JPH0897907A - Method for selecting private line - Google Patents

Abstract

PURPOSE: To attain the switching so that a new line is used for a control signal line thereby not causing a defect of data or the like in the private line switching method switching an old line into a new line when the new line is provided to the private line. CONSTITUTION: A new line 2 is formed in addition to an old line 1 between a master station to which a terminal equipment 7 connects and a slave station to which a terminal equipment 8 connects, a master station side switch 10 and a slave station side switch 11 are connected among a subscriber line terminal (a), an old line terminal (b) and a new line side terminal (c) on a terminal panel 3 of the master station side and a terminal panel 4 of the slave station side via a clip or the like, a control signal is sent from a control circuit 14 of a changeover controller 12 via the new line 2 and a control circuit 15 of the changeover controller 13 forms a loopback circuit to the new line 2 by the control signal to measure a transmission delay time of the new line 2 and controls the master station side switch 10 and the slave station side switch 11 based on the transmission delay time thereby attaining changeover without causing missing of data or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dedicated line switching method for switching from an old line to a new line so as to prevent loss of data etc. when a new dedicated line is provided. Although the leased line is formed through the switching network, it always maintains the connected state. In such a leased line, it is common to multiplex via a line terminating device corresponding to a terminal type such as a telephone or a data terminal. For such an old line, a line termination device can be shared by various terminals,
In addition, a new line is known in which the degree of multiplicity is increased and the economy and the quality are improved. Therefore, it is necessary to switch from the existing old line to the new line, and there is a demand for an efficient switching method.

[0002]

2. Description of the Related Art FIG. 8 is an explanatory view of a conventional example. M is a master station, S is a slave station, 81 and 81a are old lines, 82 is a new line,
83 and 84 are terminal boards, 85 and 86 are subscriber lines, and 87 and 8
8 is a terminal device, 89 is a transmission network, 90 and 91 are changeover switches, and 92 is a control signal line. In the case of a long-distance leased line, the transmission network 89 includes a plurality of exchanges.

The old lines 81 and 81a as dedicated lines include a line terminating device, a multiplexing device, etc., which are not shown, and the line terminating device in that case is provided corresponding to a terminal type such as a telephone or a data terminal. It is a thing. The new line 82 includes a line terminating device, a cross connect device, etc. that can be shared by various terminals, and may also include a multiplex device having an increased multiplicity. Therefore, the new line can be made smaller and more economical than the old line, and the transmission quality can be improved.

[0004]

The new line is constructed as described above, and then the old line is sequentially switched to the new line. However, the dedicated line is required to be used for 24 hours, which is important. Since the leased line cannot be disconnected, for example, when switching from the old line 81 to the new line 82, the other line is borrowed and used while the old line 81
Subscriber line side terminal a of terminal boards 83, 84 of master station M and slave station S accommodating terminal devices 87, 88 connected via
The new line side terminal c and the new line side terminal c are connected by a jumper line, and the jumper line between the subscriber line side terminal a and the old line side terminal b is disconnected.

However, there is a problem of line borrowing, and the main station M
Since it is necessary to perform the switching work between the slave station and the slave station S at the same time, there is a problem that the workability is extremely poor. Therefore, changeover switches 90 and 91 are provided in the master station M and the slave station S, and the terminal board 8
3, 84 subscriber line side terminals a, old line side terminals b and new line side terminals c via change-over switches 90, 9 via clips or the like.
A method has been proposed in which the old line 81 is switched to the new line 82 by connecting to the No. 1 and communicating the switching timing via the control signal line 92 and the like, and simultaneously operating the changeover switches 90 and 91.

However, there is a problem of newly laying the control signal line 92, which is not practical. It is conceivable to use an empty line in the old line as the control signal line 92. However, in the case of a long-distance dedicated line, the route of the empty line is unknown, so the changeover switches 90, 91 It is impossible to switch the two simultaneously to prevent the loss of data. An object of the present invention is to use a new line to be switched and connected as a control signal line to switch from an old line to a new line so as to prevent data loss.

[0007]

The private line switching method of the present invention will be described with reference to FIG. 1. (1) Main station side connected via an old line 1 and a new line 2 of the private line On the terminal boards 3 and 4 of the master station and the slave station, respectively, a master station switch 10 and a slave station for switching connection of the subscriber line side terminal a to either the old line side terminal b or the new line side terminal c. After connecting the side switch 11, the new line 2 is used as a control signal line to measure the transmission delay time and the switching control signal, and the master station side switch 10 and the slave station side switch 11 are operated simultaneously, This includes the process of switching from the old line 1 to the new line 2.
5 and 6 are subscriber lines, 7 and 8 are terminal devices, 9 is a transmission network,
Reference numerals 12 and 13 denote switching control devices, and 14 and 15 denote control circuits.

(2) In addition, on the terminal boards 3 and 4 of the main station side and the slave station side, which are connected via the old line 1 and the new line 2 of the dedicated line, to the subscriber line side terminal a. , Old line side terminal b
After connecting the master station side switch 10 and the slave station side switch 11 which switch and connect either of the terminal and the new line side terminal c, a control signal is sent from the master station side to the slave station side via the new line 2, According to the control signal, the slave side forms a loopback circuit of the new line,
The master station sends a measurement signal to the new line 2, the slave station loops the measurement signal back by the loopback circuit and sends it out, and then this loopback circuit is restored. After measuring the transmission delay time of the new line 2 based on the above, a switching control signal is sent out via the new line 2, and the main station side sends the switching control signal and at least after the transmission delay time, the main station side switch 10 And the slave station simultaneously operates the master station switch 10 and the slave station switch 1 in accordance with the switching control signal.
1 is operated to switch from the old line 1 to the new line 2.

(3) Also, on the respective terminal boards of the main station side and the plurality of slave station sides which are branched and connected via the old line 1 and the new line 2 of the dedicated line, to the subscriber line side terminals, After connecting the main station side switch and the slave station side switch that switch and connect either the old line side terminal or the new line side terminal, the master station side sends a control signal that sequentially specifies multiple slave station sides to the new line Then, the slave station specified by this control signal forms a loopback circuit of the new line, the master station side sends a measurement signal to the new line, and the slave station side loops back the measurement signal by the loopback circuit. The loopback circuit is restored, and the master station side measures the transmission delay time of the new line between the master station side and the designated slave station side based on the time from the transmission of the measurement signal to the reception, and specifies this transmission delay time. The slave station side is notified via the new line, and the master station side After sending a switching control signal via the new line, the main station sends the switching control signal and sends the switching control signal to the master station at least after the maximum transmission delay time. The switch on the station side is operated, and each slave side operates the switch on the slave station side at least after a time difference between the maximum transmission delay time and the transmission delay time of the own station,
This includes the process of switching from the old line to the new line.

(4) It is possible to detect whether or not the old line is in use, and when the old line is not in use, a switching control signal can be sent from the master station side to the slave station side through the new line.

(5) The busy / unused bit of the data can be monitored to identify whether or not the old line is in use.

(6) Further, the master station side branches the data to be sent to the slave station side through the old line, and the slave station side branches the data received through the old line and returns it to the new line. broth,
The main station side can include a process of checking the old line and the new line to be switched by collating the data branched at the own station with the data received via the new line.

(7) A signal of the same level is sent from the master station side and the slave station side to the old line and the new line, the signal is received through the old line and the new line, and the level is measured. The process may include a step of adjusting the attenuation amount of the attenuator based on the result, performing level correction of the old line and the new line, and then switching between the old line and the new line.

(8) In addition, on the respective terminal boards of the master station side and the slave station side, which are connected via the old line and the new line of the dedicated line,
Connect the main station transmitter switch, master station receiver switch, slave station receiver switch, and slave station transmitter switch that switches and connects either the old line terminal or the new line terminal to the subscriber side terminal. , A is the delay time from the master station switching control unit to the master station transmitting switch and master station receiving switch, and B is the delay time from the switching control unit to the slave station receiving switch and slave station transmitting switch. After sending the switching control signal from the switching control unit on the side to the slave station transmission side switch,
After (B-A) time for the master station transmitting side switch, (B-A) for the master station receiving side switch and the slave station receiving side switch
It is possible to include a process of transmitting after 2A), receiving and detecting the switching control signal and performing the switching operation.

(9) Also, after switching connection from the old line to the new line by the main station side switch and the slave station side switch, a polling signal designating the slave side of the old line is sent from the master station side, and this polling signal is sent. It is possible to include a process of determining that the switching has been completed and transmitting a switching execution completion notice to the slave side when receiving a response signal to the slave station.

[0016]

[Action]

(1) The master station side switch 10 and the slave station side switch 11 are connected to the subscriber line side terminal a, the old line side terminal b and the new line side terminal c of the terminal boards 3 and 4 by clips or the like, respectively.
Master station side switch 10 and slave station side switch 11 in this case
Is switched and connected to the illustrated solid line state, and does not affect the communication between the terminal devices 7 and 8 using the old line 1. For example, the master station side measures the transmission delay time of the new line 2 switched to the old line 1, notifies the slave station side of the transmission delay time, sends a switching control signal from the master station side, and the master station side For example, after transmitting the switching control signal, the master station side switch 10 is operated after a transmission delay time, and the slave station side operates the slave station side switch 11 which receives the switching control signal, whereby the master station side switch 10 and the slave station side switch are operated. 11 and 11 can be switched at the same time.

(2) Further, terminal boards 3 and 4 on the master station side and the slave station side
Subscriber line side terminal a, old line side terminal b and new line side terminal c
The master station side switch 10 and the slave station side switch 11 are connected to each other by a clip or the like. In this state, the main station side switch 1 is provided between the subscriber line side terminal a and the old line side terminal b.
0 and the slave station side switch 11 are connected by the movable contacts 10a and 11a, the subscriber line side terminal a
The jumper wire between the old terminal b and the old terminal b can be disconnected. Then, the control circuit 14 of the switching control device 12 on the master station side sends a control signal to the slave station side via the new line 2. The control circuit 15 of the switching control device 13 on the slave station side forms a loopback circuit of the new line 2 by the control signal received via the new line 2. That is, since the new line 2 has an upstream line and a downstream line as well as the old line 1, a loopback circuit is formed between the upstream line and the downstream line. Then, the master station switching control device 14 sends a measurement signal to the new line 2, the slave station side switching control device 13 sends back the measurement signal via the loop circuit by the control circuit 15, and immediately after that, the loop circuit. Restore. The switching control device 12 on the main station side can easily obtain the transmission delay time because the time from the transmission of the measurement signal to the reception thereof is twice the transmission delay time. In this case, the measured transmission delay time can be notified to the slave station side. Then, the switching control device 12 on the master station side sends a switching control signal to the slave station side via the new line 2.
The slave station side switching control device 13 controls the slave station side switch 11 to perform a switching operation by receiving the switching control signal, and the master station side switching control device 12 transmits the switching control signal before transmission. After the delay time, the main station switch 10 is controlled to perform the switching operation. Therefore, the master station side switch 10 and the slave station side switch 11 can be switched simultaneously in time. In this state, the subscriber side terminal a and the new line side terminal c
Is connected with a jumper wire, and then the clip is removed to remove the master station side switch 10 and the slave station side switch 11.

(3) In the case of a dedicated line in which a plurality of slave stations are branched and connected to the master station by the old circuit 1, a new circuit 2 is used.
Is also formed to have the same configuration as the old line 1. Even in this case, the main station side switch and the slave station side switch are connected to the subscriber line side terminal, the old line side terminal and the new line side terminal of the main station side and a plurality of slave station side terminal boards by clips etc. To do. Then, the master station side designates the slave station to form the loopback circuit of the new line 2 and transmits the measurement signal, and the time from the transmission of the measurement signal to the reception shows a value twice the transmission delay time. It is possible to measure the transmission delay time between the master station side and the slave station side via the new line. This transmission delay time is notified to the slave station side. After measuring the transmission delay time with all the slave stations, the master station side calculates the cumulative value of the transmission delay time and the maximum value among the transmission delay times corresponding to the slave stations, and notifies them to all slave stations. . Then, the switching control signal by the broadcast is transmitted via the new line. The master station sends a switching control signal and operates the master station side switch after the maximum delay time, and the slave station side determines the difference between the transmission delay time and the maximum transmission delay time between the master station side and the local station side. After a certain time, the slave side switch is operated. As a result, the master station side switch and each slave station side switch can simultaneously perform the switching operation.

(4) Whether the old line 1 is in use or not is detected by the carrier, transmission data type, etc., and when not in use, the master station side switch and the slave station side switch are operated as described above. Then, the old line 1 is switched to the new line 2.

(5) Further, in the data transmission by the dedicated line between the terminal devices 7 and 8, whether or not the actual data is transmitted is determined by the used / unused bit (S bit) of the data. Since it is displayed, it is possible to detect whether or not the old line 1 is in use by monitoring this used / unused bit.

(6) In order to determine whether or not there is an error in the correspondence between the old line 1 and the new line 2 in the main station side terminal board 3 and the slave station side terminal board 4, For example, the slave station side branches the data transmitted from the master station side through the old line 1 and sends the data to the master station side through the new line 2.
The main station side collates the data sent to the old line 1 with the data received via the new line 2, and if the collation matches, determines that the old line 1 and the new line 2 are correctly associated.

(7) The terminal devices 7 and 8 are equipped with an AGC amplifier to compensate for fluctuations in the received signal level. However, if the fluctuations are above the allowable fluctuation level, it is considered that the line is abnormal and data is A system for stopping transmission etc. is general. Therefore, from the master station side and the slave station side, old line 1 and new line 2
Signals of the same level are sent to and. The signal in this case is
It can be an out-of-band signal such as data or voice. The master station side and the slave station side compare the signal levels received via the old line 1 and the new line 2 and adjust the attenuation amount of the attenuator so that they are at the same level. In this case, the attenuator is generally connected to the high quality new line 2 side. After the level correction is performed in this way, the old line 1 and the new line 2 are switched by the master station side switch 10 and the slave station side switch 11 so that the AGC amplifiers of the terminal devices 7 and 8 can follow up. After gradually reducing the attenuation amount of the attenuator to zero, the subscriber line side terminal a of the terminal boards 3 and 4 and the new line side terminal c are connected by a jumper wire, and the main station side switch 10 is connected.
And the slave station switch 11 are removed.

(8) Further, the old line 1 and the new line 2 each have an up line and a down line, and the main station side switch is composed of a main station transmitting side switch and a main station receiving side switch, and a slave station side. The switch includes a slave station receiving side switch and a slave station transmitting side switch. Therefore, the timing for transmitting the switching control signal from the switching control unit on the main station side is set to the delay time A, B.
Based on the above, the master station transmitting side switch and the slave station receiving side switch are operated with a time difference corresponding to the transmission delay time, and similarly, the slave station transmitting side switch and the master station receiving side switch correspond to the transmission delay time. The old line is switched to the new line so that the data will not be lost by operating at the specified time difference.

(9) Further, after the switching operation by the master station side switch and the slave station side switch is performed, a polling signal designating the slave station side is transmitted from the master station side through the old line and designated by this polling signal. Since the slave station responds via the old line, the master station determines from the slave station's response signal to the polling signal via the old line that switching has been completed, and notifies the slave station of completion of switching execution. Send out. Upon receiving the switching execution completion notification, the slave station side connects the subscriber line side terminal a and the new line side terminal c of the terminal board by a jumper wire, and removes the slave station side switch.

[0025]

1 is an explanatory view of a first embodiment of the present invention, in which 1 is an old line, 2 is a new line, 3 and 4 are terminal boards, and 5 and 6.
Is a subscriber line, 7 and 8 are terminal devices, 9 is a transmission network, 10 is a master station side switch, 11 is a slave station side switch, 12 and 13 are switching control devices, 14 and 15 are control circuits, and 10a and 11a are movable. Contacts 10b, 10c, 11b, 11c are fixed contacts, a is a subscriber line side terminal, b is an old line side terminal, c is a new line side terminal, and the master station side and the slave station side are connected by a dedicated line. It shows the case.

As in the conventional example, the old line 1 and the new line 2 have the line terminating device corresponding to the terminal type such as the telephone and the data terminal, but the new line 2 is shared for the terminal type. It has a line terminating device provided therein and has a large multiplicity in the transmission network 9. The master station side switch 10 and the slave station side switch 11 can be configured by a relay, a semiconductor switch or the like.
The switching operation is controlled by 2 and 13.

First, the subscriber line side terminal a, the old line side terminal b and the new line side terminal c of the main station side and slave station side terminal boards 3 and 4 are connected to the master station side switch 10 and the slave station side switch 11, respectively. Movable contacts 10a, 11a and fixed contacts 10b, 10c, 11
b and 11c are connected by a cable as shown by a dotted line.
In this case, the subscriber line side terminal a, the old line side terminal b, and the new line side terminal c can be held in contact with each other by being sandwiched by a clip or the like. The movable contacts 10a and 11a are switch-connected to the positions shown by the solid lines.

Therefore, the master station side switch 10 and the slave station side switch 11 are in a state where the subscriber line side terminal a and the old line side terminal b of the terminal boards 3 and 4 are connected by the movable contacts 10a and 11a. Therefore, even if the jumper wire between the subscriber line side terminal a and the old line side terminal b is removed, the communication between the terminal devices 7 and 8 can be continued. The jumper wire can be removed immediately before the main station switch 10 and the slave station switch 11 are switched.

Next, a control signal is transmitted from the control circuit 14 of the switching control device 12 on the main station side via the new line 2. When the control circuit 15 of the switching control device 13 on the slave side receives and detects the control signal via the new line 2, the function of the control circuit 15 forms a loopback circuit that loops the uplink and downlink of the new line 2. To do. Next, the measurement signal is transmitted from the control circuit 14 on the main station side via the new line 2. The control circuit 15 on the slave station side folds back the measurement signal by the loopback circuit and sends it to the new line 2, and detects the measurement signal to restore the loopback circuit.

The control circuit 14 on the main station side detects the returned measurement signal and obtains the transmission delay time of the new line 2 based on the time from the transmission to the reception of the measurement signal. Examples of the measuring means in this case include a means for measuring the difference between the sending time and the receiving time of the measurement signal, a counter for counting the clock signal by sending the measurement signal, and stopping the counting by receiving the measurement signal. A means for measuring based on the count number at that time can be applied. After the measurement of the transmission delay time, the switching control signal is sent out via the new line 2. The control circuit 15 on the slave station side controls the slave side switch 11 immediately after detecting the switching control signal or after a preset time, to move the movable contact 11a to the fixed contact 11c.
Switch connection to. Further, the control circuit 14 on the main station side controls the main station side switch 10 after the transmission delay time has elapsed after the switching control signal was sent or after the sum of the preset time and the transmission delay time, The movable contact 10a is fixed to the fixed contact 1
Switch connection to 0c.

At this time, the master station side switch 10 and the slave station side switch 11 are simultaneously switched, and the old line 1
Can be switched to the new line 2. In this state,
Since the subscriber line side terminal a and the new line side terminal c of the terminal boards 3 and 4 are connected by the movable contacts 10a and 11a, the subscriber line side terminal a and the new line side terminal c are connected. Can be connected with jumper wires. Thereafter, the connection work of the old line 1 to the new line 2 is completed by removing the connection state of the dotted line by the clip or the like.

FIG. 2 is an explanatory view of the switching sequence of the first embodiment of the present invention. As shown in FIG. 1, the main station side switch 10 and the slave station side switch 11 are connected to the terminal boards 3 and 4. In the control circuit 1 of the switching control device 12 on the main station side
The control signal (a) is transmitted from 4 through the new line 2. As described above, the control circuit 15 of the switching control device 13 on the slave side forms a loopback circuit that detects this control signal and performs loopback connection between the uplink and downlink of the new line 2. The control signal in this case can adopt various signal formats such as a switching start signal and a loopback circuit formation command.

Next, from the control circuit 14 on the main station side to the new line 2
The measurement signal (b) is transmitted via the. The control circuit 15 on the slave station side returns the measurement signal (b) by folding it back by the folding circuit and detecting the measurement signal to restore the folding circuit. The control circuit 14 on the main station side receives the loopback measurement signal (c) via the new line 2 and obtains the time T1 from transmission to reception. This time T1 has a value twice the transmission delay time of the new line 2. Time T in this case
As the measuring unit of No. 1, various known units such as a timer and a counter can be applied. Further, the transmission delay time can be calculated not only as an absolute time but also as a relative time such as a count value of a counter. The measurement signal can be a single pulse, but a coded pulse signal or the like can also be used.

Next, it is possible to omit the transmission delay time notification sequence and send the switching control signal, but in order to make the sequence the same as when a plurality of slave stations are connected, the control of the master station side is performed. From the circuit 12 to the slave station via the new line 2, the notification (d) of the measurement time T1 and the maximum measurement time Tma
Notification of x (e) and notification of cumulative value ΣT of measurement time (f)
And do. In this case, since there is one slave station side with respect to the master station side, T1 = Tmax = ΣT. In this case, the transmission delay time T1 / 2 is used to notify the transmission delay time (d).
The notification of the maximum transmission delay time (e) and the notification of the cumulative value of the transmission delay time (f) can also be performed. Further, the control circuit 15 on the slave station side sets a timer (not shown) based on the notification received through the new line 2.

Next, from the control circuit 14 on the main station side to the new line 2
The switching control signal (g) is transmitted via the. At the same time as the transmission of the switching control signal (g), the control circuit 14 on the master station side sets a sum of a fixed time X1 and the transmission delay time T1 / 2 of the new line 2 in a timer (not shown), and Side control circuit 1
5 detects the reception of the switching control signal (g) via the new line 2 and sets a fixed time X1 in the timer.

The master station side switch 10 comprises a master station transmitting side switch 4WS and a master station receiving side switch 4WR, and the slave station side switch 11 also comprises a slave station transmitting side switch 4WS and a slave station receiving side switch 4WR. Control circuit 14
Is the main station transmission side switch 4 after time X1 + (T1 / 2)
The WS switching operation is performed. Also, the control circuit 15 on the slave side
Causes the slave station transmission side switch 4WS to perform the switching operation after the lapse of time X1. Therefore, the master station transmission side switch 4WS and the slave station transmission side switch 4WS are simultaneously switched. Then, both the master station side and the slave station side use timers for time T1 /
Set 2. After this time T1 / 2 has elapsed, the master station receiving side switch 4WR and the slave station receiving side switch 4WR are simultaneously switched.

Therefore, the data sent to the new line 2 by the switching of the master station transmitting side switch 4WS arrives at the slave station receiving side switch 4WR after the transmission delay time T1 / 2, and at that time, the slave station receiving side switch 4WR is switched. Therefore, the old line 1 is switched to the new line 2 without loss of data. Similarly, the data sent to the new line 2 by the switching of the slave station transmission side switch 4WS is the master station reception side switch 4W after the transmission delay time T1 / 2.
Upon arrival at R, the main station side reception switch 4WR is switched at that time, and the old line 1 is switched to the new line 2 without causing data loss.

Next, a certain time X2 is set in the timers of the control circuit 14 on the master station side and the control circuit 15 on the slave station side.
After the lapse of this time X2, the control circuit 14 on the main station side sends the polling signal (h) to the old line 1 and sets the time T2 in the timer. Further, the control circuit 15 on the slave station side has a time X2.
After the lapse of time, the time T2 is set. At the time of sending the polling signal (h), the old line 1 is in a state of being disconnected from the terminal devices 7 and 8, and the old line 1 is connected to the terminal devices 7 and 8 via the new line 2.
Since the communication between them is continued, an arbitrary signal can be transmitted to the old line 1.

Upon receiving and detecting the polling signal (h) through the old line 1, the slave side control circuit 15 clears the timer for which the time T2 is set, and outputs the response signal (i) as the old line 1.
Send to. This response signal (i) is sent to the control circuit 1 on the main station side.
When 4 detects the reception, it clears the timer and sends the switching completion notification (j) to the slave station side via the old line 1. The slave station side connects the subscriber line side terminal a and the new line side terminal c of the terminal board 4 with a jumper wire by this switching completion notification (j), and removes the cable of the dotted line path by a clip or the like.
The slave station switch 11 is disconnected. Also on the main station side, similarly, the subscriber line side terminal a of the terminal board 3 and the new line side terminal c are connected by a jumper wire, the cable of the dotted line route by a clip or the like is removed, and the main station side The switch 11 is disconnected.

FIG. 3 is an explanatory view of the second embodiment of the present invention, showing a case of a dedicated line in which two slave stations are connected to the master station, and the same reference numerals as those in FIG. 1 denote the same parts. In the figure, 24 is a terminal board of an exchange for branch connection, 26 is a subscriber line, 28 is a terminal device, 31 is a slave side switch, 33 is a switching control device, and 35 is a control circuit. In this case, the dedicated line for branch connection has a branch structure in which data and the like are transmitted from the master station side to each slave station side and communication is not possible between each slave station side.

When switching from the old line 1 to the new line 2, the subscriber line side terminal a, the old line side terminal b, and the new line side terminal c of the terminal boards 3, 4, 24 are switched in the same manner as in the above-described embodiment. The main station side switch 10 and the slave station side switches 11 and 31 are connected to each other by a cable of a dotted line path by a clip or the like. At that time, the master station side switch 10 and the slave station side switches 11, 31
Is switched and connected to the state shown by the solid line, and the subscriber line side terminal a
And the old line side terminal b are connected. Therefore, after this state is set, the jumper wire connecting between the subscriber line side terminal a and the old line side terminal b of the terminal boards 3, 4, 24 is removed. To remove the jumper wire in this case, as described above, the master station side switch 10 and the slave station side switch 11,
It can also be performed immediately before the switching operation of 31.

Next, a control signal designating the terminal device 28 is transmitted from the control circuit 14 of the switching control device 12 on the main station side via the new line 2. The control circuit 35 of the switching control device 33 on the slave side identifies that the control signal via the new line 2 designates the terminal device 28, and the function of the control circuit 35 causes the up line and the down line of the new line 2. Form a loopback circuit that loops back and connects. Further, the control circuit 15 on the side of the terminal device 8
Does not form a loopback circuit because it is not a control signal designating the terminal device 8.

The control circuit 14 on the main station side transmits a measurement signal via the new line 2. The control circuit 35 on the slave station side folds back this measurement signal by the loopback circuit and sends it to the new line 2, and detects this measurement signal to restore the loopback circuit. Further, the control circuit 14 on the master station side determines the transmission delay time of the new line 2 from the master station side to the slave station side to which the terminal device 28 is connected, based on the time from the transmission of the measurement signal to the reception thereof. Then, the transmission delay time is notified to the control circuit 35.

Next, similarly to the above, the control circuit 1 on the main station side
4 sends a control signal designating the terminal device 8 via the new line 2, causes the control circuit 15 on the slave station side to form a loopback circuit, and then sends a measurement signal to send the measurement signal to the master station side and the terminal device 8. Calculate the transmission delay time of the new line 2 with the connected slave side,
This transmission delay time is notified to the control circuit 15.

After obtaining the transmission delay time of the new line 2 between the master station side and each slave station side in the control circuit 14 of the master station side, the maximum transmission delay time and the accumulated value of the transmission delay times are obtained. And are notified to each slave station side via the new line 2 by broadcast communication. After that, the switching control signal is transmitted via the new line 2. Upon receiving and detecting the switching control signal, the control circuits 15 and 35 on the slave station side switch the slave station side switch when the difference between the transmission delay time and the maximum delay time between the master station side and the self station side elapses. By controlling 11 and 31 to switch and connect the old line 1 to the new line 2, the control circuit 14 on the main station side controls the switch 10 on the main station side when the maximum transmission delay time has elapsed, Switch connection from 1 to new line 2.

FIGS. 4 and 5 are explanatory views of the switching sequence of the second embodiment of the present invention, in which the master station side M and the first, second and third slave station sides S1, S2 and S3 are dedicated lines. As shown in FIG. 3, the main station side switch a is connected to the subscriber line side terminal a, the old line side terminal b, and the new line side terminal c of the main station side and each slave station side terminal board. 10 and the slave side switch 11,
31 and the switching control devices 12, 13 and 33 are connected respectively.

The master station side M sends a control signal (a1) designating the slave station side S1 to the new line, for example, and the control circuit of the slave station side S1 forms a loopback circuit for the new line. next,
The measurement signal (b1) is transmitted from the master station side M via the new line. After returning the measurement signal (b1) by the loopback circuit on the slave side S1, the loopback circuit is restored. Main station side M
Then, the return measurement signal (c1) is received, the time t1 is measured, and the time t1 information (d1) is notified to the slave station side S1 via the new line.

Next, another slave station side, for example, S2 is designated and a control signal (a2) is sent to the new line, a loopback circuit is formed on the slave station side S2, and then a measurement signal (b2) is sent to the new line. After sending and sending back by the loopback circuit, the loopback circuit is restored. The master station side M receives the loopback measurement signal (c2), measures the time t2, and notifies this time t2 information (d2) to the slave station side S2 via the new line. Similarly, the control signal (a3) is transmitted to the other slave station side S3 to form a loopback circuit, and then the measurement signal (b3) is transmitted and the loopback measurement signal (c3) is received. The time t3 is measured, and the time t3 information (d3) is notified to the slave station S3 via the new line.

The control circuit on the master station side M measures the measurement time t1,
The maximum measurement time tmax in t2 and t3 and the cumulative value Σti of the measurement time are obtained and notified to each slave station side S1, S2, S3 by broadcast communication via the new line (e), (f). .

Next, the control circuit on the master station side M sends out the switching control signal (g) by the broadcast communication via the new line. Each slave station side has a predetermined fixed time X1, a transmission delay time ti / 2 notified to itself, and a maximum transmission delay time tmax.
/ 2, the switching operation of the master station transmission side switch and the slave station transmission side switch 4WS is performed, and then, after the transmission delay time ti / 2 of the own station, the switching operation of the slave station reception side switch is performed, The main station receiving side switch has the maximum transmission delay time tma.
The switching operation is performed after x / 2.

For example, on the slave side S1, when the switching control signal (g) is received and detected, X1 + (tmax-t
After 1) / 2 has elapsed, the slave station transmission side switch 4WS is caused to perform the switching operation, and after t1 / 2 has elapsed, the slave station reception side switch 4WR is switched. Further, when the measurement time t3 of the slave station side S3 is the maximum, when the switching control signal (g) is received and detected, X1 + (tmax-t3) / 2 = X1 is established.
Will be switched. The above operation switches the old line to the new line.

Next, after performing the switching operation of the master station receiving side switch 4WR and each slave station receiving side switch 4WR, each slave station side S1, S2, S3 uses a timer for monitoring a polling signal after a predetermined time X2 has elapsed. Is set to Σti + ΣX3. Note that X3 is a fixed time. On the master station side M, after a lapse of a certain time X2, the slave station side S1 passes through the old line.
Is specified, the polling signal (h1) is sent, t1 + X3 is set in the timer, it is monitored whether the response signal (i1) can be received within the timer setting time, and this response signal (i1) is received. Sometimes, clear that timer. Also, the timer for monitoring the polling signal on the slave side S1 is cleared.

Next, the master station side M sets the timer to t2 + X3 and the polling signal (h2) designating the slave station side S2.
Is sent through the old line. The slave station side S2 detects this, sends a response signal (i2), and clears the polling signal monitoring timer. The master station side M receives this response signal (i
2) is received and the timer is cleared.

Next, the master station M sets the timer to t3 + X3 and the polling signal (h3) specifying the slave station S3.
Is sent via the old line, and the slave side S2 sends a response signal (i
3) is sent and the timer for monitoring the polling signal is cleared. The master station M receives this response signal (i3) and clears the timer. When the response signal to the polling signal sent to each slave station can be received, the switching completion notice (j) is sent to each slave station by broadcast communication via the old line. By the above-mentioned operation, the switching between the old line and the new line of the dedicated line between the master station M and the plurality of branch-connected slave stations S1, S2, S3 is performed so as not to cause data loss. It can be executed on the transmitting / receiving side in consideration of the transmission delay time.

FIG. 6 is an explanatory view of the essential parts of the third embodiment of the present invention. The same reference numerals as those in FIG. 1 indicate the same parts, 51 is an S-bit detecting section, 52 is a level measuring section, and 53 is an attenuator. , 7a
Indicates an AGC amplifier of the terminal device. The configuration on the master station side for switching from the old line 1 to the new line 2 is shown, but the slave station side also has a similar configuration.

When switching from the old line 1 to the new line 2, it is preferable to switch when the old line 1 is not transmitting data or the like, that is, when the dedicated line is not used. Therefore, the transmission format is performed and the S bit at the end of the 8-bit configuration is monitored to determine whether or not the old line 1 is in use.
The S bit is, for example, "1" when the line is used and "0" when the line is not used. Therefore, the S bit detection unit 51 is connected to the old line side terminal b of the terminal board 3, and the S bit transmitted through the old line 1 is monitored. When "0" continues, the old line 1 of the leased line Is not in use, the switching control signal in each of the above-mentioned embodiments is sent from the master station side to the slave station side via the new line 2.

Therefore, it is possible to switch from the old line 1 to the new line 2 in a short time without affecting the communication between the terminal devices. The old line 1 may be used / unused by carrier detection, for example.

The terminal device 7 is generally provided with an AGC amplifier 7a and automatically controls the amplification factor by following the fluctuation of the received signal level within a certain allowable range. If the level fluctuation when switching from the old line 1 to the new line 2 exceeds the allowable range, the same process as the line disconnection is performed, and smooth switching cannot be performed. Therefore, the level measurement unit 52 measures the received signal levels of the old line 1 and the new line 2.
And controls the attenuator 53. Since the quality of the new line 2 is generally better than that of the old line 1, the attenuator 53 is connected to the new line 2 side, but if the new line 2 is of poorer quality. Would connect a variable gain amplifier instead of the attenuator 53.

Signals of the same level are sent to the old line 1 and the new line 2 from, for example, the slave station (not shown). In this case, if the old line 1 is in use, an out-of-band signal can be sent to the old line 1 and the new line 2, and the level measuring unit 52 extracts the signal component with a bandpass filter or the like, Measure the level. The attenuator 53 is controlled so that the received signal levels of the old line 1 and the new line 2 are input to the main station side switch 10 at the same level or a level difference within an allowable range in which the AGC amplifier 7a can follow.

After adjusting the slave station side in this state in the same manner as the master station side, as described above, the switching operation of the master station side switch 10 and the slave station side switch is performed by the switching control signal, and the old line 1 is operated. Switch connection to new line 2. The AGC amplifier 7a of the terminal device 7 due to the switching can amplify the signal through the new line 2 to a predetermined level because the level fluctuation is zero or within an allowable range that can be followed.

Next, the attenuation amount of the attenuator 53 is gradually decreased to zero so that the AGC amplifier 7a can perform follow-up control, and in that state, the subscriber line side terminal a and the new line side terminal of the terminal board 3 are brought. The cable shown in dotted line is to be removed by connecting a jumper wire to the cable c.

FIG. 7 is an explanatory view of the fourth embodiment of the present invention. 1a and 1b are old lines, 2a and 2b are new lines, 61,
62 is an old line transmission device, 63 and 64 are new line transmission devices, 65 is a master station transmission side switch, 66 is a main station reception side switch, 67 is a slave station transmission side switch, 68 is a slave station reception side switch, 69, 70 is a terminal device, 71 is a switching control unit, 7
Reference numeral 2 is a control signal line, and this control signal line 72 uses a new line as in the above-described embodiment, and is shown separately for convenience of explanation. In addition, the transmission devices 61 and 6 of the old line
As described above, the reference numeral 2 includes a line terminating device and a multiplexer corresponding to the terminal type, and the transmission devices 63 and 64 of the new line are a line terminating device shared by the terminal type and a multiplexer having a large multiplicity. Etc. are included.

Further, as in the above-mentioned embodiment, the main station transmitting side switch 65 is connected to the subscriber line side terminal a1, the old line side terminal b1 and the new line side terminal c1 of the main station side terminal board to join. The master station receiving side switch 66 is connected to the main line side terminal a2, the old line side terminal b2, and the new line side terminal c2, and similarly, the subscriber line side terminal a3 and the old line side terminal b3 of the slave station side terminal board. And the new line side terminal c3 are connected to the slave reception side switch 68, and the subscriber line side terminal a4, the old line side terminal b4 and the new line side terminal c4 are connected.
And the slave station transmission side switch 67. At this point, the subscriber line side terminals a1, a2, a3, a4 and the old line side terminals b1, b2, b3, b4 are connected by jumper wires.

In this state, as in the above-described embodiment, the loopback circuit of the new lines 2a and 2b is formed on the slave station side, and the measurement signal is sent from the master station side to measure the transmission delay time. The delay time between the switching control unit 71 and the master station transmitting side switch 65 and the master station receiving side switch 66 obtained by the above is A, and between the switching control unit 71 and the slave station transmitting side switch 67 and the slave station receiving side switch 68. Is B, the delay time of the control signal line 72 by the new lines 2a and 2b between the master station transmission side switch 65 and the slave station reception side switch 68 is (BA). Also, before sending the switching control signal, the jumper wire on the terminal board is removed.

The timing at which the switching control signal is sent from the switching control unit 71 is set as the following condition. That is, after a delay time of 0 for the slave station transmitting side switch 67 and a (BA) delay time for the master station transmitting side switch 65, the master station receiving side switch 66 and the slave station receiving side switch 68 are connected. , The switching control signal is transmitted after a delay time of (B-2A).

Therefore, the slave station transmission side switch 67 performs the switching operation by receiving and detecting the switching control signal after the delay time B after transmitting the switching control signal, and the master station transmission side switch 65,
Since the switching control signal transmitted after the delay time of (B-A) is received and detected after the delay time A and the switching operation is performed, the switching operation is performed after the delay time B similarly to the slave station transmission side switch 67.

Further, the slave station receiving side switch 68 is set to (B-2
Since the switching control signal sent after the time A) is received and detected after the delay time B, the switching operation is performed after the time (2B-2A), and the main station receiving side switch 66 is operated after the time (B-2A). Since the switching control signal sent out is received and detected,
The switching operation will be performed after (BA) time, and
The signal later switched by the slave station transmission side switch 67 and transmitted to the new line 2b arrives at the main station side after (B-A), and at that time, the main station reception side switch 66 causes the old line 1b.
Has been switched to the new line 2b and transferred to the terminal device 69.

Similarly, the signal switched to the new line 2a by the main station transmitting side switch 65 after the time (B-A) is sent after the (B-A) time, that is, the switching control signal is sent. (2B-2A) after arriving at the slave station side, the slave station receiving side switch 68 has been switched from the old line 1a to the new line 2a at that time, and is transferred to the terminal device 70.

As described above, the master station transmitting side switch 65 and the slave station receiving side switch 68 are switched with a time difference corresponding to the transmission delay time so as to prevent data loss from the old line 1a to the new line 2a. Similarly, the slave station transmitter side switch 67 and the master station receiver side switch 66 are switched with a time difference corresponding to the transmission delay time so that no data loss occurs from the old line 1b to the new line 2b. Can be switched and connected. To perform such a switching operation,
After the confirmation by the polling signal, the subscriber line side terminals a1 and a2 and the new line side terminal c1 of the main station side terminal board are confirmed.
A switch is connected to c2 with a jumper wire, a subscriber line side terminals a3 and a4 of the slave side terminal board and new line side terminals c3 and c4 are connected with a jumper wire, and the switches 65 to 68 are removed. .

[0070]

As described above, according to the present invention, when the old line 1 and the new line 2 of the dedicated line are switched, the terminal boards 3, 4 are used.
Subscriber line side terminal a, old line side terminal b and new line side terminal c
The master station side switch 10 is connected to the slave station side switch 11, the transmission delay time of the new line 2 is measured, and the new line 2 is used as a control signal line. Therefore, the master station side switch 10 and the slave station side switch 11 are controlled based on the transmission delay time of the new line 2 without newly laying a control signal line. There is an advantage that the data can be switched without any loss of data. Also in the case of a dedicated line including a plurality of slave stations branched and connected to the master station side, similarly, the transmission delay time of the new line 2 is measured, and the master station side is measured based on the transmission delay time. Switching control between the switch and the slave side switch can be performed.

It is also possible to detect whether the old line 1 is in use and perform the above-mentioned switching control when it is not in use, and there is a large difference in transmission quality between the old line 1 and the new line 2. In this case, it is possible to adjust the attenuation amount of the attenuator according to the reception level difference, avoid a sudden change in the reception level when switching from the old line 1 to the new line 2, and perform stable switching. Further, after the switching control is performed, it is possible to confirm the completion of switching by the polling signal using the old line 1. Therefore, there is an advantage that it is possible to switch the old line from the old line to the new line with high reliability. is there.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a switching sequence according to the first embodiment of this invention.

FIG. 3 is an explanatory diagram of a second embodiment of the present invention.

FIG. 4 is an explanatory diagram of a switching sequence according to a second embodiment of this invention.

FIG. 5 is an explanatory diagram of a switching sequence according to a second embodiment of this invention.

FIG. 6 is an explanatory view of a main part of a third embodiment of the present invention.

FIG. 7 is an explanatory diagram of a fourth embodiment of the present invention.

FIG. 8 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 1 Old line 2 New line 3,4 Terminal board 5,6 Subscriber line 7,8 Terminal device 9 Transmission network 10 Main station side switch 11 Slave station side switch 12,13 Switching control device 14,15 Control circuit a Subscriber line side Terminal b Old line side terminal c New line side terminal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Handa 1-17-3 Sakado, Takatsu-ku, Kawasaki City, Kanagawa Prefecture Fuji Denso Co., Ltd. No. 3 in Fuji Denso Co., Ltd. (72) Inventor Tomohide Morita 1-17-3 Sakado, Takatsu-ku, Kawasaki City, Kanagawa Prefecture No. 3 in Fuji Denso Co., Ltd. (72) Inventor Kota Ishikawa 1-17, Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa Prefecture No. 3 in Fuji Denso Co., Ltd. (72) Inventor Takanori Hashimoto 1-37-1 Sakado, Takatsu-ku, Kawasaki City, Kanagawa Prefecture In Fuji Encouso Co., Ltd. (72) Inventor Shunichi Nakayama 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Within Fujitsu Limited

Claims (9)

[Claims] 1. An old line side terminal and a new line for a subscriber line side terminal on each of the main station side and slave station side terminal boards connected via an old line and a new line of a dedicated line. After connecting the main station side switch and the slave station side switch for switching connection of any of the side terminals, the transmission delay time is measured and the switching control signal is transmitted by using the new line as a control signal line, and the main station side is connected. A leased line switching method comprising the step of simultaneously operating a switch and the slave side switch to switch from the old line to the new line. 2. The old line side terminal and the new line to the subscriber line side terminal on the respective terminal boards of the main station side and the slave station side connected via the old line and the new line of the dedicated line. After connecting the main station side switch and the slave station side switch for switching connection of any of the side terminals, a control signal is sent from the master station side to the slave station side through the new line, and the control signal is transmitted in accordance with the control signal. The slave side forms a loopback circuit for the new line, the master station side sends a measurement signal to the new line, and the slave station side loops back the measurement signal by the loopback circuit and then restores the loopback circuit. Then, the main station side, after measuring the transmission delay time of the new line based on the time from the transmission of the measurement signal to the reception, sends a switching control signal through the new line, the main station side, , At least after transmission of the switching control signal and after the transmission delay time To operate the main station side switch,
Also, the slave station side includes a step of operating the slave station side switch simultaneously with the master station side switch in accordance with the switching control signal to switch from the old line to the new line. . 3. The old line side terminal, with respect to the subscriber line side terminal, on each terminal board of the main station side and the plurality of slave station sides that are branched and connected via the old line and the new line of the dedicated line. After connecting the master station side switch and the slave station side switch that switch and connect either of the new line side terminal and the new line side terminal, the master station side sends a control signal sequentially designating the plurality of slave station sides to the new line. , The slave station designated by the control signal forms a loopback circuit of the new line, the master station side sends a measurement signal to the new line, and the slave station side loops back the measurement signal by the loopback circuit. After sending, the loopback circuit is restored, and the master station side, based on the time from the sending of the measurement signal to the reception, the transmission delay time of the new line between the master station side and the designated slave station side. Of the transmission delay time to the designated slave station Via the new line, the master station side notifies the slave station side through the new line of the accumulated value and the maximum value of the transmission delay time, and then sends the switching control signal through the new line. The master station side sends the switching control signal to operate the master station side switch after at least the maximum transmission delay time, and each slave station side has at least the maximum transmission delay time and A leased line switching method comprising a step of operating the slave station side switch to switch from the old line to the new line after a time difference from the transmission delay time of the station. 4. The switching control signal is transmitted from the master station side to the slave station side via the new line when it is detected whether the old line is in use or not. The dedicated line switching method according to claim 1, 2, or 3. 5. The leased line switching method according to claim 4, wherein a busy / unused bit of data is monitored to detect whether or not the old line is in use. 6. The master station side branches data to be transmitted to the slave station side via the old line, and the slave station side,
The data received via the old line is branched and sent back to the new line, and the main station side compares the data branched at its own station with the data received via the new line,
4. The leased line switching method according to claim 1, further comprising a step of confirming the old line and the new line to be switched. 7. The level measurement is performed by transmitting a signal of the same level from the master station side and the slave station side to the old line and the new line, and receiving the signal through the old line and the new line. And performing a level correction between the old line and the new line by adjusting the attenuation amount of the attenuator based on the level measurement result, and then switching between the old line and the new line. The dedicated line switching method according to claim 1, 2, or 3. 8. An old line for a subscriber line side terminal on each terminal board of the master station side and the slave station side connected via the old line of the leased line and the new line. Side switch and new line side terminal to switch and connect the main station transmitter switch, master station receiver switch, slave station receiver switch and slave station transmitter switch, and from the master station side switching control unit A delay time between the master station transmitting side switch and the master station receiving side switch is A, and a delay time from the switching control section to the slave station receiving side switch and the slave station transmitting side switch via the new line is B, After the switching control signal from the switching control unit on the master station side is sent to the slave station transmission side switch, the master station reception is performed after (B-A) time to the master station transmission side switch. Side switch and the slave station receiving side switch 4. The leased line switching method according to claim 1, further comprising the step of transmitting after the time (B-2A), receiving and detecting the switching control signal and performing a switching operation. 9. The master station side switch and the slave station side switch perform switching connection from the old line to the new line, and then send a polling signal designating the slave station side to the old line from the master station side. 9. When the response signal to the polling signal is received, it is determined that the switching execution is completed, and a step of sending a switching execution completion notification to the slave station side is included. The dedicated line switching method described.