JPH0367229B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to repairing faults in multi-pair communication cables in which a plurality of pairs of telephone lines each consisting of a pair of core wires connecting a telephone exchange and a plurality of subscriber premises equipment are twisted together into a single cable; This relates to a fiber comparison device used in reupholstery work, etc.

Prior to explaining the present invention, a configuration example of a multi-pair communication cable will be briefly explained. The switching equipment installed at each subscriber's premises and the telephone office is usually _L1 , _L2.
It is connected by a pair of core wires. A 2-pair bundle of these two core wires is called a 1-pair cable, and a cable made by twisting multiple strands (for example, 50 strands) in multiple layers is called a 1 unit.For example, 24 units of this unit are bundled to form one multi-pair cable. It consists of A small number of spare cutlets are prepared for each unit. It is also based on regulations such as the arrangement and color of the core wires that make up the unit.

Conventionally, when comparing cable cores, the units to be compared are selected at both ends of a multi-pair cable (hereinafter referred to as a cable), a cut is selected from among these units, and then a cut inside the cut is selected. Find a pair of core wires L ₁ and L ₂ from , apply DC or AC voltage to the ground potential to each wire, and confirm continuity with _an indicator light or buzzer sound. A method was used to confirm the polarity of _L2 .

However, the actual telephone line between the telephone exchange and the subscriber consists of underground pipes and overhead lines, and is connected at several or more terminals along the way, so sometimes some parts of the line within the core of the unit are connected. The core wires may be crossed and connected, and the arrangement based on regulations may not always be maintained. Also, one of the core wires L ₁ and L ₂ of the cable between the exchange and the fault point is commonly grounded, and the other core wire is applied with DC voltage from the exchange, so the exchange can be disconnected from the cable. It is difficult to perform core wire comparison without disconnecting the cable, and even if the exchange equipment is separated from the cable over time, an AC signal voltage is applied between the core wire and ground for core wire comparison. Since the capacitive coupling between the lines is large,
A signal voltage similar to that of the target core wire is induced in other core wires located near the target core wire, making it difficult to confirm continuity using, for example, a buzzer sound, and in the end, relying on the intuition of a skilled worker or testing. Due to errors, the efficiency of the fiber comparison work was low.

The present invention eliminates such drawbacks of the conventional method, and in order to enable even an inexperienced worker to accurately and easily perform cable core comparison work in a short period of time, the present invention aims to eliminate the disadvantages of the conventional method by storing spare parts in the cable without separating the cable from the exchanger. A reference signal is sent from one end of the cable using the specific core wire as a control line, a reference signal is sent from one end of the cable to the target wire, and the reference signal and the reference signal are transmitted at the other end of the cable. It is an object of the present invention to provide a fiber comparison device, which has a circuit configuration for comparing the fibers, and is characterized in that the fiber number and the polarity of the fiber can be visually recognized.

The present invention will be described in detail below based on examples.

FIG. 1 is a block diagram showing the configuration of the core fiber comparison device of the present invention. C is the cable to be compared, C-1 is the cable for one unit that constitutes cable C, C-
2 is a pair of specific wire core wires (hereinafter referred to as special code wires) selected from the backup line in cable C for the control line of the control device; R is a receiving section connected to the other end of cable C. 1 is an oscillator, T ₁ and T ₂ are transformers, 2 is a connection terminal for the special code wire C-2, 3 is a connection terminal for the core wire to be measured, r is a resistor inserted on the secondary side of the transformer T ₂ , and 4 is a difference 5 is a bandpass amplifier, 6 is a demodulator, and 7 is a display mechanism. 8 is a terminal board for connecting the pair of core wires L ₁ and L ₂ in one unit according to the wire number order; 9
is a connection terminal for the special code line C-2, 10 is a channel switch, 11 and 12 are differential amplifiers, 13 is a bandpass filter, 14 is a phase shifter, 15 is a synchronous detector, 16 is a threshold value judger, 17 is a counter, and 18 is a modulator.

Next, the circuit of the control signal sending section S will be explained. The output of oscillator 1 is connected to special wire C- via transformer _T1 .
The modulated signal is guided to the connection terminal 2 of No. 2 and is input to a differential amplifier 4 which amplifies the modulated signal sent from the receiving section R side via the cable C. The output of the differential amplifier 4 is applied to a band wave generator 5 which has a characteristic of passing only the modulated signal component, and the signal component is extracted by a demodulator 6, and the polarity and core number of the core wire are displayed by the signal. The digital display 7 is driven.

On the other hand, the circuit of the receiving section R will be explained. The other end of the cable to be measured C is connected to a terminal board 8 that connects the core wires C-1 of one unit in pair by core number order, and to a terminal 9 that connects the special code wire C-2. Each core wire of one unit of cable C-1 connected to the terminal board 8 is connected to a corresponding terminal of the channel switch 10.

The channel switch 10 switches the core wires in order of wire number and counts the number of switched channels, that is, the wire number. The output of the channel switch 10 is input to a synchronous detector 15 via a differential amplifier 11. One terminal of the special code line C-2 connected to the other terminal 9 is connected to a phase shifter 14 via a differential amplifier 12 and a bandpass filter 13 that passes only the reference signal component. The output is the synchronous detector 15
added to. This synchronous detector 15 is connected to a threshold value judger 16, a counter 17 for counting the judgment result, and a modulator 18, and the output of the modulator 18 is connected to the terminal ₉ via a transformer T3. , control signal sending section S via special code line C-2
is applied to terminal 2 of

Now, the operation of the core fiber comparison device of the present invention constructed as described above will be explained.

First, the terminal of the special number wire C-2 of the cable C to be measured is connected to the terminal 9 of the receiving section R, and each core wire of the unit to be measured C-1 of the cable C is connected to the terminal board 8 in the order of the core number. On the other hand, connect the other end of the special code wire C-2 of the cable C to the terminal 2 of the control signal sending part S, and connect any pair of core wires of the unit C-1.
Connect L ₁ and L ₂ to terminal 3 of signal sending section S.

The oscillator 1 of the control signal sending section S is a sine wave oscillator, and the oscillation frequency (hereinafter referred to as f ₀ ) is
I chose 3.6KHz. This oscillation output is transmitted through transformer _T1
and _T2 , the reference signal is sent from terminal 2, and the reference signal is sent from terminal 3 to the receiver R side via cable C, which is connected to each other. Since each pair of core wires of cable C is configured with the two wires L ₁ and L ₂ as the minimum unit, the f ₀ signal sent to cable C is transmitted to the pair of core wires L ₁ and L _2. This results in an inverse phase relationship. On the other hand, various external noise powers induced in the cable C are transmitted through the cable C in an in-phase relationship when viewed from each core pair.

On the other hand, each core pair of the unit cable C-1 connected in order of core number to the terminal board 8 of the receiving section R is led to each corresponding input terminal of the channel switch 10.
This channel switch 10 sequentially switches each fiber pair connected in the order of the wire numbers while counting the wire numbers in the order of the wire numbers. This switching speed can be appropriately selected depending on the number of core wires constituting the unit, but in this embodiment it was set to 10 ms per channel. Then, the control signal is sent to the differential amplifier 11 connected to the output side of the channel switch 10 only during the time when the switching contact of the channel switch 10 is connected to the core pair connected to the terminal 3 on the signal sending section S side. Input is applied.
Since a differential amplifier outputs a signal proportional to the difference between two inputs, a signal applied to the two inputs in the same phase is suppressed, and a signal applied in opposite phase to the two inputs is amplified. Therefore, the differential amplifier suppresses the noise power induced in the L ₁ and L ₂ of the cable in the middle of the installation section of the cable C in the same phase, while the f ₀ signal sent out in the opposite phase is amplified. , becomes an input to the synchronous detector 15.
On the other hand, the reference signal sent to the terminal 9 of the receiving section R via the special code line C-2 is applied to the differential amplifier 12.
Then, as described above, noise is removed, and only the f ₀ signal is outputted, which is input to the phase shifter 14 via the bandpass filter 13 whose pass band is the f ₀ signal. The phase shifter 14 receives the reference signal transmitted via an arbitrary core pair connected to the terminal 3 of the reference signal sending section S of the unit under test C-1, which is one input of the synchronous detector. It is inserted to match the phase of the signal and the phase of the reference signal, and may not necessarily be necessary. Now, the reference signal is synchronously detected by the reference signal input in the same phase to the synchronous detector 15, and a high level DC component is extracted. If there is no output from the differential amplifier 11, that is, if the core wire pair connected to terminal 3 is broken in the middle of the cable, the reference signal cannot be received, or the polarity is reversed and the signal phase is not normal. Since the output of the synchronous detector 15 cannot be obtained, the threshold value judger 1
6, the output level of the synchronous detector 15 is “present”.
By determining whether the polarity is "absent", it is possible to determine whether the polarity is normal and conductive, or whether the polarity is reversed. Furthermore, since the counter 17 is maintained in a synchronous relationship with the channel counter of the channel switch 10, the core number is also revealed at the same time. This “signal indicating the presence or absence of polarity reversal” and “signal indicating the core number” is sent to the modulator 1.
8, and the modulated output is transmitted through the transformer _T3 and the special number line C-2 of the cable C via the terminal 9, and sent to the control signal sending section S. Note that a known modulation method such as FM or FSK can be applied. The modulated output is input to the differential amplifier 4 from the terminal 2 of the control signal sending section S. This differential amplifier 4
The output is inputted to the demodulator 6 via the bandpass converter 5, and the demodulated "polarity signal" and "line number signal" are used to display a message on a display consisting of an LED, for example, indicating whether the polarity is normal or not. ” and “Reference core number” are displayed.

Once the comparison result for a given fiber pair has been confirmed, the next fiber pair is connected to the terminal 3 of the comparison signal sending section S, and the fiber comparison is performed in the same manner as described above.

Next, an example of how the fiber comparison device of the present invention is used will be explained.

FIG. 2 schematically shows the route of the telephone line cable formed between the telephone office D and the subscriber. The cables connected to the exchange E installed in the telephone office D are lined up and connected at the main terminal board M inside the office, and the cables C', C'', C
A line is formed to the subscriber's (not shown) terminal device via... Cable illustrated here
C' and C may have multiple connection points within the path. H ₁ and H ₂ are manholes (or handholes) that open to the ground surface for inspecting and connecting underground cables, and P ₁ and P ₂ are utility poles for installing overhead cables. T is a terminal board installed on a telephone pole or the like.

Suppose that a disconnection fault occurs in the underground cable C'' running between manholes _H1 and _H2 , and a new cable _C0 for restoration is immediately connected to manholes _H1 and _H2 .
Let's assume that the line is routed using a pipe with gaps.

Faulted cable C″ connects manholes H ₁ and H ₂
disconnected within the network and removed from the line. Then, the existing cable C' and the new cable C ₀ connect the core wires of the correct wire numbers in the manhole H 1 and the existing cable C and the new cable C ₀ in _{the manhole H 2 .}

Cable C′, which is done prior to this connection work,
An example in which this device is used to confirm the wire numbers of C ₀ and C, ie, conduct core comparison work, will be explained.

The comparison signal sending part S of the fiber comparison device of the present invention is installed in the manhole _H1 , and the special number wire in the cable C' is connected to the terminal 2, and any core pair of the unit of the cable to be compared is connected to the terminal 3. do. On the other hand, connect the special number wire terminals of the cable C' which are arranged and concentrated on the main terminal board M of the telephone office D to the terminal 9 of the receiving section R of this device, and connect the core wire pairs for one unit to the terminal board 8. . Then, a core wire comparison is performed according to the above-described procedure, and the comparison result can be confirmed inside the manhole _H1 .

A similar control operation was performed on the cable C running between _the manhole _H2 and _the terminal board T installed on the utility pole _P1. This is done by connecting the receiver R to the terminal board T of each.

Cables C′ and C confirmed in this way
Connect each core pair at both ends of new cable C ₀ to cables C′ and C corresponding to the correct polarity and wire number in manholes H ₁ and H ₂ according to the wire numbers for each core pair, and Restore the line.

As explained in detail above, the fiber comparison device for multi-pair communication cables of the present invention is connected to one end of the cable under test, and applies a reference signal to the core pairs of the special number wires of the cable under test. a demodulator for sending a contrasting signal having the same level, waveform and frequency as the reference signal to the core pair of the cable, and indicating the polarity and core number of the core pair transmitted via the cable; A reference signal and a reference signal connected to the other end of the cable to be measured are connected to a reference signal transmitter having a display function and the other end of the cable to be measured, and each core wire of the cable to be measured is transmitted from the reference signal transmitter through the cable to be measured. a receiving section having a function of generating a signal specifying a pair of polarities and a core number, and sending the signal to the reference signal sending section via the cable under test; Since the fiber comparison work can be performed while visually checking the polarity and wire number of the fiber pair at the end of the cable, compared to the conventional method of placing workers at both ends of the cable and communicating with each other. , work efficiency can be greatly improved. Furthermore, since the core pairs use a signal form that can maintain a balanced state, there is little effect of electromagnetic induction on the core pairs that form other units in the cable, and there is no need to separate the exchanger and the cable under test. Since the measurement can be carried out without any noise, the time required for measurement can be shortened compared to conventional methods.In addition, since the control signal sending section and the receiving section have a simple circuit configuration, it can be made lightweight and compact, and can be easily mounted on a utility pole. It also has the advantage of being portable.

In this embodiment, the terminals 3 for connecting the pair of target core wires of the target signal sending section S are used as a pair of terminals, but they can be easily replaced by the terminal board 8 and channel switch 10 of the receiving section R. , thereby further improving the efficiency of the comparison work.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the structure of a fiber matching device for a multi-pair communication cable according to the present invention, and FIG. 2 is a conceptual diagram showing a usage pattern of the main fiber matching device. C... Cable to be compared, C-1... Cable C
Cable for one unit, C-2...Specific wire number wire pair, S...Reference signal sending section, R...Receiving section,
1... Oscillator, 2, 9... Special number wire core pair connection terminal, 3... Target core wire pair connection terminal, 4, 11, 1
2... Differential amplifier, 5, 13... Bandwidth wave generator, 6
... Demodulator, 7 ... Display mechanism, 8, T ... Terminal board, 10 ... Channel switch, 14 ... Phase shifter, 15 ... Synchronous detector, 16 ... Threshold determiner, 17 ... Counter, 18 ... Modulator, T ₁ ,
T ₂ , T ₃ ...Transformer, r...Resistor, D...Telephone office, E...Exchange, M...Main terminal board, _H1 , _H2 ...
...manhole, P...telephone pole, C', C'', C, C ₀
...Multi-pair cable.

Claims (1)

[Claims] 1 Consists of a reference signal transmitting section and a receiving section respectively connected to both terminals of a communication cable consisting of multiple pairs of core wires, and the reference signal transmitting section sends a reference signal to a pair of specific wires of the communication cable as a reference signal. , an oscillator that sends a sine wave signal of the same frequency as a reference signal to any pair of multiple pairs of core wires to be measured, and the receiver connected to the other end of the communication cable via the specific wire core wire. It consists of an amplifier for the modulated signal to be sent, a band wave generator for the modulated signal component, a demodulator, and an indicator for the core number and core polarity, and the receiving section connects the plurality of pairs of cores to be measured in the order of the core numbers. a channel switcher that sequentially switches and outputs the channel switcher pair by pair; an amplifier for the output of the channel switcher; an amplifier that uses the output of the amplifier as one input and amplifies the reference signal sent via the specific wire core; A synchronous detector which receives as input a bandpass transducer that passes a reference signal and a reference signal output via a phase shifter that controls the phase of the reference signal, and determines the polarity of the core wire from the output value of the synchronous detector. a threshold value determiner; a counter that counts a core number in synchronization with the channel switching device from the output of the threshold value determiner; and a core polarity and number obtained by the threshold value determiner and the counter. A fiber comparison device for a communication cable, comprising a modulator that sends a signal to the reference signal sending unit via the specific wire number.