1. Field of the Invention
The present invention relates generally to modular telecommunications jacks and, more particularly, to a modular jack having a two-piece housing and a shock absorbing insert.
2. Description of Related Art
Modular jack (“modjack”) receptacle connectors mounted to printed circuit boards (PC boards) are well known in the telecommunications industry. These connectors are typically used for electrical connection between two electrical communication devices. With ever-increasing operating frequencies of data and communication systems and an increased density of information to be transmitted, the electrical characteristics of such connectors are of increasing importance. In particular, it has to be ensured that these modjack type connectors do not have deleterious effects on the signals to be transmitted and that no additional interference is introduced. Based on these requirements, various proposals have been made in order to minimize negative influences, especially of modjack connectors, used with communication or transmission links.
When used as Ethernet connectors, modular jacks generally receive an input signal from one electrical device and then communicate a cleaned up corresponding output signal to a second device coupled thereto. Magnetic circuitry is used in the transfer of the input signal of one device to the output signal of the second device and also cleans the input signal during transfer from the first device to the second. Currently, modjacks are made using a single channel ferrite choke. Usually these chokes are toroidal magnetic ferrite common mode chokes for use in various filtered connectors. The chokes are used to reduce the amount of unwanted common mode signal in differential signaling applications.
For the elimination of in-phase interference signal noise components, U.S. Pat. No. 5,015,204 teaches use of a common-mode choke arranged in a connector housing around which the contact leads of a RJ-45 modjack connector are integrally wound. In this design, the common-mode choke takes up a substantial portion of the connector housing, although only two signal-conducting leads are used. Furthermore, the respective leads need a certain rigidity to provide resilient forces to continuously facilitate a secure contact with the associated modular plug connector. Unfortunately, this makes for difficult manufacturing conditions, especially when the rigid wires have to be wound around the conductive core of the choke coil and the entire assembly placed within the modjack housing.
More particularly, difficulty in manufacturing arises from the fact that currently available modjacks are manufactured such that they are formed using a single frame configuration. That is, the modjack includes a hollow box-shaped housing that is formed as a single piece component. Magnets, choke coils and other filtering components are then placed within the frame through the relatively narrow opening. These components are then potted using silica gel, which once again must be applied through the relatively small opening in the modjack housing.
Therefore, it can be seen that inserting and potting of the components is difficult because of the relative inaccessibility of the interior of the single piece modjack housing. Furthermore, the performance of the choke in known modjack designs is significantly reduced if an unbalanced DC current is applied to the circuit. This may occur in Power over Ethernet type of applications because of the saturation of the ferrite core.
Various other objects, features and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views in which:
In order to provide a modular jack with magnetic filtering (magjack) that avoids the problems of the prior art and also which is able to increase performance and ease of manufacturing, there is provided a modular jack system where the jack includes two component housing halves that are configured to mate with one another other. The filtering components or magnetics, which may include a multichannel choke, are placed inside either one or both halves of the housing and potted prior to assembly. A shock-absorbing insert is also placed between the two halves to protect any filtering components or assemblies located within the component housing. The halves of the housing are then brought together to form the assembled component enclosure or housing.
The shielding 106, as shown in
As shown more clearly in
The top and bottom PCBs 122, 124 include the resistors, capacitors and any other components associated with the chokes and transformers located inside the component housing 126, which together comprise the filtering circuitry of the magjack.
The magnetics 151 provide impedance matching, signal shaping and conditioning, high voltage isolation and common-mode noise reduction. This is needed, for example, in 10/100 Base-T Ethernet that utilizes Unshielded Twisted Pair (UTP) transmission cable. The UTP wiring is prone to noise pickup, which may result in conducted and radiated noise emission. The magnetics help to filter out the noise, provide good signal integrity and electrical isolation.
The magnetics 151 include a transformer core 158, PoE choke core 156 and transformer choke core 152. For 10/100 Mbps communications, a common-mode choke is necessary for a system to pass FCC testing. The choke presents a high impedance to common-mode noise but a low impedance for differential-mode signals. Preferably both transmit and receive channels have a choke where both chokes are wired directly to the RJ-45 connector. Another consideration is crosstalk between transmit and receive channels. Crosstalk may create problems during EMC testing. Accordingly, magnetics with a shield between the two channels can minimize crosstalk. In addition, because of the additional DC current present in the PoE magjack, PoE systems require a resized common mode choke.
Because of the above requirements, the present invention provides a unique configuration of transformers and chokes to enable proper functioning of the magjack in all presently available communications systems. As shown in the exemplary embodiment, the magnetics 151 includes multiple core assemblies. The first is a standard or non-PoE core assembly 153 and the second is a PoE core assembly 157. Each housing, 136a, 136b receives and stores a standard core assembly 153 and a PoE core assembly 157.
Both types of core assemblies include a pair of transformer cores 158, such as those sold by Steward, part no. 46TOI45-00P. A transformer choke core 152, also sold by Steward, part no. 28N0277-11P is located on top of the transformer cores 158. It is to be noted that the transformer choke core used in this exemplary embodiment includes two holes 154a, 154b in what may be called a “double donut hole” configuration. By providing the two holes 154a, 154b, the core is able to support multiple transformer channels. Two channels are illustrated herein, but additional channels may be provided if needed.
Using the double donut hole configuration lowers the cost of materials since only a single part is required versus two separate chokes, as well as providing an elegant solution for multichannel use. It should be noted that functionally a pair of discrete single-hole choke cores could be used with equal effectiveness, but at a likely increased cost. In another exemplary embodiment (not shown), the PoE core may be split through the center so that an elongated aperture extends between the two holes 154a, 154b. A particular advantage of such a configuration would be to enable the possible automation of the winding process.
The PoE core assemblies 157 also include a PoE choke core 156 for providing the necessary size for the increased current of PoE systems. Such PoE transformer cores are also available from Steward, part no. 28T0155-00P.
As the housings 136a, 136b are brought together, the latch 138a flexes slightly outwardly and moves up the ramp portion of the shoulder 138b. As the latch 138a crosses over the back edge of the ramp 138b, the latch aperture 139 fully engages the shoulder 138. The latch 139 is securely held in place by the flat end of the back portion of the shoulder 138b.
After assembly of the housings 136a, 136b, the shock absorbing insert 150 compresses against the magnetics 151. As shown in
Although the present invention has been described in terms of the presently preferred embodiments, it is to be understood that the disclosure is not to be interpreted as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art after having read the above disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US06/43982 | 11/13/2006 | WO | 00 | 11/8/2010 |
Number | Date | Country | |
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60865278 | Nov 2006 | US |