JPS6093833A - Line switching system - Google Patents

Abstract

PURPOSE:To reduce the number of kinds of control signal used in a line switching section by discriminating whether control signals sent from the preceding station should be transmitted to the next station or not in a branching/inserting station. CONSTITUTION:If the part between terminal stations 2' and 3' of an up current line A is faulty, the terminal station 3' transmits a switching instruction signal f6 to the terminal station 2'. The terminal station 2' detects this signal f6 to operate a switch 1 and switches the up line A to a line P. At this time, this signal is not transmitted for the part between terminal stations of a down current line A because the signal f6 is the switching instruction of the part between terminal stations 2' and 3'. Meanwhile, the terminal station 3' detects a line state signal f1 to operate a switch 5 and takes out the output signal of a receiver 2 from the output terminal of a receiver 4. At this time, the signal f1 is not transmitted to parts following the part between terminal stations 2' and 3' because these parts have no reference to this signal. Therefore, this state signal (f) can be used for parts other than the part between terminal stations 2' and 3'.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a line switching system, and particularly to f
Line switching system with reduced number of IEFs (% type) (b) Prior art and problems FIG. 1 shows an example of a conventional line configuration.

In the figure, radio waves are sent in the direction of the arrow, and the line shown by the right arrow is the uplink, and the line shown by the left arrow is the downlink.
P indicates a protection line, A, n, . . . indicate a working line, ■ to ■ indicate a terminal station, . indicates a transmitter, and ○ indicates a receiver.

In the same figure, the uplink working line A has a line status signal f indicating which transmission/reception section is using the -1-nili protection line P.
, -f, and switching command signals υf, .about., for switching to the uplink protection line P to the downlink working line are assigned to each transmission/reception section, respectively.

FIG. 2 is a schematic block connection diagram of the transmitter and receiver of each terminal station.

In the figure, 1 and 5 are switchers, 2 is a transmitter, 3 is a control signal oscillator that generates a line status signal or switching command signal, 4 is a receiver, and 6 is the line status signal or switching command. Each shows a control signal detector that detects the signal.

Note that the line status signal and switching command signal are sent in parallel on the working line A and the protection line P in order to improve the reliability of the transmission line.

If a failure occurs during operation with the line configuration shown in Figure 1, an example of a method for switching from the working line to the backup line is shown in the second section.
This will be explained with a diagram.

The receiver 4 of the upstream working line A of the terminal station (2) detects that the line has become abnormal between the terminal station (2) and (2) of the upstream working line A from, for example, a change in the reception level. Therefore, in order to switch this abnormal section to the terminal station ■-■ section of the uplink protection line P, for example, the transmitter 2 of the downlink working line A is used to send a switching command signal f6.
is sent to the terminal ■.

At the terminal station ■, when the control signal detector 6 of the receiver 4 of the downlink working line A detects this switching command signal f, it operates the switching device 1 of the uplink working line A and the protection line P, and switches the uplink working line A. The input signal applied to the transmitter 2 is applied to the transmitter 2 of the uplink protection line P as shown by the dotted line. Therefore, the backup line P
The input signal will be sent to the terminal station ■ using .

At the terminal station ■, the control signal detection circuit 6 of the receiver 4 of the uplink protection line P detects the line status signal f2 between the terminal stations ■ and ■ for the uplink working line, so the terminal station ■ of the uplink working line A is detected. Knowing that the line between - and ■ has been switched to the protection line P, operate the switch 5 for the uplink protection line and the working line, connect this switch 5, and send the output signal to the uplink working line as shown by the dotted line. Take it out.

If a separate control signal is assigned to each transmission/reception section in this way,
In the case of a line configuration as shown in FIG. 1, eight waves are required. In general, the number of types of control signals is not limited to two as mentioned above (it is necessary to use many more types, so in order to transmit these control signals, it is necessary to install a wideband control signal line and to use multiple types of control signals). A control signal oscillator and control signal detector are required.

This has led to problems such as an increase in the cost of the device and the need to provide a dedicated line for transmitting control signals.

IcI Object of the Invention The present invention has been made in view of the above-mentioned conventional problems, and includes:
The purpose is to provide an inexpensive line switching system that reduces the number of types of control signals.

+d) Structure of the Invention The object of the above invention is that in a line switching section that includes zero or more drop/add stations that perform signal drop/add, the control signal sent from the previous station is transferred to the next drop/add station. This is achieved by providing a line switching system characterized in that the number of M types of control signals used in the line switching section is reduced by determining whether or not to transmit the signal to the station.

(a) Examples of the invention FIG. 3 shows an example of a line configuration for explaining the present invention.

In the figure, ■ to ■ represent the terminal stations, . . . and O represent the transmitter and receiver, respectively, P represents the protection line, and A.

B... indicates the working line, the right arrow line indicates the uplink line, and the left arrow line indicates the downlink line.

One line switching section of the uplink working line A-E is between the terminal stations ■ and ■, and each line switching section has f1 to
Similarly, the line status signal f5 is assigned to the downlink working lines A-E, and the switching command signals f6 to flQ are assigned to the downlink working lines A-E, respectively.

FIGS. 4(a) to 4(d) are examples of block connection diagrams for explaining switching operations when the present invention is implemented using the line configuration shown in FIG. 3.

In the figure, 1 and 5 are switchers, 2 is a transmitter, 3 is a control signal oscillator, 4 is a receiver, and 6 is a control signal detector, respectively.

Therefore, one embodiment of the present invention will be explained with reference to the diagrams shown in FIGS. 4+a) to (C1).

Example 1 In case of failure between terminal station ■ and ■ of uplink working line A (3rd station
Figure a) As described above, the terminal station ■ uses the downlink working line A and the protection line P to send the switching command signal f6 of the uplink working line A to the uplink protection line P to the terminal station ■.

The terminal station ■ detects this command signal f6 with the receivers of the downlink working line A and the protection line, so that the uplink working line A of the terminal station ■ is detected.
Activate the switch 1 of the protection line P and input the input signal of the uplink working line A to the transmitter 2 of the uplink protection line P as indicated by the dotted arrow. Switch.

At this time, the switching command signal f6 detected by the receiver of the terminal station ■ is a switching command between the terminal stations ■ and ■, so the downlink working line A
No transmission is made between the terminal station ■ and ■.

On the other hand, the terminal station ■ is the control signal detector 6 of the receiver 4 connected to the uplink protection line P (capable of receiving all status signals)
Detects the line status signal f1 of the uplink working line A and learns that the terminal station ■-■ of the uplink working line A has been switched to the protection line P, and switches the switch 5 between the uplink working line A and the protection line P. The output signal of the uplink protection line receiver 2 is taken out from the output terminal of the receiver 4 for the uplink working line as indicated by the dotted arrow.

At this time, the line status signal f is not transmitted since it is not relevant to the terminal stations ① and ② and beyond. Therefore, this status signal f can be used at locations other than between the terminal stations (2) and (2) of the uplink working line A.

Example 2 After a failure between the terminal station ■ and ■ to the uplink working line, line C
When there is a failure between terminal station ■ and ■ (Figure 4b), as shown in Example 1, from terminal station ■ to terminal station ■, using down working line A and protection line P, to upstream working line terminal station ■ - (2) A switching command signal f6 for switching to the uplink protection line P is sent out.

On the other hand, the terminal station ■ which detected that a failure has occurred between the terminal station ■ and ■ of the uplink working line C connects the downlink working line A and the protection line P.
A switching command signal f for the uplink working line C to the uplink protection line P is sent to the terminal station (2) using the downlink working line A and the protection line P.

However, since the receiver 4 of the downlink working line A and the protection line P of the terminal station ■ has already sent the switching command signal f6 to the uplink working line to the terminal station ■, it can be said that the protection line is already in use. I understand. Therefore, the switching command signal f8 from the terminal station (2) detected by the terminal station (2) is blocked at the terminal station (2).

Therefore, the terminal station (3) cannot connect the uplink working line C to the -1ni protection line P.

Example 3 Same as special case 1 of failure between terminal station ■ and ■ of uplink working line A and further failure between terminal station ■ and ■ of uplink working line B, terminal station ■ - ■ of uplink working line switches to uplink protection line P It will be done.

However, since the terminal station ■-■ of the protection line P is not used, it is possible to switch to the uplink protection line P between the terminal station ■-■ of the uplink working line B which has failed.

Therefore, the input signal of the working line A is transmitted between the terminal stations 1 and 2 of the uplink protection line P, and the input signal of the working line B is transmitted between the terminal stations 2 and 2 of the uplink protection line P. In this case, since the switching command signal and the line status signal are transmitted only in relevant sections, the same signals can be used in other terminal station sections.

Example 4 When there is a failure between terminal station ■ and ■ of uplink C, and further failure between terminal station ■ and ■ of uplink B (Figure 4 C) Uplink protection line P
Since the signal of the faulty uplink working line C is being transmitted between the terminal stations ■ and ■, it is not possible to switch to the uplink protection line P between the terminal stations ■ and ■ of the uplink working line B.

In other words, the switching command signal f6 is detected and relayed by the downlink working line A and the protection line P at the terminal station ■, or the switching command signal f6 is detected and relayed by the downlink working line A and the protection line P at the terminal station
Since the terminal station ■ knows that the terminal station ■-■ of the uplink protection line P is being used by relaying the line status signals etc., it sends a switching command signal f7 of the uplink working line B to the uplink protection line P. It is impossible to send the data to the terminal station ■.

(f) As described in detail, according to the present invention, the same control signal is used for each line within one line switching section, and each drop/add station transfers the control signal to the next transmission/reception section. By determining whether or not to send a signal to a line, line switching becomes possible even if the types of control signals are reduced.

Therefore, the configuration of the device is simplified and the number of types of control signal oscillators and control signal detectors is reduced, so that the cost of the device is reduced and the efficiency of line usage is improved.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams for explaining the conventional line switching system, Figure 3 is a diagram showing an example of the line configuration for explaining the present invention, and Figure 4 is a diagram for explaining the present invention. Figures for explaining the switching operations are shown below. In the figure, 1 and 5 are switchers, 2 is a transmitter, 3 is a control signal oscillator, 4 is a receiver, and 6 is a control signal detector, respectively. Q However, L

Claims (1)

[Claims] In a line switching section that includes zero or more drop/add stations that drop and add signals, the drop/add station determines whether or not to send the control signal sent from the previous station to the next station. 1. A line switching method characterized by reducing the types of control signals used in the line switching section.