The present invention relates to an electrical connector, particularly for telecommunication systems in which crosstalk induced between adjacent contacts or terminals of the connectors is cancelled. The cancellation of crosstalk is effected by compensation circuits coupled to the contacts or terminals of the connector, with compensation circuits located on a board separate from the board for mounting the contacts and biased against free ends of the contacts.
Due to advancements in telecommunications and data transmissions speeds over balanced, twisted-pair cables, the connectors (such as jacks, plugs, patch panels, cross connects, etc.) are a critical impediment to high performance data transmission at higher frequencies. Performance characteristics, particularly crosstalk and return loss, degrade beyond acceptable levels at higher frequencies. This degredation is particularly true for operation at category 6 and category 6a levels.
When an electric signal is carried on the signal line, which is in close proximity of another signal line or lines carrying a signal or signals, such as in the case of adjacent pins of contacts in the connector, energy from one signal line can be coupled onto adjacent signal line by the electric field generated by the potential between the two signal lines and the magnetic field generated as a result of the changing electrical fields. This coupling, whether capacitive or inductive, is called crosstalk when this phenomenon occurs between two or more signal lines.
Crosstalk is a noise signal and degenerates the signal-to-noise margin or ratio (SIN) of the system. In telecommunication systems, reduced S/N margins result in greater error rates in the information conveyed in the signal line. Depending on the category of the system, the S/N margin must satisfy set performance criteria.
Crosstalk problems could be overcome by increasing the spacing between the signal lines, or by shielding the individual signal lines. In many cases, the wiring is preexisting and standards define the geometries and pin definitions for connectors, making the necessary changes to such systems cost prohibited. In this specific case of communication systems using balanced, twisted-pair wiring, standards defining connector geometries and pin out definitions are in effect, but were created prior to the need for high speed data communications.
These standards have created a large base of wiring and connectors and a need for connectors capable of meeting the requirements of high speed communications, while maintaining compatibility with the original connectors. The standard connector geometries and pin outs are such that a great deal of crosstalk occurs at higher signal frequencies.
Numerous connector constructions have been developed to alleviate this crosstalk problem. Such systems involve counteracting a noise signal in a line by inducing in that line a signal equal to and opposite to the noise signal such that the induced noise signal is effectively cancelled by the induced correction signal. Examples of such connectors are disclosed in U.S. Pat. Nos. 5,432,484, 5,673,009 and 6,796,847, the subject matter of each of which is hereby incorporated by reference.
The distance from the circuitry providing the compensation for the crosstalk to the point of engagement of the plug contacts and the jack contacts has been determined to be significant in the effectiveness of reducing crosstalk. Such distances are to be made as small as possible. The distance between the plug contact-jack contact engagement point to the compensation circuitry also needs to be maintained constant, as well as as small as possible, to maintain consistent performance. Additionally, the jack contacts must remain in place despite flexing to avoid inadvertent contact with the other jack contacts or improper contact with the plug contacts. The resilient jack contacts must maintain their resiliency, and must not be overstressed by the deformation caused by engagement with the plug.
As used in this application, the terms “top”, “bottom”, “side”, “front”, “rear” and the like are intended to facilitate the description of the electrical connector and parts thereof. Such terms are merely illustrative of the connector and its parts, and are not intended to limit the electrical connector and its parts to any specific orientation.
An object of the present invention is to provide an electrical connector having a primary or mounting circuit board from which the jack contacts extend and a secondary or compensation circuit board flexibly mounted in the connector housing outside of the plug receiving cavity.
Another object of the present invention is to provide an electrical connector, particularly for communication systems, effectively cancelling crosstalk induced across connector terminals even at very high transmission frequencies.
A further object of the present invention is to provide an electrical connector with reduced crosstalk at high transmission speeds or frequencies without internal shielding between its individual contacts or without changing the standard connector geometry and pin out definitions.
A still further object of the present invention is to provide an electrical connector with reduced crosstalk that is simple and inexpensive to manufacture and use.
Yet another object of the present invention is to provide an electrical connector wherein the distance between the engagement point of the jack contacts and plug contacts to the compensation circuitry is effectively reduced.
The foregoing objects are basically obtained by an electrical connector comprising a housing, a mounting circuit board, a plurality of pairs of electrical jack contacts, a compensation circuit board, and a spring. The housing has a plug receiving cavity with an open end for receiving a plug and with an inner end spaced from the open end, and has a forward chamber outside of the cavity and adjacent the open end. The mounting circuit board is in the housing adjacent the inner end. Each of the jack contacts has a mounting end engaging the mounting circuit board, a plug contacting portion extending through the cavity from the mounting end toward the open end, and a free end extending from the contacting portion into the forward chamber. The compensation board is mounted in the forward chamber of the housing outside of the plug receiving cavity, and has a compensating circuit thereon with conductive pads. The free ends of the jack contact engage the conductive paths. The spring is located in the forward chamber to bias the compensation board towards the free ends of the jack contacts.
By forming the electrical connector in this manner, the distance between the compensating circuitry on the compensation circuit board and the engagement point between the jack contact and the plug contact, and the biasing of the compensation board improves electrical performance. This performance is improved by shortening the distance from the plug engagement point to the crosstalk compensation provided by the compensating circuit on the compensation circuit board. As the jack contacts are deflected by insertion of the plug into the plug receiving cavity, the individual jack contacts are forced to sweep or slide along the conductive pads on the compensation circuit board providing a wiping action to enhance the electrical connection therebetween. The spring biasing the compensation circuit board allows the compensation circuit board to move within the housing in response to the insertion of the plug in a manner to reduce stress in the jack contact structure while providing a reliable mechanical and electrical connection.
Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the present invention.
Referring to the drawings which form a part of this disclosure:
According to a first exemplary embodiment of the present invention, the electrical connector 40 is in the form of a communications and/or data transmission jack. The connector has a housing 42, a mounting circuit board 44, a compensation circuit board 46 and a spring 48 for biasing the compensation circuit board. The housing has a plug receiving cavity 50 with an open end 52 for receiving a plug 54, and an inner end 56 spaced from open end 52. A forward chamber 58 is located within the housing outside of cavity 50 and adjacent to open end 52, and receives compensation circuit board 46. The mounting circuit board 44 is mounted in the housing adjacent inner end 56. A plurality of pairs of electrical jack contacts are arranged in the housing and engage the compensation circuit board, as will be explained hereinafter.
Housing 42 comprises a nose housing part 60 and an insulator housing part 62. These two housing parts can be coupled to one another in any suitable and conventional fashion, including ultrasonic welding and resilient latch connections. While each of the two parts is formed separately, they are secured to one another such that they are not readily detachable.
Nose housing part 60 has a substantially parallelepiped shape, and comprises a forwardly tapered abutment 64 on its top outer surface and a forwardly extending resilient latch arm 66 extending from its rear end adjacent to, spaced from and parallel to its outer bottom surface. The forward end of latch arm 66 has a forwardly tapered abutment 67. Abutment 64 and latch arm 66 facilitate connection of electrical connector 40 in an outlet or receptacle face plate, a patch panel or other suitable mounting structure.
The interior of the nose housing part is primarily formed of and divided into plug receiving cavity 50 and forward chamber 58. Each of cavity 50 and chamber 58 forms a distinct and separate portion of that interior. An interior shield 65 (
Insulator housing part 62 (
Eight resilient jack contacts 78, 80, 82, 84, 86, 88, 90 and 92 extend from mounting circuit board 44 and from its surface opposite that from which insulation displacement contacts 72 extend. As illustrated in
First and second jack contacts form a pair with reverse configurations such that the two contacts cross one another without touching. The fourth and fifth contacts cross one another without touching in a similar manner. The seventh and eighth contacts cross another without touching in a similar manner.
Each of the jack contacts have a mounting end 96 that extends from the over mold and engages mounting circuit board 44. On the opposite side of the over mold, each contact has a plug contacting portion extending from the over mold to a free end 100 between the free end and the over mold. Each jack contact plug contacting portion has a generally V-shaped bent portion 102 defining a plug contacting engagement point 104 at its apex. The plug contacting portion, including the engagement point, extends through plug receiving cavity 42 with the free end extending from the plug receiving cavity into the forward chamber 58. Lateral S-shaped offset bends 106 are provided in the first, second, forth, fifth, seventh and eighth jack contacts adjacent the over mold to provide for the crossovers discussed above. The front part of the V-shaped bent portion extends at an angle to the longitudinal axis of the electrical connector substantially equal to the angle of the compensation circuit board to that longitudinal axis before plug insertion, as shown in
Over mold 94 comprises a rear surface with a perpendicular surface portion 94a and an angled surface portion 94b oriented at an obtuse angle relative thereto. These surface portions allow over mold 94 to tilt relative to mounting circuit board 44 when plug 54 is inserted and presses on the jack contacts, as shown in
Compensation board 46 is supported in chamber 58 by spring 48. Spring 48 comprises, as particularly illustrated in
Base leg 108 includes two parts 114 and 116, with part 114 located closer to bend 112 than part 116. The parts extend parallel to one another and are laterally offset by an angularly oriented intermediate leg part 118. Base leg part 114 includes a resilient tang formed in an opening 122. Tang 120 is oriented in a plane at an acute angle relative to the plane of the remainder of base leg part 114, and extends forwardly in the electrical connector. The free end of tang 114 and a surface of intermediate leg part 118 face another at a predetermined distance for securing spring 48 within forward chamber 58, as explained in detail hereinafter.
Angled leg 110 includes a substantially rectangular main portion 124 underlying a bottom surface of compensation board 46 and substantially rectangular end portions 126 and 128. These end portions engage the opposite ends of compensation circuit board 46, with end portion 126 extending from a free end of angled leg 110 and end portion 128 being adjacent bend 112 connecting base leg 108 and angled leg 110. End portion 126 is substantially perpendicular to the plane of main portion 124, and extends along the entire width of the base portion. End portion 128 is formed from an opening in the bend and extends substantially perpendicular to the plane of main portion 124. Both end portions extend from the main portion in the same direction, providing abutments to engage the opposite ends of the compensation circuit board.
A unitarily formed, one piece spring retainer 130, illustrated separately in
An axially extending, rectangular slot 148 is formed in the bottom surface 136 and opens into laterally or vertically passage 142. This slot defines an axially facing, rectangular end abutment 150 axially spaced from front surface 152 of central member 132. The axial spacing between abutment 150 and front surface 152 corresponds to the spacing between the free end of tang 120 and intermediate leg part 118 of spring 48. When spring 48 and spring retainer 130 are coupled, the free end of tang 120 engages abutment 150, while intermediate leg part 118 engages an edge of front surface 152 to prevent relative axial movement between the spring and the spring retainer. The spring is mounted in the spring retainer by sliding the free end of leg part 114 into passage 142 from front surface 152. Tang 120 is received in opening 122 until the free end of the tang is freed to move resiliently laterally into an engagement with end abutment 150 by entering slot 148.
Also located within forward chamber 58 of nose housing part 60 is a comb insert 154, illustrated separately in
Side parts 160 and 162 extend parallel to the longitudinal axis of electrical connector 40, and contain laterally outwardly opening, rectangular recesses 176. The recesses receive and engage latch arms 134 connecting spring retainer 130 to comb insert 154. Axially and rearwardly extending, generally rectangular end portions 178 of the side parts abut the surface of mounting circuit board 44. Rear end part 158 is spaced laterally above the side parts and joins the rear ends of side parts 160 and 162 adjacent end parts 178. In this manner, rear end part 158 is spaced axially and laterally relative to front end part 156, and defines a recess 180 that in the assembled position illustrated in
A stuffer cap of generally conventional design is provided to cover the insulation displacement contacts and the free end of insulator housing part 62 and to force wires into those insulation displacement contacts. The general configuration of the stuffer cap is adequately illustrated in
A shield 212 with an electrically conductive metallic internal layer is mounted on the exterior surfaces of the stuffer cap walls. The configuration of the shield is mated to conform to and adhere to the configuration of the stuffer cap walls. The shield includes a plurality of tabs 214 connected by fold lines 216. The tabs also include a slot 218 conforming to the configuration of slot 204. The mounting of the shield on the outer surface of the stuffer cap is apparent from the illustrations of
The electrical circuitry on mounting circuit board 44 is graphically depicted in
Three layouts for the electrical circuitry of the compensation circuit board are graphically illustrated in
The assembled connector is illustrated in
Engagement points 104 on the jack contacts provide a predetermined and set location for the engagement of the plug contacts with the jack contacts. This engagement point is located close to the compensation circuitry on the compensation circuit board. This arrangement, in combination with the positioning of the jack contacts maintained by the comb insert, allows the predetermined and high degree of effectiveness using a minimal amount of compensation for reducing crosstalk through the plug and the electrical connector. Minimizing the amount of corrective coupling improves maintaining connector balance and maintaining high frequency Return Loss (impedance) performance.
Compensation circuit board 46 and the free ends of the jack contacts are parallel in the unmated state (
The angle of the compensation circuit board is dependent on angled leg 110 of spring 44. The angled leg of the spring is approximately parallel to the free ends of the contacts to reduce stress in the jack contacts at and beyond the plug mating point.
The angle of the compensation circuit board is also parallel to the free ends of the jack contacts to create the shortest electrical path from the plug mating point to the point of primary compensation on compensation board 46. If the compensation circuit board is mounted at an angle that is different than the angle of the free ends of the jack contacts, the electrical path is increased.
The term “wipe” describes the distance that the jack contact travels along the conductive pads on the compensation circuit board during plug insertion. The angle of spring 48 relative to the angle of the free ends of the jack contacts promotes an adequate “wipe” before spring deflection occurs forward of over mold 94. If deflection of the spring is immediate, the amount of “wipe” is reduced. If the amount of “wipe” is reduced, corrosive buildup on the jack contacts or the conductive pads will not be removed during plug insertion, and all eight contacts will not be in contact with the compensation circuit board after plug insertion.
The strength of the jack contacts relative to the strength of the spring ensures that all eight jack contacts are always in contact with the compensation circuit board after plug insertion. Each individual jack contact must generate a force on compensation circuit board 46 less than ten percent of the force generated by spring 48 over the same deflection distance on the compensation circuit board.
An electrical connector 260 according to a second exemplary embodiment of the present invention is illustrated in
An electrical connect or 290 according to a fourth exemplary embodiment of the present invention is illustrated in
While several embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.
This application is related to application Ser. No. 12/285,428 of Shadi A. AbuGhazaleh and Douglas P. O'Connor, filed Oct. 3, 2008 and entitled Crosstalk Prevention Cover, the subject matter of which is hereby incorporated by reference.