JPH0813024B2 - Time division multiplex communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a time division multiplex communication system.

(Prior Art) An interface for connecting each terminal device is provided corresponding to a plurality of terminal devices, and the interface is connected by a bus, and a different channel is assigned to each interface and via each interface. The data of each terminal device is obtained, and a plurality of predetermined channels are time-division multiplexed using these as channel data.
It has a multiplexing unit that sends out to the high-speed line (digital line) as a frame, and also divides the received frame-unit data into predetermined channels, and applies these as channel data to the interface of the corresponding channel. There is a time division multiplex communication system in which data of a plurality of channels is transmitted and received by time division.

Conventionally, such a time division multiplex communication system has at least a pair of time division multiplex devices A and B having two multiplexers 1a and 1b and a plurality of interfaces 4a to 4m at high speed as shown in FIG. Information from the low-speed lines 5a1 to 5mn (l, m, n = 1,2,3 ...) connected to the line 2 and connected to each terminal device,
The line terminating equipment (DSU) 6a, which is multiplexed by the multiplexer 1a or 1b through the corresponding interfaces 4a to 4m,
Information is transmitted via the DSUs 6a and 6b on the high-speed line 2 to which 6b is connected, and sent to the other party's time division multiplexer. Then, in the time division multiplexing device on the receiving side, the multiplexing unit 1a or 1b decomposes the multiplexed information for each channel, and the terminal device is connected via the corresponding interfaces 4a to 4m. Information is transmitted to the low speed lines 5a1 to 5mn.

The DSUs 6a and 6b convert transmission information into signals suitable for transmission and send them to the high-speed line 2, and amplify, identify and reproduce the signals received from the high-speed line 2, and decode them to take out information signals.

There are two multiplexing units 1a and 1b for each time division multiplexing device.
One of them is for current use, and the other is for standby. In this way, when one of the multiplex units is duplicated due to duplication, switching to the standby multiplex device does not cause any trouble.

Each multiplexer 1a, 1b is provided with a switch 7a, 7b at the input / output unit on the high-speed line 2 side, and this switch is opened at the time of standby in the multiplexing unit that has become standby,
Disconnected from high speed line 2.

That is, the multiplexing units 1a and 1b have clock extraction units 8a and 8b, transmission units 9a and 9b, and reception units 10a and 10b, as shown in FIG.
In order to connect / disconnect to / from the high-speed line 2, the transmission side and the reception side of the high-speed line 2 are connected to the clock extraction units 8a and 8b via the switches 7a and 7b. Internal bus 3 is transmitting internal 3a
And the receiving internal bus 3b. Clock extraction unit 8a, 8
The transmitters 9a and 9b and the receivers 10a and 10b are connected to b. The transmitters 9a and 9b are connected to the transmission internal bus 3a of the internal bus 3, and the receivers 10a and 10b are connected to the internal bus 3. Each is connected to the reception internal bus 3b. Transmitters 9a, 9b and receiver 10
a and 10b are each interface 4a by a control unit not shown.
A command for transmission or reception is given for each channel via ~ 4m, and the channel that receives the command transmits or receives information according to the command. The clock extraction units 8a and 8b extract the clock signal on the high-speed line, capture the transmission information in synchronization with this clock signal, give it to the reception units 10a and 10b, and also transmit the transmission information from the transmission units 9a and 9b. To do.

By the way, in the communication system using the conventional time division multiplexing apparatus using such two multiplexing units 1a and 1b, the multiplexing unit 1b (or 1a) in the standby state is provided on the high-speed line connection side of the multiplexing unit. By opening switch 7b (or 7a), it is physically disconnected from DSUs 6a and 6b, which is not desirable from the line side, and also monitors line control information through the system in the multiplexing unit in standby. Because I can't
It is not possible to know whether the multiplexing unit in the standby state is in the normal state or the abnormal state, and when the standby side multiplexing unit fails, the standby side multiplexing unit is switched to the active state, which causes confusion in communication. I am worried. Therefore, in order to solve this problem, in order not to disconnect the line from the multiplexer and the circuit in the standby state, if the switch is kept closed and the connection is maintained, the lines between the two multiplexers and the DSU will be separated. Since information is transmitted in parallel with each other, there is a problem in that the information frame is out of phase and correct information is not transmitted.

(Problems to be Solved by the Invention) As described above, a channel is assigned to each low-speed line, information from a channel to be transmitted via a high-speed line is time-division multiplexed, and received information is decomposed for each channel to obtain the corresponding information. The conventional multiplexer that distributes to a low-speed line is provided with two multiplexers 1a and 1b so that no trouble occurs when the multiplexer fails, one of which is the current one and the other of which is the standby. . The standby unit is disconnected from the high-speed line, but if such a terminal section duplex communication mode is realized, the multiplexing unit in the standby state will be physically disconnected from the DSU. This is not preferable, and there is a problem that the control information cannot be monitored for the line to be connected to the waiting multiplexing unit. Then, if the line control information of the standby side multiplexing unit cannot be monitored, it is impossible to know the abnormality of the standby side multiplexing unit. Therefore, when the standby side multiplexing unit has an abnormality, the standby side multiplexing unit is put into the active state. There is a concern that it will switch and cause communication problems.

In order to solve this problem, in order not to disconnect the standby multiplexing unit and the line, if you keep the connection state, the information is transmitted in parallel between the two multiplexing units and the DSU by each line. Therefore, there is a problem in that the phase of the information frame shifts, and thus correct information cannot be transmitted.

Therefore, the object of the present invention is to avoid duplicating the multiplexing unit and physically disconnecting the standby multiplexing unit from the high-speed line side when operating one of them as the current and the other as the standby. Another object of the present invention is to provide a time-division multiplex communication system capable of monitoring control information of a line to be connected to a standby multiplexing unit and enabling information transmission without any trouble.

[Structure of Invention]

(Means for Solving Problems) In order to achieve the above object, the present invention is configured as follows. That is, the transmission information from a plurality of low-speed lines is time-division-multiplexed, transmitted as a multiplexed frame through the high-speed line, and a multiplexer having a multiplexing function for decomposing the multiplexed frame received through the high-speed line is provided. In the time division multiplexing communication system using the time division multiplexing device, wherein the reception information decomposed by the multiplexing unit is distributed as reception information to corresponding low speed lines in a plurality of low speed lines, the time division multiplexing device is Control means for generating a control signal for switching between the active state and the standby state, and the multiplexing function when the active state is set by the control signal, and the predetermined idle pattern when the standby state is set by the control signal At least two systems of multiplexers that generate data, and the outputs of the receiving outputs of these multiplexers And a means for separating the dollar pattern data, and the high-speed line side is connected to the time-division multiplexing device connection side with an output transmitted from the multiplexing unit of a plurality of systems of the time-division multiplexing device. Separation means for receiving and separating the idle pattern data is provided.

(Operation) In such a configuration, the time division multiplexing apparatus has a control means for generating a control signal for switching between the active state and the standby state, and also has at least a two-system multiplexing unit. And, the multiplexing unit of the two systems, one is in the working state,
The control means provides a control signal to keep the others in a standby state.
The multiplexing unit set to the active state by this control signal is
The transmission function from a plurality of low-speed lines is time-division-multiplexed, transmitted as a multiplexed frame through the high-speed line, and the multiplexed frame received through the high-speed line is decomposed. The multiplexing unit set to the standby state generates predetermined idle pattern data. Then, at the time of reception, the receiving side outputs of the two-system multiplexing unit are received through the separating means. As a result, the idle pattern data is separated and only the necessary reception information is extracted and distributed to the low speed circuit. Further, during transmission, the idle pattern data is separated and sent to the high speed line by receiving the output transmitted from the two-system multiplexing unit of the time division multiplexer through the separating means provided on the high speed line side.

In this way, the time division multiplexing apparatus has a plurality of multiplexing units, one of which is in an active state and the other of which is in a standby state, and the multiplexing unit in the standby state generates predetermined idle pattern data. With respect to the signal obtained through these multiplex units, the idle pattern data is removed by the separating means, and only the necessary information is extracted and given to the high speed line or the low speed line. The multiplexing unit in the standby state does not have to be physically separated from the high-speed line side. Therefore, this makes it unnecessary to physically separate the waiting multiplexing unit from the high-speed line side when the multiplexing unit is duplicated and one is used as the active side and the other is operated as the standby side. It is possible to provide a time division multiplex communication system capable of monitoring the control information of the line to be connected to the internal multiplexing unit and enabling information transmission without any trouble.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a block diagram showing a configuration of an apparatus according to the present invention. As shown in FIG. 1, the time division multiplexing communication system of the present invention is provided with stations 11a and 11b in a high speed line 2 and the stations 11a and 11b are provided. 1
The line termination devices (D) corresponding to the two systems of the multiplexing units 21a and 21b of the time division multiplexing devices 20a and 20b, respectively,
SU) 26a1, 26a2, 26b1, 26b2 are provided. Line terminator (DS
U) 26a1, 26a2, 26b1 and 26b2 are the same as those described in the conventional example. The time division multiplexers 20a and 20b are low-speed lines 25a
Interfaces 24a to 24m for exchanging information with 1 to 25mn (l, m, n = 1,2,3 ...), and a multiplexing unit 21a that multiplexes transmission information and decomposes reception information by channel. 21b,
It is composed of a reception logic gate 24 that takes the logical product of the reception output side information of the two multiplexing units 21a and 21b and sends the information to the interfaces 24a to 24m. When the multiplexing units 21a and 21b are for standby, When receiving the transmission information from the low-speed line side, it generates idle pattern digital data (hexadecimal data FF; binary notation 1111 1111 data) and sends it to the high-speed line side, and also receives from the high-speed line side. When receiving information, it has the function of generating idle pattern digital data (FF in hexadecimal data) and transmitting it to the low-speed line side.

Further, when the stations 11a and 11b are transmission ends to the high-speed line 22, of the transmission information sent from the two multiplexing units 21a and 21b in the time division multiplexing apparatus on the transmission side via the DSU, It has a transmission logic gate that takes the logical product of the transmission information from both multiplexing units 21a and 21b in order to select and transmit only the transmission information from the current multiplexing unit.

 Next, the operation of the present system having such a configuration will be described.

The time division multiplexer 20a (or 20b) sends the information from the low speed lines 25a1 to 25mn assigned to a specific channel to the multiplexer 21a or 21b through the corresponding interfaces 24a to 24m, and time division is performed for a plurality of channels. Then, the information is transmitted from the DSU 26a1, 26a2 (or 26b1, 26b2) to the high speed line 22 via the station 11a (or 11b). One of the two multiplexing units 21a and 21b in the time division multiplexing apparatus on the transmitting side is for standby, and this multiplexing unit for standby receives transmission information from the interfaces 24a to 24m.
An idle pattern that is a continuous pattern of FF data is generated. Therefore, via the DSUs 26a1 and 26a2 (or 26b1 and 26b2), the station 11a (or 11b) receives the idle pattern digital data from the standby multiplexing unit and the frame-by-frame transmission information from the working multiplexing unit in parallel. Will be entered. The station 11a (or 11b) has a transmission logic gate, and receives these signals from both multiplexers and takes the logical product of both. Since the idle pattern is digital data of FF, as a result of taking the logical product, only the transmission information from the working multiplexing unit can be extracted.

The transmission information thus selected is transmitted from the partner station 11b (or 11a) via the DSUs 26b1 and 26b2 (or 26a1 and 26a2) through the high speed line 22 to the partner time division multiplexer 2.
Sent to 0b (or 20a). Then, the multiplexing unit 21a or 21b of the device on the receiving side decomposes the multiplexed information for each channel, and the corresponding interfaces 24a-2
Information is transmitted to the low-speed lines 25a1 to 25mn to which the terminal device is connected via 4m.

2 for the time division multiplexer 20b (or 20a) on the receiving side
One of the multiplex units 21a and 21b is used for the current and the other is used for the standby, the active multiplex unit decomposes the received information for each channel, and the standby multiplex unit idles to FF when there is the received information. Outputs digital data of the pattern. Then, these are logical gates for reception 34 that take the logical product of both.
Therefore, the reception logic gate 34 outputs the reception information decomposed for each channel from the current multiplexing unit. This output information is given to the low speed lines 25a1 to 25mn to which the terminal device is connected via the corresponding interfaces 24a to 24m for each channel.

The configuration of the multiplexing units 21a and 21b will be described in detail. That is,
The multiplexers 21a and 21b are, as shown in FIG.
8a, 28b, transmitters 29a, 29b, receivers 30a, 30b, reference clock generators 32a, 32b, clock control ports 34a, 34b, transmission clock generators 35a, 35b, and high-speed line 22 clock extraction They are connected via the parts 28a and 28b.

The clock extraction units 28a, 28b extract the clock signal on the high-speed line, capture the transmission information in synchronization with this clock signal, give it to the reception units 30a, 30b, and transmit the transmission information from the transmission units 29a, 29b at high speed. It is transmitted in synchronization with a clock signal on the line. The internal bus 23 is divided into a transmission internal bus 23a and a reception internal bus 23b. Clock extraction unit 28a, 28b
Are connected to the transmitters 29a and 29b and the receivers 30a and 30b, and the transmitters 29a and 29b are connected to the transmission internal bus 23a of the internal buses 23,
Then, the reception units 30a and 30b are connected to the reception internal bus 23b of the internal buses 23, respectively. The transmitters 29a, 29b and the receivers 30a, 30b are given a command for transmission or reception for each channel by the control unit 36 that is the center of control, and for the commanded channels via the respective interfaces 24a to 24m, Information is transmitted or received according to a command. The reference clock generators 32a, 32b generate a reference clock signal to be used in the multiplexer based on the clock signal on the high-speed line extracted by the corresponding clock extractor 28a, 28b. In addition, the transmission clock generator 35a,
Reference numeral 35b is for generating clock signals for transmission and reception with reference to a reference clock signal, and the transmitting units 29a, 29b.
Synchronizes with this transmission clock signal to multiplex and output channel-specific information, and the receiving units 30a and 30b synchronize with this transmission clock signal and decompose information on a frame-by-channel basis into channels. Further, the transmitters 29a and 29b do not accept the channel information even if it is input, and instead have a function of generating continuous digital data of hexadecimal FF including line control information as an idle pattern. The clock control ports 34a and 34b are for controlling whether or not the transmission clock generators 35a and 35b are in the operating state.
Clock control port 34a which received enable signal from 36,
34b is in the operating state, and the clock control boats 34a, 34b that have received the disenable signal are in the non-operating state.

In such a configuration, the multiplexing unit 21a is currently in use,
It is assumed that the multiplexing unit 21b is for standby. This is determined by whether the control unit 36 gives an enable signal or a disenable signal to the clock control ports 34a and 34b. In this case, the enable signal is applied to the clock control ports 34a and 34b of the multiplexing unit 21a, and the disenable signal is applied to the clock control port 34b of the multiplexing unit 21b.

Information from the low speed lines 25a1 to 25mn is the interface
Multiplexers 21a, 2 through 24a to 24m and internal bus 23a
It is transmitted to 1b. Then, the information from the low speed lines 25a1 to 25mn is transmitted to the multiplexing unit 21a in the active state, and the information multiplexed here is sent to the station 11a via the DSU 26a. The information transmitted to the multiplexing unit 21b in the standby state is the idle pattern of the digital data FF including the line control information by the operation of the transmission unit 29b of the multiplexing unit 21b to which the disenable signal is given, which is the DSU 26b. It is sent to the station 11a via. That is, since the transmission clock generation unit 35b of the multiplexing unit 21b does not output the transmission clock signal by the disable signal, the transmission unit 29b that multiplexes the information for each channel in synchronization with the transmission clock signal does not perform the multiplexing. Therefore, the idle pattern including the line control information is generated instead.

In the station 11a, the logical product of the above information received from the two DSUs 26a1 and 26b2 is obtained and transmitted through the high speed line 22 to the time division multiplexer of the other party.

At the receiving end, this sent information is sent to the DSUs 26b1 and 26b2 via the station 11b, and the receiving side time division multiplexer.
The output of the transmission clock generation unit 35a (or 35b) in the assimilation state transmitted to the working state multiplexing unit 21a (or 21b) in 20b, where the clock control port 34a (or 34b) receives the enable signal. The information decomposed for each channel is transmitted to the low speed line side in synchronization with the clock signal. Further, the information transmitted to the multiplexing unit 21b (or 21a) in the standby state is the transmission clock generation unit 35b (or 35a) in the inoperative state due to the clock information port 34b (or 34a) that has obtained the disable signal. Since there is no clock signal output from, the received signal is not decomposed for each channel, and instead an FF idle pattern is output and sent to the low speed line side. Then, a logical product is taken by the receiving logic gate 33 and transmitted to the device on the low speed line side corresponding to each channel through the internal bus 23b.

When an abnormality occurs in the current multiplexing unit, the control unit 36
Further, a disenable signal is given to the clock control port of the multiplexing unit in which the abnormality has occurred, the transmission clock signal to the multiplexing unit in which the abnormality has occurred is stopped, and the operating unit shifts from the active state to the standby state. Further, the enable signal is given to the clock control port of the multiplexing unit in the standby state, and the transmission clock signal is given to the multiplexing unit in the standby state to shift to the working state. As a result, when moving the multiplexing unit from the active to the standby state, it can be implemented without disconnecting the multiplexing unit connected to the high-speed line, and after moving to the standby state Although an FF idle pattern is sent to the low-speed line side from the multiplexing unit in which an error has occurred, it is practically isolated from the system, so communication can continue without any trouble.

When the multiplexing section is duplicated in this way, an idle pattern is generated from the multiplexing section in the standby state, and the idle pattern is generated by passing the output from the multiplexing section in the standby state and the output from the multiplexing section in the active state through a logic gate. Since the pattern is removed and only necessary transmission information is extracted and transmitted / received, one multiplexer is used for the two multiplexers and the other is used without disconnecting the multiplexer in the standby state and the high-speed line side. It can be used as a standby.

In addition, accompanying this, the multiplexing unit on the standby side is connected to the line, and since line control information can be transmitted, the line control information of the multiplexing unit on the standby side can be used to multiplex during standby. When switching from the active multiplexing unit to the standby multiplexing unit, if an abnormality also occurs in the standby multiplexing unit, switching is not performed and communication is disabled. It becomes possible to avoid such behaviors.

As described above, according to the present invention, time division multiplexing, in which information of a low speed line is transmitted using a high speed line, among devices for transmitting information of a low speed line by time division and multiplexing and transmitting a multiplexed frame through the high speed line. In the device, for the pair of multiplexing units connected to the high-speed line with terminal section duplication,
When the transmission clock is cut off, it goes into a standby state, and when in a standby state, an idle pattern is generated.
The outputs of the paired multiplexers are connected to the line terminator by removing the idle pattern by extracting the idle pattern by passing the logic gates. It is now possible to keep the connected line in a substantially separated state without electrically disconnecting it, and also to switch from the active multiplexing unit to the standby multiplexing unit using the transmission clock. Since it can be performed only by control of, switching becomes easy. Further, since the operation of the standby multiplexing unit is not stopped, by generating an idle pattern including circuit control information, it is possible to monitor the abnormality of the standby multiplexing unit, which has been impossible in the past. This usually monitors the control information of the multiplexed frame to detect the occurrence of an abnormality on the high-speed line side. Is switched to the active multiplexing unit and the standby multiplexing unit, and is also performed for the active multiplexing unit so that the switching operation does not occur if an error is detected in the standby multiplexing unit. Therefore, it becomes possible to avoid switching the switch without knowing that the standby multiplexing unit is in an abnormal state and causing communication disruption.

The present invention is not limited to the embodiments described above and shown in the drawings, but can be modified and implemented as appropriate without departing from the scope of the invention.

〔The invention's effect〕

As described above in detail, according to the present invention, when the multiplexing unit is duplexed and one is used as the active and the other is used as the standby, the control information of the line to be connected to the standby multiplexing unit is monitored. In addition, it is possible to provide a time division multiplex communication system capable of transmitting information without any trouble.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of a multiplexing unit of the present apparatus, FIG. 3 is a block diagram showing a configuration of a conventional apparatus, and FIG. It is a block diagram showing a configuration of a multiplexing unit. 11a, 11b ... Station, 20a, 20b ... Time division multiplexer, 21a, 21
b …… Multiplexing unit, 22 …… High-speed line, 24a-24m …… Interface, 25a1-25mn …… Low-speed line, 26a1,26a2,26b
1,26b2 …… Circuit Termination Unit (DSU), 28a, 28b …… Clock extractor, 29a, 29b …… Transmitter, 30a, 30b …… Receiver, 32a,
32b ... reference clock generator, 34a, 34b ... clock control port, 35a, 35b ... transmission clock generator, 36 ... control unit.

Claims (1)

[Claims] 1. A multiplexing unit having a multiplexing function for time-division multiplexing transmission information from a plurality of low-speed lines, transmitting the multiplexed information through a high-speed line as a multiplexed frame, and decomposing the multiplexed frame received through the high-speed line. In the time division multiplex communication system using a time division multiplex device, the received information decomposed by the multiplexer is distributed as reception information to corresponding low speed lines in a plurality of low speed lines. And a control means for generating a control signal for switching between the active state and the standby state, and the multiplexing function when the active state is set by the control signal, and the predetermined function when the standby state is set by the control signal. Of at least two systems that generate idle pattern data of And a separating means for separating the idle pattern data, and the high-speed line side is connected to the time-division multiplexing device connecting side with the output transmitted from the multiplex units of the time-division multiplexing device. Receiving means for receiving and separating the idle pattern data, each time division multiplexer is a multiplexer of a plurality of systems,
A time division multiplex communication system characterized in that one is kept in a working state and the other is kept in a standby state.