JPH104425A - Remote multiple system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cut the cost of transmission lines of an access network which consists of a switching center and plural remote multiplexers by providing only two lines for two-way transmission, i.e., one line for one-way as transmission lines which connects between the switching center and remote multiplexers, and between the remote multiplexers. SOLUTION: Transmission lines 8a and 8b, 9a and 9b, and 10a and 10b are two-way transmission lines which connect between a switching center 1 and a remote multiplexer #1, remote multiplexers #1 and #2, and the multiplexer #2 and the center 1 respectively. Although these transmission lines are a ring connection format, they logically constitute a one-to-one star type network and are a dual type between the multiplexers #1 and #2 and a remote multiplexer interface part 2 of the center 1. In each multiplexer #1 and #2, a termination part 3 of each multiplexer #1 and #2 adds (sends) or extracts (receives) a signal for its own device and bypasses a signal for other device with a one-way transmission line as zero system and the other way transmission line as one system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remote multiplexing system for efficiently storing subscribers scattered over a wide area in an exchange.

[0002] Analog, ISDN,
In the case of providing a communication service such as a dedicated line, if the exchange and each remote subscriber are connected by individual lines, the cost will be high. In many cases, a subscriber accommodation system in which a subscriber line is multiplexed in a multiplexing apparatus and connected to an exchange is adopted.

[0003] Each of such remote multiplexing devices is connected to an exchange via an optical transmission line (optical fiber or the like). However, when the size of the remote multiplexing device is small, the efficiency of use of the transmission line is poor, and when a failure occurs, Improvements are desired in terms of the complexity of the measures.

[0004]

2. Description of the Related Art FIG. 15 is an explanatory view of a conventional example. FIG.
In the example, the remote multiplexing device # 1 (84) and the remote multiplexing device # 2 (86) are provided at two points away from the exchange 80, and the remote multiplexing devices # 1 and # 2 are provided in the exchange 80. A remote multiplexing device interface section 81 for interfacing with the remote multiplexing device # 1 is provided therein. I have. Each of the remote multiplexers # 1 and # 2 is provided with a duplex transmission line between the exchange 80 and the remote multiplexer # 1 to ensure reliability.
The transmission line 89 is connected to the transmission line 89 of the 8, 1 system,
, And it is possible to switch which system becomes the active system by a control signal from the exchange 80 via a control channel. Similarly, the remote multiplexing apparatus # 2 is connected to the switching center via a 0-system transmission line 90 and a 1-system transmission line 91.
Here, each of the transmission lines 88, 89, 90, 91 is 1 in FIG.
Although shown by two lines, each line is actually composed of two transmission lines for transmitting signals in both the up and down directions. Here, when the loop length returning from the exchange to the exchange via the remote multiplexer # 1 and the remote multiplexer # 2 is N (km), and the number of connections between the sections is M (number) (FIG. In the case of 15, M =
2), optical transmission path length = N × M × 2 (km).

[0005] The type of connection between the exchange and each remote multiplexing device by one-to-one individual lines is called physical star (star) connection. However, as shown in FIG. 15, the transmission line 89 of the first system between the exchange 80 and the remote multiplexer # 1 bypasses the remote multiplexer # 2 and is connected to the exchange 80. The transmission line 90 of system 0 adopts a ring connection form bypassing the remote multiplexer # 1.

[0006] Such connection is economical in the case of laying a transmission line (the distance is shorter when connecting cables in which a plurality of transmission lines are bundled in order than when individually connecting lines to an exchange). This is because it is advantageous. Also, in terms of reliability, the transmission path of the system 0 and the system 1 is connected by the same cable as the switching center, and the other system is normal even if one system becomes faulty by passing through another route. It is advantageous in that there is a possibility.

Each of the remote multiplexers # 1 and # 2 accommodates each subscriber included in each of the areas # 1 and # 2, and includes therein an analog terminal (A terminal) such as an analog telephone, an ISDN. There are terminals or dedicated lines, etc., and the signals of each subscriber are multiplexed by respective remote multiplexing devices and connected to the exchange, and communication between subscribers in the exchange and communication via other exchanges are performed. .

FIG. 16 shows a configuration for monitoring the state of a transmission line in a conventional example. FIG. 16 shows only the configuration related to the connection between the exchange 80 and the remote multiplexer # 1 in the configuration shown in FIG. 15, and the connection configuration regarding the remote multiplexer # 2 is the same as that of the remote multiplexer # 1. Not shown. The transmission line termination unit 82 provided in the remote multiplexing device interface unit 81 of the exchange 80 in FIG. 15 is separated into the 0-system transmission line termination unit 82a and the 1-system transmission line termination unit 82b of FIG. The transmission line 88 of the 15 system is the two transmission lines 88a of FIG.
15 corresponds to (up) and 88b (down), the transmission line 89 of the first system in FIG. 15 is two transmission lines 89a (up) and 89 in FIG.
b (down). Also, the remote multiplexing device # of FIG.
The 1 (84) is provided with 0-system and 1-system transmission path terminating sections 82a and 82b corresponding to the transmission path terminating section 85 in FIG.
Transmission lines 88a and 88b and transmission lines 89a and 89, respectively.
b.

The remote multiplexing device interface unit 81 is provided with a transmission line monitoring / controlling unit 81a for transmitting and receiving a monitoring signal and a control signal to and from the remote multiplexing device # 1 through a control channel. In communication between the devices # 1, one system is used as an ACT system, and the other system is placed in a standby state as a spare. In the example of FIG. 16, the ACT system is used as the transmission line of the 0 system. The state of the transmission line is determined by the downstream transmission line 8
8b and 89b are monitored by the detection function indicated by ● provided in the transmission line terminating units 82a and 82b of each system of the remote multiplexing apparatus # 1, and when a failure is detected, the notification function indicated by ○ is driven, The transmission is performed as shown by で via the upstream transmission lines 88a and 89a, and is notified to the transmission line monitoring / control unit 81a of the remote multiplexing device interface unit 81. The state of the upstream transmission lines 88a and 88b is determined by the transmission line termination units 82a and 82b of each system of the remote multiplexer 1 system 81.
Is monitored by a detection function provided in the transmission line monitoring unit. Immediately when a failure occurs, the transmission line monitoring / control unit 81a is notified.

FIG. 17 shows an example of transmission line system selection control according to a conventional example. In the configuration of FIG.
When a failure occurs in the transmission lines 8a and 88b, the transmission line monitoring / control unit 81a can detect a failure in the 0-system transmission line by the operation described above. In this case, the transmission path monitoring / control unit 81a sets the ACT transmission path to “1” via the control channel of the 0 transmission path (when the 0 transmission path can be used).
A control signal for "system designation" is transmitted. Further, a control signal having the same content as that of setting the ACT transmission line to “designate the first transmission line” is transmitted via the control channel of the first transmission line. As a result, FIG.
As shown by the thick line in FIG. 7, the control channel of the ACT system is selectively controlled to be transmitted by the system 1 transmission line.

[0011]

An optical transmission line is used as the transmission line between the above-mentioned remote multiplexing device and the exchange. However, if the number of subscribers accommodated in the remote multiplexing device is small, the optical transmission line ( If a large-capacity optical fiber is individually connected to the exchange, there is a problem that the use efficiency of the transmission line is poor.

When an access network of an optical transmission line is formed in a form in which remote multiplexing devices are star-connected in an area where subscribers are scattered over a wide area, the optical transmission line length increases in proportion to the number of remote multiplexing devices connected. Therefore, there is a problem that the installation cost of the optical transmission line increases linearly and it is economically difficult to realize an access network.

An object of the present invention is to provide a far-end multiplexing system capable of reducing the cost of a transmission line of an access network including a switching center and a plurality of remote multiplexing devices. In addition, according to the present invention, even if the method of far-end multiplexing is changed, the method of monitoring the transmission path system and controlling the selection between the remote multiplexing device and the remote multiplexing device interface of the exchange is the same as that of the conventional star connection. Is another purpose.

[0014]

FIG. 1 is a block diagram showing the principle of the present invention. In FIG. 1, 1 is an exchange, 2 is a remote multiplexer interface unit, 3 is a transmission line termination unit, and 4 is an area #.
1 analog terminal (A terminal) or ISDN terminal (I terminal)
Remote multiplexers # 1 and 5 provided with a subscriber line multiplexing unit (not shown) for accommodating a subscriber line such as... Remote multiplexing devices # 2 and 7 having a subscriber line multiplexing unit (not shown) are provided with transmission line termination units 8a and 8b, 9a and 9
b, 10a and 10b are bidirectional transmission lines connecting the exchange 1 and the remote multiplexer # 1, the remote multiplexer # 1 and the remote multiplexer # 2, and the remote multiplexer # 2 and the exchange 1 respectively. is there.

According to the present invention, only one transmission line is provided in each direction for connection between the exchange and the remote multiplexing device and between the remote multiplexing device. Then, the same transmission path is shared. However, in a ring connection mode, a logical one-to-one connection exists between the remote multiplexer and the remote multiplexer interface of the exchange.
Of the star-type connection (communication channel, control channel), and the transmission line is logically duplexed into a 0 system and a 1 system between each remote multiplexing device and the exchange. Each remote multiplexing device adds (transmits) or extracts (receives) its own signal at the terminal end of each remote multiplexing device with the transmission line for one direction as system 0 and the transmission line for the other direction as system 1. , Bypasses signals for other devices.

In the case of FIG. 1, a remote multiplexer #
1, the loop length to the exchange 1 via the remote multiplexer # 2 is N (km), the number of connections (the number of connections between each remote multiplexer)
Is M (pieces), the transmission path length is N × 2 (km),
The transmission path length has a value irrelevant to M, and the transmission path length can be reduced as compared with the conventional star-type connection configuration.

The transmission line termination of each remote multiplexing device is the same as the monitoring / notification and transmission line selection of the transmission line termination of the conventional remote multiplexing device and the transmission line termination of the conventional remote multiplexing device interface. A simple configuration can be achieved by sharing with the control method.

[0018]

FIG. 2 shows an example of the configuration of remote multiplexing according to the present invention, and FIG. 3 shows an example of a highway format of a transmission line.

In FIG. 2, 2 to 7 and 8a, 8b to 1
Reference numerals 0a and 10b represent the same symbols as those in FIG. 1, respectively. In the remote multiplexing device interface unit 2 of the exchange, 3a is a transmission line termination unit of the 0 system, and 30 is a transmission unit of the 0 system (S Display), 31 is a 0-system receiving unit (displayed as R), 3b
Is a transmission line termination part of the first system, 32 is a reception part (R) of the first system, 3
Reference numeral 3 denotes a first-system transmission unit (S).

In the remote multiplexer # 1 (4), reference numeral 5a denotes a 0-system transmission line terminator, 50 denotes a 0-system receiving unit (R), 51
Is a transmission unit (S) of the 0 system, 5b is a transmission line termination unit of the 1 system, 5
Reference numeral 2 denotes a first-system receiving unit (R), and 53 denotes a first-system transmitting unit (S). Reference numeral 4a designates a function of adding a transmission signal to each channel assigned to the remote multiplexer # 1 from the communication channel and the control channel multiplexed on the transmission line, and a function of adding a reception signal from the assigned channel. (Dro
p) An addition / extraction bypass unit 4b having a function and a function of bypassing the signal of another remote multiplexing device. A selector & subscriber line multiplexing unit that multiplexes a transmission signal from a subscriber line and outputs the multiplexed signal to the addition / extraction bypass unit 4a.

In the remote multiplexer # 2 (6), reference numeral 7a denotes a 0-system transmission line terminator, 70 denotes a 0-system receiver (R), 71
Is a transmission unit (S) of the 0 system, 7b is a transmission line termination unit of the 1 system, 7b
Reference numeral 2 denotes a first-system receiving unit (R), and reference numeral 73 denotes a first-system transmitting unit (S). 6a and 6b correspond to 4 of the remote multiplexer # 1.
Descriptions corresponding to a and 4b are omitted.

Transmission lines 8a, 8b, 9a, 9 connecting between the remote multiplexing device interface section 2 and the remote multiplexing device # 1.
b, 10a, and 10b are each composed of one optical fiber, and have two signal paths, namely, a signal path indicated by each of them, and a signal path indicated by each, and the connection between the switching center and the remote multiplexer # 1 is established. Represents the connection between the exchange and the remote multiplexer # 2.

A transmission line 8a represents a system 0 connection (communication channel and control channel) for transmission from the exchange to the remote multiplexer # 1, and a transmission line 8a transmits from the exchange to the remote multiplexer # 2. It represents a part of the connection of the system 0 for the connection. A transmission line 8b represents a 0-system connection for transmission from the remote multiplexer # 1 to the exchange, and a transmission line 8b represents a 0-system connection for transmission from the remote multiplexer # 2 to the exchange. Represent a part. Transmission lines 9a and 9 between remote multiplexing device # 1 and remote multiplexing device # 2
b respectively form a part of the connection, in which a part of the connection of the system 1 of the remote multiplexer # 1 and a part of the connection of the system 0 of the remote multiplexer # 2.
Transmission line 10 for connecting between remote multiplexing apparatus # 2 and the exchange
10a and 10b, the signal paths shown respectively represent a part of the system 1 connection between the remote multiplexing apparatus # 2 and the exchange, and the signal paths shown in FIG.
Indicates the connection of the system.

In the remote multiplexer # 1, an analog terminal, I
A digital signal from an SDN terminal or a dedicated line (a signal from an analog terminal is A / D converted by an adapter not shown, and a signal to an analog terminal is D / A converted) is converted to a selector & subscriber line multiplexing unit 4b. Multiplexed in the addition / extraction bypass unit 4a.
1 is added to the communication channel assigned. In addition, the remote multiplexing device # on the highway format on the transmission line
The signal of the communication channel assigned to 1 is extracted, input to the selector & subscriber line multiplexing unit 4b, and selectively output to the terminal and the dedicated line.

In the example of the transmission path highway format shown in FIG. 3, overhead (path management information, etc.) is added at the head.
Is a payload in which information to be transmitted is stored. In this payload, communication channels (communication contents) and control channels are arranged corresponding to each remote multiplexing device. Are added or withdrawn by the corresponding remote multiplexing device. FIG.
In addition to the example shown in FIG. 1, there is a format in which, for example, only communication channels are continuously arranged corresponding to each remote multiplexing device, and thereafter, only control channels corresponding to each communication channel are arranged. FIG. 9).

Each remote multiplexing device shown in FIG. 2 adds (ADD) and extracts (DRO) only a communication channel and a control channel intended for itself.
P) However, all communication channels and control channels for other devices are bypassed to the adjacent remote multiplexer.

Ring connection (logical star connection)
A method of realizing the transmission line monitoring control and the transmission line system selection control in the above will be described with reference to FIGS. FIG. 4 shows a configuration for monitoring the status of a transmission line according to the present invention.

In FIG. 4, reference numeral 2 denotes a remote multiplexer interface unit of an exchange, 20 denotes a transmission line monitoring / control unit, and 3a,
Reference numerals 3b, 4, 5a, 5b, 6, 7a, and 7b denote the same parts as those in FIG. 2, and reference numerals 3a and 3b denote transmission line terminations of the 0-system and the 1-system of the remote multiplexer interface unit 2.
4 and 6 are remote multiplexers # 1, # 2, 5a and 5b, respectively.
Is the transmission line terminating unit of the 0-system and 1-system of the remote multiplexer # 1, 7
Reference numerals a and 7b denote transmission line termination units of the 0-system and the 1-system of the remote multiplexer # 2. Further, the remote multiplexers # 1 and # 2 of FIG. 4 are respectively provided with devices (4a, 4b), (6) in which the selector & subscriber line multiplexing unit and the addition / extraction bypass unit shown in FIG.
a, 6b).

4 correspond to the connections included in the respective transmission paths shown in FIG. 2, and in the example of FIG. 4, each of the remote multiplexers # 1 and # 2 has 0
The system is operating as an ACT communication channel (connection), and the remote multiplexing apparatus # 1 communicates with the system 0 transmission line terminating unit 3a of the exchange via the upstream and downstream connections of the system 0 transmission line terminating unit 5a. , The remote multiplexing device # 2 communicates with the 0-system transmission line terminating unit 7a and the exchange's 0-system transmission line terminating unit 3a through the upstream and downstream connections.

As shown in FIG. 4, the monitoring and notification of the state of the transmission path between the remote multiplexing device and the remote multiplexing device interface unit (switching station) connected in a ring connection (logical star connection) are performed as follows. That is, each remote multiplexer #
1 and # 2 have a detection function of indicating the state of the adjacent transmission line by ●,
This is performed by the notification function indicated by ○. Specifically, the 0-system transmission line termination unit 5a of the remote multiplexing apparatus # 1 is connected to the 0-system transmission line termination unit 3
a of the system A (via the transmission lines 8a and 8b in FIG. 2), and notifies the connection of the system 1 (the transmission lines 9a, 9b and 10a, 1 in FIG. 2).
0b) is detected and notified between the 1-system transmission line termination unit 5b of the remote multiplexing device # 1 and the 1-system transmission line termination unit 3b of the exchange. The transmission path monitoring / control unit 20 of the unit 2 is notified. Similarly, state detection and notification of each connection of the remote multiplexing apparatus # 2 are also performed between the transmission line termination units 7a and 7b of the 0 and 1 systems and the transmission line termination units 3a and 3b of the exchange.

The transmission path terminating sections 5a and 5b of the 0-system and 1-system of the remote multiplexing apparatus # 1 shown in FIG. The configurations of 3a and 3b and the connection to be monitored have the same configurations and functions as those of the conventional example shown in FIGS. 16 and 17, and the transmission path of the conventional physically star-type remote multiplexing device. It is compatible with the interface at the end and has compatibility.

FIG. 5 is a diagram showing an example of transmission line system selection control according to the present invention. FIG. 5 shows the configuration shown in FIG.
This is an example of transmission path system selection control when a failure occurs in section B between remote multiplexing apparatuses # 1 and # 2. When a failure occurs in the section B, the transmission line monitoring and control unit 20 of the remote multiplexing device interface unit 2 detects the transmission line state of each connection from the 0-system transmission line termination unit 3a and the 1-system transmission line termination unit 3b, A failure section of the path is determined, and based on the determination result, an ACT transmission path is designated for each remote multiplexing device (0
System or 1 system). The control signal for system selection (switching) is sent from the transmission line monitoring / control unit 20 through the control channel of the transmission line.
Connections between the selector / subscriber line multiplexing units (4b, 6b) and the addition / extraction bypass units (4a, 6a) are switched in accordance with a control signal in the extraction bypass units (4a, 6a).

The transmission path failure section and the principle of transmission path selection shown in FIG. 5 will be described with reference to FIGS. FIG. 6 shows an example of the configuration of an exchange and remote multiplexing devices, and shows an example in which three remote multiplexing devices are provided. In the figure, CX is a remote multiplexing device interface unit (2 in FIG. 2) of the exchange, and the left side is C system of 0 system.
X, the right side is the CX of the first system. RX1 to RX3 are remote multiplexing devices. The remote multiplexing device RX1 has a 0-system connection and a 1-system connection with the exchange, respectively, as shown in FIG.
The remote multiplexing device RX2 is provided with a 0-system connection and a 1-system connection, respectively, as shown in FIG.
X3 is provided with a 0-system connection and a 1-system connection with the exchange, respectively, and as a transmission line section, a section between the CX of the 0 system and RX1 as a section A as shown in FIG. Sections B to D are provided in order as each section up to.

FIG. 7 is an explanatory diagram of a transmission path failure section and a selected connection. In the configuration shown in FIG.
(a) shows the notification route and the selected connection (after the failure detection) for the transmission path failure section, and (b) shows the state of the connection selected when the transmission path failure occurs in the section B.

In (a), the occurrence of a fault in the section A means that the transmission path monitoring / controlling is performed by the notification channel of the control channel of the remote multiplexer RX1 having the connection as the 0 system.
The control unit (20 in FIG. 4) is notified. When this failure is detected, the remote multiplexer RX
1 selects system 1 and the other remote multiplexing devices RX2 and RX3 also select system 1 (the connection of system 0 is made, and other RX2 and RX3 also have connection of system 0 via the same transmission path). For). In the failure in the next section B, the remote multiplexing device RX1 having the connection as the system 1 and the remote multiplexing device RX2 having the connection as the system 0 notify the failure through the respective connections. In this case, as shown in FIG. 7 (b), the selected system connection is such that the remote multiplexer RX1 selects the system 0 connection, the remote multiplexer RX2 selects the system 1 connection, and the remote multiplexer RX.
3 also selects the 1-system connection. In the sections C and D, when a fault in each section is detected by the notification route shown in FIG.
RX3 is selected for each selected connection.

Next, a method of generating the configuration information of the remote multiplexing device will be described with reference to FIGS. FIG. 8 is an explanatory diagram of generation of configuration information when a remote multiplexing device is added, and FIG. 9 is a diagram illustrating a transmission line highway format.

In FIG. 8, it is assumed that only the remote multiplexer RX1 and the remote multiplexer RX3 are initially installed in the exchange. A remote multiplexer (RX) mounting information table 21 is provided in the remote multiplexer interface section 2 of the exchange.
And a communication channel / allocation management table 22. In the initial state, the remote multiplexing device RX1 has a subscriber line multiplexing unit MX # 1 under its control and a position information counter (a mounting position relative to the exchange). ) Is “1”, the control channel is # 1, and # 1 is allocated as a communication channel area, and an identification number (ID) which is a unique number on the ring
Is assigned “1”. The identification number (ID) is used as a control channel number.

The remote multiplexer RX3 includes subscriber line multiplexing units MX # 1 and MX # 2 for multiplexing and demultiplexing the signals of the subscriber lines of a plurality of terminals (under the communication channel of 2).
), The position information counter is "2", the control channel is # 2, # 2 and # 3 are allocated as communication channel areas, and the identification number (ID) is "3".

The mounting information of each remote multiplexing device is notified in a highway format shown in FIG. 9 which will be described later. When the remote multiplexing device is mounted (when the system is opened, when the remote multiplexing device is added and reduced), each remote multiplexing device is notified. Is notified to the remote multiplexing device interface unit 2 via the control channel, and the mounting information of the subscriber line multiplexing unit of each remote multiplexing device is notified to the remote multiplexing device interface unit 2 via each communication channel. Based on this information, the remote multiplexing device interface unit 2
Recognizes the configuration information of the ring-connected remote multiplexing device,
Stored in tables 21 and 22. The remote multiplexing device mounting information table 21 stores a mounting state and a position information counter (relative mounting position information from the exchange) respectively corresponding to the ID, and a communication channel / allocation management table 22.
, Each communication channel area, mounting state, and ID are set.

In contrast to the first configuration, the subscriber line multiplexing unit M
When the remote multiplexing device RX2 (with ID = 2) equipped with X1 is installed later, the control channel #
3 to the remote multiplexing device interface unit 2. The remote multiplexing device RX2 recognizes that the allocation management information of the communication channel area # 4 is unused, allocates it to itself, and assigns it to the communication channel area # 2 of the communication channel / allocation management table 22. "In mounting" and "own ID" are set, and as shown by the dotted line in FIG.
1 and 22 are updated in response to the addition of RX3. As a result, the control channel and communication channel of each of the 0-system connections RX1, RX2, and RX3 are set as shown in FIG.

FIG. 9 shows a transmission line highway format in the configuration of FIG. 8, and after overhead (OH),
A communication channel area group is arranged followed by a control channel group. The communication channel area group is composed of a plurality of communication channel areas # 1, # 2,..., And each communication area is provided with one subscriber line multiplexing unit (MX) provided under the remote multiplexer shown in FIG. The capacity required to transmit the information of Each communication channel area includes, as shown in FIG. 9, allocation management information including mounting information indicating whether a subscriber line multiplexing unit (MX) using the communication channel is mounted / unmounted, and ID of the remote multiplexing device, Communication information (contents to be communicated).

Each control channel of the group includes control information and mounting management information including mounting information and a position information counter. In the description of FIGS. 8 and 9 above, after the remote multiplexing device is mounted, the position information is always used by the control channel. A method of recognizing this position information by each remote multiplexing device will be described with reference to FIG. .

FIG. 10 is a diagram for explaining a mounting position recognition method. FIG. Shows the connection configuration between the exchange and the remote multiplexer, shows only one transmission line (corresponding to the connection of system 0 of each remote multiplexer) of the remote multiplexer connected to the exchange, and does not show the other transmission line. ing. in this case,
The remote multiplexing devices RX1, RX3, and RX2 are arranged in the switching station in the order of RX1, RX3, and RX2.
3 is set to ID = 3, and RX2 is set to ID = 2, and each ID corresponds to the control channel number shown in FIG.

The signal of the highway format shown in FIG. 9 is transmitted on the upstream transmission line. Immediately after mounting, the signal of the position information counter in the RX mounting information table 21 (see FIG. 8) of the remote multiplexer interface unit 2 (see FIG. 8). The content has not been set. In this case, the position information counter in each control channel is not set, and a signal is output from the remote multiplexer interface unit of the exchange to the downstream and upstream of the 0-system transmission path. In this case, the remote multiplexers RX1 and R2
The processing executed in X2 and RX3 is shown in FIG. ~
D. Is shown in

In this case, each remote multiplexing device identifies each control channel of the highway format and performs the following processing. The value "1" is set to the position information counter in the control channel corresponding to the ID of the own device used by the own remote multiplexing device.

"1" is added to the value of the position information counter in the control channel not used by the own remote multiplexing device (not corresponding to the own device ID). B. In the case of, the position information counter of the control channel # 1 (because the ID of RX1 is 1) of the highway signal transmitted from the rear of the transmission path (RX2, RX3) is RX
In step 1, "1" is set (no matter what has been set before then, "1" is set here). This control channel #
The signal of 1 is received by the exchange and recognizes the value "1" of the position information counter of RX1.

C. In the case of, when a highway signal from the rear of the 0-system uplink transmission line is input to RX2, RX2
= 2, the value of the position information counter in the control channel # 2 used by the own device is set to "1" (a in C.). The control channel # 2 is supplied to the next RX3 via the transmission line of the system 0, and the RX3 performs the processing of +1 on the position information counter of the control channel # 2 which is not used by the own device, thereby increasing the value. Becomes "2" (b in C.). Further, this signal is supplied to the RX1 at the next stage. Here, the position information counter of the control channel # 2 not used by the own device is incremented by "+1", and the value becomes "3" (c of c.). ). The value "3" of the position information counter of the control channel # 2 is input to the remote multiplexer interface of the exchange, and the value of the position information counter of RX2 is recognized.

D. In the case of, when a highway signal from the rear of the upstream transmission line of system 0 is input to RX3, RX3
= 3, the value of the position information counter in the control channel # 3 used by the own device is set to "1" (a in D.). When passing through RX1, the value of the position information counter of control channel # 3 is incremented by "1" and the value of the position information counter of control channel # 3 not used by itself is incremented by "2". (D. b). The value "2" of the position information counter of the control channel # 3 is received and recognized by the remote multiplexer interface unit 2.

The value of the position information counter of each control channel is set in the RX mounting information table 21 of FIG. Such recognition of the position information counter can be performed at all times, but is executed only when the configuration of the remote multiplexing device connected to the exchange is changed (addition or removal) to update the contents of the RX mounting information table 21. You may do it.

FIGS. 11 and 12 are explanatory views (before addition) and (after addition) of a method of adding a remote multiplexing device according to the present invention.
As shown in FIG. 11, as a first system configuration, only a remote multiplexer RX1 and a remote multiplexer RX3 are connected to an exchange. In this configuration, when a new remote multiplexer RX2 is added between the remote multiplexers RX1 and RX3, the following is performed.

As shown in FIG. 11, the remote multiplexing device RX1 has a 0-system connection (control channel, communication channel).
Is controlled to be an ACT system. As shown in FIG. 11, the remote multiplexing device RX3 selectively controls the system 1 connection to be the ACT system.

The transmission path between the remote multiplexers RX1 and RX3 is disconnected. In this state, communication between the exchange and the RX1 and between the exchange and the RX3 are continued by the connection selectively controlled in the above.

The transmission line termination of the system 1 of the remote multiplexing device RX1 and the transmission line termination of the system 0 of the added remote multiplexing device RX2 are connected by a transmission line as shown in FIG. As shown in FIG. 12, the transmission line termination of the system 0 and the transmission line termination of the system 1 of the added remote multiplexer RX2 are connected by a transmission line.

Next, from the remote multiplexer interface section of the exchange, the 0-system connection is established by the control channels corresponding to the respective remote multiplexers RX1, RX2 and RX3.
When the selection control for the T-system is instructed, the communication between each remote multiplexing device and the remote multiplexing device interface section is performed via the 0-system connection for the respective control channel and communication channel as shown in FIG.

FIGS. 13 and 14 show configuration examples (part 1) and (part 2) of the system according to the present invention. FIG. 13, FIG.
In the figure, 2 is a remote multiplexing device interface section of the exchange, and 4-1 to 4-4 are remote multiplexing devices # 1 to # 4, respectively.
Reference numerals 4, a to e denote a remote multiplexer interface unit 2, a remote multiplexer # 1, a remote multiplexer # 2,... A remote multiplexer interface 2 as shown in FIGS.
, A transmission line (optical fiber) connecting the respective devices, which is shown as a single line in the figure, is actually composed of two transmission lines.

In the remote multiplexing device interface unit 2, reference numeral 20 denotes a transmission line monitoring / control unit, and reference numerals 3a and 3b denote 0 system and 1 system.
A transmission line termination unit provided corresponding to the system, an E / O conversion unit (indicated by E / O) for converting an optical signal on the transmission line into an electric signal and an inverse conversion thereof, and a numeral 35 for the transmission line From the frame (having highway format) signal to each remote multiplexer #
i is converted into a frame of a time slot (HWi) accommodating a communication channel and a control channel corresponding to i.
A frame conversion unit (indicated by FCON) that performs the inverse conversion.

Reference numeral 24 denotes 0 from the transmission line terminations of the 0 and 1 systems.
A transmission route selection unit that selects a signal of a system to be used from among signals of a time slot (HWi) corresponding to each remote multiplexing device of the system and the system 1 under the control of the transmission line monitoring and control unit 20. The signals of each system include bidirectional signals. An exchange mechanism (communication path switch and control unit) of the exchange, not shown, is provided at a stage subsequent to the transmission route selection unit 24.

In the remote multiplexing devices # 1 (4-1) to # 4 (4-4), 40 is a control unit for controlling the entire remote multiplexing device, and 41 is provided corresponding to the 0 system and 1 system. The transmission path terminating section 42 is provided in each transmission path terminating section 41, and the same E / O conversion section as that of the above-mentioned switching center 34 is provided in each transmission path terminating section 41. A frame conversion unit (indicated by FCON) for converting a time slot (HWi) accommodating the communication channel and the control channel allocated to the own device into a frame in the remote multiplexing device and performing the inverse conversion thereof, and 44 is a device for the own device. Communication channel,
An addition / extraction bypass unit for extracting a reception signal of a control channel signal, adding a transmission signal, and bypassing a communication channel and a control channel of another device, and 45 selects one of a 0-system and a 1-system transmission route. A transmission route selection unit 46 controlled by the control unit 40 multiplexes digital signals (analog terminal signals are A / D converted) from analog terminals, ISDN terminals, leased lines, and the like accommodated in a remote multiplexer. And a subscriber line multiplexing unit that separates the reception signal extracted from the addition / extraction bypass unit 44 into signals of each subscriber line.

The transmission line monitoring / control unit 20 of the remote multiplexer interface unit 2 includes a transmission line state detection function and a notification function in each of the remote multiplexers # 1 to # 4, and a transmission line termination unit of the remote multiplexer interface 2. The monitoring results can be received by the transmission line status detection function in 3a and 3b, and by recognizing the contents, the fault location is identified, and for each of the related remote multiplexing devices, either 0 system or 1 system is determined. A control signal for instructing whether to use the ACT system is transmitted from one of the transmission line terminating units 3a and 3b to an individual remote multiplexing device through a control channel. At this time, when the system 0 is designated as the ACT system, a control signal for designating the system is sent from the transmission line terminator 3a of the system 0 of the remote multiplexer interface 2 to the transmission line a to the remote multiplexer # 1. , 1 system, the transmission line e from the transmission line termination unit 3b of the 1 system of the remote multiplexer interface unit 2 to the remote multiplexer # 4.
Is transmitted to the system. In response to this, each remote multiplexing device converts the system specified by the control unit 40 to AC.
The respective transmission route selectors 45 are controlled so as to be T-system.

A transmission line c (FIG. 13) for connecting between the remote multiplexer # 2 shown in FIG. 13 and the remote multiplexer # 3 shown in FIG.
Transmission line c is connected to transmission line c in FIG. 13), a failure section is recognized by the above-described method, and the remote multiplexers # 1 and # 2 are connected by the 0-system connection. The communication is performed with the remote multiplexer interface 2, and the remote multiplexers # 3 and # 4 communicate with the remote multiplexer interface 2 through the first system connection.
It is controlled by the transmission line monitoring / control unit 20 of the remote multiplexing device interface unit 2.

In the configuration shown in FIGS. 13 and 14, each remote multiplexing device is connected to the exchange in a logical star configuration. For this purpose, an addition / extraction bypass unit 44 and a transmission route selection unit 45 are provided. Have been. Therefore, when the remote multiplexing device used in the conventional physical star connection system configuration (FIG. 15) is transferred to the logical star configuration system of the present invention, the configuration relating to the transmission path is changed and This can be realized by adding the above-mentioned addition / extraction bypass unit 44 and transmission route selection unit 45 to each remote multiplexing device. Conversely, in order to make the logical star type system configuration of the present invention a physical star type, it can be realized in the form of a remote multiplexing device that does not have the above-mentioned addition / extraction bypass unit and transmission route selection unit.

[0062]

According to the present invention, the addition of a remote multiplexing device
Using the extraction function and the bypass function, it is possible to form a logical star connection between each remote multiplexing device and the exchange, and it is possible to reduce the required length of the transmission path. Also, by connecting the two transmission lines in a ring,
Duplicate individual connections of system 0 and system 1 can be formed between the exchange and each remote multiplexing device, and the reliability of the system can be ensured.

Each remote multiplexing device notifies the remote multiplexing device interface unit of the state of the adjacent transmission line, so that the remote multiplexing device interface unit transmits data independently of the number and position of the remote multiplexing devices connected in a ring. The remote multiplexing device interface unit identifies the notification contents, identifies the faulty transmission line section, and designates either the 0-system connection or the 1-system connection to each remote multiplexing device. It is possible to operate normally even when a failure occurs.

When adding / removing (removing) the remote multiplexing device,
By the implementation notification (implemented, not implemented) from the remote multiplexing device,
The switching station can automatically generate the configuration information. By setting and updating the location information using the implementation management information using the control channel, the switching center can recognize the physical location of each remote multiplexer on the ring.

When adding or removing a remote multiplexer, there is no need to interrupt the connection service by switching connections to existing remote multiplexers other than the target remote multiplexer.

[Brief description of the drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is a diagram showing a configuration example of remote multiplexing according to the present invention.

FIG. 3 is a diagram illustrating an example of a highway format of a transmission path.

FIG. 4 is a diagram showing a configuration of transmission path state monitoring according to the present invention.

FIG. 5 is a diagram showing an example of transmission path system selection control according to the present invention.

FIG. 6 is a diagram illustrating a configuration example of an exchange and a remote multiplexing device.

FIG. 7 is an explanatory diagram of a transmission path failure section and a connection selected.

FIG. 8 is an explanatory diagram of generation of configuration information when a remote multiplexing device is added.

FIG. 9 is a diagram showing a transmission path highway format.

FIG. 10 is a diagram for explaining a mounting position recognition method.

FIG. 11 is an explanatory diagram (before addition) of a method for adding a remote multiplexing device according to the present invention.

FIG. 12 is an explanatory diagram (after expansion) of a method for adding a remote multiplexing device according to the present invention.

FIG. 13 is a diagram (part 1) illustrating a configuration example of a system according to the present invention.

FIG. 14 is a diagram (part 2) illustrating a configuration example of a system according to the present invention.

FIG. 15 is an explanatory diagram of a conventional example.

FIG. 16 is a diagram showing a configuration for monitoring a transmission line state according to a conventional example.

FIG. 17 is a diagram illustrating an example of transmission line system selection control according to a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Switching center 2 Remote multiplexer interface part 3 Transmission line termination part 4 Remote multiplexer # 1 5 Transmission path termination part 6 Remote multiplexer # 2 7 Transmission path termination part 8a, 8b Between exchange 1 and remote multiplexer # 1 Transmission lines 9a, 9b Remote multiplexer # 1 and remote multiplexer # 2
Transmission line between 10a and 10b Transmission line between remote multiplexer # and exchange 1

Claims (10)

[Claims] In a remote multiplexing system for accommodating subscribers scattered over a wide area in a switching center, one remote multiplexing device is physically located between the switching center and the remote multiplexing device. , Sequentially connected in a ring via a bidirectional transmission line that is connected to the exchange finally through another remote multiplexing device, and each remote multiplexing device is logically connected to the exchange via the transmission line. Each remote multiplexing device is allocated to its own device from a control signal control channel and a communication signal communication channel assigned to each remote multiplexing device on the transmission line. An addition / extraction bypass unit for adding a transmission signal to each of the assigned channels, extracting a reception signal, and bypassing a channel signal allocated to another device; and between the addition / extraction bypass unit and a plurality of subscriber lines. To And a subscriber line multiplexing section provided. 2. The remote multiplexing device according to claim 1, wherein the remote multiplexing device forms a 0-system bidirectional connection for its own device on a transmission line connected to one of the transmission line terminating units of the switching center. A single system bidirectional connection for each device is formed on a transmission line connected to the other transmission line terminating unit of the exchange, and each remote multiplexing device uses one of the systems according to an instruction from the exchange. A remote multiplexing system characterized by being selectively controlled as 3. The remote multiplexing device according to claim 1, wherein each of the remote multiplexing devices detects a transmission path condition between the remote multiplexing device and an adjacent remote multiplexing device and detects a failure. It has a function of notifying the multiplexing device interface unit, and has a transmission line monitoring / control unit in the remote multiplexing device interface unit. When the transmission line monitoring / control unit receives the notification from each of the remote multiplexing devices, it establishes a notification route. In accordance with the recognized faulty section, the remote multiplexing device identifies the selected connection for forming a connection with the exchange by using the transmission line excluding the faulty section, and selects the system. A remote multiplexing system, wherein system switching is performed by transmitting an instruction to each remote multiplexing device via the control channel. 4. The remote multiplexer or subscriber according to claim 1, wherein a new remote multiplexer or subscriber line multiplexer is added to the ring-connected remote multiplexer or an existing remote multiplexer is removed. A function of notifying, from the line multiplexing unit, an implementation notification including implementation or non-implementation via the control channel, wherein the exchange stores configuration information of the remote multiplexing apparatus or the subscriber line multiplexing unit based on the notification. Remote multiplexing. 5. The transmission unit according to claim 4, wherein the remote multiplexer interface unit of the exchange sets an identification number (ID) corresponding to each control channel number, and the remote multiplexer corresponding to each ID is ring-connected. A remote multiplexing method comprising a mounting information table indicating whether or not the remote multiplexing device is mounted on a road, and allocating a control channel used by each remote multiplexing device according to the assignment of the ID. 6. A remote multiplexing device interface unit according to claim 4 or 5, wherein the remote multiplexing device interface unit of the switching center is provided with, for each communication channel, whether a subscriber line multiplexing unit of the remote multiplexing device using the communication channel is mounted. A remote multiplexing method comprising: a communication channel / allocation management table representing a communication channel; and dynamically allocating a communication channel on a transmission path to each remote multiplexing device independently of a control channel. 7. The mounting information table and the communication channel / allocation management table according to claim 5 or 6, wherein the mounting information table generated when a remote multiplexing device or a subscriber line multiplexing unit is added or removed is updated. A remote multiplexing system. 8. An apparatus according to claim 5, wherein said mounting information table has an area for storing position information indicating a relative position with respect to an exchange corresponding to each mounted remote multiplexing device. When a position information counter area is provided in each control channel provided corresponding to the ID on the transmission line and the transmission is performed through one of the transmission lines, each remote multiplexing device transmits the control channel assigned to its own device. A fixed value is set in the position information counter, 1 is added to the position information counters of the other control channels, and the exchange determines the position by the value of the position information counter of each control channel corresponding to the mounted ID. Remote multiplexing characterized by obtaining information. 9. The system according to claim 1, wherein 0 is assigned to each remote multiplexing device.
A transmission line termination unit of the system 1 and a reception unit and a transmission unit of the transmission line termination unit of the system 0 are connected to the corresponding downlink and uplink transmission lines connected to the switching center or the remote multiplexing device at the preceding stage. The receiving unit and the transmitting unit of the transmission line termination unit of the system 1 are connected to the corresponding transmission lines of the downstream and the upstream connected to the remote multiplexing device or the exchange in the subsequent stage. Said 1
The transmission unit of the transmission line termination unit of the system is connected via the addition / extraction bypass unit, and the reception unit of the transmission line termination unit of the first system and the transmission unit of the transmission line termination unit of the 0 system are connected to the addition / extraction unit. A remote multiplexing system characterized by being connected via a drawer bypass unit. 10. A communication system according to claim 9, further comprising a transmission route selecting unit provided between said addition / extraction bypass unit and said subscriber line multiplexing unit. A remote multiplexing system, wherein one of the control channel signals is selected to be connected to the subscriber line multiplexing unit.