JPH0310250B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention provides a method for converting multiple communication routes from existing lines to new lines without affecting the communication on the existing lines to be switched during communication line switching work. The present invention relates to a multi-to-continuous switching system for communication lines that performs switching between communication lines and monitoring the plurality of communication routes.

Conventional configuration and its problems In conventional fiber switching, it is necessary to confirm that the existing fiber to be switched is not in communication, and then disconnect the existing fiber and connect the existing fiber and the new fiber. A first means for connecting the new core wire to the existing core wire, and a second means for cutting the existing core wire after both core wires are electrically connected.
There are means to do so.

Since the first means cannot be applied to the fibers that are in communication, it is impossible to switch the fibers until the communication of the existing fibers ends. When communication starts during work,
The communication is interrupted.

Further, the second means is such that the level of the transmission signal fluctuates at a moment when the existing core wire and the newly installed core wire are electrically connected, and the balance of the communication line including the existing core wire is deteriorated. Becomes more susceptible to noise. If the communication line is a telephone line, it is possible to continue communication even if the level of the voice signal changes momentarily or even if there is some noise. However, if the communication line is a data line, instantaneous level fluctuations or noise can cause communication to be interrupted.

For this reason, when the communication line to be switched is a data line, the work standard stipulates that communication should be stopped, then the switch should be carried out, and the state of the communication line after the switch should be monitored.

However, in recent years, the number of data lines has increased and communication lines have become increasingly digital, making it difficult to carry out switching work using conventional fiber switching techniques.

Further, the first and second means are both
Since switching was performed for each core, there was a problem of poor work efficiency.

By the way, as a prior art, in order to switch the communication route from the existing line to the new line without affecting the communication on the existing line, and to confirm that the switch has been reliably carried out, there is a method before, during and after the switch. A communication line switching device capable of monitoring the route has been proposed in Japanese Patent Application No. 58-37011 (referred to as the first prior invention) and Japanese Patent Application No. 58-37012 (referred to as the second prior invention).

The patent application No. 58-37011 is shown in Figure 1.

In the figure, Mc1 is the first switching circuit, Mc2 is the second switching circuit, RT1 and RT1' are the first and second resistance conversion sections, RT2 and RT2' are the third and fourth resistance conversion sections, and Rv is the signal receiving section, Oc is the signal transmitting section,
CT1 is the first control unit, CR2 is the second control unit, S is the transmitter, R is the receiver, T1, T2, T3 are the first T
1', T2', T3' are terminals provided in the second resistance conversion section, T4, T5, T6 are terminals provided in the third resistance converter, T4',
T5' and T6' indicate terminals provided in the fourth resistance conversion section.

The communication line switching device K of the first prior invention is the first,
It consists of second switching circuits Mc1 and Mc2, and the first switching circuit Mc1 connects the first and second resistance converters RT1,
RT1', first control unit CT1, signal reception unit Rv and transmission unit S, second switching circuit Mc2 connects third and fourth resistance conversion units RT2, RT2', second control unit CT
2. Consists of a signal transmitter Oc and a receiver R,
The first circuit control unit is configured by the first control unit CT1 and the transmitter S,
A second circuit control unit with the second control unit CT2 and the receiver R;
Configure.

Ci (i = 1 to 6) is a conductive clip that has the function of establishing electrical continuity between the existing line Po or the new line P _N and the first and second switching circuits Mc1 and Mc2. The terminals T1 to T6 (T1' to T6') of the first (second) resistance conversion section RT1 (RT1') and the third (fourth) resistance conversion section RT2 (RT2') are connected by the code Hc that provides continuity. It is connected to the. 1st, 2nd, 3rd and 4th resistance converter RT
1, RT1' and RT2, RT2' are composed of mechanical contacts and a group of resistors, and the resistance value between the terminals of each resistance converting section changes over time.

The operation of the communication line switching device according to the prior art invention of the first application is almost the same as the operation of the present invention, so a description thereof will be omitted in the present invention.

The prior art inventions of the first and second prior applications had the drawback that they could not be automatically switched.

OBJECTS OF THE INVENTION It is an object of the present invention to eliminate the drawbacks of the prior invention, to automatically switch communication lines, and to improve workability and reliability.

Structure of the Invention The present invention provides a first switching circuit and a second switching circuit, and connects both switching circuits with an air circuit, and the first switching circuit has first and second core switching parts, The second switching circuit is provided with third and fourth core switching units, and each of the first, second, third, and fourth core switching units is provided at a location where communication line switching is performed. is a group of terminals (T ₁ , T ₂ ) connected to the existing line,
(T ₁ ′, T ₂ ′), (T ₅ , T ₆ ), (T ₅ ′, T ₆ ′), terminal group (T ₃ , T′ ₃ ), (T ₄ ), ( _T'4 )
and connect the terminal groups (T ₁ , T' ₁ ), (T ₂ , T' ₂ ), (T ₅ , T' ₅ ), (T ₆ , T' ₆ ) on both sides of the switching point of the existing communication line. , the terminal group (T ₃ , T′ ₃ ), (T ₄ , T′ ₄ )
are connected to both ends of the newly installed line, and the reference signal from the signal transmission unit is transmitted through the third and fourth core switching units, the existing and newly installed communication lines, and the first and second core switching units. is connected to the signal receiving section through the air circuit, operates the first control section and the second control section, and switches between the existing line and the new line, wherein each of the core wire switching sections , a first step of selecting one core pair from a plurality of core pairs of the existing line;
switch, a second switch and a third switch that selects one fiber pair from a plurality of fiber pairs on the new line, and a short circuit (ON) or an open (open) of any one fiber pair between the switching point of the existing line. OFF), a fifth switch that can short-circuit (ON) or open (OFF) any one fiber pair between the existing line and the new line, and further the second switch or the third switch.
A sixth switch that switches the external circuit to the first switch and the sixth switch, a seventh switch that switches the external circuit signal to the first switch and the sixth switch, and a resistance converter that can reduce the resistance from a high resistance value to a low resistance value between the first switch and the sixth switch. between the first switch and the third switch, configured to short-circuit the fourth switch, open the fifth switch, and select any one fiber pair from the existing line and the new line. The resistance converter inserted in the switch is reduced from a high resistance value to a low resistance value, and then, in the fifth switch, the contact point that is electrically connected to the arbitrary one-core wire pair is short-circuited, and the fifth switch is connected to the fifth switch. In the switch No. 4, open the contact that has electrical continuity with the arbitrary one-core wire pair,
The resistance converter inserted between the first switch and the second switch that selected the arbitrary one-core wire pair is increased from a low resistance value to a high resistance value, and the first switch is changed to a second or second switch. The signal transmitter sends out an alternating current signal to one core wire pair that is electrically connected to the switch when the switch is connected to one of the three switches, and the alternating current signal and the reference signal from the signal transmitter are used. synchronously detecting the signal with a synchronous detector of the signal receiving section, displaying the detected output on a display, monitoring the selected single fiber pair, and inputting the detected output to the first control section; The above control is carried out for the plurality of core pairs of the existing line and the new line, and the plurality of core pairs of the communication line are automatically switched, and the plurality of core pairs of the communication line are automatically switched before, during and after switching. , characterized in that the communication line is configured to be able to be monitored.

DESCRIPTION OF THE EMBODIMENTS FIG. 2 shows a block diagram of an embodiment of the multiple-pair continuous switching system for communication lines of the present invention.

In the drawings, FIG. 1 and the first reference numerals indicate the same parts, the same portions, and corresponding parts.

In the figure, Hgj (j = 1 to 6) is a continuity probe, which has the function of providing electrical continuity between multiple core pairs of the existing line Po or the new line P _N and the switching devices Mc1 and Mc2. The core switching section RT1 is
(RT1') and RT2 (RT2') terminal group T ₁ to _{T 6}
(T ₁ ′ to T ₆ ′).

In the present invention, a connector having a structure that allows electrical continuity with a communication line to be taken out from the outside is used, the connector is attached to the communication line, and the continuity probe is connected to the connector. A method of obtaining electrical continuity from a communication line through a connector is also used.

It is also possible to use a method in which the conductive probe has a needle or blade portion, and the needle or blade penetrates the communication line coating to obtain direct electrical continuity from the communication line. However, the method of the present invention has improved workability and reliability.

Here, the terminal groups T ₁ to _{T 6} and T ₁ ′ to _{T 6} ′ can be electrically connected to a plurality of core wires,
Tj and T′j (j=1 to 6) constitute a pair.

In this embodiment, the continuity probe Hgj
(j=1 to 6) can obtain electrical continuity with n pairs of core wires, and each terminal group Tj (j=1 to 6) is composed of n terminals.

Core switching parts RT1, RT1' and RT2, RT2'
is composed of a mechanical contact and a resistance conversion section that controls the resistance value, and the resistance value between the terminal groups of each core wire switching section changes over time.

To perform switching, first select the switching point X of the existing line Po.
Connect the continuity probe Hgj at two locations across the
(j = 1 to 4) to establish electrical continuity with the existing line Po, and conduction probe Hgj (j = 5, 6) to establish electrical continuity with the new line P _N.

In the switching device Mc2, the signal transmitting unit Oc is a general oscillator, and outputs an AC signal Ac and a reference signal _RF for synchronous detection in a balanced manner. It is desirable that the level of the AC signal Ac is as low as possible so as not to affect communication on the existing line Po, but a level of about -50 dBm is sufficient in practice.

Prior to switching, it is desirable to transmit and receive the AC signal Ac between the switching points and check the electrical continuity and polarity of the communication line.
The AC transmission/reception route is the core switching section RT2, RT2'→
Terminal group T ₆ , T ₆ ′ → Continuity probe Hg 4 → Continuity probe Hg 1 → Terminal group T ₁ , T ₁ ′ → Core wire switching section RT
1, RT1'→signal receiving section Rv will be explained.

The AC signal Ac is transmitted and received by selecting one fiber pair of the existing line Po, and the transmission and reception is repeated for a plurality of fiber pairs. The selection and repetition of the core wire pairs for transmitting and receiving the AC signal Ac are performed by the core switching units RT1, RT1' and RT2, RT2', and the core switching units are configured to select and repeat the selection and repetition of the core pair that transmits and receives the AC signal Ac.
controlled by. Here, when the control unit CT1 of the switching device Mc1 outputs the drive signal Sc, it also outputs the control signal _CR , and the control signal _CR is sent to the empty line Pv via the transmitter S, and the control unit CT1 of the switching device Mc2 outputs the control signal CR. Then, the control signal C _R ' from the transmitter S is received by the receiver R,
A control signal _CR is input to the control unit CT2. Here, on the empty line Pv, the reference signal _RF is also transmitted and received along with the control signal C _R ', so the receiver R needs to have a function of receiving only the control signal C _R '. However, this does not apply when the control signal C _R ′ and the reference signal _RF are transmitted and received on separate empty lines.

Further, the AC signal Ac is transmitted through the terminal group T ₅ , T ₅ ′ → continuity probe Hg 3 → continuity probe Hg 2 → terminal group T ₂ , T ₂ ′ and terminal group T ₄ , T ₄ ′ → continuity probe
For the path Hg6 → continuity probe Hg5 → terminal group T ₃ , T ₃ ′, switch device Mc1 and
It is sent and received between Mc2.

When AC signal Ac is input to signal receiver Rv,
The signal receiving section _Rv converts the _AC signal Ac into the fifth
Synchronous detection is performed using the synchronous detector SD shown in the figure, and the detection output signal
Output Ot. For example, control for automatically transmitting and receiving the alternating current signal Ac for a plurality of core pairs is possible by inputting the detection output signal Ot to the control unit CT1. This can be done manually without outputting the detection output signal Ot to the control unit CT1.

Here, the route for transmitting and receiving the AC signal Ac can be set arbitrarily, and the effect remains the same.

After that, the terminal groups T ₁ , T ₂ , T ₁ ′ to _{T 2} ′, T ₅
~ T ₆ , T ₅ ′ ~ T ₆ ′ is shorted (ON), T ₁ ~ _{T 3} ,
Open (OFF) between T ₁ ′ to T ₃ ′, T ₄ to _{T 6} , and T ₄ ′ to _{T 6} ′
The core switching units RT1, RT1',
Controls RT2 and RT2'. Thereafter, at the switching point X, electrical continuity of the existing line Po is interrupted. When electrical continuity is interrupted, if the latter method described above is used to obtain electrical continuity from the communication line using a conductive probe with a needle or blade, it is generally used in the construction of communication lines. It is possible to use a core wire cutting tool that
When the method of the present invention is used, electrical continuity inside the connector is turned on or off as the connector is separated or mated at the switching point X, thereby separating the connector. It is possible.

If the transmission signal is flowing from A to B on the existing line Po, the flow of the transmission signal is A.
→ Continuity probe Hg1 → Terminal group T ₁ , T ₁ ′ → Core wire switching section RT1, RT1′ → Terminal group T ₂ , T ₂ ′ → Continuity probe Hg2 → Continuity probe Hg3 → Terminal group
T ₅ , T ₅ ′ → Core switching section RT2, RT2′ → Terminal group
T ₆ , T ₆ '→continuity probe Hg4→B.

After that, the core switching parts RT1, RT1', RT2,
Operate RT2'. Each core switching section RT1, RT
1', RT2, and RT2' must be the same so as not to deteriorate the balance of the existing line Po.
Each core switching section RT1, RT1', RT2, RT
The flow of the transmission signal after the operation of 2' is as follows:
A → Continuity probe Hg1 → Terminal group T ₁ , T ₁ ′ → Core wire switching section RT1, RT1' → Terminal section T ₃ , T ₃ ′ → Continuity probe Hg5 → Continuity probe Hg6 → Terminal group
T ₄ , T ₄ ′ → Core switching section RT2, RT2′ → Terminal group
T ₆ , T ₆ '→continuity probe Hg4→B.

The fiber switching is carried out one fiber pair at a time, and the selection of the fiber pair to be switched and the repetition for a plurality of fiber pairs are automatically and sequentially carried out under the same control as the transmission and reception of the control signal Ac. Ru.

Furthermore, even during and after the operation of the core switching section, the AC signal Ac is transmitted and received through the same route as the transmission signal, so the signal receiving section Rv
It is possible to monitor the path of the transmission signal using the detected output signal Ot.

FIG. 3 shows an embodiment of the core switching section RT1. However, the core switching parts RT1, RT1', RT2,
Since the configuration and operation of RT2′ are all the same,
The explanation will be given below by taking the core switching unit RT1 as an example.

In Figure 3, SR is a terminal, and the switching device Mc
1, the signal receiving unit Rv includes a switching device Mc2.
is connected to the signal transmitter Oc.

Before switching, when transmitting and receiving the reference signal Ac, each contact of the switches SW4 and SW5 is opened. For example, when receiving the alternating current signal Ac by the terminal t ₁ i of the terminal T ₁ , the path from the terminal t ₁ i to the switch SW1(i) to the switch SW7(i) to the terminal SR is selected. By changing the contact point of the switch SW1 from 1 to n, n routes can be selected. Similarly, in the case of terminal t ₂ i of terminal group T ₂ , terminal t ₂ i → switch SW2(i) → switch
SW6(1) → Switch SW7(2) → Terminal SR or terminal group
In the case of terminal t ₃ i of T ₃ , terminal t ₃ i → switch SW3
The path (i)→switch SW6(2)→SW7(2) is selected. Here, the switch SWj (j=1 to 4) is
It can be configured with general relays.

By selecting the above-mentioned routes, it is possible to check the electrical continuity and polarity of the route through which the transmission signal flows within the communication line, conductive clip, and switching device. However, this confirmation operation is
This operation is to improve the reliability of fiber switching, and can be omitted.

After the confirmation operation is completed, electrical continuity of the existing line between the terminal group T ₁ and the terminal group T ₂ is cut off. At this time, all contacts of switch SW4 are short-circuited (ON), all contacts of switch SW5 are open (OFF), and the connection between a and b in the resistance converter RC is in an open state as shown in Figure 3. Therefore, the path of the transmission signal flowing on the existing line is terminal group T ₁ → switch SW4 → terminal group T ₂ . The switching of the communication line connected to the i-th terminal of the terminal group will be explained below.

The state of the switch contacts before the start of the switching will be described. Switch SW4 is #1 to #i
-1 is open (OFF), contacts #i to #n are short-circuited (ON), and switch SW5 has contacts #1 to #n short-circuited (ON).
#i-1 is shorted (ON) and contacts #i to #n are open (OFF). In addition, the contacts of switches SW1, SW2, and SW3 are set to i, and the contacts of switches SW1, SW2, and SW3 are set to i.
Contact point 6 is set to 2. a of resistance converter RC
.about.b is currently open, so the transmission signal path is from terminal t ₁ i to switch SW4 (#1) to terminal t ₂ i.

After that, a to b of the resistance converter RC as described later.
The resistance value between them decreases from infinity to near 0Ω, and after the resistance value changes, the contact #i of the switch SW5 is short-circuited (ON). Thereafter, the contact of switch SW6 is set to 1, and then contact #1 of switch SW4 is opened. At this time, the resistance value between a and b of the resistance converter RC is near 0Ω, and the switch
After the operation of SW4 is completed, it increases to infinity. Here, it is desirable that the decrease and increase in the resistance value between a and b change continuously in order to reduce the influence on the transmission signal.

As a result, the transmission signal that took the route of the existing line Po → terminal t ₁ i → switch SW4 (#1) → terminal t 2 i before the operation of the core wire switching unit RT1 is transferred to the existing line Po → terminal t ₁ i → switch SW4 (#1) → terminal t 2 i.
Po → terminal t ₁ i → switch SW5 (#1) → terminal t ₃ i
→The route will be switched to the new line P _N.

Furthermore, if the contact of SW7 is set to 1 while the resistance converter RC is in operation, the reference signal Ac is always
Therefore, it is possible to monitor the electrical continuity and polarity of the communication line to be switched.

FIG. 4 shows an embodiment of the resistance conversion section RC.

In FIG. 4, PC is a photocoupler, which causes a current to flow through the light emitting diode LED on the input side to emit light, and when the light beam hits the CdS on the output side, the resistance value of the CdS changes. PS is a constant voltage source and always supplies constant voltage V _B. Also, VS is a voltage generator that provides voltage Es to resistor Rs.
The voltage generator VS is a counter circuit or
It can be configured with a ROM circuit.

Photocoupler requires control because the relationship between the current value flowing through the light emitting diode LED and the resistance value of CdS differs from element to element.

First, in order to perform control, the contact points of switch SW8 and switch SW9 are set to 1. Since point X is the virtual installation point of operational amplifier OP and is xOV,
The current value flowing through CdS is Is, and CdS and resistor Rs
Let the resistance values of R _ON and rs be _{R ON =} V _B / | Is | = V _B / | E _S |/r _S = V _B・r _S・1/ | E _S | expressed. Therefore, the resistance value R _ON on the output side of the photocoupler PC can be completely controlled by the voltage _ES .

In the circuit shown in FIG. 4, when E _S <OV, the output of the operational amplifier OP becomes a positive voltage. The transistor Tr is for current enhancement, and the operational amplifier OP
When the output of becomes positive, the emitter voltage Vo increases in the positive direction. Here, the voltage Vo is the resistance value of the resistor Rf is rf, and the current flowing through the light emitting diode LED is If
If the forward voltage of the light emitting diode LED is vo, it is expressed as Vo=If·rf+vo, which is expressed by the voltage Vo, and the voltage value Vo is written into the memory circuit MR.
Memory circuit MR can be configured with a RAM circuit.

As shown above, depending on the voltage value E _S , the resistance value R _ON on the output side of the photocoupler PC and the photocoupler PC
The current value If flowing to the input side of is determined in one way.

After the control is completed, the contacts of switches SW8 and SW9 are set to 2, and the voltage value Vo is continuously outputted from the memory circuit MR. As a result, a current If flows to the input side of the photocoupler PC, and the resistance value on the output side changes as set during the control. The change in the resistance value R _ON can be arbitrarily set depending on how the voltage value Es is applied.

FIG. 5 shows an embodiment of the signal receiving section Rv.
In FIG. 5, DA is a differential amplifier, the reference signal _RF is input from 0, and the AC signal Ac is input from P. BF is a bandpass filter. The bandpass filter BF to which the reference signal _RF is input is for separating the control signal _CR '. Further, Fs is a phase shifter, and it is desirable that the phase shifter Fs be adjusted so that the detection output of the synchronous detector SD becomes maximum. LF is a low-pass filter, M _T is a display device, and display device M _T displays the wave detector output of the synchronous detector SD. If there is no need to display the detected output, the display M _T can be omitted.

In this embodiment, the AC signal Ac and the reference signal
Set the frequency of R _F between 3300Hz and 3500Hz,
The output level of AC signal Ac and reference signal R _F is −60 dBm and −50 dBm, respectively, and the AC signal Ac is
When transmitted onto the existing line Po where a digital signal with a signal speed of 200 kb/s is flowing on the communication line, the core switching units RT1, RT1', RT2,
We have confirmed that the digital signal path can be monitored before, during and after RT2' operation.

FIG. 6 is a diagram showing an example of the operation timing of the fiber switching unit RT1. In Figure 5, R _ON is the resistance value on the output side of the photocoupler PC, SWj (j = 1
~9) is the switch, and the horizontal axis shows the change in resistance value on the output side of the photocoupler PC and the switch.
The state of the contact of SWj (j=1 to 9) is shown.
Here, a case will be described in which the communication line connected to the i-th terminal of the terminal group Tj (j=1 to 3) is switched.

Curves 1 and 3 of R _ON shown in FIG. 5 are the changes in resistance value when controlling the photocoupler PC,
2 and 4 are changes in resistance value when switching communication lines. Here, Rmax is preferably 1 MΩ or more, and Rmin is preferably 10Ω or less.

In this example of operation timing, t ₁ = t ₂ =
500msec, _t3 = _t6 = 20msec, _t4 = _t5 = 10msec, _t7
= 30 msec, and when the existing line was switched to the new line, multiple communication routes could be transferred from the existing line to the new line without affecting communication on the existing line.

However, for the values of t ₁ to _{t 7} , t ₁ = t ₂ , t ₃ = t ₆ ,
It is not necessary that t ₄ =t ₅ , and it is possible to set it to other values taking into account the operating characteristics of the photocoupler and switch used in the device according to the invention. Furthermore, although the case where the control of the photocoupler is executed for each fiber pair switching is shown, the control method can shorten the working time by executing the photocoupler control only once before switching the plurality of fiber pairs.

In this embodiment, the configuration of the resistance converter is explained using a photocoupler, but it is also possible to use a relay and a fixed resistor, and it is also possible to use a potentiometer or a volume variable resistor. .

In addition, one switching device has a built-in signal transmitter,
Although a configuration has been described in which the other switching device has a built-in signal receiving section, it is also possible to have a configuration in which both switching devices have a built-in signal transmitting section and the signal receiving section is separated, and the effect remains the same.

Effects of the Invention As explained above, the device according to the present invention automatically or as needed switches multiple communication routes on an existing line to a new line without affecting the communication at a location where communication lines are to be switched. Since it is possible to manually move the line and monitor the route, there is no need to stop communications during the communication line switching work, which improves the reliability of the switchover work and significantly increases work efficiency. Ta.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the patent application No. 58-37011, Fig. 2 is a block diagram of an embodiment of the device of the present invention, and Fig. 3 is a diagram after switching the existing and new communication line shown in Fig. 2. FIG. 4 is an example of the resistance conversion section shown in FIG. 3, FIG. 5 is a block diagram of the signal receiving section shown in FIG. 2, and FIG. 6 is a diagram showing the operation timing of the device of the present invention. An example is shown. Hgj (j=1 to 6): Continuity probe, Tj, T′j
(j=1 to 6): terminal group, RT1, RT1', RT2,
RT2': Core switching section, Hc: Cord, CT1, CT
2: Control unit, Sc: Drive signal, C _R , CR _′ : Control signal, S: Transmitter, R: Receiver, Oc: Signal transmitter,
Rv: Signal receiver, Ot: Detection output signal, Ac: AC signal, R _F : Reference signal, Mc1, Mc2: Switching device,
Po: Existing line, P _N : New line, Pv: Empty line,
t ₁ j, t ₂ j, t ₃ j (j = 1 to n): terminal, SWj (j = 1 to
9): Switch, SR: Terminal, RC: Resistance converter,
PS: constant voltage source, PC: photocoupler, OP: operational amplifier, Tr: transistor, Rs, Rf: resistor,
VS: Voltage generator, MR: Memory circuit, DA: Differential amplifier, BF: Bandpass filter, Fs: Phase shifter, SD: Synchronous detector, LF: Low-pass filter, M _T : Display.

Claims (1)

[Claims] 1 A first switching circuit and a second switching circuit are provided, both switching circuits are connected by an air circuit, and the first switching circuit is connected to the first and second core switching sections, and the second switching circuit is connected to the first switching circuit and the second switching circuit. is provided with a third and fourth core switching section, and at a location where communication line switching is performed, each of the first, second and third and fourth core switching sections is provided with a wire connected to the existing line. Group of terminals to be connected (T ₁ , T ₂ ), (T′ ₁ , T′ ₂ )
(T ₅ , T ₆ ), (T′ ₅ , T′ ₆ ) and terminal groups T ₃ , T′ ₃ and T ₄ , T′ ₄ to be connected to the new line, and the terminal group (T ₁ , T ′ ₁ ), (T ₂ , T′ ₂ ) and (T ₅ , T′ ₅ ), (T ₆ ,
T' ₆ ) are connected to both sides of the switching point of the existing communication line, and the terminal groups (T ₃ , T' ₃ ) and (T ₄ , T' ₄ ) are connected to both ends of the new line, and the third and fourth connecting the reference signal from the signal transmitting section to the signal receiving section through the fiber switching section, the existing and newly installed communication lines, and the first and second fiber switching sections, and via the air circuit;
In the communication line switching device that operates the first control unit and the second control unit to switch between an existing line and a new line, each of the core wire switching units switches one core pair from the plurality of core pairs of the existing line. 1 from the plurality of core pairs of the newly installed line.
A third switch for selecting a fiber pair, a fourth switch that can short-circuit (ON) or open (OFF) any one fiber pair between the switching point of the existing line, and an arbitrary switch between the existing line and the new line. A fifth switch that can short-circuit (ON) or open (OFF) one core pair of wires, and a sixth switch that switches to the second or third switch, and a signal from an external circuit to the first switch and the sixth switch. A seventh switch is provided between the first switch and the sixth switch to reduce the resistance from a high resistance value to a low resistance value, and the fourth switch is short-circuited and the fifth switch is opened. and reducing the resistance value of the resistance converter inserted between the first switch and the third switch that selects an arbitrary one-core wire pair from the existing line and the new line from a high resistance value to a low resistance value, Thereafter, the fifth switch short-circuits the contacts that are electrically connected to the arbitrary one core pair, and the fourth switch
The contact point that has electrical continuity with the core wire pair is opened, and the resistance converter inserted between the first switch and the second switch that selected the arbitrary one core wire pair is changed from a low resistance value to a high resistance value. the signal transmitter sends an alternating current signal to the single core wire pair electrically connected by the switch with the first switch connected to either a second or third switch; Then, using the alternating current signal and the reference signal from the signal transmitter, perform synchronous detection with a synchronous detector of the signal receiver, display the detection output on a display, and monitor the selected single fiber pair. At the same time, the detection output is input to the first control unit, and the control described above is carried out for the plurality of core pairs of the existing line and the new line, and the plurality of core pairs of the communication line are automatically switched. 1. A multi-pair continuous switching system for a communication line, characterized in that the communication line is configured to be able to monitor the communication line before, after and during the switching of the plurality of core wire pairs.