EP0829884A1 - Telecommunications cable for high bit rate signals - Google Patents

Abstract

The telecommunications cable contains multiple individually insulated conductors(3-4) enclosed as a group by a first insulating sheath (5). This sheath is enclosed by a screen (6) having a metallic face and an insulating face. An outer sheath (7) made of an insulating material encloses the screen. To aid identification of the conductors enclosed in the cable, the outer sheath carries markings (B1,B2) either along its length or spirally around its periphery. The markings are formed by extrusion of coloured filaments of a plastic material as the outer sheath is being formed. The filaments may include a fluorescent material to aid visibility in low light.

Description

The present invention relates to a cable basic telecommunications for high signals frequency, telephone and / or data processing, particularly intended for data transmission digital broadband of the order of 100 to 500 Mbps.

In a local network installed in a building, there are two kinds of cables: low cables capacity with 4, 8 or 12 pairs, called cables horizontal distribution 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 distributor general and floor distributors, or between floor distributors.

According to European patent application EP-A-0 599 672, a basic telecommunication cable includes two fourths of insulated conductor wires which are together surrounded by a first sheath in one insulating material located directly in contact with insulated conductors, without the latter are drowned in the first sheath. A screen metal is placed around the sheath.

The screen serves as shielding to avoid disturbance of the signals carried by the cable by external electromagnetic radiation and attenuates any crosstalk with basic cables neighbors. An electrical continuity wire is placed between the first sheath and the screen and is intended for 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 under the shaped like a thin metallic sheet. However, in practical, the screen is aluminum foil which one side is covered externally with a film polyester which reinforces the aluminum foil and protects cable tools from attack aluminum foil, during the manufacturing of the elementary cable. The metallic screen face, in aluminum, is in direct contact with the first sheath.

In a main telecommunication cable containing several bundles formed by such basic cables, a main screen surrounds the set of elementary cables and is itself surrounded by an outer insulating holding sheath and protective PVC or fire-retardant material without halogen.

When manufacturing the main cable, identification strips, such as ribbons thin laminated or paper, are inserted freely between the screens of the elementary cables and the main screen. On site, after stripping and clear cut of the outer sheath and of the screen main, 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 especially when the threads of each elementary cable in the main cable must be connected respectively to contacts insulation displacement switches of a respective distributor module, the elementary cables are open and must be suitably identified in order to connect each conductive wire insulated at a contact. During these connection operations, laminates identification intermingle so that it is often difficult to associate the strips with elementary cables, which is a source of error in the connections. This intermingling is all the more more pronounced than the number of elementary cables in the main cable is high.

The present invention aims to remedy the disadvantages mentioned above and particularly to provide a means of identification with each elementary cable which does not mix with those of other cables elementary, independently of elementary cables themselves.

To this end, a telecommunications cable basic for high speed signals including several individually insulated conductors, a first sheath of insulating material surrounding together the insulated conductors, and a screen having a metallic face and an insulating face and surrounding the first sheath is characterized by a cable identification marking integrated into a outer envelope surrounding the insulating face of the screen.

According to a first embodiment, the face metallic 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 jacket of the cable is in extruded plastic with the marking under the shape of one or more colored nets or bands 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 envelope external is merged with the external metallic face of the screen. The metal face of the screen thus has a dual role of supporting identification marking of the elementary and metal / metal contact cable with screens of other elementary cables in a cable main. Advantageously, no continuity thread electrical in the elementary cables according to the second achievement is planned.

The marking on said outer envelope includes cable identification markings, periodically preferably axially to the cable, and / or separate ribbons impregnated in the envelope.

The invention also relates to a cable for main telecommunications comprising several basic telecommunication cables, conforming to the invention, a main screen having one side internal metal surrounding the elementary cables, and an outer protection and support sheath surrounding the main screen.

The main cable can include at least one stuffing element, preferably comprising at minus an optical fiber.

• la figure 1 est une vue en perspective schématique d'une coupe transversale d'un câble de télécommunication élémentaire selon une première réalisation de l'invention ;
• la figure 2 est une vue en coupe schématique d'un câble de télécommunication principal comprenant plusieurs câbles élémentaires selon l'invention ;
• la figure 3 est une vue en perspective schématique d'une coupe transversale d'un câble de télécommunication élémentaire selon une seconde réalisation de l'invention ;
• la figure 4 est une vue en coupe longitudinale schématique d'une extrémité dégainée d'un câble élémentaire à connecter, selon la première réalisation ; et
• la figure 5 est une vue en coupe longitudinale schématique d'une extrémité dégainée d'un câble élémentaire à connecter, selon la seconde réalisation.

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 appended 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.

Referring to Figure 1, a flat cable elementary 1 includes two twisted star quads 2. Each of the quads 2 includes four threads solid annealed copper conductors 3 which are insulated from each other by insulating sleeves individual 4, for example polyethylene or polypropylene.

The two quartes 2 are juxtaposed one beside on the other in a first sheath 5, called sheath of maintenance of quarters. The retaining sheath 5 surrounds insulated conductors 3-4 without being embedded in the retaining sheath 5. The sheath support 5 is thin and is made of material thermoplastic, preferably transparent way to distinguish different colors from individual conductor sheaths 4 in the two quartes. According to another variant, the sheath of retaining 5 is a helical ribbon, 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 line of tear 51 so as to tear the sheath 5 during a connection of 3-4 insulated conductors by example to insulation displacement contacts of a module distributor.

The flat cable 1 also includes a screen metal shielding.

According to a first embodiment , the screen 6 consists of a composite thin 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 61 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. Sheath 7 has a thickness of a few tenths of a millimeter and is therefore thinner than sheath 5 and therefore more flexible. The additional cost provided by the sheath 7 is thus relatively small. A second tearing line 71 is housed between the screen 6 and the second sheath 7 of way to tear one end of the sheath 7 when connection of one end of the cable 1.

Sheath 7 identifies flat cable 1 with one or more predetermined color (s) and possibly by a predetermined periodic reference frame axially at cable, such as a sign, relief or number, or predetermined alphanumeric characters, so to distinguish cable 1 from other elementary cables neighbors in a main cable, like this will appear below with reference to Figure 2. By example, the distinguishing mark of cable 1 can be also consisting of one or more nets or bands of predetermined colors that extend longitudinally or helically on the sheath 7, and which are either extruded at the same time as the extrusion of the sheath 7, ie 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 an MX1 mark and two bands helical fluorescent colors and / or reliefs different B1 and B2 integrated into the sheath 7, the sheath color 7 being different from that (s) tapes.

Referring now to Figure 2, a main cable CA brings together eight bundles of four pairs of wires each, each bundle being constituted by an elementary flat cable 1 as shown in Figure 1. The AC cable thus includes 32 pairs. The eight elementary cables 1 are combined in a main metallic screen E, which is surrounded by a support and protection sheath outside G. One or more stuffing rods are also circumscribed with the elementary cables 1 by the screen E of the CA cable. According to the realization illustrated in Figure 2, a small JG stuffing rod is arranged substantially in the center of the AC cable, and a JP packing rod with a substantially section analogous to flat elementary cables 1 is arranged at the edge of the AC cable. A rush, such as the rush of jamming JP, can be a tube in material thermoplastic or elastomer in which extend several optical fibers in bulk or several fiber modules.

Thanks to different identification markings second sheaths 7 of the eight elementary cables 1, that is to say thanks to colors of second sheath different and / or different marks "MX1" and / or bands of different colors B1, B2, cables elementary 1 are easily spotted and identifiable after stripping the sheath G and 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 held by a holding sheath 5 preferably transparent, as in the first embodiment. A tearing line 51 is also provided under the sheath 5.

Around the sheath 5 in the cable 10 is only provided a composite metal screen 60 which is rolled up or extended in the same way as the screen 6. Unlike screen 6, the insulating face in polyester of screen 60 constitutes the internal face 60I of the screen and is in contact with the 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 combined in one AC cable as shown in Figure 2, screens 60 elementary cables 10 are in contact with each other with others, so there is no need to provide an electrical continuity wire in each of the elementary cables 10, like the wire of continuity 61 in cable 1. A single wire of electrical continuity FC can be provided between the main screen E and the outer sheath G in the 10 or AC cable, although this FC wire is not strictly necessary.

Identification of elementary cables 10 in the AC cable is made by periodic marks respective and different between them on screens 60 elementary cables 10, such as signs, reliefs, "SR10" alphanumeric numbers or characters, inscribed by stamping, or with ink or paint suitable, for example. According to another variant, cable identification consists of nets or respective narrow width ribbons of color different or 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 realizations are connectable indifferently in the same distributor modules, although cables 1 and 10 do not contain, except requested, electrical continuity wire.

As illustrated in Figure 4, after tearing of the end of the identification sheath 7 of the cable 1 according to the first embodiment, by pulling on the tearing line 71, the end of the screen 6 is not only severed, but is also incised in a few incisions substantially longitudinal 62 evenly distributed peripherally. Then incised portions of the screen 63 are folded 180 ° towards the external face screen 6E and the insulating sheath 7. The internal face metallic 61 of screen 6 becomes the external face folded incised portions 63. These latter are then trapped between jaws, contacts or the like of a grounding means, schematized by arrows PT. The continuity of shielding by a substantially 360 ° connection avoids any high frequency electromagnetic leak.

When the electrical continuity wire 61 is present in cable 10, it is wrapped around of all the folded-down portions 63.

The screen 60 in the elementary cable 10 according to the second realization can be put directly to the earth with the same PT earthing means, since the external face 60E of the screen 60 is the face metallized, as shown in Figure 5.

Claims (10)

Basic telecommunications cable (1; 10) for broadband signals comprising several individually insulated conductor wires (3-4), one first sheath of insulating material (5) surrounding together the insulated conductors, and a screen (6 ; 60) having a metal face and an insulating face and surrounding the first sheath (5), characterized by an identification marking (MX1, B1, B2; SR10, R1, R2) of the cable integrated into an external envelope (7; 60E) surrounding the insulating face (6E; 60I) of the screen (6; 60). Cable (1) according to claim 1, in which the metal face of the screen (6) constitutes an internal face (61) of the screen in contact with the first sheath (5), and said envelope external is a second sheath made of insulating material (7). Cable according to claim 2, comprising a tearing line (71) housed between the screen (6) and the second sheath (7). Cable according to claim 2 or 3, in which the outer casing (7) is made of material extruded plastic with marking in the form of a or several 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 portions incised (63) of the screen (6) folded down substantially at 180 ° to the second sheath (7). Cable (10) according to claim 1, in which the insulating face of the screen (60) constitutes an internal face (60I) of the screen in contact with the first sheath (5), and said outer casing coincides with the face metallic (60E) of the screen (60). Cable (1; 10) according to any one of claims 1 to 6, wherein the marking on said external envelope (7; 60E) comprises cable identification marks, preferably periodically axially to the cable, and / or ribbons distinct (B1, B2, R1, R2) impregnated in the envelope. Telecommunications cable (AC) including several basic telecommunication cables (1 ; 10) according to any one of claims 1 to 7, a main screen (E) having one side internal metal surrounding the elementary cables (1; 10), and an outer sheath for protection and support (G) surrounding the main screen. Cable according to claim 8, comprising at least one stuffing element (JG; JP), preferably comprising at least one optical fiber (FO). Cable according to claim 8 or 9, when it only includes elementary cables according to claim 6, comprising only one single electrical continuity wire (FC).

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