel 23 for transferring call control signals. When setting the conference, the subscriber of the subscriber terminal 1 inputs the telephone number of the subscriber terminal 7 using the keyboard 43, and the controller 18 transmits a call control signal of the call request via the signal channel 23 to the exchange in the exchange. Transmit to controller 31. Next, the exchange controller 31 transmits an incoming call signal to the subscriber terminal 7 using the signal channel, and then receives a response signal from the subscriber terminal 7 using the signal channel in the same manner. One information channel in the digital subscriber line 2 of the subscriber terminals 1 and 7 is interconnected. Similarly, the subscriber terminal 7 calls the subscriber terminal 8 and connects the remaining information channel in the digital subscriber line 2 of the subscriber terminal 7 to the subscriber terminal 8. The subscriber terminal 8 calls the subscriber terminal 6 and connects the remaining information channel in the digital subscriber line 2 of the subscriber terminal 8 to the subscriber terminal 6. Finally, the subscriber terminal 6 calls the subscriber terminal 1 and connects the remaining information channel in the digital subscriber line 2 of the subscriber terminal 6 to the subscriber terminal 1. At this point, each subscriber terminal sets two information channels 21 and 22 in the digital subscriber line to the communication control device 19.
, Each terminal is connected to the information channels 21 and 22
And a switch 32 in the digital exchange 3 is connected in a loop, and the voice of the speaker of each subscriber terminal as described above is transmitted to the other subscriber terminals in the loop. In the present invention, the loop configuration or the number of terminal connections can be arbitrarily changed by the call connection function of the exchange. For example, as shown in FIG. 5, a plurality of loops can be formed in the network. . On the other hand, it is also possible to provide a plurality of loop networks in the ISDN switching network,
In this case, the terminal can join any loop network by the switching function of the ISDN switching network. Even when attention is focused on one loop network, even if a fault occurs at a plurality of locations at the same time, the faulty location is isolated by switching the connection using the switching function of the ISDN switching network in the same manner, and the remaining normal status is restored. Terminals can be connected by one loop network. As is apparent from the above description, according to the present invention, an ISD is performed by utilizing a call connection function of an ISDN exchange.
An arbitrary number of subscriber terminals accommodated in the N exchange network
The existing telephone line can be used to connect to the loop network. For this reason, especially when the public network is converted to ISDN, a loop network can be configured on a domestic scale.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing an embodiment of the present loop network system using three exchanges and five subscriber terminals. FIG. 2 is a diagram showing one embodiment of a double loop network system having the same configuration as that of FIG. 1; FIG. 3 shows a user / user in the ISDN basic interface.
The figure which shows the transmission frame structure between networks. FIG. 4 is a diagram showing an implementation example of a telephone conference system using the present invention. FIG. 5 is a diagram showing an example in which two loop network systems are configured in an ISDN network. [Description of Signs] 1 ... Subscriber terminal 2 ... Digital subscriber line 3 ... Digital exchange 4 ... Trunk line, 12 ... Decoder circuit, 13 ... Echo canceller circuit, 14 ... Amplifier circuit, 15 ... Attenuator circuit, 16 ... Mixing circuit , 17 ... coder circuit, 19 ... communication control device 21, 22 ... information channel 23 ... signal channel

Continuation of the front page (56) References Japanese Patent Publication No. Sho 60-501534 (JP, A) Japanese Patent Laid-Open No. Sho 59-111498 (JP, A) Japanese Patent Laid-open No. Sho 59-111497 (JP, A) IBM Technical Disclosure Bulletin, Vol. . 15 No. 1, June 1972, L.A. P. West, “HIGHLY A VAILABLE LOOP CARR IER SYSTEM”, pages. 337-339 (58) Fields investigated (Int. Cl. ⁶ , DB name) H04L 12/02 H04L 12/42 H04M 11/00 303 INSPEC JICST file (JOIS) WPI (DIALOG)

Claims (1)

(57) [Claims] A transmission line having at least three ISDN terminals having a first information channel for transmitting and receiving digital information, a second information channel, and a control channel for transmitting and receiving control information.
Accommodated through, a digital switch for connecting upper Symbol first information channel between the upper Symbol ISDN terminal and a second information channel, the first information via the control channel from the ISDN terminal Upon receiving control information requesting that each of the channel and the second information channel be connected to a different ISDN terminal, the control unit transmits the control information based on the control information.
The first information channel and the second information channel of the DN terminal
Switch to connect each to a separate ISDN terminal
Connect at least three ISDN terminals in a loop
And perform communication between the at least three ISDN terminals.
A digital exchange characterized by forming a loop network .