JP4991393B2 - Signal transmission path and patch cord - Google Patents

Description

The present invention relates to a signal transmission line suitable for a LAN.
The present invention also relates to a patch cord used for a signal transmission path suitable for a LAN.

With the practical application of LAN, the development of a communication cable for signal transmission suitable for high-speed communication is strongly demanded. As the transmission rate becomes higher, it is necessary to improve the crosstalk attenuation characteristic of the communication cable, and a communication cable using a cruciform interposition is known as a communication cable with improved crosstalk attenuation characteristics (for example, Patent Documents). 1). In this known communication cable, twisted pair wires having different twisting pitches are respectively arranged in four storage areas defined by cross-shaped cross sections, thereby improving crosstalk attenuation characteristics between adjacent twisted wires. It has been.
Japanese Patent Laid-Open No. 11-53958

  In many local information wiring systems (LANs), an external network such as the Internet is connected to devices such as a floor switch and a switching hub via an optical communication cable. The floor switch is connected to the patch panel via a patch cord constituting the equipment cable. The patch panel is connected to outlets distributed on the floor via a horizontal cable functioning as a trunk line. The outlet is connected to each terminal via a patch cord constituting a work area code. Therefore, three types of cables, that is, an equipment cable, a horizontal cable, and a work area code, are connected to the signal transmission path between each terminal and the floor switch. In the case of a cross-connect channel, the patch panel has a primary side patch panel and a secondary side patch panel, and these patch panels are connected to each other by a patch cord.

  In the LAN wiring configuration, the horizontal cable functions as a trunk line on each floor, and is arranged so that a large number of wirings are densely packed. For this reason, alien crosstalk, which is crosstalk between cables, easily occurs in horizontal cables, and the occurrence of alien crosstalk is particularly noticeable in a high frequency band. On the other hand, a communication cable using a cruciform interposition can properly improve the crosstalk attenuation characteristics between the twisted wires arranged in the cable because the distance between the adjacent twisted wires is appropriately secured. The characteristics satisfying the standard value are obtained. However, in a place where wiring is concentrated, such as horizontal cables used in various data centers, there are limits to reducing alien crosstalk from the cable side because many cables are densely arranged.

  Furthermore, in many data centers, high-density mounting type switching hubs and patch panels are used. In such a place, a large number of wirings must be accommodated in a limited space. There is also a strong demand for minimizing the space occupied by various codes including codes.

An object of the present invention is to realize a signal transmission path in which alien crosstalk is reduced even when wirings are densely packed in a horizontal cable.
Another object of the present invention is to realize a patch cord having an effect of suppressing alien crosstalk.
Another object of the present invention is to provide a patch cord that has an effect of suppressing alien crosstalk and requires only a small space.

The signal transmission path according to the present invention is a LAN signal transmission path for connecting a device and a terminal,
A first patch cord connecting the device and the patch panel, a horizontal cable connecting the patch panel and the outlet, a second patch cord connecting the outlet and the terminal, and a primary side patch panel of the patch panel And a third patch cord connecting the secondary patch panel ,
The first, second and third patch cords and the horizontal cable are composed of multiple pairs of twisted wires, and each pair of twisted wires is composed of twisted pairs of a plurality of core wires,
The outer diameter of the conductor that constitutes the core wire of the twisted pair of the horizontal cable is set to 0.5 mm, and the outer diameter of the conductor that constitutes the core wire of the twisted pair of the first to third patch cords is the horizontal It is set to approximately 0.3 mm, which is thinner than the outer diameter of the conductor constituting the core wire of the twisted pair of the cable,
The outer diameter of the core wire of the twisted pair of the first to third patch cords is set to be equal to or less than half the outer diameter of the core wire of the twisted pair of the horizontal cable,
The range of the twist pitch of the twisted pair of the first to third patch cords is set to be shorter than the range of the twisted pitch of the twisted pair of the horizontal cable,
The insertion loss per unit length of the first to third patch cords is set to exceed approximately twice the standard value of the insertion loss per unit length of the horizontal cable in a frequency band exceeding 10 MHz,
It is characterized by having an attenuating action against alien crosstalk in a high frequency band exceeding 50 MHz .

  As a result of various experiments and analysis of various signal transmission paths including the LAN by the present inventor, it has been found that the insertion loss of the cables constituting the transmission path acts strongly as a method for suppressing alien crosstalk. That is, when a cable with a large insertion loss is connected to a part of the signal transmission path constituting the LAN, it has been found that the crosstalk signal generated by the inter-cable interference is strongly attenuated while propagating through the cable with a large insertion loss. In particular, according to the experimental results, it was confirmed that the crosstalk signal was significantly attenuated in a high frequency band exceeding 50 MHz. Based on the results of this experiment, in the present invention, as a patch cord constituting the equipment cable and work area cord connected to both sides of the horizontal cable which is the trunk of the floor, the insertion of about twice or more the insertion loss of the horizontal cable is inserted. Use a cable with loss. That is, alien crosstalk occurs mainly in horizontal cables where wiring is concentrated. Therefore, if a patch cord with a large insertion loss is used as the work area code in the signal path from the external network to the terminal, the alien crosstalk generated by the horizontal cable is attenuated while propagating the work area code, A signal in which the crosstalk signal is attenuated is transmitted. In addition, even if alien crosstalk occurs in the horizontal cable on the transmission path from the terminal to the floor switch, the crosstalk signal is attenuated while propagating through a device cable with a large insertion loss, and communication with reduced crosstalk is performed. Can do. In this way, by connecting a cable with a large insertion loss to both sides of the horizontal cable, even if alien crosstalk occurs in the horizontal cable, crosstalk is suppressed and good communication can be performed.

  Note that when a cable with a large insertion loss is used as a cord constituting the device cable, work area cord, and patch cord, the signal that should be transmitted is attenuated. However, the total length of the device cable, work area cord and patch cord is at most 10 m, which is shorter than the length of the horizontal cable, so that the signal quality is not adversely affected. Alternatively, by slightly shortening the total length of the signal transmission path, for example by shortening the total length from the floor switch to the terminal from about 100 m to about 90 m, even if a patch cord having a larger insertion loss than the horizontal cable is connected, There is no negative impact on signal quality. In the present specification, the “device” includes devices such as a floor switch, a switching hub, and a router.

In a preferred embodiment of the signal transmission line according to the present invention, the first, second and third patch cords and the horizontal cable are composed of multiple pairs of twisted wires, and the first, second and third patch cords Is composed of a pair of twisted wires in which a plurality of conductors are twisted, and is smaller than the conductor outer diameter of the core wire of the pair of twisted wires of the horizontal cable, and has an attenuation effect on alien crosstalk in a high frequency band exceeding 50 MHz. It is characterized by having.
The insertion loss of the cable can be increased by reducing the outer diameter of the conductor of the core wire. At this time, by reducing the conductor outer diameter of the core wire constituting the twisted pair wire to about 0.3 mm, the insertion loss is about twice that of the conventional twisted pair wire constituting the horizontal cable. It is possible to effectively attenuate the generated crosstalk signal.

  Furthermore, by reducing the conductor outer diameter of the core wire of the patch cord by about half, the outer diameter of the core wire is also reduced and the outer diameter of the cable is also reduced by about half, resulting in a thinner patch cord with a smaller bending radius. The Therefore, since the volume occupied by the patch cord is significantly reduced, a signal transmission line suitable for a signal transmission line using a high-density mounting type patch panel or switching hub is realized.

A preferred embodiment of the signal transmission line according to the present invention is characterized in that the twisted pair of the first, second and third patch cords has a twisted pitch shorter than the twisted pitch of the twisted pair of the horizontal cable. To do.
When the outer diameter of the conductor constituting the core wire is reduced to increase the insertion loss, the diameter of the core wire constituting the twisted pair wire is also reduced. In this case, if the core wires are twisted together at the same twisting pitch as the twisting pitch of the pair of twisted wires of the horizontal cable, there is a possibility that crosstalk between the twisted wires (crosstalk within the cable) increases. Therefore, in the present invention, as the conductor outer diameter and the core wire are made thinner, the twist pitch is shortened to reduce crosstalk between the twisted wires.

The signal transmission path according to the present invention is a LAN signal transmission path for connecting a device and a terminal,
A first patch cord connecting the device and the patch panel, a horizontal cable connecting the patch panel and the outlet, a second patch cord connecting the outlet and the terminal, and a third patch connecting the patch panels With a cord,
The first, second and third patch cords and the horizontal cable are composed of multiple pairs of twisted wires, and the twisted wires of the first, second and third patch cords are twisted pairs of horizontal cables. It has an outer diameter smaller than the outer diameter of the wire, and has a twisted pitch shorter than the twisted pitch of the twisted wire of the horizontal cable. Thus, by reducing the outer diameter of the twisted pair wire and shortening the twist pitch, a signal transmission path that suppresses alien crosstalk and also suppresses crosstalk within the cable is realized.

  In another preferred embodiment of the signal transmission line according to the present invention, the patch panel includes a primary side patch panel and a secondary side patch panel, and a third patch cord connecting between the patch panels. The pair of twisted wires constituting the patch cord 3 has an outer diameter smaller than the outer diameter of the pair of twisted wires of the horizontal cable and has a twist pitch shorter than the twist pitch of the pair of twisted wires of the horizontal cable. To do.

  In another preferred embodiment of the signal transmission line according to the present invention, at least a part of the patch cords is constituted by a flat type patch cord in which a plurality of twisted wires are arranged in parallel in the same plane. It is characterized by that.

  A patch cord according to the present invention is a patch cord used in a signal transmission path in which a device and a patch panel, an outlet and a terminal, and a patch panel are connected by a patch cord, and the patch panel and the outlet are connected by a horizontal cable. The twisted pair wire constituting the cord has an insertion loss that is at least twice as large as the insertion loss of the twisted pair wire constituting the horizontal cable.

  Patch cords are cords with plugs attached to both ends of the cable, and cords with a plug attached to one end of the cable and a jack attached to the other end. These cords are suitable for connecting between the device and the patch panel, between the primary patch panel and the secondary patch panel, and between the outlet and the terminal. Moreover, the patch cord according to the present invention has an insertion loss larger than twice the insertion loss of the horizontal cable, and has a function of suppressing alien crosstalk in the high frequency band. In addition, the crosstalk signal can be attenuated by the patch cord.

The patch cord according to the present invention connects a device, a primary side patch panel, a primary side patch panel and a secondary side patch panel, and an outlet and a terminal by a patch cord, and connects the secondary side patch panel and the outlet to a horizontal cable. In the patch cord used for the signal transmission path for LAN connected by
The twisted pair wire constituting the patch cord has an insertion loss larger than twice the insertion loss of the twisted pair wire constituting the horizontal cable.

  In a preferred embodiment of the patch cord according to the present invention, the twisted pair wire constituting the patch cord is constituted by a core wire having a conductor outer diameter smaller than the conductor outer diameter of the core wire of the pair twisted wire constituting the horizontal cable, and the horizontal It has the twist pitch shorter than the twist pitch of the twisted pair wire of the cable.

  As the insertion loss of the patch cord is increased, the outer diameter of the patch cord is reduced to about half that of the conventional patch cord, and the bending radius is also reduced to about half. As a result, a patch cord that can suppress alien crosstalk and is suitable for high-density mounting is realized.

In the signal transmission line according to the present invention, since a patch cord having a large insertion loss is connected to both sides of a horizontal cable in which alien crosstalk is likely to occur, alien crosstalk generated in the horizontal cable is caused by the equipment cable and the work area code. Attenuation can be performed, and communication with reduced crosstalk can be performed.
The patch cord according to the present invention has an effect of suppressing alien crosstalk, and the cable outer diameter and bending radius are reduced to about half, so that a patch cord suitable for high-density mounting is realized.

FIG. 1 shows an example of a LAN signal transmission path according to the present invention, FIG. 1A shows an interconnect channel signal transmission path, and FIG. 1B shows a cross-connect channel signal transmission path. The floor switch 1 is connected to the patch panel 3 via the equipment cable 2. The equipment cable 2 is composed of a small-diameter patch cord having an insertion loss larger than twice the insertion loss of the horizontal cable, and its length is set to 1 to 5 m. The patch panel 3 is connected to outlets 5 distributed on the floor via a horizontal cable 4 that is a trunk line of the floor. As the horizontal cable, a normal cable having a relatively small insertion loss and a large diameter is used, and its length is set to 90 m or less. The outlet 5 is connected to each terminal 7 via a work area code 6. The work area cord 6 has a length of 1 to 5 m, and is composed of a thin patch cord according to the present invention. In the cross-connect channel, as shown in FIG. 1B, the patch panel 3 has a primary side patch panel 3a and a secondary side patch panel 3b, and the patch panel between the patch panels is a patch cord according to the present invention. A connection cord 8 is connected to be switchable.
Since the horizontal signal cable mainly occupies the LAN signal transmission path, alien crosstalk generated in the signal transmission path is mainly generated by the horizontal cable 4.

Next, the structure of the device cable 2, the horizontal cable 4, the work area cord 6, and the patch cord 8 will be described. The horizontal cable 4 is constituted by a multi-pair cable in which a plurality of pairs of twisted wires are combined. In many-pair cables, both cables including and not including intervening cables are used. For the horizontal cable, use a cable that meets the insertion loss standard of the horizontal cable standard stipulated by the ANSI / TIA / EIA standard. A core wire covered with an insulator is used .

  The device cable 2, the work area cord 6 and the connection cord 8 are all constituted by patch cords constituted by four pairs of twisted wires shown in FIG. In FIG. 2, reference numerals 10 a to 10 d indicate four twisted pairs, each twisted pair is a twisted pair of two core wires, and its nominal impedance is set to 100 ohms. The four twisted wires 10 a to 10 d are covered with the sheath 11. The core wire of the twisted pair wire constituting the device cable 2, the work area cord 6 and the connection cord 8 has a structure in which the outer periphery of a conductor in which, for example, seven twisted conductor wires having a diameter of 0.1 mm are twisted is covered with an insulator. A core wire is used, and the outer diameter of the conductor is also set to 0.3 mm.

Next, the outer diameter dimension of the patch cord of the present invention is compared with a conventional patch cord that is normally used for LAN and meets the category 5e standard of the ANSI / TIA / EIA standard. Table 1 compares the patch cord according to the present invention and the conventional patch cord with respect to the conductor outer diameter, the core wire outer diameter, and the cable outer diameter (four pairs of twisted pair cables).
In a LAN cable having an impedance of 100 ohms, the thickness of the insulator covering the conductor is substantially proportional to the outer diameter of the conductor. Therefore, when the outer diameter of the conductor is reduced to increase the insertion loss of the cable, the thickness of the insulator covering the conductor is also reduced, so the outer diameter of the core wire is also reduced. The diameter becomes even thinner. As a result, a patch cord having an effect of suppressing alien crosstalk and having a smaller outer diameter is realized.

  The patch cord used for the work area cord 6 that connects the outlet and the terminal and the connection cord 8 that connects between the patch panels is a patch cord in which plugs are connected to both ends of the cable. The patch cord used for the device cable is a cord in which a plug is connected to one end of the cable and a jack is connected to the other end.

Next, a comparison of insertion loss between the patch cord and the horizontal cable according to the present invention will be described. Table 2 compares the insertion loss value of the horizontal cable defined in the category 5e channel standard of the ANSI / TIA / EIA standard with the insertion loss value of the patch cord according to the present invention. The unit is dB / 100m.
As apparent from Table 2, the insertion loss of the patch cord according to the present invention is increased to about twice the insertion loss of the horizontal cable standard defined in the ANSI / TIA / EIA standard.

Next, the twist pitch of the twisted pair wire will be described. As an example, the twist pitch of the pair of twisted wires of the horizontal cable and the patch cord is set as follows.

Horizontal cable Patch cord pair 1 9mm 10mm
Pair 2 11mm 7mm
Pair 3 14mm 9mm
Pair 4 19mm 8mm

The twisting pitch of the horizontal cable is appropriately determined so as to reduce the crosstalk between the twisted wires in consideration of the outer diameter of the core wire and the like. On the other hand, in the patch cord according to the present invention, in order to increase the insertion loss of the cable by reducing the outer diameter of the conductor, the twisted pitch is set to be the same as that of the horizontal cable. There is a possibility that the probability of becoming parallel increases and the crosstalk between the twisted wires increases. Therefore, in the patch cord of the present invention, the twist pitch of the patch cord is set shorter than the twist pitch of the pair of twisted wires of the horizontal cable to suppress the occurrence of crosstalk between the twisted wires. As a result, a patch cord having an effect of suppressing alien crosstalk and having reduced in-cable crosstalk is realized.

  Next, the results of experiments conducted on the effect of suppressing alien crosstalk will be described. The interconnect channel shown in FIG. 1A was used as the LAN wiring configuration, and a signal transmission path was configured by combining a 90 m horizontal cable, a 5 m equipment cable, and a 5 m work area code. In the signal transmission line according to the present invention, the device cable and the patch cord having the above-described configuration as the work area cord are connected to the horizontal cable satisfying the above-described standard, and four cables having four pairs of twisted wires are assembled. Alien crosstalk was measured. As a comparative example, the same horizontal cable is used, the same cable as the equipment cable and the cable used for the horizontal cable as the work area cord is connected, and similarly, four cables having four pairs of twisted wires are assembled to create an alien. Crosstalk was measured.

  The experimental results are shown in FIG. FIG. 3A shows the alien crosstalk of the signal transmission path using the same cable as the horizontal cable as the equipment cable and work area code, and FIG. 3B shows the alien crosstalk of the signal transmission path according to the present invention. The alien crosstalk measurement is performed by arbitrarily selecting one of the four cables, and setting the signal transmission path including one of the selected cables as a signal transmission path for measurement. . Then, the other three signal transmission paths are channels 1 to 3, and the alien crosstalk between the corresponding channels 1 to 3 of the remaining three cables is measured for each channel. In FIG. 3, the broken line indicates the ANSI / TIA / EIA channel standard. A solid line, a one-dot chain line, and a dotted line indicate alien crosstalk of channel 1, channel 2, and channel 3. The horizontal axis represents frequency (MHz) and the vertical axis represents alien crosstalk (dB).

  3A and B are compared, when the average value of the measured alien crosstalk is compared, a difference is recognized from the time point of 50 MHz, and the alien crosstalk is 60 dB in the case of the conventional signal transmission line at the frequency of 50 MHz. In the case of the signal transmission line of the present invention, it is 63 dB, and the effect of suppressing alien crosstalk was recognized. Furthermore, at a frequency of 300 MHz, the alien crosstalk measured in the case of the conventional signal transmission line is 43 dB, and in the case of the signal transmission line of the present invention, it is 51 dB. Further, at 500 MHz, 40 dB alien crosstalk was measured in the case of the conventional signal transmission line, and 50 dB alien crosstalk was measured in the signal transmission line of the present invention. From this experimental result, it was confirmed that the alien crosstalk was suppressed by connecting the patch cord according to the present invention to the horizontal cable as the equipment cable and the work area cord.

  FIG. 4 is a view showing a modification of the patch cord of the present invention. The patch cord according to the present invention can be applied not only to the four pairs of patch cords shown in FIG. 2 but also to a flat type patch cord in which four pairs of twisted wires are arranged in parallel in the same plane.

It is a figure which shows an example of the signal transmission path by this invention. It is a figure which shows an example of the patch cord by this invention. It is a graph which shows the alien crosstalk characteristic of the signal transmission path by this invention, and the conventional signal transmission path. It is the figure which comprised the patch cord by this invention as a flat type cable.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Floor switch 2 Equipment cable 3 Patch panel 4 Horizontal cable 5 Outlet 6 Work area cord 7 Terminal 8 Connection cord 10a-10d Twisted wire 11 Sheath

Claims (5)

A signal transmission path for LAN that connects devices and terminals,
A first patch cord connecting the device and the patch panel, a horizontal cable connecting the patch panel and the outlet, a second patch cord connecting the outlet and the terminal, and a primary side patch panel of the patch panel And a third patch cord connecting the secondary patch panel ,
The first, second and third patch cords and the horizontal cable are composed of multiple pairs of twisted wires, and each pair of twisted wires is composed of twisted pairs of a plurality of core wires,
The outer diameter of the conductor that constitutes the core wire of the twisted pair of the horizontal cable is set to 0.5 mm, and the outer diameter of the conductor that constitutes the core wire of the twisted pair of the first to third patch cords is the horizontal It is set to approximately 0.3 mm, which is thinner than the outer diameter of the conductor constituting the core wire of the twisted pair of the cable,
The outer diameter of the core wire of the twisted pair of the first to third patch cords is set to be equal to or less than half the outer diameter of the core wire of the twisted pair of the horizontal cable,
The range of the twist pitch of the twisted pair of the first to third patch cords is set to be shorter than the range of the twisted pitch of the twisted pair of the horizontal cable,
The insertion loss per unit length of the first to third patch cords is set to exceed approximately twice the standard value of the insertion loss per unit length of the horizontal cable in a frequency band exceeding 10 MHz,
A signal transmission path characterized by having an attenuating action against alien crosstalk in a high frequency band exceeding 50 MHz . 2. The signal transmission line according to claim 1, wherein the twisted pair wires constituting the first to third patch cords have an outer diameter of 0.4 mm, in which a conductor having an outer diameter of approximately 0.3 mm is covered with an insulator. A signal transmission line comprising a core wire . 3. The signal transmission path according to claim 1, wherein the conductor constituting the core wire of the first to third patch cords is a conductor formed by twisting seven conductor wires having a diameter of 0.1 mm. A signal transmission path characterized by comprising .   The signal transmission path according to claim 1 or 2, wherein at least a part of the first to third patch cords is a flat type in which a plurality of twisted wires are arranged in parallel in the same plane. A signal transmission line characterized by comprising a patch cord. The patch cord used for the signal transmission path according to claim 1, wherein the pair of twisted wires is composed of a pair of twisted wires in which a plurality of core wires are twisted, The outer diameter of the conductor constituting the core wire of the twisted pair is set to approximately 0.3 mm, which is thinner than the outer diameter of the conductor of the twisted pair of the horizontal cable, and the outer diameter of the core wire is set to 0.4 mm. A patch cord characterized by