JPH08240753A - Self-supporting type optical cable and dropping method - Google Patents

Abstract

PURPOSE: To provide a self-supporting type optical cable with which the efficient conduction of a dropping operation is possible and to provide a method for dropping using the self-supporting type optical cable. CONSTITUTION: This horseshoe type member 1 has an approximately horseshoe shape in section and is constituted integrally with a supporting wire 4. Plural coated optical fibers 2 are housed in the horseshoe type member 1. The aperture of the horseshoe type member 2 is provided with closing members 3 at suitable intervals to hold the coated optical fibers 2 housed in the horseshoe type member 2 so as not to sag outside. The coated optical fibers 2 which are to be dropped and are housed in the horseshoe type member 1 from the apertures between the closing members 3 are selectively drawn out at the dropping point and are laid as they are to a subscriber house. As a result, the workability of dropping is greatly improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical cable, and more particularly, to an optical cable that is imaginarily suspended in a subscriber optical line connecting a station and a subscriber, and a drop-down method for laying the optical cable to the subscriber. It is a thing.

[0002]

2. Description of the Related Art With the recent development of optical fiber networks, the installation of subscriber optical lines connecting stations with a large number of subscribers has been promoted. In the subscriber optical line, it is necessary to take out a part of the core wire from the imaginary suspended optical cable and drop it into the house of each subscriber. Since this withdrawal work is performed for each subscriber, this work efficiency becomes a problem.

As an example of the conventional pulling operation, the optical cable is cut at each pulling point and the required optical fiber core wire is pulled down. All other optical fiber cores were connected. As described above, cutting and connecting the optical cable at each pull-down point requires a large amount of work, which complicates the laying work, laying time, laying cost, and increasing line cost. Further, transmission loss occurs when connecting the optical fiber cores. There is a problem that the optical loss of the line increases because the number of connection points increases as the distance from the station increases.

In the subscriber optical line, in many cases, the optical cable is suspended in the air. Since transmission loss occurs in an optical fiber due to lateral pressure or the like, it is necessary to prevent lateral pressure from being applied during installation work and in the installed condition. Therefore, a self-supporting optical cable is used.

As a conventional self-supporting optical cable, for example, a messenger wire and a tubular body are integrally formed as described in Japanese Utility Model Laid-Open No. 59-90911.
It is known that an optical fiber cable is housed in a tubular body. In such a self-supporting optical cable, although a drain hole is provided, the entire circumference of the accommodated optical fiber cable is covered by the pipe body, so the pipe body is removed at each pulling point, It was necessary to take out the optical fiber cable. In addition, it was necessary to install a connection box at the portion where the pipe body was removed in order to protect the portion. Such work has led to complicated construction work, increased installation time, installation cost, and track cost.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a self-supporting optical cable capable of efficiently performing a pulling operation. It is also an object of the present invention to provide a withdrawal method using this self-supporting optical cable.

[0007]

According to a first aspect of the present invention, there is provided a support member for suspending an optical cable in an imaginary manner, and a long member having a cross section with an open bottom. The elongated member is supported by the support member along the longitudinal direction thereof, and accommodates an elongated member such as an optical cable or a pipe line having an optical fiber core wire or a tensile strength member inside the elongated member. It is characterized by doing.

According to a second aspect of the invention, in the self-supporting optical cable according to the first aspect, the elongated member is formed of rubber or plastic.

According to a third aspect of the invention, in the self-supporting optical cable according to the first or second aspect, the opening of the elongated member has a closed portion intermittently in the longitudinal direction. It is a feature.

According to a fourth aspect of the present invention, in the self-supporting optical cable according to the third aspect, the width of the opening of the elongated member is 10 mm or more, and the closing portion is the elongated member. The members are arranged at intervals of 15 cm or more in the longitudinal direction of the member.

According to a fifth aspect of the present invention, in the self-supporting optical cable according to the third or fourth aspect, the self-supporting optical cable includes an integral member for integrating the supporting member and the elongated member, The closing portion is configured as a part of the integrated member.

According to a sixth aspect of the present invention, in the self-supporting optical cable according to any one of the first to fifth aspects, the elongated body is fixed to an inner surface of the elongated member. It is characterized by that.

According to a seventh aspect of the present invention, in the self-supporting optical cable according to any one of the first to fifth aspects, the elongated body is provided with a thermoplastic adhesive on the inner surface of the elongated member. It is characterized by being fixed in.

According to an eighth aspect of the present invention, in the self-supporting optical cable according to any one of the first to fifth aspects, a protrusion for fitting the elongated body is provided on an inner surface of the elongated member. It is provided, and the elongated body is fitted to the projection and fixed to the inner surface of the elongated member.

According to a ninth aspect of the present invention, in the self-supporting optical cable according to any one of the first to eighth aspects, the elongated body has a slack with respect to the support line and has the elongated shape. It is characterized by being housed in a member.

According to the tenth aspect of the present invention, a part of the optical fiber core wires is selected from the optical cables suspended imaginarily, and the optical fiber core wires or the optical cable including the optical fiber core wires is added. In the method of laying down even a person, the self-supporting optical cable according to any one of claims 1 to 9 is used as the optical cable suspended in an aerial manner, It is characterized in that, without cutting the long member from one point, the long member necessary for withdrawing is pulled out from the long member and withdrawn to the subscriber.

[0017]

According to the first aspect of the present invention, since the lower portion of the cross-section of the long member serving as the outer cover is open, the outer cover is not required to be removed and is accommodated from the lower opening. It is possible to easily perform work such as taking out, cutting, and pulling out a long body such as an optical fiber core wire or an optical cable or a conduit having a tensile strength body built therein. At this time, it is not necessary to cut and connect the entire self-supporting optical cable at the pull-down point, achieving a great simplification of the laying work,
It is possible to reduce the installation time, installation cost, and line cost. Moreover, since the number of connection points can be reduced, transmission loss can be reduced. The long member may be formed of rubber or plastic, as in the second aspect of the invention.

According to the third aspect of the present invention, since the opening of the long member has intermittently closed portions in the longitudinal direction, the long member accommodated in the long member can be accommodated. These can be well contained in the long member without the body hanging down.

According to the invention described in claim 4, the width of the opening of the elongated member is 10 mm or more, and the interval of the closed portion is 15 c.
By setting the length to be m or more, it is possible to take out the drop line with a simple tool and improve the work efficiency.

According to the invention described in claim 5, the closing portion can be formed as a part of an integrated member for integrating the support member and the elongated member. This integrated member can be formed, for example, by molding with resin or the like. With this configuration, it is possible to process a long-sized member as a member having the same cross-section over the entire length when it is manufactured by extrusion while having a closed portion, which facilitates the processing and increases the processing speed, which reduces the cost. It leads to reduction. In this case, the closing part of the integrated member is
It also has a function of holding the elongated body through the opening of the elongated member.

According to the invention described in claim 6, the elongated body is fixed and accommodated in the inner surface of the elongated member. This makes it easier to select the optical cable to be dropped,
It is possible to prevent the pull-down lines pulled out at the pull-down point from being entangled with each other.

As a fixing method, for example, a thermoplastic adhesive can be used as in the invention described in claim 7. With this, for example, when a long member is formed by extrusion molding, the heat can be used to fix the member, which simplifies the processing and reduces the cost. Also,
As in the invention described in claim 8, a fitting projection may be provided on the inner surface of the long member to fix the long body to the inner surface of the long member. In this case, since it can be fixed to the inner surface of the long member without being constrained in the longitudinal direction, it can be fixed so as not to be a resistance at the time of pulling out.

According to the ninth aspect of the present invention, the long body can be easily taken out at the pulling-down point by accommodating the long body in the long member with slack.

According to a tenth aspect of the present invention, the self-supporting optical cable according to any one of the first to ninth aspects is used, and a long length required from the opening of the long length member at the pull-down point. Pull out the body and drop it to the subscriber.
At this time, it is not necessary to cut and connect the entire self-supporting optical cable at the pull-down point, so that the laying work can be greatly simplified, and the laying time, laying cost, and line cost can be reduced. In addition, for example, the self-supporting optical cable according to any one of claims 1 to 9 is laid in series for several spans, and a long body that is to be withdrawn by the withdrawal distance downstream is cut from the withdrawal point. By pulling out from the pull-down point and using it as the pull-down line, it is not necessary to connect the optical fiber core wire in the section where a series of strides are made, and the connection at the pull-down point can be omitted. As a result, the workability of withdrawal can be greatly improved.

[0025]

1 is a perspective view showing a first embodiment of a self-supporting optical cable of the present invention. In the figure, 1 is a horseshoe-shaped member, 2 is an optical fiber core wire, 3 is a closing member, and 4 is a support wire.

As shown in FIG. 1, the horseshoe-shaped member 1 has a substantially horseshoe-shaped cross section with an open lower portion, and can accommodate a plurality of optical fiber core wires 2 therein. The opening of the horseshoe-shaped member 1 is provided with closing members 3 at appropriate intervals to hold the optical fiber core wire 2 housed inside the horseshoe-shaped member 1 so as not to hang down outside.
The openings between the closing members 3 are used for operations such as cutting and pulling out the optical fiber core wires 2 housed inside.
In addition, water does not collect inside due to this opening.
Furthermore, as shown in FIG. 1, if the opening is suspended downward, rainwater can be prevented from directly entering the inside.

As a specific example, the width of the opening of the horseshoe-shaped member 1 may be 10 mm or more, and the closing members 3 may be arranged at intervals of 15 cm or more. By setting the size to this extent, workability can be improved. If the width of the opening is 10 mm or more, for example, the optical fiber core wire 5 housed inside can be inserted without inserting a simple tool through the opening or using a special tool.
Can be taken out. Further, by disposing the closing member 3 at intervals of 15 cm or more, it is possible to easily pull out the optical fiber core wire 5 without forcibly bending it when taking it out.

The horseshoe-shaped member 1 can be made of, for example, rubber or plastic. Of course, it is also possible to use other materials. Further, the closing member 3 can be configured as a separate member, or can be integrated with the horseshoe-shaped member 1. At this time, the horseshoe-shaped member 1 and the closing member 3 may be separately formed of the same material, and the horseshoe-shaped member 1 and the closing member 3 may be fused and integrated. When configured as a separate member, the material may not be the same as that of the horseshoe-shaped member 1.

The support line 4 is arranged along the horseshoe-shaped member 1. The horseshoe-shaped member 2 is supported by this support line 4. The support wire 4 is pulled by a predetermined tension when the self-supporting optical cable is laid, and is locked to, for example, a utility pole.

FIG. 2 is a sectional view of an example of an optical cable housed in a horseshoe-shaped member. In the figure, 11 is an optical cable,
12 is an optical fiber core wire, 13 is a steel core, and 14 is a jacket. In addition to the above-described optical fiber core wire 5, the horseshoe-shaped member 1 can also accommodate an optical cable 11 as shown in FIG. In the optical cable 11 shown in FIG. 2, steel cores 13 are arranged on both sides of an optical fiber core wire 12 and are integrated by an outer jacket 14. As a specific example, as the optical fiber core wire 12, for example, a nylon-coated core wire having a diameter of 0.9 mm can be used, and as the jacket, PVC or the like can be used. As a whole, an optical cable having a width of about 7 mm and a thickness of about 4 mm can be used. Of course, an optical cable having another shape such as a substantially circular shape may be housed in the horseshoe-shaped member 1.

Further, the horseshoe-shaped member 1 may contain a tubular body made of, for example, plastic or the like. After laying the self-supporting optical cable, an optical fiber core wire can be inserted into the tube body by pumping with a gas. Of course, it is possible to accommodate electric wires and the like, and it is also possible to accommodate these by mixing them.

The optical fiber core wire 5 accommodated in the horseshoe-shaped member 1, the elongated member such as the optical cable 11 and the tubular body are accommodated with slack with respect to the support wire 4. This allows
Even if tension is applied to the support wire 4 and the horseshoe-shaped member 1, no tension is applied to the optical fiber core wire 5, the optical cable 11, the tube body, and the like that are accommodated, and good transmission conditions can be maintained. In addition, from the horseshoe-shaped member 1 to the optical fiber core wire 5,
The work of taking out the optical cable 11, the tube, and the like can be easily performed.

FIG. 3 is a sectional view showing a second embodiment of the self-supporting optical cable of the present invention. In the figure, the same parts as those in FIG. Reference numeral 21 is a fitting projection. In the second embodiment, an example in which the optical fiber core wire 5 is fixed to the inner surface of the horseshoe-shaped member 1 is shown.

In FIG. 3A, the optical fiber core wire 5 is fixed to the inner surface of the horseshoe-shaped member 1 with an adhesive. Various kinds of adhesives can be used, and as one of them, for example, a thermoplastic adhesive can be used. The horseshoe-shaped member 1 can be formed by, for example, extrusion molding, but when a thermoplastic adhesive is used, the heat can be used to form the horseshoe-shaped member 1 for bonding.

In FIG. 3B, a fitting projection 21 is provided on the inner surface of the horseshoe-shaped member 1. The optical fiber core wire 5 accommodated inside the horseshoe-shaped member 1 is fitted and fixed to the fitting projection 21.

FIG. 3C also shows an example in which the fitting protrusion 21 is provided in the same manner. Here, the optical cable 11 shown in FIG. 2 is fitted to the fitting projection 21. Optical cable 11
Has a recess formed in the center thereof, and the fitting projection 21 can be fitted into this recess to lock the optical cable 11.

As shown in FIGS. 3A to 3C, the optical fiber core wire 5 and the optical cable 1 are formed on the inner surface of the horseshoe-shaped member 1.
1. By fixing the tube body and the like, it becomes easy to identify each optical fiber core wire 5, the optical cable 11, the tube body, and the like, and it becomes easy to select the optical fiber core wire 5 and the like to be withdrawn during the withdrawing operation. Further, since the optical fiber core wire 5 and the like can be housed in the horseshoe-shaped member 1 in an orderly manner, problems such as entanglement inside do not occur. In addition, FIG.
In the configuration in which the fitting protrusion 21 is provided as shown in (C),
The fitting protrusions 21 may be arranged apart from each other, and the gripping force thereof is weaker than that of the adhesive. Therefore, when pulling out the optical fiber core wire 5 or the like at the time of pulling it down, it is not necessary to give much resistance.

Note that each of the configurations shown in FIG. 3 can be configured without using the closing member 3 shown in FIG. Of course, the closing member 3 may be provided.

FIG. 4 is a perspective view showing a third embodiment of the self-supporting optical cable of the present invention, and FIG. 5 is a sectional view of the portion a similarly. In the figure, the same parts as those in FIG. Reference numeral 31 is a mold member, and 32 is a closed portion.

The mold member 31 is provided intermittently,
The horseshoe-shaped member 1 and the support wire 4 are integrated. In addition, a closing portion 32 that partially closes the opening of the horseshoe-shaped member 1 is formed, and the horseshoe-shaped member 1 is reliably held by the support wire 4. Further, the closing portion 32 also has the function of the closing member 3 shown in FIG. 1, and holds the optical fiber core wire, the optical cable, the tubular body and the like housed in the horseshoe-shaped member 1. The molding member 31 can be molded with resin or the like.

Also in the third embodiment, specifically, the width of the opening of the horseshoe-shaped member 1 may be 10 mm or more, and the mold members 31 may be arranged at intervals of 15 cm or more. By setting the size to this extent, workability can be improved. The width of the opening is 1
If it is 0 mm or more, for example, a simple tool can be inserted through the opening and the optical fiber core wire 5 accommodated inside can be taken out. Further, by disposing the mold members 31 at intervals of 15 cm or more, it is possible to easily pull out the optical fiber core wire 5 without forcibly bending it when taking it out.

As described above, in the third embodiment, the closed portion of the horseshoe-shaped member 1 is integrally formed with a so-called molding resin that integrates the support wire 4 and the horseshoe-shaped member 1, so that the horseshoe-shaped member 1 is extruded. When manufacturing, the entire length can be processed as a member having the same cross section, the processing can be facilitated, the linear speed of the processing can be increased, and the cost can be reduced.

FIG. 6 is an illustration of an embodiment of the withdrawal method of the present invention. 41 is a self-supporting optical cable, 42
Is a telephone pole, and 43 is a subscriber's home. The self-supporting optical cable 41 is the self-supporting optical cable of the present invention as shown in the above-mentioned first to third embodiments. The self-supporting optical cable 41 is suspended imaginarily by using a utility pole 42 or the like. The self-supporting optical cable 41 can be arranged in series for several spans. Now, consider a case where the optical fiber core wire or the optical cable housed in the self-supporting optical cable 41 is dropped from the drop point to the subscriber's home 43. At this time, from the withdrawal point to the subscriber's home 4
The length of the cable required for pulling up to 3 is x.

First, as shown in FIG. 6 (A), a cutting point is set at a position downstream of the drop point, that is, on the opposite side of the switching center, by the length x of the cable required for the drop. Cut the optical fiber core, optical cable, tube, etc.

Then, as shown in FIG. 6 (B), the optical fiber core or the optical cable, the tubular body or the like to be withdrawn is selected and pulled out from the opening of the horseshoe-shaped member 1 at the withdrawal point. At this time, in the case of the self-supporting optical cable shown in the above-mentioned second embodiment, it is easy to identify the optical fiber core wire or the optical cable, the tubular body, etc. at the time of cutting and drawing. Further, by taking a large unobstructed opening of the horseshoe-shaped member 1, cutting and drawing can be easily performed.

As shown in FIG. 6C, the optical fiber core wire, the optical cable, the tube body and the like thus drawn out are
The customer's house 43 may be laid as it is and connected to the indoor line. This completes the withdrawal work to the subscriber's home 43. In addition, at the pulling-down point, it is more preferable to perform a work of fixing the pulled-down optical fiber core wire, the optical cable, the tube body, or the like so as not to be bent.

As described above, according to the pulling-down method of the present invention, only the necessary one is cut off without performing the troublesome work of cutting all the optical fiber core wires, optical cables, etc. at the pulling-down point and then connecting them as in the conventional case. Since it is only cut and pulled out, the withdrawal work can be greatly simplified. Also, the transmission loss due to the withdrawal can be minimized.

In the above-described embodiment, the horseshoe-shaped member is used as the cross-sectional shape of the long member having the open lower part.
The sectional shape is not limited to the horseshoe shape, and an appropriate shape having an open lower portion can be used.

[0049]

As is apparent from the above description, according to the self-supporting optical cable of the present invention, the long member serving as the jacket has an opening at the lower section, so that the work of removing the jacket is performed. It is possible to easily perform operations such as taking out, cutting, and pulling out a long body such as an optical fiber core wire or an optical cable or a pipe line having a built-in tensile strength body housed therein. At this time, it is not necessary to cut and connect the entire self-supporting optical cable at the pull-down point, so that the laying work can be greatly simplified, and the laying time, laying cost, and line cost can be reduced. Moreover, since the number of connection points can be reduced, transmission loss can be reduced. In addition, it is desirable that the long member is formed of rubber or plastic that can be formed into a stable shape at low cost by extrusion.

Further, by providing a closed portion intermittently in the longitudinal direction at the opening portion of the long member, the long member accommodated in the long member does not hang down, and these are attached to the long member. It can be well housed inside. At this time,
If the width of the opening of the long member is 10 mm or more and the distance between the closed portions is 15 cm or more, the drop line can be taken out with a simple tool, and the work efficiency can be further improved. The closed portion of the long member can be configured as a part of an integrated member for integrating the support member and the long member. This integrated member is
For example, it can be formed by molding with resin or the like. With this configuration, even when the horseshoe-shaped member is extruded, it can be processed as a member having the same cross section over the entire length even if it has a closed portion, and the processing becomes easy and the linear speed of processing can be increased, resulting in cost reduction. It can be reduced. In this case, the closed portion of the integrated member also has a function of holding the elongated body through the opening of the elongated member.

Further, the long body may be fixed to the inner surface of the long member, which facilitates selection of the optical cable to be pulled down, and the pull-down lines pulled out at the pull-down point are entangled with each other. Can be prevented. As a fixing method, for example, a thermoplastic adhesive can be used. Thereby, for example, when a long member is extruded, the heat can be used to fix the member, which simplifies the processing and reduces the cost. Further, a fitting projection may be provided on the inner surface of the long member to fix a long body such as an optical cable to the inner surface of the long member. In this case, without restraining in the longitudinal direction,
Since it can be fixed to the inner surface of a long member, it can be fixed so that it does not become a resistance when pulled out.

Further, by storing the long body in a long member with slack, the long body can be easily taken out at the pulling-down point.

When the self-supporting optical cable of the present invention as described above is used, the pulling operation is performed by pulling out a long member such as the required optical cable from the opening of the long member at the pulling point and pulling it down to the subscriber. Therefore, the installation work can be greatly simplified, and the installation time, installation cost, and line cost can be reduced. In addition, for example, the self-supporting optical cable of the present invention is laid across a series of spans for several spans, and the optical cable or the long body to be pulled down on the downstream side by the pulling distance is cut from the pulling point, and pulled out from the pulling point. By using it as a drop line, it is not necessary to connect the optical fiber cores in the section where a series of lines are crossed, and the connection at the drop point can be omitted. Thereby, there is an effect that the workability of withdrawal can be significantly improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a self-supporting optical cable of the present invention.

FIG. 2 is a cross-sectional view of an example of an optical cable housed in a horseshoe-shaped member.

FIG. 3 is a sectional view showing a second embodiment of the self-supporting optical cable of the present invention.

FIG. 4 is a perspective view showing a third embodiment of the self-supporting optical cable of the present invention.

FIG. 5 is a sectional view of part a in the third embodiment of the self-supporting optical cable of the present invention.

FIG. 6 is an explanatory diagram of an embodiment of the withdrawal method of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Horseshoe-shaped member, 2 ... Optical fiber core wire, 3 ... Closure member, 4 ... Support wire, 11 ... Optical cable, 12 ... Optical fiber core wire, 13 ... Steel core, 14 ... Outer sheath, 21 ... Fitting protrusion, Three
1 ... Mold member, 32 ... Closure part, 41 ... Self-supporting optical cable, 42 ... Utility pole, 43 ... Subscriber house.

Front page continued (72) Inventor Shigeru Tanaka 1 Taya-cho, Sakae-ku, Yokohama, Kanagawa Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Kazuo Hokari 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph Telephone Co., Ltd. (72) Inventor Osamu Kawada 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (10)

[Claims] 1. A support member for suspending an optical cable in an imaginary manner, and a long member having a cross-section with an open lower portion, the long member being supported by the support member along its longitudinal direction. A self-supporting optical cable, characterized in that the elongated member accommodates an elongated member such as an optical cable or a conduit having an optical fiber core wire or a strength member inside. 2. The self-supporting optical cable according to claim 1, wherein the elongated member is made of rubber or plastic. 3. The self-supporting optical cable according to claim 1, wherein the opening of the elongated member has a closed portion intermittently in the longitudinal direction. 4. The width of the opening of the elongated member is 10 mm.
The self-supporting optical cable according to claim 3, wherein the closing portions are arranged at intervals of 15 cm or more in the longitudinal direction of the elongated member. 5. An integrated member for integrating the support member and the elongated member, wherein the closing portion is configured as a part of the integrated member. Item 5. The self-supporting optical cable according to item 3 or 4. 6. The self-supporting optical cable according to any one of claims 1 to 5, wherein the elongated body is fixed to an inner surface of the elongated member. 7. The self-supporting optical cable according to claim 1, wherein the elongated body is fixed to the inner surface of the elongated member with a thermoplastic adhesive. . 8. A protrusion for fitting with the elongated body is provided on an inner surface of the elongated member, and the elongated body is fitted with the protrusion to be fixed to an inner surface of the elongated member. The self-supporting optical cable according to any one of claims 1 to 5, wherein 9. The self-supporting type according to claim 1, wherein the elongated body is accommodated in the elongated member with a slack with respect to the supporting wire. Optical cable. 10. A pulling-down method for selecting a part of optical fiber core wires from an optical cable suspended imaginarily and laying the optical fiber core wires or an optical cable including the optical fiber core wires to a subscriber, The self-supporting optical cable according to any one of claims 1 to 9 is used as the optical cable suspended aerially, and the long member is provided from one point near the subscriber in a laying route of the optical cable. A method of withdrawing, characterized in that the elongated body necessary for withdrawing is pulled out from the elongated member without cutting, and is withdrawn to the subscriber.