JP2692267B2 - Transmission line switching circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] A transmission line switching circuit for switching a transmission route according to a failure of a transmission line for transmitting a multiplexed signal exchanged between transmission terminal stations, and forming one transmission line For the purpose of providing a transmission path switching circuit capable of simultaneously switching a plurality of channels, a branching means for branching a transmission path for transmitting a multiplexed signal into two paths and a multiplexing means branched through the branching means. Of the first / second channel setting means for setting the first switch unit to the number of channels included in the transmission path for transmitting the multiplexed signal, and the input of the multiplexed signal from the transmission path While performing through one preset route for input,
The switching means for switching to another input route when one of the input routes fails and an alarm is generated, and the number of channels of the input route for fetching the multiplexed signal into the switching means is second.
3rd / 4th channel setting means for setting the switch part of and the signal for switching to another input route when an alarm occurs due to one of the input routes becoming an obstacle And an alarm detecting means for sending to the means.

[Industrial applications]

The present invention relates to a transmission line switching circuit that switches a transmission route according to a failure of a transmission line that transmits a multiplexed signal exchanged between transmission terminal stations.

Generally, data transmitted through a communication network is required to be transmitted through a highly reliable line.

For example, in frequency division multiplexing (hereinafter referred to as FDM),
The voice switch method has been adopted as a measure for high reliability in the technology of using one transmission path as a plurality of communication paths at the same time.

When this voice switch method is used as a dedicated line in a modem signal, the dial pulse is not used, and the ringer signal for sending this dial pulse has been used as a switching device by replacing the signal in the disconnection state or the normal state. .

Further, in the FDM system, the main signal and the ringer signal can be treated as separate frequencies, and there is an advantage that a redundant system of the data line can be constructed without affecting the main signal.

On the other hand, in a digital data system, a system that does not have a circuit that can discriminate a ringer signal that can transmit not only an analog signal but also a synchronous data signal is configured, so it is not possible to transfer the existing FDM system to a digital data system as it is. It will be possible.

Therefore, it is necessary to have a circuit configuration that can more efficiently transfer the FDM system to a digital data system as it is.

[Conventional technology]

FIG. 5 is a diagram for explaining a conventional example of a transmission line switching circuit, and FIG.
FIG. 7 is a diagram for explaining the system system, and FIG. 7 is a diagram for explaining the details of the system system.

The transmission line switching circuit shown in FIG. 5 includes a first switch unit 1a.
And the second switch section 1b, and the analog / digital conversion section 6 is installed between the path forming the transmission path.

The route input to the terminal device is referred to as an up route (or route), and the route output from the terminal device is referred to as a down route (or route).

The above-mentioned first switch unit 1a is a hybrid transformer (hereinafter referred to as H) that allocates the analog output signal from the terminal device to encoders (hereinafter referred to as CODs) 2 (1) and 2 (2) corresponding to two routes. It is composed of 11).

On the other hand, the second switch unit 1b includes a ground detection circuit 12 for detecting a ground condition in decoders (hereinafter referred to as DEC) 3 (1) and 3 (2), and a DEC3 (1) corresponding to two routes. ), 3 (2) output is selected based on the control signal from the ground detection circuit 12 and used as an input signal to the terminal device.
And

Further, the above-mentioned analog / digital converter 6 converts the analog signal and the digital signal respectively and operates as an interface between the analog signal and the digital signal, COD2 (1), 2 (2) and DEC3 (1), 3 ( 2) and a ringer bit transfer circuit (hereinafter abbreviated as SR) 4 (1), 4 (2) that extracts and transfers only the ringer bit from the outputs of DEC3 (1), 3 (2). .

FIG. 6 shows a situation in which a network system is configured between the A-transmission terminal station and the D-transmission terminal station, which are equipped with the transmission path switching circuit and the analog / digital conversion section 6 while connecting the terminal device as described above.

The transmission line between the transmission terminal stations is for transmitting multiplexed signals. In addition, the A transmission terminal station and the B transmission terminal station are routed, the A transmission terminal station and the C transmission terminal station are routed, and the C transmission is performed. Route between terminal station and D transmission terminal station, route between B transmission terminal station and D transmission terminal station, and between the A transmission terminal station and B transmission terminal station 24
The channel (24CH) transmission path is 24CH between the B transmission terminal station and the C transmission terminal station, and the 3CH channel is between the B transmission terminal station and the D transmission terminal station.
It is assumed that the transmission path of is set.

Also, the terminal equipment of the A transmission terminal station is set to transmit signals on 24CH, and the terminal equipment of the B and C transmission terminal stations is set to
Those set to transmit signals on 24CH and 3C
In some cases, the terminal device of the D transmission terminal station is set to transmit a signal in 3CH.

FIG. 7 shows the details of the network system shown in FIG. 6, and shows an example between the A transmission terminal station and the C transmission terminal station.

For example, in the case of the A transmission terminal station in which the transmission path of 24CH is set, the output signal from the terminal device TA1 is branched into a route and a route via the first switch unit 1a. on the other hand,
When a signal is taken into the terminal device TA2 through the second switch unit 1b through the route and the route, the second switch unit 1b is normally connected to the route, and when a failure such as disconnection of the route occurs, the second switch unit 1b is connected. The part 1b is switched to the root side.

The 24CH transmission line connected to the terminal device TC1 in which the 24CH transmission line of the C transmission terminal station is set and the 3CH transmission line connected to the terminal device TC2 in which the 3CH transmission line is set are It only passes through the transmission terminal.

In the case of the C transmission terminal station, the terminal device TC1 in which the transmission path of 24CH is set and the terminal device TC2 in which the transmission path of 3CH is set
Are installed and perform the same processing as the A transmission terminal station.

It is assumed that the multiplexed signal transmitted through the transmission line between the transmission terminal stations shown in FIGS. 6 and 7 is a digital signal, and it requires 1CH per 64K bits.

Further, each transmission line switching circuit composed of the first switch section 1a and the second switch section 1b adopts a method of exchanging signals via a data bus (not shown) of 1.5 Mb / s, Moreover, the 1.5 Mb / s data bus carries signals on the data bus in 24 time slots (hereinafter referred to as TS).

It should be noted that the first and second parts constituting the transmission line switching circuit shown in FIG.
Since the switch units 1a and 1b of the above adopt the address calling method in CH units as described below, they switch the transmission line in 1CH units, and therefore the 1st / 1st according to the number of CHs.
The second switch units 1a and 1d are configured.

The signal processing situation of this example will be described below with reference to FIGS.

For example, in the A transmission terminal station, when an input signal from the route is detected by the ground detection circuit 12, the ground detection circuit 12 controls the relay switch circuit 13 so that the route is selected. .

Further, when the relay switch circuit 13 is controlled by the ground detection circuit 12 so as to select the route and the route open in the route, the signal input from the DEC3 (1) corresponding to the route is sent to the terminal device TA1.

In addition, the above-mentioned 1.5 Mb / s data bus and COD2 (1), 2
Between (2) / DEC3 (1) and 3 (2), C is used in the data bus.
It uses the H address calling method.

Therefore, the number of CHs handled by the relay switch circuit 13 is a CH unit. That is, as shown in FIG. 6, it is handled by a transmission line where a network is formed between the A transmission terminal station and the D transmission terminal station.
CH is fixed to the maximum number of CH (24 CH in this example).

For example, there is a 3CH transmission line between the B transmission terminal station and the D transmission terminal station, a 24CH transmission channel between the B transmission terminal station and the C transmission terminal station, and a 24CH channel between the A transmission terminal station and the B transmission terminal station. When configuring a network with transmission lines, COD / DEC and relay switch circuits for 24 routes corresponding to 24CH are installed in each transmission terminal station device, and COD / DEC corresponding to the number of CHs set from them DEC and relay switch circuits will be used.

[Problems to be solved by the invention]

COD / DEC is required when applying a plurality of switching methods according to the FDM technology to the digital transmission system as described above.

Moreover, in this case, DEC is indispensable because SR is the only means for detecting the state of open or disconnection of the line.

Furthermore, when using COD / DEC, it is necessary to switch transmission lines on a line-by-line basis.

That is, since the address calling method for each CH is used between the data bus and the COD / DEC, it becomes impossible to collectively switch the multiplexed CHs, which results in inefficient transmission path switching.

An object of the present invention is to provide a transmission line switching circuit capable of simultaneously switching a plurality of channels forming one transmission line.

[Means for solving the problem]

FIG. 1 shows a diagram for explaining the principle of the transmission line switching circuit of the present invention.

The principle diagram of the transmission line switching circuit of the present invention shown in FIG.
Branching means 11a and the first / second channel setting means 20 (1), 20 (2) constituting the switch section 1c, and the switching means 13a, the third / fourth means constituting the second switch section 1d. The channel setting means 20 (3), 20 (4) and the alarm detection means 50 are provided, and the branching means 11a described above preliminarily stores the multiplexed signal from the terminal device connected to the transmission terminal station. It divides into two routes (i) and (j) for transmission having the set number of channels, and the first / second channel setting means 20 (1), 20 (2)
By setting the time slot length for transmitting the multiplexed signal branched via the branching means 11a and the time slot number at the beginning of the time slot length, the two routes for transmission (i) and (j) are previously set. The switching means 13 sets the number of channels to be set, and the switching means 13 fetches the multiplexed signal from one of the two input routes (m) and (n) which has been set in advance. m) or (n), and when one of the routes (m) or (n) becomes an obstacle and causes an alarm, it is switched to another input route (n) or (m). The third / fourth channel setting means 20 (3), 20 (4)
The number of channels corresponding to one input route (m) or (n) for fetching the multiplexed signal to the switching means 13a is set, and the alarm detection means 50 is used for one input route (m). ) Or (n) becomes an obstacle and an alarm is generated, the alarm is detected and a signal for switching to another input route (n) or (m) is sent to the switching means 13a. The first and second switch sections 1c and 1d having the above structure constitute a transmission path switching circuit, which is a means for solving this problem.

[Action]

CHs (time slots) that require route switching on a data bus carrying multiplexed signals are set by the first to fourth channel setting means 20 (1) to 20 (4), and output routes (i ),
Set the number of CH (time slot) of (j) and
A plurality of CHs (time slots) set by the fourth channel setting means 20 (3) to 20 (4) are serially switched by the switching means 13a serially by the switching means 13a, and thus a plurality of CHs (time Slots) can be processed at one time with a set of hardware (channel setting means and switching means) configuration.

〔Example〕

Hereinafter, the gist of the present invention will be specifically described with reference to the embodiments shown in FIGS.

FIG. 2 is a diagram for explaining an embodiment of a transmission line switching circuit of the present invention, FIG. 3 is a diagram for explaining an embodiment of an AIS detection circuit in the transmission line switching circuit of the present invention, and FIG. 4 is a TS of the present invention.
The figure explaining a structure and TS setting situation is shown, respectively. still,
The same reference numerals indicate the same objects throughout the drawings.

The first embodiment of the transmission line switching circuit of the present invention shown in FIG.
As the branching means 11a described in the figure, H11 performing the same operation as described in FIG. 5, as the switching means 13a, the relay switch circuit 13 consisting of a set of three-state buffers, and the first to fourth channel setting means 20. As (1) to 20 (4), time slot setting section (hereinafter referred to as TS setting section)
20a (1) to 20a (4) and TS length setting section 20b (1) to 20b
(4), and an alarm detection circuit (hereinafter referred to as AI
This is an example constituted by 50a (1) and 50a (2) referred to as S detection circuit.

Also, the AIS detection circuits 50a (1), 50a (2) shown in FIG.
Detects the case where the input multiplexed signal indicates all 1's, sets the least significant bit (LSB) of the multiplexed signal to "0", and outputs it to the relay switch circuit 13.

FIG. 3 shows a part of the configuration of the above-mentioned AIS detectors 50a (1), 50a (2). This is an all-1 detection for detecting the case where all 8 bits, which are the handling units of multiplexed signals, are in the all-1 state. A circuit 51, a generator circuit (hereinafter referred to as a GEN circuit) 52 that generates a signal in which the least significant bit (LSB) is set to "0" by the detection signal, and an insert that inserts the signal from the GEN circuit 52 into a multiplexed signal. Circuit (hereinafter referred to as INS circuit) 53.

FIG. 4 shows the structure of a time slot (TS), and the TS of this embodiment is a case where an 8 Mbit data bus is used.
It is composed of up to 120TS.

In the setting of the used TS in this embodiment, first, the TS length setting units 20b (1) to 20b (4) set the TS length (for example, 24TS).
Is set, and then the TS setting section 20a (1) to 20a (4) starts the TS length set by the TS length setting section 20b (1) to 20b (4).
This is done by setting the number (TS1 or TS25 in the embodiment of FIG. 4).

The TS setting as described above is set from the maintenance operation panel (not shown).

Next, the operation of this embodiment will be described below with reference to FIGS.

The system system of this embodiment is the same as that shown in FIG. 6, and the digital multiplexed signal handled in the transmission path switching circuit is a serial digital signal, and 1CH (1T
S) is set to carry 64 Kb / s.

Further, the input / output of the digital multiplexed signal to / from the transmission path switching circuit is performed through a data bus (not shown), and this data bus is assumed to be 8 Mb / s (having 120 TS).

The relay switch circuit 13 of this embodiment is composed of a set of three-state buffers for selecting a serial digital multiplexed signal signal, and the on / off control by the gates of the three-state buffers corresponds to each transmission line. AIS that is installed in each transmission line and detects, for example, the alarm occurrence status of each transmission line
This is performed by detection signals from the detection circuits 50a (1) and 50a (2).

A preset to 24CH shown in Figs. 6 and 7
The multiplexed signal output from the terminal device TA1 connected to the transmission terminal station to the data bus of 8 Mb / s is branched and transmitted to the route at H11.

At this time, the TS length setting unit 20b (1) and the TS length setting unit 20b
(2) sets 24CH length (24TS length), TS setting section 20a
(1) and the TS setting section 20a (2) set the starting numbers, for example, TS1 and TS25, and output them to the data bus.

On the other hand, in the route and the multiplexed signal from the route, the number of CHs preset in the route and the route and the beginning number of the CH are the CH length (TS length is the TS length setting unit 20b (1) and the TS length setting unit 20b. Set in (2).

From this route and the multiplexed signal from the route, the relay switch circuit 13 selects the multiplexed signal from the normal route (which is the direct route) and sends it to the terminal device TA2.

Here, if the route becomes an obstacle due to disconnection or the like, an alarm is generated by an alarm generator (not shown), the AIS detection circuit 50a (1) detects this alarm, and sends an alarm detection signal to the relay switch circuit 13.

Further, for example, when the AIS detection circuit 50a (1) all 1 detection circuit 51 detects that all 8 bits, which are the unit for handling the multiplexed signal of the route, are all 1, for example,
A signal in which the least significant bit (LSB) is set to "0" by the detection signal is sent to the relay switch circuit 13.

The relay switch circuit 13 is thereby switched to the route side, and the multiplexed signal from the route (in this case, this route becomes the detour route) is selected and transmitted to the terminal device TA2.

The detour route is a transmission line that is switched and used when the direct route becomes the above-mentioned obstacle.

Also, in the case of the transmission path set to 3CH, it has a direct route and a detour route as in the case of 24CH, and when the direct route is a failure, it is switched to the detour route and used.

As described above, the relay switch circuit 13 processes a plurality of CHs at a time with one set of 3-state buffers, and also processes them.
The number of CHs (TSs) can be set to the required number, and the remaining CHs
Since (TS) can be used for other purposes, transmission lines can be switched more efficiently.

〔The invention's effect〕

According to the present invention as described above, it is possible to provide a transmission line switching circuit capable of efficiently switching transmission lines.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the principle of the transmission line switching circuit of the present invention, FIG. 2 is a diagram for explaining an embodiment of the transmission line switching circuit of the present invention, and FIG. 3 is an embodiment of an AIS detection circuit of the present invention. FIG. 4 is a diagram for explaining a TS configuration and a TS setting situation in the present invention, FIG. 5 is a diagram for explaining a conventional example of a transmission line switching circuit, FIG. 6 is a diagram for explaining a system system, FIG. 7 is a diagram for explaining the details of the system system, respectively. In the figure, 1a, 1b, 1c, 1d are the first / second switch units, 2 (1), 2
(2) is COD, 3 (1), 3 (2) is DEC, 4 (1), 4
(2) SR, 11 H, 11a branching means, 12 ground detection circuit, 13 relay switch circuit, 13a switching means, 20
(1) to 20 (4) are first to fourth channel setting means, 20
a (1) to 20a (4) are TS setting units, 20b (1) to 20b (4)
Is a TS length setting unit, 50 is an alarm detecting means, 50a (1), 50a
(2) is AIS detection circuit, 51 is all 1 detection circuit, 52 is GEN
A circuit, 53 is an INS circuit, respectively.

Claims (1)

(57) [Claims] 1. A plurality of transmission terminal stations are configured via a communication network, and a plurality of routes for inputting / outputting a multiplexed signal to / from the plurality of transmission terminal stations via the communication network are faulty in the route. A transmission path switching circuit comprising a first / second switch section (1c, 1d) for switching in accordance with the above, wherein the first switch section (1c) is connected to a terminal device connected to the transmission terminal station. The multiplexed signal to be sent out has two paths ((i),
Branching means (11a) for branching to (j)), and for transmitting the multiplexed signal branched through the branching means (11a) according to a preset number of channels,
By setting a time slot length corresponding to the number of channels and a time slot number at the beginning of the time slot length, two transmission routes ((i), (j)) of the transmission line are set to a preset number of channels. ) To set each 1 /
The second channel setting means (20 (1), 20 (2)) is provided and configured, and the second switch section (1d) is used for inputting the input of the multiplexed signal from the transmission line. One of the routes ((m), (n)) that is set in advance ((m) or (n))
And switching means (13a) for switching to the other route ((n) or (m)) when one of the routes ((m) or (n)) becomes an obstacle and an alarm occurs. Third / fourth channel setting means for setting the two input paths ((m) and (n)) for fetching the multiplexed signal into the switching means (13a) in correspondence with the respective channel numbers. (20 (3), 20 (4)) and one of the routes for input ((m) or (n)) becomes an obstacle and an alarm is generated, the alarm is detected and the other route ( Alarm detection means (5) for sending a signal for switching to (n) or (m) to the switching means (13a)
0) and a transmission path switching circuit.