One type of plug used to terminate cordage (ie., multi-wire cabling) is the 110-type patch plug, manufactured by Avaya Communications of Basking Ridge, N.J. One end of the 110-type patch plug permanently terminates a multi-wire cable, while the other end mates removably to the insulation displacement contacts (IDCs) of a 110-type connecting block, which is also manufactured by Avaya Communications. 110-type patch plugs are often used in voice and data transmission applications. In such transmissions, a balanced signal transmission path is formed by each pair of conductors, called the TIP conductor and the RING conductor. A typical 8-wire cable can therefore support four different voice or data signal transmission paths.
A 110-type patch plug has one or more pairs of contacts (typically 1, 2, 3, or 4 pairs) that form the electrical connections between the conductors of a multi-wire cable and the IDCs of a 110-type connecting block. One end (i.e., the mating end) of each patch-plug contact is a blade that engages a split-beam contact of the 110-type connecting block. The other end (ie., the cable end) of each patch-plug contact has a split-beam contact (e.g., an IDC) that terminates one of the cable conductors. The blades are sequenced in a liner alternating fashion between TIP and RING conductors in order to be aligned with the split-beam contacts of a 110-type connecting block.
One common type of conventional multi-wire cabling used for telecommunications applications has one or more twisted pairs of copper wires, where each twisted pair carries the TIP and RING signals for one balanced transmission path. In order to reduce crosstalk between these transmission paths, a different twist rate is used for each different twisted pair within such cordage. A twist rate may be characterized in terms of the number of times the wires of a twisted pair circle one another over a particular length of cordage, e.g., in terms of revolutions per foot.
Near-end crosstalk (NEXT) refers to unwanted signals induced in one transmission path due to signals that are transmitted over one or more other transmission paths appearing at the end nearest to where the transmitted signals are injected. Near-end crosstalk often occurs when the wires, contacts, and/or other conductors that form the various transmission paths are in close proximity to one another. The twist rates for cordage for telecommunications applications is typically carefully selected and strictly maintained within the cordage to limit such near-end crosstalk.
Prior art patch plugs have a volume within which the twisted pairs and ultimately the individual wires are distributed from a multi-wire cable to the IDCs of a 110-type patch plug and a contact base. Lack of control over twist rates within the volume may lead to near-end crosstalk. Moreover, lack of control over routing paths within the volume may result in the levels of such crosstalk varying significantly from one patch plug/cordage assembly to another, due to variations in those routing paths from assembly to assembly. The resulting electrical/transmission performance variability may be intolerable for certain high-performance, high-speed telecommunications systems. There have been, and are, numerous arrangements for alleviating the crosstalk problem, the examples of which are shown in the aforementioned Baker et al. patents and in the Lin application. These arrangements are directed primarily to the reduction of NEXT where the connector is used to terminate cordage having two or more twisted pairs, and, for the most part, feature wire guide channels through which different twisted pairs are routed to, for example, the insulation displacement contacts (IDCs) of the connector. It has been found that closer management of the routing of the individual twisted pairs, both at the transition from the cable to the wire guide troughs and within the connector between the transition and the IDCs than is currently available, is needed to reduce near end crosstalk (NEXT) even further.