Electrical connectors – With insulation other than conductor sheath – Plural-contact coupling part
Reexamination Certificate
2001-11-09
2003-05-06
Bradley, P. Austin (Department: 2833)
Electrical connectors
With insulation other than conductor sheath
Plural-contact coupling part
C439S344000
Reexamination Certificate
active
06558204
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a plug assembly for data transmission, and to a method of wiring the same. The preferred embodiment of the invention provides a plug suitable for category
6
data transmission installations which provides reduced near end and far end cross-talk levels as compared with conventional data transmission plugs.
2. The Prior Art
The use of mating plugs and jacks in data transmission installations is well known. As data transmission rates have increased more care has been applied to the design of all plugs and jacks in order to reduce to a minimum cross-talk induced by the plugs and jacks. Various schemes have been proposed for substantially reducing the cross-talk induced by a jack including, in particular, the use of cross-talk cancelling components on the circuit board to which the jack is conventionally secured.
Dealing with the problem of the cross-talk generated within the plug has proved more difficult. In this context, it must be remembered that the plugs in question are inherently of small size and they are required to have an array of parallel contacts for mating with corresponding contacts in the jack. The array of parallel contacts itself induces cross-talk within the plug. Further, the need to untwist the usually twisted pairs of conductors in order to connect the individual conductors to the contacts induces further cross-talk. Because of the small size of the plug, the techniques used for the purposes of reducing cross-talk in jacks cannot be applied directly to the plug. To an extent, the cross-talk induced by a plug may be cancelled by appropriate selection of cancellation components on the circuit board of the jack into which the plug is inserted. Unfortunately, however, the cross-talk induced by a plug tends to be very variable, at least in part as a result of the variations in positions of the conductors within the plug. Accordingly, including cross-talk cancelling components on the jack circuit board cannot be used reliably as a method of compensating for cross-talk induced in a plug inserted into the jack.
Typically, a plug may have eight contacts which are separately connected to the conductors of four twisted pairs of conductors. For the purposes of this discussion the conductors of the first twisted pair are designated A and B; the conductors of the second twisted pair are designated C and D; the conductors of the third twisted pair are designated E and F; and the conductors of the fourth twisted pair are designated G and H. By convention one conductor of each pair is coloured to identify the pair and the other conductor of each pair is predominantly white but has bands of colour corresponding to its associated coloured conductor. For the purposes of this discussion conductors A,C,E and G will be considered to be coloured conductors and conductors B,D,F and H will be predominantly white conductors. In standard four twisted pair cables the coloured conductors are coloured brown, green, blue and orange and for the purposes of this description conductor A will be regarded as,the brown conductor, conductor C will be regarded as the green conductor, conductor E will be regarded as the blue conductor and conductor G will be regarded as the orange conductor. It follows from the above that conductor B will be predominantly white but with brown bands, conductor D will be predominantly white but with green bands, conductor F will be predominantly white but with blue bands and conductor H will be predominantly white but with orange bands.
In the standard and enhanced version of the common RJ45 plug the conductors are connected toga linear array of eight parallel side-by-side contacts. The common
258
A and
568
B wiring conventions require the conductors to be connected to the contacts so that the conductor order, measured from end to end of the linear array, is ABCFEDGH. This arrangement is recognised as reducing the cross-talk particularly between the CD pair and the EF pair.
RJ45 type plugs still, however, produce a significant amount of cross-talk which in turn makes it very difficult to produce plugs which satisfy category
6
cross-talk standards. Cross-talk is largely induced by the parallel array of contacts within the plug and by the fact that the conductors must run parallel to each other in the zone immediately adjacent the connection to the contacts. The problem of cross-talk is further complicated by the fact that the individual conductors are, at the present time, to an extend randomly located within the plug body. As a result, although some plugs may attain an acceptable cross-talk level, others which are nominally identical do not. As noted above, the variation between plugs of nominally identical design also renders it impracticable to compensate for plug cross-talk by means of additional components associated with a jack socket of the circuit board on which the jack socket is mounted.
We have now found that the cross-talk induced in a plug can be reduced if, in a region between the contacts and the point where the cable enters the plug, the conductors of the CD pair and the conductors of the EF pair are constrained to run with the C and E conductors adjacent each other.
In one embodiment the D and F, conductors are also constrained to run adjacent each other. In other words, in a region adjacent the contacts the conductors of the CD and EF pairs are constrained to run with the conductors which are connected to pins
3
and
5
close to each other and the conductors which are connected to pins
4
and
6
close to each other.
We have devised a number of plug arrangements which utilise this routing of conductors C,D,E and F to reduce cross-talk. The different plug arrangements provide different degrees of cross-talk reduction. Whilst in many applications a plug which produces the maximum reduction in cross-talk will be required, other applications which are less demanding may utilise less efficient embodiments of the invention.
In addition to reducing cross-talk, the preferred embodiments of the present invention provide accurate control for the position of the conductors within the plug. As a result, plugs according to the preferred embodiment of the invention provide more consistent levels of cross-talk than similar plugs of the prior art. As a result, to the extent that cross-talk is produced by the plugs in the preferred embodiment this can, to an extent, be compensated for by a design of the jack or jack mounting board with which the plug is, in use, to be associated.
The desired arrangement can conveniently be achieved by use of a wiring manifold as part of the plug assembly.
In one embodiment of the invention the wiring manifold defines two channels, one for receiving the D and F conductors and the others for receiving the C and E conductors. In this embodiment the AB pair and the GH pair bypass the wiring manifold and remain as respective twisted pairs as they pass the zone of the wiring manifold. Preferably, the wiring manifold and an associated load bar include inter-engaging latching means whereby the wiring manifold is, in use, secured to the load bar. Preferably, the wiring manifold is of a polycarbonate material, although in some embodiments of the invention a relatively soft and flexible material, for example silicone rubber, may be used.
In another embodiment of the present invention we have found that cross-talk induced in a plug can be reduced if, in the region between the contacts and the point where the cable enters the plug, the conductors of the CD pair and the conductors of the EF pair are constrained to run with the C and E conductors adjacent each other and with the F conductor adjacent the E conductor and the D conductor adjacent the C conductor. In a particularly preferred arrangement the C and E conductors are located one above another; and the F conductor is at substantially the same level as the E conductor. In one embodiment the F conductor is located to one side of the vertical plane passing through the C and E conductors, and the D conductor
Bradley P. Austin
Dykema Gossett PLLC
Gushi Ross
LandOfFree
Plug assembly for data transmission and method of wiring same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Plug assembly for data transmission and method of wiring same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Plug assembly for data transmission and method of wiring same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3037569