FR2753562A1 - TELECOMMUNICATION CABLE FOR HIGH SPEED SIGNALS - Google Patents

Abstract

An elementary cable or bundle comprises several insulated conductor wires (3-4), a first sheath of insulating material (5) surrounding the insulated conductor wires, and a screen (6) having a metallic face and an insulating face. In order to identify elementary cables contained in large numbers in a main cable sheath, during their connection, an identification marking of the elementary cable is integrated into a second sheath of insulating material (7; 60E) surrounding the insulating face (6E ; 60I) of the screen (6; 60), or to the metal outer face of the screen. For example, the marking is in the form of one or more colored plastic threads extruded into the second sheath.

Description

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  Telecommunication cable for high speed signals The present invention relates to a basic telecommunication cable for high frequency signals, telephone and / or data processing, particularly intended for the transmission of digital data at high speed of the order of 100 to 500 Mbit / s. In a local network installed in a building, there are two kinds of cables: low capacity cables with 4, 8 or 12 pairs, called horizontal distribution cables or capillary cables, and high capacity cables with 24, 32, 64 or 128 pairs, called vertical distribution cables or bypass cable. The bypass cables can be made up of capillary cables. The bypass cables extend between a general distributor and floor distributors, or between

floor distributors.

  According to European patent application EP-A-0 599 672, an elementary telecommunication cable comprises two quarters of insulated conductive wires which are together surrounded by a first sheath made of an insulating material located directly in contact with the insulated conductive wires, without the latter are embedded in the first sheath. A screen

  metal is placed around the sheath.

  The screen serves as a shield to avoid disturbance of the signals transported by the cable by external electromagnetic radiation and attenuates any crosstalk with neighboring elementary cables. An electrical continuity wire is placed between the first sheath and the screen and is intended for

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  be wrapped around a ground terminal of a module

  distributor and thus connect the screen to earth.

  According to EP-A-0 599 672, the screen is in the form of a thin metal sheet. However, in practice, the screen is an aluminum sheet, one side of which is covered on the outside with a polyester film which reinforces the aluminum sheet and protects the cable tools against attack by the aluminum sheet, during of the manufacture of the elementary cable. The metallic screen face, made of aluminum, is in direct contact with the first sheath. In a main telecommunication cable containing several bundles formed by such elementary cables, a main screen surrounds all of the elementary cables and is itself surrounded by an outer insulating sheath for holding and protecting PVC or fire-retardant material without

halogen.

  During the manufacture of the main cable, identification strips, such as thin plasticized or paper tapes, are inserted freely between the screens of the elementary cables and the main screen. On site, after stripping and clear cutting of the outer sheath and the main screen, the identification strips having different colors between them are used to identify

the elementary cables.

  When one end of the cable must be connected for example to a distributor, and more particularly when the conducting wires of each elementary cable in the main cable must be connected respectively to insulation displacement contacts of a respective distributor module,

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  the elementary cables are open and must be properly identified in order to connect each insulated conductor wire to a contact. During these connection operations, the identification strips intertwine, so that it is often difficult to associate the strips with the elementary cables, which is a source of error in the connections. This intermingling is all the more pronounced as the number of elementary cables

  in the main cable is high.

  The present invention aims to remedy the aforementioned drawbacks and in particular to provide a means of identification for each elementary cable which does not mix with those of other elementary cables, independently of the elementary cables themselves. To this end, an elementary telecommunications cable comprising several insulated conductive wires, a first sheath of insulating material surrounding the insulated conductive wires, and a screen having a metallic face and an insulating face, is characterized by an identification marking of the integrated cable. to an external envelope surrounding the face

screen insulator.

  According to a first embodiment, the metal face of the screen constitutes an internal face of the screen in contact with the first sheath, as according to the prior art. The outer envelope is then a second sheath made of insulating material

  thin, separate from and surrounding the screen.

  For example, the outer casing of the cable is made of extruded plastic with the marking in the form of one or more colored nets or bands

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  extruded (B1, B2) having colors different from

  the color of the sheath, and sometimes between them.

  According to a second embodiment, the insulating face of the screen constitutes an internal face of the screen in contact with the first sheath, and the external envelope is merged with the external metallic face of the screen. The metal face of the screen thus has a dual role of supporting the identification marking of the elementary cable and of metal / metal contact with the screens of other elementary cables in a main cable. Advantageously, no electrical continuity wire in the elementary cables according to the

  second achievement is planned.

  The marking on said outer casing includes identification marks of the cable, preferably periodic axially to the cable, and / or

  separate ribbons impregnated in the envelope.

  The invention also relates to a main telecommunications cable comprising several elementary telecommunication cables, in accordance with the invention, a main screen having an internal metallic face surrounding the elementary cables, and an outer protective and retaining sheath.

surrounding the main screen.

  The main cable can comprise at least one stuffing element, preferably comprising at least

minus an optical fiber.

  Other characteristics and advantages of the present invention will appear more clearly on

  reading the following description of several

  preferred embodiments of the invention with reference to the corresponding accompanying drawings in which: - Figure 1 is a schematic perspective view of a cross section of an elementary telecommunication cable according to a first embodiment of the invention; - Figure 2 is a schematic sectional view of a main telecommunication cable comprising several elementary cables according to the invention; - Figure 3 is a schematic perspective view of a cross section of an elementary telecommunication cable according to a second embodiment of the invention; - Figure 4 is a schematic longitudinal sectional view of a stripped end of an elementary cable to be connected, according to the first embodiment; and - Figure 5 is a schematic longitudinal sectional view of a stripped end of an elementary cable to be connected, according to the second embodiment. With reference to FIG. 1, an elementary flat cable 1 comprises two twisted star quads 2. Each of the quarter 2 comprises four solid conductive wires of annealed copper 3 which are insulated from each other by individual insulating sheaths 4, for example made of polyethylene or polypropylene. The two quartes 2 are juxtaposed one next to the other in a first sheath 5, called the quartet retaining sheath. The retaining sheath 5 is thin and is made of thermoplastic material, preferably transparent so as to distinguish the different colors of the individual sheaths of conductive wire 4 in the two quarters. According to another variant, the retaining sheath 5 is a ribbon tape

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  helically, or a ribbon laid lengthwise, the longitudinal edges of which are glued or welded to form an oval or elliptical tube. Under the first sheath 5 is provided a tearing cord 51 so as to tear the sheath 5 during connection of the insulated conductive wires 3-4 for example to contacts

  insulation displacement modules.

  The flat cable 1 also includes a screen

metal shielding.

  According to a first embodiment, the screen 6 consists of a thin composite sheet having an internal metallic face 6I, constituted by an aluminum sheet, and an insulating external face 6E, constituted by a polyester sheet, for example adhesive-bonded to the sheet in aluminium. To facilitate the implementation of the screen, it can be constituted by a composite ribbon wound helically around the sheath 5 or extended longitudinally along the sheath 5; the overlapping longitudinal edges of the screen can be welded or stapled or glued around the sheath 5, which also improves the high frequency electromagnetic compatibility of the screen. Between the retaining sheath 5 and the internal screen face 6I extends a tinned copper electrical continuity wire 61, which is optional, for earthing the screen 6 according to the invention, as specified below. . A second thin identification sheath 7 intimately surrounds the screen 6 and thus envelops the insulating external face 6E of the screen. The sheath 7 has a thickness of a few tenths of a millimeter and is therefore thinner than the sheath 5 and therefore more flexible. The additional cost provided by the sheath 7 is thus

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  relatively small. A second tearing cord 71 is housed between the screen 6 and the second sheath 7 so as to tear one end of the sheath 7 during

  connection of one end of the cable 1.

  The sheath 7 identifies the flat cable 1 by one or more predetermined color (s) and possibly by a predetermined periodic reference axially to the cable, such as a sign, relief or number, or predetermined alphanumeric characters, so as to distinguish cable 1 from other neighboring elementary cables in a main cable, as will appear below with reference to FIG. 2. For example, the distinctive mark of cable 1 can also consist of one or more colored nets or bands predetermined which extend longitudinally or helically on the sheath 7, and which are either extruded at the same time as the extrusion of the sheath 7, or inscribed for example

  with one or more permanent inks on the sheath 7.

  The marks, marks or nets are preferably fluorescent so that they are more visible under

low light.

  According to the embodiment illustrated in FIG. 1, the elementary cable is identified by a double marking consisting of a mark MX1 and two fluorescent helical bands of different colors and / or reliefs B1 and B2 integrated into the sheath 7, the color of the sheath 7 being different from that (s)

tapes.

  Referring now to FIG. 2, a main cable CA gathers eight bundles with four pairs of conductive wires each, each bundle being constituted by an elementary flat cable 1 as shown in FIG. 1. The cable CA thus comprises 32 pairs. The eight elementary cables 1 are combined

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  in a main metallic screen E, which is surrounded by a holding and external protective sheath G. One or more stuffing rods are also circumscribed with the elementary cables 1 by the screen E of the cable CA. According to the embodiment illustrated in FIG. 2, a small jamming rod JC is disposed substantially in the center of the cable CA, and a jamming rod JP with a section substantially similar to the elementary flat cables 1 is disposed at the periphery of the cable CA. A rod, such as the jamming rod JP, can be a tube made of thermoplastic or elastomer material in which several bulk optical fibers F0 or more

fiber modules.

  Thanks to the different identification markings of the second sheaths 7 of the eight elementary cables 1, that is to say by means of different colors of second sheath and / or different marks "MXl" and / or bands of different colors B1 , B2, the elementary cables 1 are easily identifiable and identifiable after the sheathing of the sheath G and of

screen E during a connection.

  According to a second embodiment of an elementary cable shown in FIG. 3, an elementary flat cable 10 gathers, like the flat cable 1, eight solid copper conductor wires 3 surrounded by respective insulating sheaths 4 and distributed in two twisted star quads 2. The two quartes in the cable 10 are maintained by a holding sheath 5 preferably transparent, as in the first embodiment. A tear line 51 is also

provided under the sheath 5.

  Around the sheath 5 in the cable 10 is only provided a composite metallic screen 60 which

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  is wound or extended in the same way as the screen 6. Unlike screen 6, the polyester insulating face of the screen 60 constitutes the internal face 60I of the screen and is in contact with the retaining sheath 5 The metallic aluminum face 60E of the screen 60 constitutes the external face 60E of the screen and thus envelops the insulating internal face 60I of the screen. When several cables 10 are joined in an AC cable as shown in FIG. 2, the screens 60 of the elementary cables 10 are in contact with each other, so that it is not necessary to provide an electrical continuity wire in each of the elementary cables 10, such as the continuity wire 61 in the cable 1. A single electrical continuity wire FC can be provided between the main screen E and the outer sheath G in the cable 10 or CA, although this wire FC is not

strictly necessary.

  The identification of the elementary cables 10 in the cable CA is carried out by respective periodic marks and different from each other on the screens 60 of the elementary cables 10, such as signs, reliefs, numbers or alphanumeric characters "SR10", registered by stamping, or with suitable ink or paint, for example. According to another variant, the identification of the cables consists of nets or ribbons of respective small width of different color or of different reliefs R1, R2 printed

  or stamped on the external face 60E of the screen 60.

  The ends of the elementary cables 1 and 10 according to the two embodiments can be interconnected in the same distributor modules,

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  although cables 1 and 10 do not contain, except

  requested, electrical continuity wire.

  As illustrated in FIG. 4, after tearing the end of the identification sheath 7 of the cable 1 according to the first embodiment, by pulling on the tearing cord 71, the end of the screen 6 is not only sectioned, but is also incised in a few substantially longitudinal incisions 62 regularly distributed peripherally. Then incised screen portions 63 are folded 180 towards the external screen face 6E and the insulating sheath 7. The internal metal face 6I of screen 6 becomes the external face of the folded incised portions 63. These are then trapped between jaws, contacts or the like of a grounding means, shown schematically by arrows PT. The continuity of the shielding through a substantially 360 connection avoids

  any high frequency electromagnetic leak.

  When the electrical continuity wire 61 is present in the cable 10, the latter is wound around

  of all the folded-down portions 63.

  The screen 60 in the elementary cable 10 according to the second embodiment can be earthed directly with the same grounding means PT, since the external face 60E of the screen 60 is the face

  metallized, as shown in Figure 5.

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Claims (1)

CLAIMS i - Elementary telecommunications cable (1;) comprising several insulated conductive wires (3-   4), a first sheath of insulating material (5) surrounding the insulated conductive wires, and a screen (6) having a metal face and an insulating face, characterized by an identification marking (MXl, B1I, B2; SR10, R1 , R2) of the cable integrated into an external envelope (7; 60E) surrounding the face   insulating (6E; 60I) of the screen (6; 60).   2 - Cable (1) according to claim 1, in which the metal face of the screen (6) constitutes an internal face (6I) of the screen in contact with the first sheath (5), and said external envelope is a second sheath made of insulating material (7). 3 - Cable according to claim 2, comprising a tearing line (71) housed between   the screen (6) and the second sheath (7).   4 - Cable according to claim 2 or 3, wherein the outer casing (7) is made of extruded plastic with the marking in the form of one or more extruded colored nets or bands having colors different from the color of the sheath. - Cable conforms to any of   claims 2 to 4, comprising one end   torn from the second sheath (7), and incised portions (63) of the screen (6) folded down substantially 180 to the second sheath (7). 12 2753562   6 - Cable (10) according to claim 1, wherein the insulating face of the screen (60) constitutes an internal face (60I) of the screen in contact with the first sheath (50), and said external envelope is confused with the face metallic (60E) of the screen (60).   7 - Cable (1; 10) according to any one   of claims 1 to 6, wherein the marking on   said external envelope (7; 60E) comprises identification marks of the cable, preferably periodically axially to the cable, and / or separate ribbons (B1, B2, Ri, R2) impregnated in the envelope.   8 - Telecommunication cable (CA) comprising several elementary telecommunication cables (1   ) according to any of the claims   1 to 7, a main screen (E) having an internal metallic face surrounding the elementary cables (1; 10), and an outer sheath for protection and   support (G) surrounding the main screen.   9 - Cable according to claim 8, comprising at least one stuffing element (JC; JP), preferably comprising at least one optical fiber (FO). 10 - Cable according to claim 8 or 9, when it comprises only elementary cables according to claim 6, comprising only one   single electrical continuity wire (FC).