United States Patent 15
`
`US005969295A
`Patent Number:
`
`(11)
`
`5,969,295
`
`Boucino et al.
`[45]
`Date of Patent:
`Oct. 19, 1999
`
`
`[54] TWISTED PAIR COMMUNICATIONS CABLE
`
`[75]
`
`Inventors: Thomas Boucino, Hickory; Mahesh R.
`Patel, Conover; Robert A. Wessels,
`.
`Hickory, all of N.C.
`
`[73]
`
`.
`.
`:
`Assignee: CommScope, Inc. of North Carolina,
`Hickory, N.C.
`
`[21]
`
`Appl. No.: 09/005,335
`
`[22]
`
`Filed:
`
`Jan. 9, 1998
`
`[51]
`[52]
`
`[58]
`
`[56]
`
`Tint, C1. occ cccccsccssssssssssssssssssesssssssssssssssssst HO01B 7/00
`US. Ce ececcccccccccccceesescsesesesescseseecseseecseaee 174/113 C
`
`Field of Search |... 174/113 R, 120 R,
`174/113 C, 113 AS
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`483,285
`1,977,209
`2,204,737
`2,340,926
`3,588,313
`3,603,715
`3,621,118
`3,927,247
`4,038,489
`4,132,854
`4,374,881
`4,683,349
`4,729,409
`4,731,506
`
`9/1892 Guilleaume oe eeeeeeeeeeeeee 173/28
`10/1934
`Sargent ..........
`. 173/264
`...
`6/1940 Swallow et al.
`wee 174/28
`2/1944
`Bradley occ
`creseeeeee 138/77
`
`6/1971
`Delves-Broughton
`...........00. 174/28
`9/1971
`Vinnhorst et al.
`.....
`see
`11/1971
`Bunish et al.
`.....
`« 174/115
`12/1975 Timmons...
`eeeereeeneneee 174/36
`7/1977
`Stenson et al.
`see
`1/1979 Kemeny et al.
`ee eeeeeereneeee 428/36
`2/1983
`Hamilton oo...
`7/1987
`Takebe o....cccceessscssssssseesesssssssneeee 174/69
`3/1988
`Paul
`....
`w 138/115
`3/1988
`Lee veceeesssssssssssessssssssssseessssessene 174/115
`
`
`
`....
`...
`
`. 350/96.23
`Carroll ..........
`10/1988
`4,778,246
`ceeeeeseceeceeee 174/34
`Tessier et al. oo.
`7/1992
`5,132,488
`ZAM seessesecsseesssseeessseecsssesesssesessns 174/95
`T/L9IB
`5,227,585
`eee iy fo04 Nogelsang :
`ne bertos
`5305,
`OY,
`SL.
`ceeccsecsscesssesesecneees
`5,493,071
`2/1996 Newmoyer servssssssssssesseeee 174/113 R
`
`5,541,361
`7/1996
`Friesin et al. occ
`eeeeneceeeeeee 174/34
`ccccccsscccssessssseeeee 174/36
`5,574,250
`11/1996
`Hardie et ale
`4/1997 Newmoyer et al.
`174/113 R
`5,619,016
`5,661,836
`8/1997
`Sano et al. wceccccseseeeeeeees 285/111
`5,789,711
`8/1998
`Gaeris et al. oes 174/113 C
`
`FOREIGN PATENT DOCUMENTS
`
`2459 844
`5-101711
`1343447-A1
`
`7/1976
`4/1993)
`10/1987
`
`2161 656
`
`7/1985
`
`Germany ovseseeessesssseeee HO1B 11/20
`
`Japan wesc eeeee HOB 7/02
`Russian Federation
`“HOLB 11/02
`
`United Kingdom veeeeeeaceeee HO2G 3/04
`
`Primary Examiner—Dean A. Reichard
`Assistant Examiner—William H Mayo, III
`Attorney, Agent, or Firm—Alston & Bird LLP
`[57]
`
`ABSTRACT
`
`A communications cable is provided that includes a cable
`jacket, twisted pairs of insulated conductors, and a spacer
`separating the twisted pairs of insulated conductors. The
`spacer extends within the cable jacket and has a longitudi-
`nally extending center portion and a plurality of wall por-
`tions radiating from the center portion thereby defining a
`plurality of compartments within the cable jacket. The
`twisted pairs of insulated conductors are disposed in the
`compartments thereby reducing cross talk in the communi-
`cations cable.
`
`13 Claims, 3 Drawing Sheets
`
`;
`—
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`=
`
`SS
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`=
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`aa eh =
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`
`
`
`

`

`U.S. Patent
`
`Oct. 19, 1999
`
`Sheet 1 of 3
`
`5,969,295
`
`
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`
`
`Page 2
`
`CommsScope Exhibit 1028
`
`U.S. Patent
`
`Oct. 19, 1999
`
`Sheet 1 of 3
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`5,969,295
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`
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`
`
`
`
`U.S. Patent
`
`Oct. 19, 1999
`
`Sheet 1 of 3
`
`5,969,295
`
`
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`
`
`
`

`

`U.S. Patent
`
`Oct. 19, 1999
`
`Sheet 2 of 3
`
`5,969,295
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`
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`BIWh-Or/Wh
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`300
`200
`700
`FREQUENCY (MHz)
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`400
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`
`
`-20=
`-40=
`2 -60-
`-80-3
`-1004
`FIG. 4B. -12°
`
`0
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`BIWh-Gr/Wh
`
`
`
`
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`300
`200
`100
`FREQUENCY (MHz)
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`400
`
`om
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`0
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`BIWh-Br/Wh
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`
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`
`
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`-20=
`40
`4
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`-80 =
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`fot
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`
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`
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`
`
`300
`200
`100
`FREQUENCY (MHz)
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`U.S. Patent
`
`Oct. 19, 1999
`
`Sheet 3 of 3
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`5,969,295
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`Or/Wh-Br/Wh
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`“100°
`
`300
`200
`FREQUENCY (MHz)
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`
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`mo
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`FIG. 4D.
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`
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`0
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`Or/Wh-Gr/Wh
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`
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`
`400
`
`FIG. 4E
`
`
`
`-100 0
`
`100
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`200
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`300
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`FREQUENCY (MHz)
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`Br/Wh-Gr/Wh
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`300
`400
` 200
`FREQUENCY (MHz)
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`

`

`5,969,295
`
`1
`TWISTED PAIR COMMUNICATIONS CABLE
`
`FIELD OF THE INVENTION
`
`The present invention relates broadly to communications
`cable and more particularly, to communications cable con-
`taining at least one twisted pair of insulated conductors.
`
`BACKGROUND OF THE INVENTION
`
`Insulated conductors such as those used in communica-
`tions cable are often provided as twisted pairs consisting of
`two insulated conductors twisted about each other to form a
`two conductor group. The typical assembly for these com-
`munications cables comprises two or more twisted pairs of
`insulated conductors bundled together and contained in
`a
`jacket. This assembly facilitates the installation of the cable.
`In addition, the jacket can be easily connected to other cable
`components by stripping the jacket and making the proper
`connections to the insulated conductors.
`
`One problem associated with the conventional twisted
`pair assembly is that cross talk can occur between twisted
`pairs of insulated conductors thus negatively affecting the
`signals transmitted by these conductors. Cross talk espe-
`cially presents a problem in high frequency applications
`because cross talk increases logarithmically as the frequency
`of the transmission increases. Because cross talk is affected
`to some degree by the distance between adjacent twisted
`pairs, one method of minimizing its occurrences is to space
`the twisted pairs apart using spacing means such as dis-
`closed in U.S. Pat. No. 5,132,488 to Tessier et al. However,
`although such a construction can physically separate adja-
`cent twisted pairs, there is still some degree of cross talk
`interaction between twisted pairs in this type of construc-
`tion.
`In addition, there remains a need to provide easy
`connectorization between the twisted pair cable and other
`cable components.
`
`SUMMARY OF THE INVENTION
`
`In accordance with the present invention, a communica-
`tions cable is provided comprising a cable jacket, twisted
`pairs of insulated conductors within the jacket, and a spacer
`separating the twisted pairs of insulated conductors. The
`spacer extends within the cable jacket and has a longitudi-
`nally extending center portion and a plurality of wall por-
`tions radiating from the center portion thereby defining a
`plurality of compartments within the cable jacket. A twisted
`pair of insulated conductors is disposed in respective ones of
`the compartments and generally a twisted pair of insulated
`conductors is provided in each of the compartments. In
`addition, the individual twisted pairs are preferably each
`twisted with a different lay length from the other twisted
`pairs of the cable.
`
`In one embodiment of the invention, the communications
`cable comprises a tubular cable jacket, a spacer situated
`within the cable jacket and separate from the cable jacket,
`and twisted pairs of insulated conductors separated by the
`spacer. In this embodiment, the spacer has a longitudinally
`extending center portion and a plurality of longitudinally
`extending wall portions radiating from the center portion to
`define a plurality of compartments within the cable jacket
`with a twisted pair of insulated conductors disposed in each
`of the compartments. Preferably, the communications cable
`includes four compartments. The wall portions of the com-
`munications cable can also be configured so as to define
`compartments of a helical configuration within the cable
`jacket so that the respective twisted pairs located within the
`
`10
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`15
`
`20
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`30
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`35
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`40
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`45
`
`50
`
`55
`
`60
`
`65
`
`2
`compartments extend helically about the longitudinal axis of
`the cable. Preferably, the respective twisted pairs are twisted
`helically at
`a lay length of between about 3 and about 8
`inches. In order to connect the cable to
`other cable
`components, the jacket is stripped from the cable and the
`spacer can be moved away or removed from the twisted
`pairs for easy connection.
`In another embodiment of the invention, the communi-
`cations cable comprises a tubular cable jacket, a spacer
`extending longitudinally within the cable jacket, and twisted
`pairs of insulated conductors separated by the spacer. In this
`embodiment, the spacer has a longitudinally extending cen-
`ter portion and a plurality of longitudinally extending wall
`portions radiating from the center portion to the cable jacket
`and connected thereto such that the spacer and the cable
`jacket define a plurality of compartments. A twisted pair of
`insulated conductors is disposed in each of the compart-
`ments. In this embodiment, the longitudinally extending
`walls of the spacer are
`thin and preferably increase in
`thickness from the center portion to the jacket. In addition,
`the cables associated with this embodiment preferably define
`four compartments. In order to connect the cables of this
`embodiment to cable components, the jacket is stripped
`away and the thin walls of the spacer broken to provide
`access to the twisted pairs of insulated conductors.
`
`The communications cable of the invention sufficiently
`separates individual twisted pairs from one another to reduce
`cross talk between twisted pairs in the cable. Specifically,
`because the spacer extends continuously from the center
`portion to
`the jacket,
`the twisted pairs are sufficiently
`insulated from one another thereby reducing cross talk
`therebetween. In addition, the cables of the invention can be
`easily connectorized to other cable components by stripping
`the cable jacket from the cable and either moving the spacer
`away from the twisted pairs or breaking the spacer off. Thus,
`the communications cable of the invention can be used in
`plenum for various types of applications.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`Other features and advantages of the present invention
`will become apparent from the following detailed descrip-
`tion of the invention taken in conjunction with the drawings,
`in which:
`
`a perspective view of a communications cable
`FIG. 1 is
`having four pairs of twisted insulated conductors in accor-
`dance with the present invention;
`
`a cross-sectional view of the cable of FIG. 1
`FIG. 2 is
`taken along lines 2—2 illustrating a spacer having four
`longitudinally extending walls defining four compartments
`in the cable wherein the spacer is separate from the sur-
`rounding jacket;
`FIG. 3 is a cross-sectional view of an alternative embodi-
`ment of the invention illustrating a spacer having four
`longitudinally extending walls defining four compartments
`in the cable and connected to the surrounding jacket; and
`FIG. 4 is
`a cross talk graph comparing the communica-
`tions cable of the invention to conventional cable construc-
`tions.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`Referring now to FIG. 1, there is shown a multi-pair
`communications cable designated generally by 10 having a
`cable jacket 12,
`a spacer 14, and four twisted pairs of
`insulated conductors 16,
`18, 20 and 22. The jacket 12
`
`

`

`5,969,295
`
`3
`surrounds the spacer 14 and the twisted pairs 16, 18, 20 and
`22 and is preferably tubular in shape. The jacket 12 is made
`of a flexible polymer material and is preferably formed by
`melt extrusion. Any of the polymer materials conventionally
`used in cable construction may be suitably employed. Suit-
`able polymers include polyvinylchloride, polyvinylchloride
`alloys, polyethylene, polypropylene and flame retardant
`materials such as fluorinated polymers. Preferably, the jacket
`12 is extruded to
`a thickness of between 15 and 25 mils
`(thousandths of an inch) to allow the jacket to be easily
`stripped from the twisted pairs of insulated conductors 16,
`18, 20 and 22.
`The spacer 14 is situated within and is longitudinally
`coextensive with the cable jacket 12. As illustrated in FIG.
`2, the spacer 14 includes a longitudinally extending center
`portion 24 and a plurality of wall portions 26, 28, 30 and 32,
`radiating from the center portion. The spacer 14 defines
`compartments 34, 36, 38 and 40 in the jacket 12 for the
`twisted pairs 16, 18, 20, and 22. Each of the compartments
`34, 36, 38 and 40 is of sufficient size to receive a corre-
`sponding twisted pair 16, 18, 20, and 22. The communica-
`tions cable has a plurality of compartments and preferably at
`least four compartments to receive at least four respective
`insulated conductor pairs. As illustrated in FIGS. 1-3, the
`communications cable has four compartments for receiving
`twisted pairs. Although the illustrated cable can receive four
`insulated conductor pairs, it will be understood by those
`skilled in the
`art that not all of the compartments may
`include a insulated conductor pair during normal installation
`and operation of the cable.
`As shown in FIG. 1, the insulated conductors of each
`twisted pair 16, 18, 20, and 22, are twisted helically around
`one another. The twisted pairs 16,
`18,
`20, and 22
`are
`typically twisted at a lay length of between about 0.25 and
`about 1.50 inches. Preferably, each of the twisted pairs of
`insulated conductors has a different lay length from the other
`twisted pairs of the cable.
`As shown in FIG. 1 for purposes of illustration using only
`one pair 16 of twisted insulated conductors, each insulated
`conductor in the twisted pair comprises a conductor 42
`surrounded by a layer of an insulating material 44. The
`conductor 42 may be a metallic wire or any of the well-
`known metallic conductors used in wire
`and cable
`applications, such as copper, aluminum, copper-clad
`aluminum, and copper-clad steel. Preferably, the wire is 18
`to 26 AWG gauge. The twisted wires are surrounded by a
`layer of the insulating material. Preferably, the thickness of
`the insulating material is less than about 25 mil, preferably
`less than about 15 mil, and for certain applications even less
`than about 10 mil. The insulating material can also be
`foamed or expanded through the use
`of
`a blowing or
`foaming agent. Suitable insulating materials for the twisted
`wires include polyvinylchloride, polyvinylchloride alloys,
`polyethylene, polypropylene, and flame retardant materials
`such as fluorinated polymers. Exemplary fluorinated poly-
`mers for use in the invention include fluorinated ethylene-
`propylene (FEP), ethylenetrifluoroethylene (ETFE), ethyl-
`ene
`chlorotrifluoroethylene
`(ECTFE),
`perfluoroalkoxypolymers (PFA’s), and mixtures thereof.
`Exemplary PFA’s include copolymers of tetrafluoroethylene
`and perfluoropropylvinylether (e.g. Teflon PFA 340) and
`copolymers of tetrafluoroethylene and perfluoromethylvi-
`nylether (MFA copolymers which are available from Ausi-
`mont S.p.A.). In addition, the insulating material can contain
`conventional additives such as pigments, nucleating agents,
`thermal stabilizers,
`acid acceptors, processing aids, and
`flame retardant compositions (e.g. antimony oxide).
`If
`
`10
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`15
`
`20
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`25
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`30
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`35
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`40
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`45
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`50
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`55
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`60
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`65
`
`4
`desired, the insulating material used for the twisted wires
`may not be the same for each twisted wire pair. For example,
`three of the wire pairs may be surrounded by a foamed
`polyvinylchloride and the fourth wire pair surrounded by a
`different insulating material such as a foamed FEP.
`FIGS. 1 and 2 illustrate one embodiment of the invention
`wherein the spacer 14 is separate from the cable jacket 12.
`In this configuration, the wall portions 26, 28, 30 and 32
`radiate from the center portion 24 and terminate proximate
`to the jacket 12. As shown in FIG. 1, the wall portions 26,
`28, 30, and 32 of the communications cable 10 can be
`configured so as to define longitudinally extending passage-
`ways or compartments of a helical configuration within the
`cable jacket 12 so that the respective twisted pairs 16, 18, 20
`and 22 located within the compartments extend helically
`around the longitudinal axis of the cable. Typically, the
`spacer 14 and the twisted pairs 16, 18, 20, and 22 are twisted
`to provide this helical configuration thereby holding these
`cable components together. Furthermore, this helical con-
`figuration improves the impedance uniformity of the cable
`by maintaining uniformity of spacing of the respective
`twisted pairs 16, 18, 20 and 22 despite bending of the cable
`10. The cable components are twisted helically at a prede-
`termined lay length defined as the length it takes for one of
`the cable components (e.g. twisted pairs)
`to make one
`complete helical turn. Preferably, the lay length is between
`about 3 and about 8 inches.
`The communications cable 10 illustrated in FIGS. 1 and
`2 is manufactured by extruding the spacer 14 using a suitable
`polymer material such as the materials described for use in
`the jacket 12. The spacer 14 is formed into a desired shape
`as it exits the extruder and is cooled or quenched to harden
`the spacer. The spacer 14 is then bunched with four twisted
`wire pairs 16, 18, 20 and 22 such that the twisted wire pairs
`are oriented in the grooves of the spacer. The spacer 14 and
`the twisted wire pairs 16, 18, 20, and 22 can also be twisted
`helically during the bunching process to increase impedance
`uniformity of the cable 10. Once the spacer 14 and the
`twisted wire pairs 16, 18, 20, and 22 are bunched, the jacket
`12 is then extruded around the spacer 14 and twisted wire
`pairs 16, 18, 20 and 22 to form the cable 10.
`The communications cable 10 of FIGS. 1 and 2 can be
`easily connected to other cable components. First, the jacket
`12 is stripped from the cable 10 thus revealing the spacer 14
`and the twisted pairs 16, 18, 20 and 22. The spacer 14 can
`then be pulled away from the twisted pairs 16, 18, 20 and 22
`and clipped to the cable 10 to allow the twisted pairs to be
`connected to other cable components. Alternatively, the
`spacer 14 can be cut away to allow easy connectorization of
`the twisted pairs 16, 18, 20 and 22.
`FIG. 3 illustrates another embodiment of the invention
`wherein the cable 50 comprises a cable jacket 52, a spacer
`54 extending longitudinally within the cable jacket, and
`twisted pairs of insulated conductors 56, 58, 60 and 62. In
`this embodiment, the spacer 54 has a longitudinally extend-
`ing center portion 64 and a
`plurality of longitudinally
`extending wall portions 66, 68, 70 and 72 radiating from the
`center portion to the cable jacket 52 and connected to the
`cable jacket. The spacer 54 and jacket 52 define compart-
`ments 74, 76, 78 and 80 for receiving the twisted pairs of
`insulated conductors 56, 58, 60 and 62. As illustrated in FIG.
`3, the longitudinally extending wall portions 66, 68, 70 and
`72 preferably increase in thickness from the center portion
`64 to the jacket 52. The wall portions 66, 68, 70 and 72 are
`thin to allow the wall portions to be broken thereby permit-
`ting easy connectorization of the twisted pairs 56, 58, 60 and
`62 as described in more detail below. Preferably, the thick-
`ness of the wall portions 66, 68, 70 and 72 is not greater than
`8 mils.
`
`

`

`5,969,295
`
`5
`The embodiment illustrated in FIG. 3 is produced by first
`bunching the twisted pairs 56, 58, 60 and 62 together and
`advancing the twisted pairs to an extrusion apparatus. A
`polymer melt of suitable jacket material is then extruded
`around the twisted pairs to form the jacket 52 and the spacer
`54 as an integral unit. Alternatively, the embodiment illus-
`trated in FIG. 3 can be manufactured similarly to
`the
`embodiment in FIGS. 1 and 2 by extruding the jacket 52
`such that the jacket 52 becomes integrally bonded to the wall
`portions 66, 68, 70 and 72 of the spacer 54.
`The communications cable 50 of FIG. 3 can be easily
`connected to other cable components. The typically method
`of connectorization is to first strip the jacket 52 from the
`cable 50. The spacer 54 and the jacket 52 are then removed
`by breaking off the spacer in the area where the jacket 52 is
`stripped. The thin wall portions 66, 68, 70 and 72 of the
`spacer 54 allow the spacer to be easily broken off to expose
`the twisted pairs 56, 58, 60 and 62. The twisted pairs 56, 58,
`60 and 62 can then be easily connected to other cable
`components.
`
`FIG. 4 illustrates a comparison between the cross talk of
`the twisted pairs of a conventional bunched cable having no
`spacer and the communications cable according to FIGS. 1
`and 2. Specifically, FIG. 4 illustrates the cross talk between
`the twisted pairs of insulated conductors of these cables with
`Bl=blue, Or=orange, Wh=white, and Br=brown. In FIG. 4,
`the solid trace corresponds to the conventional cable con-
`struction with no spacer, the short dashed trace corresponds
`to the cable of FIGS. 1 and 2, and the long dashed trace
`corresponds to the Category 6 586A requirement proposed
`by TIA/EIA. As shown in FIG. 4, the cross talk of the
`communications cable 10 of the invention is well below the
`Category 6 586A requirement proposed by TIA/EIA.
`Furthermore, the cross talk measurements of the communi-
`cations cable 10 average 8 to 10 dB better than the cross talk
`measurements of the conventional cable construction.
`The twisted pair communications cable of the invention in
`operation minimizes cross talk between the twisted pairs of
`insulated conductors and is an improvement over conven-
`tional twisted pair communications cable designs.
`Specifically, as illustrated in FIG. 4, the twisted pair com-
`munications cable of the invention reduces cross talk by as
`much as 10 dB over conventional cables which do not use
`spacer constructions. Moreover, the twisted pair cable of the
`invention minimizes capacitance imbalance as desired for
`such cables. The communications cable of the invention can
`be easily connectorized by splitting open the thin jacket and
`removing the spacer to allow the insulated conductors to be
`connected to the appropriate connections.
`It is understood that upon reading the above description of
`the present invention and reviewing the accompanying
`drawings, one skilled in the art could make changes and
`variations therefrom. These changes and variations are
`included in the spirit and scope of the following appended
`claims.
`What is claimed is:
`1.
`A communications cable consisting essentially of:
`a cable jacket;
`a spacer extending within said cable jacket, said spacer
`having a longitudinally extending center portion and
`plurality of longitudinally extending wall portions radi-
`ating from said center portion, said longitudinally
`extending wall portions increasing in thickness from
`said center portion to said jacket, said spacer and said
`cable jacket defining a plurality of compartments
`within said cable jacket; and
`
`6
`a twisted pair of insulated conductors disposed in respec-
`tive ones of said compartments, each of said twisted
`pairs of insulated conductors having a different lay
`length.
`2. The communications cable according to claim 1
`wherein the wall portions of said spacer extend to said cable
`jacket and are connected to said cable jacket.
`3. The communications cable according to claim 1
`wherein said spacer is separate from said cable jacket.
`4. The communications cable according to claim 3
`wherein said cable includes a longitudinal axis, said wall
`portions are configured so as to define compartments of a
`helical configuration within the cable jacket, and the twisted
`pairs located within said compartments extend helically
`about the longitudinal axis of the cable.
`5. The communications cable according to claim 4
`wherein the twisted pairs extend helically at a lay length of
`between about 3 inches and about 8 inches.
`6.
`A communications cable consisting essentially of:
`a tubular cable jacket;
`
`a spacer situated within said cable jacket and separate
`from said cable jacket, said spacer having a longitudi-
`nally extending center portion and a plurality of lon-
`gitudinally extending wall portions radiating form said
`center portion, said longitudinally extending wall por-
`tions increasing in thickness from said center portion to
`said jacket, said spacer and said cable jacket defining a
`plurality of compartments within the cable jacket; and
`a twisted pair of insulated conductors disposed in each of
`said compartments, each of said twisted pairs of insu-
`lated conductors has a different lay length.
`7. The communications cable according to claim 6
`wherein said cable includes a longitudinal axis, said wall
`portions are configured so as to define passageways of a
`helical configuration within the cable jacket, and the twisted
`pairs located within said passageways extend helically about
`the longitudinal axis of the cable.
`8. The communications cable according to claim 7
`wherein the twisted pairs extend helically at a lay length of
`between about 3 inches and about 8 inches.
`9. The communications cable according to claim 6
`wherein said spacer defines four compartments within the
`cable jacket.
`10.
`A communication cable comprising:
`a tubular cable jacket;
`a spacer extending longitudinally within said cable jacket,
`said spacer having a longitudinally extending center
`portion and a plurality of longitudinally extending wall
`portions radiating from said center portion to said cable
`jacket and connected thereto,
`said longitudinally
`extending wall portions increasing in thickness from
`said center portion to said jacket, said spacer and said
`cable jacket defining a plurality of a compartments; and
`a twisted pair of insulated conductors disposed in each of
`said compartments.
`11. The communications cable according to claim 10
`wherein each of said twisted pairs of insulated conductors
`has a different lay length.
`12. The communications cable according to claim 10
`wherein said longitudinally extending wall portions have a
`thickness of less than about 8 mils.
`13. The communications cable according to claim 10
`wherein said spacer and said jacket define four compart-
`ments.
`
`10
`
`15
`
`20
`
`35
`
`40
`
`50
`
`55
`
`60
`
`65
`
`