Patent Application
20110275239
1. Field of the Invention
The present invention is directed generally to communication cables.
2. Description of the Related Art
Conductors that are not physically connected to one another may nonetheless be coupled together electrically and/or magnetically. This coupling creates undesirable signals in adjacent conductors referred to as crosstalk. By placing two elongated conductors (e.g., wires) alongside each other in close proximity (referred to as a “compact pair arrangement”), a common axis can be approximated. The compact pair arrangement is often sufficient to avoid crosstalk if other similar pairs of conductors are in close proximity to the first pair of conductors. Further, if the opposing currents in the conductors are equal, magnetic field “leakage” from the conductors will decrease rapidly as the longitudinal distance along the conductors is increased. If the voltages are also opposite and equal, an electric field primarily concentrated between the conductors will also decrease as the longitudinal distance along the conductors is increased. Twisting the pairs of conductors will tend to negate the residual field couplings and allow closer spacing of adjacent pairs. On the other hand, if for some reason the conductors within a pair are spaced far enough apart, undesired coupling and crosstalk may occur.
A conventional communication cable, such as the cable 10 illustrated in cross-section in
Each of the wires W-1 to W-8 includes an elongated electrical conductor 16 surrounded by an outer insulating layer 18. The electrical conductor 16 may include stranded conductors, a solid conductor (e.g., a conventional copper wire), and the like. The outer insulating layer 18 may be implemented as a conventional insulating flexible plastic jacket.
In accordance with wiring standards, the insulating layer 18 of the wire W-4 of the twisted pair P1 may be solid blue and the insulating layer 18 of the wire W-5 of the twisted pair P1 may be blue and white striped. The color blue has been illustrated in
The cable 10 may include an outer cable sheath or jacket 12 that surrounds the twisted pairs P1-P4 longitudinally. The jacket 12 is typically constructed from an electrically insulating material. The jacket 12 defines an interior 13 having a central portion 11.
Each of the twisted pairs P1-P4 serves as a differential signaling pair wherein signals are transmitted thereupon and expressed as voltage and current differences between the wires of the twisted pair. Each of the twisted pairs P1-P4 can be susceptible to electromagnetic sources including another nearby cables of similar construction. Signals received by one or more of the twisted pairs P1-P4 from such electromagnetic sources external to the cable's jacket 12 are referred to as “alien crosstalk.” Each of the twisted pairs P1-P4 can also receive signals from one or more wires of the three other twisted pairs within the cable's jacket 12, which is referred to as “local crosstalk” or “internal crosstalk.”
Inside the prior art cable 10, the twisted pairs P1-P4 are positioned in a predetermined pair lay sequence or order about the central portion 11 of the interior 13 defined by the jacket 12. The predetermined order depicted in
Starting with the first twisted pair P1, in
As is appreciated by those of ordinary skill in the art, each of the twisted pairs P1-P4 has a determined twist length, commonly referred to as a pair lay or pitch. To reduce crosstalk, the pair lays are different for each of the twisted pairs P1-P4. Further, the twisted pairs P1-P4 may be twisted together as a bundle that is typically referred to as a quad.
Optionally, the cable 10 may include a central filler or spline 14 that separates the twisted pairs P1-P4 from one another longitudinally.
Occasionally, cable manufactures will produce cables specifically designed to be used for making patch cord that are wired to the TIA-568 A wiring format. A cable 20 illustrated in
In the cable 20, the position of the second twisted pair P2 in the “B-wiring” format has been switched with the position of the third twisted pair P3 in the “B-wiring” format. Further, in the cable 20, the second twisted pair P2 may be constructed using the pair lay (or pitch) used to construct the third twisted pair P3 in the “B-wiring” format and the third twisted pair P3 may be constructed using the pair lay (or pitch) used to construct the second twisted pair P2 in the “B-wiring” format. Thus, the order of the pair lays inside the cable 20 may remain the same as the order of the pair lays inside the cable 10. Therefore, the cable 20 may be constructed by exchanging the insulation colors of the wires W-3 and W-6 (green and white striped, and solid green, respectively) of the third twisted pair P3 with the insulation colors of the wires W-1 and W-2 (orange and white striped, and solid orange, respectively) of the second twisted pair P2.
Alternatively, different pair lays (or pitches) could be assigned to one or more of the twisted pairs P1-P4 positioned in predetermined order shown in
Inside the prior art cable 20, the twisted pairs P1-P4 are positioned in a predetermined pair lay sequence or order about the central portion 11 of the interior 13 defined by the jacket 12. The predetermined order depicted in
Starting with the first twisted pair P1, the twisted pairs P1-P4 are arranged in the following predetermined order clockwise about the central portion 11:
Cables having the “A-wiring” format (e.g., the cable 20) are not typically sold to end users. Instead, cables having the “A-wiring” format are generally supplied to assembly houses that produce finished patch cords. Further, a cable having the “B-wiring” format (e.g., the cable 10) is often used to make a patch cord having the “A-wiring” format (e.g., the cable 20). This may be achieved by rearranging the twisted pairs P1-P4 to connect the wires W-1 to W-8 to contacts positioned inside a plug in accordance with the TIA-568 A wiring format. The “B-wiring” format is by far the most prevalent wiring format used in structured cabling systems.
Referring to
The contacts P-T1 to P-T8 of the plug 30 are each connected to a different wire (W-1 to W-8) of the four twisted pairs P1-P4. The wires W-1 to W-8 of the twisted pairs P1-P4 are connected to the plug contacts P-T1 to P-T8, respectively. The twisted pair P1 (i.e., the wires W-4 and W-5) is connected to the adjacent plug contacts P-T4 and P-T5 to form a first differential signaling pair. The twisted pair P2 (i.e., the wires W-1 and W-2) is connected to the adjacent plug contacts P-T1 and P-T2 to form a second differential signaling pair. The twisted pair P3 (i.e., the wires W-3 and W-6) is connected to the troublesome “split” plug contacts P-T3 and P-T6 to form a “split” third differential signaling pair. The twisted pair P4 (i.e., the wires W-7 and W-8) is connected to the adjacent plug contacts P-T7 and P-T8 to form a fourth differential signaling pair. The plug contacts P-T3 and P-T6 flank the plug contacts P-T4 and P-T5. The second and fourth differential signaling pairs are located furthest apart from one another and the first and third differential signaling pairs are positioned between the second and fourth differential signaling pairs.
The plug 30 is configured to be received inside a jack or outlet (not shown) having a plurality of outlet contacts arranged in a series. The plug 30 and the outlet are each types of communication connectors. The outlet includes a different outlet contact for each of the plug contacts P-T1 to P-T8. When the plug 30 is received inside the outlet, each of the plug contacts P-T1 to P-T8 forms an electrical connection with a corresponding one of the outlet contacts. When connected together to form these electrical connections, the plug 30 and outlet form a communication connection.
Referring to
Inside the plug 40, the twisted pair P1 (i.e., the wires W-4 and W-5) is connected to the adjacent plug contacts P-T4 and P-T5 to form a first differential signaling pair. The twisted pair P3 (i.e., the wires W-3 and W-6) is connected to the adjacent plug contacts P-T1 and P-T2 to form a second differential signaling pair. The twisted pair P2 (i.e., the wires W-1 and W-2) is connected to the troublesome “split” plug contacts P-T3 and P-T6 to form a “split” third differential signaling pair. The twisted pair P4 (i.e., the wires W-7 and W-8) is connected to the adjacent plug contacts P-T7 and P-T8 to form a fourth differential signaling pair. The second and fourth differential signaling pairs are located furthest apart from one another and the first and third differential signaling pairs are positioned between the second and fourth differential signaling pairs.
The plug 40 is configured to be received inside a jack or outlet (not shown) having a plurality of outlet contacts arranged in a series. The outlet includes a different outlet contact for each of the plug contacts P-T1 to P-T8.
When the plug 40 is received inside the outlet, each of the plug contacts P-T1 to P-T8 forms an electrical connection with a corresponding one of the outlet contacts. When connected together to form these electrical connections, the plug 40 and outlet form a communication connection.
Referring to
As is appreciated by those of ordinary skill in the art, typical Augmented Category 6 RJ-45 type hardware can cause a considerable amount of undesirable common mode signal that presents itself most noticeably on the twisted pair P1 associated with the plug contacts P-T1 and P-T2, and the twisted pair P4 associated with the plug contacts P-T7 and P-T8. The plug-outlet interface is typically the origin of undesired mode conversion coupling in a communication connection. At this location, the wires of the split twisted pair, the plug contacts P-T3 and P-T6, and the outlet contacts connected to the plug contacts P-T3 and P-T6, are spaced apart from one another, and may couple (capacitively and/or inductively) with the other conductors of the communication connection.
A challenge of the structural requisites of conventional communication cabling standards relates to the fact that the wires of the split twisted pair are connected to widely spaced plug contacts P-T3 and P-T6, respectively, which straddle the plug contacts P-T4 and P-T5 to which the wires of the flanked twisted pair are connected. This arrangement of the plug contacts P-T1 and P-T8 and their associated wiring can cause a signal transmitted on the split twisted pair to impart different voltages and/or currents onto the first and second outside twisted pairs effectively causing differential voltages between a composite of both wires of the first outside twisted pair, and a composite of both wires of the second outside twisted pair. These differential voltages are the result of an undesired coupling referred to hereafter as a “modal launch” or “mode conversion,” that unfortunately may enhance alien crosstalk elsewhere in a system.
The undesirable common mode signals traveling on the plug tines P-T1 and P-T2 are approximately equal in magnitude but opposite in direction to the undesirable common mode signals traveling on the plug tines P-T7 and P-T8. They travel down the length of the cable looking for a path to ground. Taken together these two signals can be viewed as a differential-mode signal propagating along a “quasi pair” of conductors. The first “wire” of the “quasi pair” includes conductors connected to the plug tines P-T1 and P-T2, acting together as a single first conductor. The second “wire” of the “quasi pair” includes conductors connected to the plug tines P-T7 and P-T8, acting together as a single second conductor.
In other words, the wires of the first outside twisted pair behave as a first two-stranded or “composite” wire and the wires of the second outside twisted pair behave as a second two-stranded or “composite” wire. As a result, a small “coupled” portion of the differential signal originating on the split twisted pair appears as two opposite common, or “even,” mode signals on the first and second “composite” wires. Unfortunately, the wider spacing of the first and second “composite” wires enhances vulnerability and sourcing of unwanted crosstalk in other nearby cables, such as cables in the same bundle or conduit.
In both the “A-wiring” and “B-wiring” formats, the composite conductors of the “quasi pair” includes wires that are spaced apart from one another diagonally across of the central portion 11 of the interior 13 of the cable. In other words, the first outside twisted pair (i.e., the first composite conductor) is spaced apart diagonally from the second outside twisted pair (i.e., the second composite conductor) across of the central portion 11 of the interior 13 of the cable. In embodiments that include the spline 14, this distance may be further increased by the spline 14 interposed between the twisted pairs P1-P4. Because of the rather large distance between the first and second composite conductors and the relatively uncontrolled geometry of the core, (compared to the tightly controlled geometry of each of the twisted pairs P1-P4), energy is easily radiated from the “quasi pair.” This energy or signal may differentially couple with similarly constructed “quasi pairs” in surrounding cables to create alien crosstalk.
Therefore, a need exists for cables that radiate and/or conduct less crosstalk. In particular, a cable configured to radiate and/or conduct less alien crosstalk resulting from the modal conversion discussed above is desirable. The present application provides these and other advantages as will be apparent from the following detailed description and accompanying figures.
Each of the wires W-1 to W-8 includes the elongated electrical conductor 16 surrounded by the outer insulating layer 18. The electrical conductor 16 may include stranded conductors, a solid conductor (e.g., a conventional copper wire), and the like. The outer insulating layer 18 may be implemented as a conventional insulating flexible plastic jacket.
The cable 100 may include an outer cable sheath or jacket 112 that surrounds the twisted pairs P1-P4 longitudinally. Thus, the twisted pairs P1-P4 are housed inside the jacket 112, which may be constructed from an electrically insulating material. The jacket 112 defines an interior 113 having a central portion 111.
Each of the twisted pairs P1-P4 serves as a differential signaling pair wherein signals are transmitted thereupon and expressed as voltage and current differences between the wires of the twisted pair. Inside the cable 100, the twisted pairs P1-P4 are positioned in a predetermined order about the substantially centrally located central portion 111. The predetermined order of the twisted pairs P1-P4 inside the cable 100 is different from the “A-wiring” and “B-wiring” formats in one substantial way; inside the cable 100, the first twisted pair P1 is positioned diagonally across the central portion 111 of the interior 113 of the cable 100 from the fourth twisted pair P4. Thus, the second twisted pair P2 is positioned diagonally across the central portion 111 from the third twisted pair P3. Starting with the first twisted pair P1, in
In this predetermined order, the fourth twisted pair P4 is adjacent the third twisted pair P3. Further, the fourth twisted pair P4 is also adjacent the second twisted pair P2. The fourth twisted pair P4 is closer to the third twisted pair P3 and the second twisted pair P2 than the fourth twisted pair P4 is to the first twisted pair P1. Also, the third twisted pair P3 is closer to the first twisted pair P1 and the fourth twisted pair P4 than the third twisted pair P3 is to the second twisted pair P2. When connected to the plug contacts P-T1 to P-T8 of the plug 30 illustrated in
As is appreciated by those of ordinary skill in the art, each of the twisted pairs P1-P4 has a determined twist length, commonly referred to as a pair lay or pitch. To reduce crosstalk, the pair lays are different for each of the twisted pairs P1-P4. As mentioned above, the twisted pairs P1-P4 may be twisted together as a bundle (not shown). The twist length of the bundle is referred as a cable lay or cable lay length.
To avoid adversely affecting the normal electrical characteristics of the cable, the fourth twisted pair P4 may be constructed using the pair lay used for the third twisted pair P3 in the “B-wiring” format and the third twisted pair P3 may be constructed using the pair lay used for the fourth twisted pair P4 in the “B-wiring” format. Thus, the predetermined order depicted in
Alternatively, different pair lays (or pitches) configured to meet desired electrical parameters may be assigned to one or more of the twisted pairs P1-P4 positioned in predetermined order shown in
Optionally, the cable 100 may include a central filler or spline 114 having dividing walls 121-124 that maintain separation between the twisted pairs P1-P4 along the entire length of the cable. The spline 114 may be made from a non-condive material such as polyethelyn or Fluorinated ethylene propylene (FEP). The dividing walls 121-124 divide the inside of the cable 100 into longitudinally extending quadrants Q1-04 as shown in
In the embodiment illustrated, the first dividing wall 121 separates the first quadrant Q1 from the second quadrant Q2. The first twisted pair P1 is positioned inside the first quadrant Q1 and the second twisted pair P2 is positioned inside the second quadrant Q2. Thus, the first dividing wall 121 separates the first twisted pair P1 from the second twisted pair P2. The second dividing wall 122 separates the second quadrant Q2 from the third quadrant Q3. The fourth twisted pair P4 is positioned inside the third quadrant Q3. Thus, the second dividing wall 122 separates the second twisted pair P2 from the fourth twisted pair P4. The third dividing wall 123 separates the third quadrant Q3 from the fourth quadrant Q4. The third twisted pair P3 is positioned inside the fourth quadrant Q4. Thus, the third dividing wall 123 separates the fourth twisted pair P4 from the third twisted pair P3. The fourth dividing wall 124 separates the fourth quadrant Q4 from the first quadrant Q1. Thus, the fourth dividing wall 124 separates the third twisted pair P3 from the first twisted pair P1.
Unlike in the prior art cable 10 illustrated in
The “quasi pair” of the cable 100 illustrated in
Depending upon the implementation details, the “quasi pair” of the cable 100 (which is formed by the adjacent twisted pairs P2 and P4) may be more mechanically more stable than the “quasi pair” of the cable 10 illustrated in
Similarly, returning to
For example, referring to
By way of another non-limiting example, and depending upon the implementation details, the “quasi pair” of the cable 100 formed by the adjacent twisted pairs P3 and P4 may be more mechanically more stable than the “quasi pair” of the cable 20 formed by the diagonally arranged twisted pairs P3 and P4 and illustrated in
As explained above, depending upon whether the cable 100 is connected to hardware using the TIA-568 B wiring format or the TIA-568 A wiring format, the “quasi pair” may include either the twisted pairs P2 and P4 or the twisted pairs P3 and P4. It is believed the wiring configuration of the cable 100 causes these “quasi pairs” to emit and/or receive less electromagnetic energy than is emitted and/or received by the “quasi pairs” formed in the conventional cables 10 and 20 (illustrated in
It is further believed this reduction in the emission and/or reception of electromagnetic energy, as well as, the unique way in which the “quasi pairs” in nearby cables constructed in accordance with the cable 100 mechanically and electrically interact with one another, reduce the amount of alien crosstalk conveyed between the “quasi pairs” of such nearby cables compared with the amount of alien crosstalk conveyed between nearby cables constructed according to the cable 10 (see
From a manufacturing point of view, the cable 100 illustrated in
As mentioned above, alternatively, different pair lays (or pitches) configured to meet desired electrical parameters may be assigned to one or more of the twisted pairs P1-P4 positioned in predetermined order shown in
Because only the color of the insulating layers 18 of the twisted pairs P3 and P4 changes, certain aspects of the performance of the cable 100 do not change from that of the original prior art cable 10. However, the transmission data from the cable 100 depicted in
Reduced coupling between the “quasi pairs” in nearby cables reduces an amount of modal alien crosstalk between those nearby cables, which reduces a total amount of alien crosstalk occurring between the nearby cables. Inside a communications system (not shown) including conventional RJ-45 type hardware, the reduced coupling between the “quasi pairs” in nearby cables constructed in accordance with the cable 100 reduces a total amount of alien crosstalk occurring inside the system (compared to a total amount of alien crosstalk occurring inside a system including only conventional cables). These reductions in the total amount of alien crosstalk occurring between the nearby cables, and the total amount of alien crosstalk occurring inside a system, have been demonstrated in simulations as well as in actual empirical experiments designed to measure alien crosstalk.
An electrical simulation was performed using ANSOFT simulation tools. Referring to
As explained above, the twisted pair P4 and the twisted pair P2 together form a “quasi pair” when the cable 100 is connected to hardware using the TIA-568 B wiring format. To simplify the simulation, in each of the cables 10-A, 10-B, 100-A, and 100-B, the two separate wires W-7 and W-8 or conductors of the twisted pair P4 were modeled as a single copper conductor C1 and the two separate wires W-1 and W-2 or conductors of the twisted pair P2 were modeled as a single copper conductor C2. The conductor C1 has a diameter approximately equal to the combined diameter of the two conductors of the twisted pair P4. The conductor C2 has a diameter approximately equal to the combined diameter of the two conductors of the twisted pair P2. For ease of illustration, in
Only one complete twist of the “quasi-pair” was used in the simulation. The length of the twist was substantially equal to the cable lay length (i.e., approximately 4 inches).
The two “quasi pairs” of the adjacent cables 10-A and 10-B were modeled side-by-side as they would be positioned within cables positioned alongside one another. Similarly, the two “quasi pairs” of the adjacent cables 100-A and 100-B were also modeled side-by-side as they would be positioned within cables positioned alongside one another. The effective dielectric constant between the two “quasi pairs” of the adjacent cables 10-A and 10-B and between the two “quasi pairs” of the adjacent cables 100-A and 100-B was estimated to be about 2.5.
For a range of simulated frequencies (e.g., about 10 MHz to about 500 MHz), the simulation calculated a minimum amount, a maximum amount, and an average amount of alien crosstalk occurring between (1) the two “quasi pairs” of the cables 10-A and 10-B and (2) the two “quasi pairs” of the cables 100-A and 100-B. To determine these values, the cable 10-A was rotated relative to the cable 10-B a total of 180 degrees in 30 degree increments and the cable 100-A was rotated relative to the cable 100-B a total of 180 degrees in 30 degree increments. After each incremental rotation, the amount alien crosstalk occurring between (1) the two “quasi pairs” of the cables 10-A and 10-B and (2) the two “quasi pairs” of the cables 100-A and 100-B was determined for the simulated frequencies in the range. Then, for each simulated frequency, a minimum amount, a maximum amount, and an average amount of alien crosstalk were determined.
As can be seen in
Those of ordinary skill in the art appreciate that the alien crosstalk simulated above included only intermediate alien crosstalk that occurs between adjacent cables. Differential mode coupling between “quasi-pairs” is converted into additional alien crosstalk in a communications system that uses typical RJ-45 type hardware, which adds to the total alien crosstalk in the system. To evaluate the effect of the predetermined order of the twisted pairs P1-P4 of the cable 100 on total alien crosstalk, at least a portion of a communications system (such as a channel, which includes additional hardware components) must be considered.
Each of the seven channels (e.g., the channel 300) has a near-end plug “PLUG-NE” opposite a far-end plug “PLUG-FE.” The near-end plugs “PLUG-NE” and the far-end plugs “PLUG-FE” may be selectively coupled one at a time to the measurement ports M1 and M2 of the first and second instruments 302 and 304, respectively. The first and second test instruments 302 and 304 are connectable to either the near-end plug “PLUG-NE” or the far-end plug “PLUG-FE” of one of the seven channels under test as dictated by the TIA 568 C.2 specification. Tests are conducted by selectively connecting the measurement port M1 of the first instrument 302 to the near-end plug “PLUG-NE” of one of the seven channels, and the measurement port M2 of the second instrument 304 to either the near-end plug “PLUG-NE” or the far-end plug “PLUG-FE” of a different one of the seven channels. These connections are formed as prescribed by the TIA 568 C.2 industry standard.
The connections formed between the first and second test instruments 302 and 304 and the channels are not considered part of the four connector channel under test. The electrical effects of the connections formed between the first and second test instruments 302 and 304 and the channels are taken into account by the specification and/or negated by the first and second test instruments 302 and 304.
In
The channel 300 includes a first patch cord 306. The first patch cord 306 is terminated with the plug “PLUG-NE.” The plug “PLUG-NE” is connectable to the measurement port M1 of the first test instrument 302, or to the measurement port M2 of the second test instrument 304, as dictated by the measurement and channel/pair combination being tested. The first patch cord 306 is punched down to insulation displacement contacts (not shown) of the jack “JACK1.” The first patch cord 306 has a length of about three meters.
The channel 300 includes a second patch cord 308. A near end of the second patch cord 308 is terminated with the plug “PLUG1” which is connected to the jack “JACK1.” A far end of the second patch cord 308 is connected to the plug “PLUG2.” The plug “PLUG2” is connected to the jack “JACK2.” The second patch cord 308 has a length of about two meters.
The channel 300 includes a first section of horizontal cable 310. A near end of the first section of horizontal cable 310 is punched down to the insulation displacement contacts (not shown) of the jack “JACK2.” A far end of the first section of horizontal cable 310 is punched down to the third connection 311 (the punch down block). The first horizontal cable 310 has a length of about eighty-five meters.
The channel 300 includes a second section of horizontal cable 312. A near end of the second section of horizontal cable 312 is punched down to the third connection 311, which is a consolidation point. A far end of the second section of horizontal cable 312 is punched down to the insulation displacement contacts (not shown) of the jack “JACK3.” The second horizontal cable 310 has a length of about five meters.
The channel 300 includes a third patch cord 314. A near end of the third patch cord 314 is terminated with the plug “PLUG3.” The plug “PLUG3” is connected to the jack “JACK3.” A far end of the third patch cord 314 is connected to the plug “PLUG-FE.” The plug “PLUG-FE” is connectable to the measurement port M2 of the test instrument 304 when dictated by the measurement and channel/pair combination being tested. The third patch cord 314 has a length of about five meters.
As is apparent to those of ordinary skill in the art, patch cords (typically made using stranded conductors) are usually connected to RJ-45 plugs (e.g., the plug 30 illustrated in
The patch cords 306, 308, and 314 of each of the seven channels were constructed using conventional patch cordage constructed similar to the cable 10 illustrated in
Initially, all of the cables and connectors of the seven channels were terminated as described above. Alien near-end crosstalk (“ANEXT”) and alien attenuation to crosstalk ratio-far end (“AACR-F”) were measured and PSANEXT and PSAACR-F were calculated and recorded.
Next, the wiring at the near end of the first horizontal cable 310 and the far end of the second horizontal cable 312 in each of the seven channels was modified where the horizontal cables 310 and 312 connect to the jacks “JACK2” and “JACK3,” respectively. Specifically, at the jack “JACK2,” the positions of twisted pairs P3 and P4 in the first horizontal cable 310 where interchanged at the insulation displacement contacts (not shown) of the jack “JACK2.” Similarly, at the jack “JACK3,” the positions of twisted pairs P3 and P4 in the second horizontal cable 312 where interchanged at the insulation displacement contacts (not shown) of the jack “JACK3.” These interchanges were done to replicate or approximate the construction of the cable 100. By approximating the structure of the cable 100 in this manner, the same cable/cable bundles used in the initial testing were also used for subsequent testing thereby insuring the inherent electrical performance of the cables and connectors remained the same throughout the testing. Therefore, any change observed in alien crosstalk performance would be a result of the rearrangement of the positions of the twisted pairs P3 and P4 in the seven channels and not any change in inherent performance of the cables or connectors.
The wiring of the third connection 311 forming the consolidation point was not changed. The third connection 311 uses a simple method of wiring where the twisted pairs P1-P4 are “piggy backed” on top of each other. Unlike in RJ-45 jacks and plugs, the third connection 311 does not include split pairs and the pairs are spaced apart by a significant distance from one another so as to reduce the influence of any one pair to the other remaining pairs. Therefore, modal alien crosstalk is not considered a factor in the electrical performance of the third connection 311. Electrical results validate this premise. Therefore, the wiring of the third connection 311 can remain the same throughout testing without effecting the results.
ANEXT and AACR-F of the modified channel configuration were measured and PSANEXT and PSAACR-F were calculated and recorded for the modified channel configuration.
Table A below lists margins between the Augmented Category 6 specifications for PSANEXT and the PSANEXT values measured for both the initial configuration of the channel 300 and the modified configuration of the channel 300. Table B below lists margins between the Augmented Category 6 specifications for the PSAACR-F and the PSAACR-F values measured for both the initial configuration of the channel 300 and the modified configuration of the channel 300. As may be seen in Tables A and B, the worst case PSANEXT and PSAACR-F values improved in the modified configuration compared to the initial configuration. Specifically, in Tables A and B, the worst case PSANEXT value improved by about 1.3 dB, and the worse case PSAACR-F value improved by about 3.8 dB.
In
Referring to
It should be noted that in the example shown here, only the twisted pairs P3 and P4 in the horizontal cables 310 and 312 (shown in
The cable 100 is configured for use with a communications connector having a plurality of connections, such as a plurality of contacts arranged in a series like the plug contacts P-T1 to P-T8. Non-limiting examples of suitable communications connectors for use with the cable 100 include a conventional RJ-45 plug (e.g., the plug 30 illustrated in
While the predetermined order of the twisted pairs P1-P4 of the cable 100 has been described for use with Category 6 and Category 6A cables, those of ordinary skill in the art appreciate that the predetermined orders of the twisted pairs P1-P4 may be used in other types of network cable, Ethernet cable, and the like. By way of non-limiting examples, the predetermined orders of the twisted pairs P1-P4 of the cable 100 may be used to construct cables of other Categories, such as Category 5 cables, Category 5e cables, Category 6A cables, Category 7 cables, Category 7A cables, and the like.
The foregoing described embodiments depict different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely exemplary, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as “associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being “operably connected,” or “operably coupled,” to each other to achieve the desired functionality.
While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from this invention and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of this invention. Furthermore, it is to be understood that the invention is solely defined by the appended claims. It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations).
Accordingly, the invention is not limited except as by the appended claims.
