Communication cable

Abstract

To provide a communication cable having a large number of twisted-pair wires that can suppress the occurrence of near-end crosstalk. [Solution] The communication cable (1) of the present invention is a communication cable (1) having a plurality of core wire units (10), each of the plurality of core wire units (10) having a plurality of twisted pair wires (12) that are bundled together, in each of the plurality of core wire units (10) the twisted pair pitch of the plurality of twisted pair wires (12) is different, between two adjacent core wire units (10) of the plurality of core wire units (10) the twisted pair pitch of the plurality of twisted pair wires (12) is different from each other, between two adjacent core wire units (10) of the plurality of core wire units (10) the bundled twist pitch is different from each other, and the bundled twist pitch is greater than 60 mm and less than 120 mm.

Description

Technical Field

[0001] The present invention relates to a communication cable.

Background Art

[0002] In recent years, communication cables such as LAN (Local Area Network) cables have been used for connecting various devices such as between servers, between servers and switches, between servers and personal computers, robotic sensors, and gigabit-capacity cameras, and are required to be suitable for high-speed data communication.

[0003] Patent Document 1 discloses a communication cable which is a multi-pair cable suitable for such high-speed communication. The multi-pair cable has a large number of twisted pairs in which two insulated electric wires are twisted together.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in a communication cable having a large number of twisted pairs as described in Patent Document 1, near-end cross talk (NEXT) is likely to occur.

[0006] An object of the present invention is to provide a communication cable having a large number of twisted pairs that can suppress the occurrence of near-end cross talk.

Means for Solving the Problems

[0007] According to one aspect of the present invention for solving the above problems, a communication cable having a plurality of core wire units, Each of the aforementioned multiple core wire units has multiple twisted pairs of wires, In each of the aforementioned multiple core wire units, the pair twist pitch of the multiple stranded wires is different. Between two adjacent core wire units among the plurality of core wire units, the pair twist pitches of the plurality of twisted wires are different from each other. Between two adjacent core wire units among the plurality of core wire units, the stranding pitch is different from that of the other. The aforementioned twisted strand pitch is characterized by being greater than 60 mm and less than 120 mm. A communication cable will be provided. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a communication cable having a large number of twisted-pair wires that can suppress the occurrence of near-end crosstalk. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a cross-sectional view of a communication cable according to an embodiment of the present invention. [Figure 2] Figure 2 is a flowchart of a method for manufacturing a communication cable according to an embodiment of the present invention. [Modes for carrying out the invention]

[0010] The following describes a communication cable according to an embodiment of the present invention. However, the communication cable of the present invention is not limited to the embodiments shown below. In this specification, the "~" indicating a numerical range includes both an upper limit and a lower limit.

[0011] [Communication Cable] Figure 1 is a cross-sectional view of a communication cable 1 according to one embodiment of the present invention.

[0012] Communication cable 1 is a so-called LAN cable. Communication cable 1 has multiple core wire units 10, and each of the multiple core wire units 10 has multiple twisted-pair wires 12, each consisting of two insulated wires 11 twisted together (paired). In each of the multiple core wire units 10, the multiple twisted-pair wires 12 are further twisted together (bundle-twisted).

[0013] In each of the multiple core wire units 10, the twisting pitch of the multiple stranded wires 12 is different. This creates a difference in twisting pitch, causing the electromagnetic fields to cancel each other out and suppressing near-end crosstalk that occurs within the core wire unit 10. Specifically, as shown in Figure 1, each of the multiple stranded wires 12 is color-coded, for example, blue, orange, green, and brown, and arranged in this order clockwise in the circumferential direction of the cross-section of the core wire unit 10. Each of these color-coded stranded wires 12 has a different twisting pitch.

[0014] The twisted-pair pitch is the length of the twisted-pair wire 12 when one of the two insulated wires 11 that are twisted together and extend in a spiral is traced around the spiral axis once. Furthermore, "different" here means different when considering the tolerance of the twisted-pair pitch. Specifically, since the twisted-pair pitch has a tolerance of about ±5%, "different" means that it differs when comparing the average of many twisted-pair pitches.

[0015] Furthermore, between two adjacent core wire units 10 (two core wire units 10 adjacent in the circumferential direction in the cross-section of the communication cable 1), the twisting pitches of the multiple twisted wire pairs 12 are different. This creates a difference in the twisting pitch, causing the electromagnetic fields to cancel each other out and suppressing near-end crosstalk that occurs between the core wire units 10. Specifically, as shown in Figure 1, each of the multiple core wire units 10 is assigned the labels A, B, C, and D, and they are arranged in this order clockwise in the circumferential direction of the cross-section of the communication cable 1. In this case, when comparing core wire unit 10 A with core wire unit 10 B, core wire unit 10 B with core wire unit 10 C, core wire unit 10 C with core wire unit 10 D, and core wire unit 10 D with core wire unit 10 A, the twisted pair pitches of the multiple twisted wires 12 are all different. On the other hand, when comparing core wire unit 10 A with core wire unit 10 C, or core wire unit 10 B with core wire unit 10 D, the twisted pair pitches of the twisted wires 12 may be different or the same. In this embodiment, they are the same.

[0016] The pair-strand pitch is not particularly limited, but for example, it is 9.0 mm to 18.0 mm. Also, when the pair-strand pitch of the smaller of two adjacent pair-strand wires 12 is set to 1.0, the pair-strand pitch of the adjacent pair-strand wires 12 is, for example, about 1.1 to 1.9.

[0017] Furthermore, the twisted strand pitches differ between two adjacent core wire units 10 among the multiple core wire units 10. This creates a difference in the twisted strand pitch, causing the electromagnetic fields to cancel each other out and suppressing near-end crosstalk between the core wire units 10. Specifically, for example, when comparing core wire unit 10 A with core wire unit 10 B, and when comparing core wire unit 10 B with core wire unit 10 C, the twisted strand pitches of the four pairs of twisted wires 12, which are color-coded in four colors, are different. On the other hand, when comparing core wire unit 10 A with core wire unit 10 C, or when comparing core wire unit 10 B with core wire unit 10 D, the twisted strand pitches may be different or the same. In this embodiment, they are the same.

[0018] The collective twist pitch is the lengthwise distance of the core wire unit 10 when tracing one pair of the twisted pairs 12 out of the plurality of pairs of twisted pairs 12 that are collectively twisted and spiral-shaped, around the spiral axis for one turn. Also, "different" here means different considering the tolerance of the collective twist pitch. Specifically, since the collective twist pitch has a tolerance of about ±10%, "different" means different when comparing the average of a large number of collective twist pitches.

[0019] The collective twist pitch is not particularly limited, but it is preferably more than 60 mm and less than 120 mm. When the collective twist pitch becomes as long as 120 mm or more, the pitch becomes unstable (the variation becomes large), and the function of suppressing dropped calls deteriorates. On the other hand, when it is as small as 60 mm or less, due to the twisting of the collective twist pitch, the twist pitch of the twisted pairs fluctuates, affecting the twist pitch difference between the twisted pairs 12, and the function of suppressing dropped calls deteriorates. From this perspective, it is more preferable that the collective twist pitch is more than 70 mm and less than 110 mm.

[0020] Among two adjacent core wire units 10, when the smaller collective twist pitch is taken as 1, the collective twist pitch in the adjacent core wire units 10 is, for example, about 1.05 to 1.8.

[0021] In the communication cable 1, it is preferable that the plurality of core wire units 10 are collectively twisted. By collectively twisting the plurality of core wire units 10, near-end crosstalk is suppressed. The collective twist pitch of the plurality of core wire units 10 is not particularly limited, but it is preferably more than 200 mm and less than 350 mm. The collective twist pitch of the plurality of core wire units 10 is the lengthwise distance of the communication cable 1 when tracing one of the plurality of core wire units 10 that are collectively twisted and spiral-shaped, around the spiral axis for one turn.

[0022] In the communication cable 1, the number of core wire units 10 is not particularly limited, as long as there are multiple units. In this embodiment, the number of core wire units 10 is four. Also, the number of twisted wire pairs 12 in the core wire unit 10 is not particularly limited. In this embodiment, the number of twisted wire pairs 12 in the core wire unit 10 is four pairs. That is, in this embodiment, the communication cable 1 has four core wire units 10, and each of the four core wire units 10 has four pairs of twisted wire pairs 12. Thus, in this embodiment, the communication cable 1 has a total of 16 pairs of twisted wire pairs 12.

[0023] As shown in Figure 1, the core wire unit 10 of the communication cable 1 has a plurality of insulated wires 11, an internal intervening 13, and an inner sheath layer 14. Each of the plurality of insulated wires 11 has a conductor 11a and an insulating layer 11b. In addition to the plurality of core wire units 10, the communication cable 1 further has a retaining layer 40 and an outer sheath layer 50. Preferably, the communication cable 1 further has a central intervening 20 and inter-unit intervening 30. Each of these will be described below.

[0024] (conductor) The conductor 11a is a wire formed from a conductive metal material. The conductor 11a may be a single wire or a stranded wire made by twisting multiple wires together. Here, "twist pitch" refers to the length of the conductor 11a required for any one helical soft copper wire to complete one revolution around the helical axis when multiple soft copper wires are twisted together. In this embodiment, the conductor 11a is a single wire.

[0025] The diameter of the conductor 11a is not particularly limited. The diameter of the conductor 11a is appropriately selected depending on the application and type of the communication cable 1. For example, the diameter of the conductor 11a is in the range of 0.3 to 0.7 mm. In this embodiment, the diameter of the conductor 11a is approximately 0.5 mm.

[0026] (Insulating layer) The insulating layer 11b covers the conductor 11a. The material of the insulating layer 11b is not particularly limited as long as it has insulating properties. In this embodiment, the material of the insulating layer 11b is polyethylene. The thickness of the insulating layer 11b is, for example, in the range of 0.1 to 0.3 mm. In this embodiment, the thickness of the insulating layer 11b is 0.2 mm.

[0027] (Intervention within the unit) The internal intervening 13 isolates multiple stranded wires 12 within the core wire unit 10. The internal intervening 13 extends in the longitudinal direction of the communication cable 1 (the longitudinal direction of the core wire unit 10). The shape of the internal intervening 13 is not particularly limited as long as it isolates multiple stranded wires 12 from each other. In this embodiment, the cross-sectional shape of the internal intervening 13 perpendicular to the direction of extension is a plus sign shape. That is, in this embodiment, the internal intervening 13 is a cross-shaped intervening. The material of the internal intervening 13 is also not particularly limited as long as it can perform the above function. In this embodiment, the material of the internal intervening 13 is polyethylene. In the internal intervening 13, the thickness of each of the two plate-like members that intersect to form a cross is not particularly limited, but for example, it is 0.25 mm to 0.8 mm. In this embodiment, the thickness of each of the two plate-like members is 0.6 mm. The length of the plate-like members in the cross-section of the core wire unit 10 is 3 mm to 8 mm. In this embodiment, the length of the core wire unit 10 of the plate-shaped member in cross-section is 4 mm. The intervening 13 within the unit is twisted to match the multiple stranded pairs 12 that are twisted together. As a result, the twist pitch of the intervening 13 within the unit is the same as the twisting pitch of the stranded pairs.

[0028] (inner coat) The inner sheath layer 14 covers the multiple stranded wires 12 and the unit interlining 13, defining the outer shape of the core wire unit 10. In this embodiment, the inner sheath layer 14 is cylindrical, and the multiple stranded wires 12 and the unit interlining 13 are arranged inside the cylindrical inner sheath layer 14. The inner sheath layer 14 creates a space in which the stranded wires 12 are arranged together with the unit interlining 13. The size of the inner sheath layer 14 is not particularly limited as long as it can cover the multiple stranded wires 12 and the unit interlining 13. The outer diameter of the inner sheath layer 14 is, for example, 4 mm to 8 mm. In this embodiment, the outer diameter of the inner sheath layer is 6 mm. The material of the inner sheath layer 14 is not particularly limited. In this embodiment, the material of the inner sheath layer 14 is polyvinyl chloride.

[0029] (central intervention) The central separator 20 is positioned at the center of the communication cable 1 and isolates the multiple core wire units 10 in the radial direction of the communication cable 1. In this embodiment, the core wire units 10 are arranged at equal intervals around the central separator 20. Also in this embodiment, each of the multiple core wire units 10 is in contact with the central separator 20. The central separator 20 is not particularly limited as long as it can perform the above-mentioned isolation function. In this embodiment, the central separator 20 is cylindrical in shape extending in the direction of the communication cable 1, and more specifically, it is a string with a circular cross-section.

[0030] The outer diameter of the central separator 20 can be appropriately set according to the desired radial isolation distance of the multiple core wire units 10 in the cross-section of the communication cable 1. The outer diameter of the cylindrical central separator 20 is, for example, 3 mm to 7 mm. In this embodiment, the outer diameter of the central separator 20 is 4 mm. The material of the central separator 20 is not particularly limited. In this embodiment, the material of the central separator 20 is polyethylene, and more specifically, low-density polyethylene.

[0031] (Inter-unit intervention) The inter-unit intervening 30 is positioned between multiple adjacent core wire units 10 in the communication cable 1, isolating the multiple core wire units 10 in the circumferential direction in the cross-section of the communication cable 1. The inter-unit intervening 30 is not particularly limited as long as it can perform this isolation function. In this embodiment, the inter-unit intervening 30 is filled inside the retaining layer 40 of the communication cable 1 so as to fill the space between the multiple core wire units 10 and the central intervening 20. It is preferable that the inter-unit intervening 30 can maintain a desired circumferential distance between the multiple core wire units 10. Here, the shortest distance between multiple circumferentially adjacent core wire units 10 is preferably 1 mm or more from the viewpoint of suppressing the occurrence of near-end crosstalk between units. On the other hand, from the viewpoint of making the communication cable 1 thinner, it is preferable that the shortest distance between multiple circumferentially adjacent core wire units 10 is 10 mm or less. The shortest distance refers to the shortest distance (L in Figure 1) between the virtual circumscribed circles (circles shown by dashed lines in Figure 1) that are in contact with the multiple stranded wires 12 of adjacent core wire units 10 in the cross-section of the communication cable 1 from the outside. It is preferable that the inter-unit intervening 30 is arranged between the core wire units 10 so as to maintain this distance.

[0032] The inter-unit intervening 30 preferably exhibits the isolation function described above and bends in accordance with the bending of the communication cable 1. From these viewpoints, the inter-unit intervening 30 is, for example, a fiber. Examples of fibers include chemical fibers. In this embodiment, the inter-unit intervening is a polypropylene fiber. More specifically, in this embodiment, there are four spaces between the core wire units 10, and two 20,000d polypropylene fibers are filled in each of the four spaces as the inter-unit intervening 30.

[0033] (Retaining layer) The retaining layer 40 covers the multiple core wire units 10, the central interlayer 20, and the inter-unit interlayer 30. The retaining layer 40 is wound around the multiple core wire units 10, the central interlayer 20, and the inter-unit interlayer 30, or extruded. The thickness of the retaining layer 40 is, for example, 0.02 to 0.5 mm. In this embodiment, the thickness of the retaining layer 40 is 0.04 mm.

[0034] The retaining layer 40 may be made of a resin film or a resin tube. If the retaining layer 40 is a resin film, examples of resin film materials include polyester, polypropylene, polyethylene, polyethylene terephthalate, nylon, aramid fiber, and acrylic fiber. In this specification, "resin film" is a concept that includes not only thin films of resin but also nonwoven fabrics, woven fabrics, etc. The resin film may be in the form of a tape. In this embodiment, the material of the retaining layer 40 is polyethylene terephthalate, and the retaining layer 40 is a polyethylene terephthalate tape. The width of the tape-shaped resin film is, for example, more than 5 mm and less than 25 mm. The tape-shaped resin film is wound transversely with respect to the length direction of the communication cable 1. Here, "transverse winding" means winding the resin film spirally so that parts of it overlap. The retaining layer 40 may be one layer or multiple layers. The thickness of the retaining layer 40 is, for example, 0.02 mm to 0.5 mm. In this embodiment, the thickness of the retaining layer 40 is 0.04 mm.

[0035] When the retaining layer 40 is a resin tube, the retaining layer 40 is formed, for example, by extrusion molding. Examples of materials for the resin tube include polyethylene, polyester, and polypropylene. Polyethylene may also include ethylene vinyl acetate (EVA).

[0036] (Outer coat layer) The outer sheath layer 50 covers the retaining layer 40. In this embodiment, the outer sheath layer 50 is the outermost layer in the communication cable 1. The outer sheath layer 50 may be a single layer or multiple layers. In this embodiment, the outer sheath layer 50 is a single layer. Examples of materials for the outer sheath layer 50 include resin. Examples of resins include polyolefin, polyvinyl chloride, and heat-resistant polyethylene. In this embodiment, the material for the outer sheath layer 50 is polyvinyl chloride. The thickness of the outer sheath layer 50 is not particularly limited. The thickness of the outer sheath layer 50 is, for example, in the range of 0.3 to 1.0 mm. In this embodiment, the thickness of the outer sheath layer 50 is 0.7 mm.

[0037] [Manufacturing method for communication cables] Figure 2 is a flowchart of the method for manufacturing the communication cable 1 according to the embodiment.

[0038] Communication cable 1 can be manufactured, for example, by the following method.

[0039] As shown in Figure 2, the method for manufacturing the communication cable 1 includes the steps of preparing a plurality of stranded wires 12 having a predetermined pairing pitch (S110), twisting the plurality of stranded wires 12 together (S120), covering them with a retaining layer 40 (S130), and covering them with an outer sheath layer 50 (140).

[0040] In the step of preparing the stranded wires 12 (S110), the drawn conductor 11a is covered with an insulating layer 11b to prepare the insulated wire 11. Specifically, the insulated wire 11 is manufactured by extruding polyethylene while conveying a plurality of soft copper wires twisted at a predetermined twist pitch in the longitudinal direction. The manufactured insulated wires 11 are twisted in pairs at a predetermined twist pitch to prepare the stranded wires 12.

[0041] In the process of twisting multiple stranded wires 12 together (S120), multiple stranded wires 12 are arranged around a unit intervening 13 (cross intervening), the multiple stranded wires 12 and the unit intervening 13 are twisted together at a predetermined twisting pitch, and the stranded wires 12 and the unit intervening 13 are covered with an inner sheath layer 14 to manufacture a core wire unit 10. Here, when arranging multiple stranded wires 12 around the unit intervening 13, the twisting pitch of each stranded wire 12 is made different.

[0042] In the step of covering with a pressing layer 40 (S130), multiple core wire units 10 are arranged around the central intervening 20, and inter-unit intervening 30 are placed between the core wire units 10, and these are covered with the pressing layer 40. Specifically, a tape-shaped pressing layer 40 is wound horizontally. Here, when arranging multiple core wire units 10 around the central intervening 20, the bundled twist pitch is made different between adjacent core wire units 10, and the paired twist pitch of the paired strands 12 is made different between adjacent core wire units 10.

[0043] In the process of covering with the outer layer 50 (140), the retaining layer 40 is covered with the outer layer 50. Specifically, the outer layer 50 is extruded and molded around the retaining layer 40.

[0044] (effect) According to this embodiment, it is possible to provide a communication cable having a large number of twisted wire pairs that can suppress the occurrence of near-end crosstalk. Specifically, it is possible to provide a communication cable that corresponds to a higher category than Cat.5e, which requires a high crosstalk suppression function due to its high frequency, such as a Cat.6 compatible communication cable. [Examples]

[0045] The present invention will be described in more detail below with reference to examples. However, the scope of the present invention is not limited in any way by these examples.

[0046] 1. Fabrication of communication cables (1) Fabrication of the communication cable for Sample 1 A communication cable for Sample 1 was fabricated. The communication cable for Sample 1 has four core wire units 10, as shown in Figure 1. These four core wire units 10 are labeled A, B, C, and D according to their positions in a clockwise direction in the cross-section of the communication cable, as shown in Figure 1. At this time, core wire units A and C have the same configuration, and core wire units B and D also have the same configuration, but core wire units A and C have a different configuration from core wire units B and D (see Table 1). Below, we will first explain how to manufacture the core wire units located at positions A and C in Figure 1, and then explain how to manufacture the core wire units located at positions B and D.

[0047] (i) Fabrication of the core wire units to be placed at positions A and C in Figure 1. Insulated wires were manufactured by extruding polyethylene onto multiple soft copper wires (conductors). Then, two of these insulated wires were twisted together to achieve the twist pitches shown in Table 1. Specifically, four pairs of twisted wires were produced, each with a twist pitch of 9.5 mm, 12.5 mm, 10.5 mm, and 15.5 mm, as shown in Table 1. The twisted wires with different twist pitches are color-coded. Specifically, one of the two insulated wires in each pair has an insulating layer of one of the following colors: blue, orange, green, or brown. As shown in Table 1, the twisted wires with twist pitches of 9.5 mm, 12.5 mm, 10.5 mm, and 15.5 mm correspond to blue, orange, green, and brown, respectively.

[0048] Next, stranded wires with these four different twist pitches were arranged sequentially around the cross-shaped separator (internal separator) as shown in Figure 1. Specifically, stranded wires with twist pitches of 9.5 mm (blue), 12.5 mm (orange), 10.5 mm (green), and 15.5 mm (brown) were arranged around the cross-shaped separator in a clockwise direction. The four pairs of stranded wires and the cross-shaped separator were twisted together to achieve the combined twist pitch shown in Table 1, and polyvinyl chloride was extruded around them to form the inner sheath layer 14. Following these steps, core wire units to be placed at positions A and C in Figure 1 were manufactured.

[0049] (ii) Fabrication of the core wire units to be placed at positions B and D in Figure 1 Except for changing the paired twist pitch and bundled twist pitch as shown in Table 1, the core wire units to be placed at positions B and D were manufactured using the same procedure as the core wire units to be placed at positions A and C.

[0050] (iii) Insulation of the four core wire units As described above, the four core wire units, positioned at locations A, B, C, and D in Figure 1, were arranged at equal intervals around a 4mm diameter low-density polyethylene string (central interlayer). Two 20,000d polypropylene fibers (inter-unit interlayers) were then filled between each of the four core wire units. These were then twisted together at a 300mm pitch, and a binding tape was wrapped horizontally around them to form a binding layer. Finally, polyvinyl chloride was extruded around the binding layer to form an outer sheath layer and fabricate a communication cable.

[0051] (2) Fabrication of communication cables for samples 2-15 Except for changing the stranding pitch as shown in Table 1, the communication cables for Samples 2-15 were fabricated in the same manner as the communication cable for Sample 1.

[0052] 2. Evaluation The crosstalk within and between core wire units of the communication cables of samples 1 to 15, prepared as described above, was evaluated.

[0053] (1) Intra-unit near-end crosstalk and inter-unit near-end crosstalk Near-end crosstalk within a unit was evaluated by assessing the near-end crosstalk attenuation between two pairs of twisted wires within the same core unit. Near-end crosstalk between units was evaluated by assessing the near-end crosstalk attenuation between two pairs of twisted wires contained in different core units within the same communication cable. The evaluation of near-end crosstalk attenuation was performed in accordance with ANSI / TIA-568-2.D standard "6.6.9 Horizontal cable NEXT loss" by using a network analyzer to measure 801 points for each pair of communication cables wound on a drum (inner diameter 300 mm) between 1 and 250 MHz, and determining the minimum margin from the standard value. Near-end crosstalk attenuation was evaluated according to the following criteria. ○: Minimum margin is 2.0dB or higher △: Minimum margin is between 0dB and less than 2.0dB ×: Minimum margin is less than 0dB

[0054] (2) Overall evaluation The overall evaluation was based on the following criteria. ○: The evaluation results for both the intra-unit near-end crosstalk and inter-unit near-end crosstalk described above were "○". △: There were no "×" marks in the evaluation results for intra-unit near-end crosstalk and inter-unit near-end crosstalk mentioned above, but there were some "△" marks. ×: Either the evaluation result for intra-unit near-end crosstalk or inter-unit near-end crosstalk was "×".

[0055] Table 1 shows the parameters of each communication cable that was fabricated, along with the evaluation results for each.

[0056] [Table 1]

[0057] As shown in Table 1, in samples 1, 7, 10, and 15, where the twisted strand pitch of any of the core wire units was 60 mm or less or 120 mm or more, the near-end crosstalk attenuation within the unit was small, and the evaluation result for near-end crosstalk within the unit was ×. Also, in samples 2, 8, and 14, where the twisted strand pitch was the same between two adjacent core wire units, the near-end crosstalk attenuation between the units was small, and the evaluation result for near-end crosstalk between the units was ×. On the other hand, in samples 3-6, 9, and 11-13, where the twisted strand pitch of all core wire units was greater than 60 mm and less than 120 mm, and where the twisted strand pitch differed between two adjacent core wire units, the evaluation results for near-end crosstalk between units and within units were both △ or better, and the overall evaluation was also good at △ or better.

[0058] In particular, in samples 6 and 9, where the twisted stranding pitch of all core wire units was greater than 70 mm and less than 110 mm, the evaluation results for near-end crosstalk between units and within units were both positive (○), and the overall evaluation was also positive (○), indicating an even better result. [Industrial applicability]

[0059] The communication cable according to the present invention is useful, for example, for high-speed communication LAN cables. [Explanation of Symbols]

[0060] 1. Communication cable 10-core wire unit 11 Insulated wires 11a Conductor 11b Insulating layer 12 strands 13. Intervention within the unit 14 Inner coat 20 central intervention 30 Inter-unit intermediaries 40 Retaining layer 50 Outer layer

Claims

1. A communication cable having multiple core wire units, Each of the aforementioned multiple core wire units has multiple twisted pairs of wires, In each of the aforementioned multiple core wire units, the pair twist pitch of the multiple stranded wires is different. Between two adjacent core wire units among the plurality of core wire units, the pair twist pitches of the plurality of twisted wires are different from each other. Between two adjacent core wire units among the plurality of core wire units, the stranding pitches differ from each other. The aforementioned twisted strand pitch is characterized by being greater than 60 mm and less than 120 mm. Communication cable.

2. A communication cable according to claim 1, characterized in that the twisted strand pitch is greater than 70 mm and less than 110 mm.

3. A communication cable according to claim 1, characterized in that the number of core wire units in the communication cable is four, and the number of twisted wire pairs in the core wire units is four.

4. A communication cable according to claim 1, wherein each of the plurality of core wire units further comprises an intervening positioned at the center of the plurality of core wire units.

5. A communication cable according to claim 1, Each of the aforementioned plurality of core wire units further has an inner sheath that covers the plurality of stranded wire pairs, The communication cable is characterized by further comprising a retaining layer that covers the plurality of core wire units, and an outer sheath layer that covers the retaining layer.

6. A method for manufacturing a communication cable having multiple core wire units, A step of preparing multiple stranded wires having a predetermined pair-pair pitch, A step of twisting together a plurality of paired wires, each having a different paired twist pitch, such that the combined twist pitch is greater than 60 mm and less than 120 mm. Between two adjacent core wire units among the plurality of core wire units, the pair twist pitches of the plurality of twisted wires are different from each other. The process of arranging the plurality of core wire units such that the twisted strand pitches are different between two adjacent core wire units, A method for manufacturing a communication cable, characterized by having [a certain feature].

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