Abstract:
A hybrid connector system comprising a special jack, a standard coaxial plug effective to make contact with the jack in one mode when inserted therein, and a wire pair plug operable to engage the special jack in another mode when plugged thereinto, the wire pair plug element being adaptable to, or configured especially for, use with shielded twisted pair cables, unshielded twisted pair cables, or ordinary telephone lines. The jack or socket member has first second and third concentric contact members, two of which are arranged to engage respectively, the central and shell contacts of a coaxial cable plug. The third of the contact elements of the socket member is interposed between the first and second contact elements, and the three contact elements are positioned to engage corresponding contact elements of the special plug which, when inserted into the socket completes connection to first and second ones of a wire pair and, optionally, a shield of such wire pair. Switch means are arranged to be operated between open and closed conditions by one of the kinds of plugs which the hybrid jack is designed to receive.

Description:
FIELD OF THE INVENTION 
     This invention relates to transmission line connectors and more particularly to a plug and jack system in which the jack can receive and make the correct connections to either a standard coaxial cable plug or a shielded or unshielded wire pair plug. 
     BACKGROUND OF THE INVENTION 
     Plug and socket arrangements for transmission lines have long been used in telephony, and audio equipment, as well as in high frequency transmission lines such as seen in television and data processing work station systems. 
     In telephony and audio equipment, plug and jack arrangement have long been known wherein the plug may be long or short and have two or three or more axially spaced conductor elements which engage complex arrangements of cantalever sprung contact elements in the jack or socket, and wherein some of these contact elements in the socket may operate to make or break connections when displaced by the plug element. In some cases the system is such that a short plug is used for one kind of apparatus, such as a microphone, and a long plug for another kind of apparatus such as a tape unit, for example, and the contact elements in the jack automatically make the appropriate connections. 
     For high frequency transmission systems, the transmission lines have been divided into distinct classes, such as coaxial cable, twisted pair, shielded twisted pair, and twin-x. There have been developed for each of these high frequency wiring systems particular kinds of connectors, and when an equipment is to receive either of two different kinds of cables it has been customary to provide two jacks or sockets in the equipment, each unique to the type of cabling system the plug of which it is to receive. 
     Thus, although various connector systems have been known, some of which accommodate different length plugs or cause internal switching action to take place as aforesaid, there has remained an unsatisfied need for a practical connector system having a jack which will receive a standard coaxial plug such as a BNC coaxial cable plug and, in the alternative, a plug for a shielded or unshielded wire pair transmission vehicle, an moreover a need for such a hybrid arrangement wherein the jack will respond automatically to make appropriate transition from unbalanced electrical scheme of the coaxial cable to a balanced system such as usually used in the wire pair arrangement. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, the foregoing and other needs are met by a hybrid connector system comprising a special jack, a standard coaxial plug effective to make contact with the jack in one mode when inserted therein, and a wire pair plug operable to engage the special jack in another mode when plugged thereinto, the wire pair plug element being adaptable to, or configured especially for, use with shielded twisted pair cables, unshielded twisted pair cables, or ordinary telephone lines. 
     According to one aspect of the invention the jack or socket member has first second and third concentric contact members, two of which are arranged to engage respectively, the central and shell contacts of a coaxial cable connector. The third of the contact elements of the socket member is interposed between the first and second contact elements, and the three contact elements are positioned to engage corresponding contact elements of a special plug which, when inserted into the socket completes connection to first and second ones of a wire pair and, optionally, a shield of such wire pair. 
     According to still another aspect of the invention, there are switch contact means arranged for operation by and upon insertion of the respective coaxial and special wire pair plugs, or one of them to be operated between open and closed conditions by and upon insertion of one or the other of the kinds of plugs which the hybrid connector is designed receive. 
     Accordingly, the invention includes the combination f a socket member having first, second and third concentric contact elements together with switch means operable in a given state to effect connection between the second and third elements and in another state not to effect such connection, and plug members of first and second types each proportioned to couple with said first and second contact elements but in the case of the first type class f plugs and elements there being in such first class type plug element a member having an extent axially of the plug member adapted to engage the switch means to operate the same from one state to the other, while plug members of the second type do not effect such state change. 
     The foregoing and other objects, advantages and aspects of the invention will be evident from this specification as a whole. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows, diagrammatically, a prior art BNC coaxial cable jack and plug pair. 
     FIG. 2 shows a jack an plug pair embodying the invention, wherein the plug shown is for shielded or unshielded twisted pair wire and the jack can receive either that or the BNC plug of FIG. 1. 
     FIG. 3 shows a jack and plug pair of a second embodiment of the invention, again wherein the plug shown is for shielded or unshielded twisted pair wire and the jack can receive either that plug or a standard BNC plug. 
     In each of FIGS. 1-3 the shown partly in cross-section, and in each a schematic or typical electrical elements to be connected is included. 
     FIG. 4 shows, diagrammatically, various combinations of the plugs and jacks of FIGS. 1-3 which illustrate the utility of aspects of the invention in new and existing systems. 
    
    
     DETAILED DESCRIPTION 
     In each of the illustrated embodiments of the jack of the invention shown, the jack is connected to a winding 10 of a transformer 12, another winding of which 14 is connected to a driver/receiver D/R for receiving signals from and delivering signals to a cable connected to the jack. In the prior art example shown in FIG. 1, the BNC jack B comprises a barrel shaped contact member 20 within which is mounted a central contact element 22. Element 22 is supported in a post 24 of dielectric material and is tubular in shape to receive the central conductor 26 of a BNC plug A. The plug A includes a hollow cylinder 30 of dielectric material which fits over the post 24 and conductive coupling 32 which fits over and electrically contacts the barrel 20 of the jack when the two are mated, all as is well known in the art. 
     In the typical circuit shown, the central contact element 22 of the jack is connected via a conductor 34 to one terminal 36 of transformer winding 10, and the barrel element 20 is connected via conductor 38 to the other terminal 40 of that winding. Usually, the barrel 20 is grounded, as indicated at 42, and therefore, the connection to the transformer is termed &#34;unbalanced&#34;. The plug is usually mounted on the end of a coaxial cable (FIG. 4), with the central or pin element 26 of the plug constituting an extension of the center conductor of the cable, and the coupling 32 being connected to the outer or shield conductor of the cable. 
     In each of the embodiments of the invention shown in FIGS. 2 and 3, a new jack and a corresponding new plug enable use in a balanced system such as is suitable for a twisted pair cable. This is accomplished by providing an additional contact element which, in the preferred embodiments of the invention, is in the form of an additional barrel, intermediate contact within but electrically isolatable from the outer barrel contact of the jack. In each case the new, twisted pair cable plug engages the center, intermediate and outer barrel elements to provide first and second connections for a twisted wire pair and, via the outer barrel, a ground connection for the cable shield, if present. 
     Moreover, in each of the preferred embodiments shown in FIGS. 2 and 3, the new jack of the invention can receive the standard BNC plug of FIG. 1 and has switch elements which couple the additional and outer barrel contacts of the jack so as to function in the same way as a standard BNC plug and jack combination for use in a conventional unbalanced coaxial cable system. 
     Referring now more particularly to FIG. 2, the jack C the invention has a conductive barrel 20&#39; which has outer dimensions which are identical to those of the barrel 20 of FIG. 1. Mounted with the barrel 20&#39; is a dielectric post 24&#39;, which like the post 24 of FIG. 1, carries an axial tubular contact element 22&#39; which is identical to the tubular element 22 of FIG. 1. 
     In accordance with the invention the post 24&#39; carries an additional barrel including metallic sleeve element 50, the outer diameter of which is of the same order as that of the similarly positioned post 24 of a standard BNC jack (FIG. 1), but in no event larger than the inner diameter of the hollow dielectric cylinder 30 of the standard BNC plug of FIG. 1. 
     The base of the sleeve element 50, FIG. 2 carries one or more contactor elements 60, 62 which are deflectable into contact with an inwardly projecting ring portion 64 carried by the outer barrel 20&#39; but are normally clear thereof so as to constitute normally open switch means therewith. 
     The center contact 22&#39; of the jack of FIG. 2 may be connected via a wire 34&#39; to one terminal 36&#39; of a winding 10&#39; of a transformer 12&#39; for coupling to a driver/receiver D/R, similarly to the connections of FIG. 1. However, in this case the other terminal 40&#39; of the winding 10&#39; is connected to the intermediate barrel contact 50. 
     When a standard BNC plug such as the plug A of FIG. 1, is inserted in the jack C of FIG. 2 of the invention, the cylinder 30 of the plug bears against the contactor elements 60, 62, deflecting them into conductive engagement with the ring portion 64 of the outer barrel 20&#39;. Thus, an electrical condition obtains which is identical to the plug-jack function of FIG. 1. That is, the outer barrel 20&#39; of FIG. 2 is connected via the switch means 60, 62, 64 to the conductor 38&#39; and terminal 40&#39; to one end of the winding 10&#39; and the other end of that winding is connected via the other terminal 36&#39; and conductor 34&#39; to the center pin of the coaxial plug. 
     It is a primary feature of the invention that when the plug E of the invention shown in FIG. 2 is inserted into the jack C of FIG. 2 that, instead of an unbalanced coaxial connection being made, a balanced twisted pair type hook-up is achieved. As shown in FIG. 2, the plug shown has a cylinder 30&#39; which is generally similar to the cylinder 30 of a BNC plug of FIG. 1 with two important exceptions: it is shorter, as indicated at 70, and it carries an internal conductive sleeve 72. Because the cylinder 30&#39; is shorter, it does not operate to close the normally open switch means 60, 62, 64, and because it carries the sleeve 72, it makes contact with the intermediate contact 50 of the jack of the invention shown in FIG. 2. 
     Accordingly contact is made from the plug sleeve contact 72 to the jack intermediate or additional barrel 50. At the same time, the center pin contact 26&#39; engages conductively the axial sleeve contact 22&#39; of the jack and thus an electrical connection is made via wire 34&#39; to terminal 36&#39; of winding 10&#39;. Since the intermediate barrel 50 is isolated from the grounded outer barrel 20&#39;, the connection to the winding 10&#39; can be a balanced one without change of the driver/receiver. Moreover, the connection from the outer coupling 28&#39; of the plug to the outer barrel 20&#39; is identical to that of those parts of a BNC connector system (such as one of FIG. 1). Therefore, the outer ground shield of the twisted pair cable, if such shield is provided, is terminated to ground via the jack barrel 20&#39; as indicated at 42&#39;. 
     FIG. 3 shows an alternate embodiment of the plug and jack combination of the invention. In this configuration, the switch means 80, 82 are located externally of the jack outer barrel 20&#34; and have separate logical functions. The jack F structure is otherwise like that of FIG. 2, and similar parts are given similar numbers, except that they are distinguished by a double prime, (&#34;) for example the outer barrel of the jack is numbered 20&#34; and the inner or intermediate barrel is numbered 50&#34; (50 having been a new number if FIG. 2, the drawings have no 50&#39;). 
     Externally of the barrel shaped contact element 20&#34; are the pair of spring contact elements 80, 82 insulated from the barrel 20&#34; as indicated at 84, 86. Contact element 80 is connected by a resistor or other suitable impedance 88 to one terminal 40&#34; of winding 10&#34; of transformer 12&#34;. Terminal 40&#34; of the transformer winding 10&#34; is also connected to the second outer spring contact 82 and also to the intermediate barrel contact 50&#34;. The outer barrel shaped contact 20&#34; is connected to ground as indicated at 42&#34; and is dimensioned to be the same as the usual outer cylindrical contact of a BNC coaxial cable jack. 
     When a standard BNC plug A as shown in FIG. 1 is connected into the jack F of FIG. 3, the outer barrel of the BNC plug A engages over the contact barrel 20&#34;, of the jack F and is locked thereon by means of the screw grooves of the usual BNC configuration. Moreover, the outer barrel of the BNC connector A bears against both contact elements 80 and 82, thereby connecting those elements 80, 82 to the outer conductor of the coaxial cable connected to the BNC plug. As of result, the terminal 40&#34; of the transformer is connected to the outer shell of the BNC via contact 82 and the other transformer terminal 36&#34; is connected to the center conductor of the BNC plug via the center contact 22&#34; of the jack and conductor 34&#34;. In addition, terminal 40&#34; is connected to the outer shell of the BNC plug via contact 80 and impedance 88. This allows impedance matching and also provides a point at which a signal can be developed, that, is a signal across impedance 88, which can be utilized for control purposes which form no part of the present invention. 
     A special plug D in accordance with the invention is provided as shown in FIG. 3 for use with a shielded twisted pair cable. When the plug is engaged on the outer contact 20&#34; of the jack F, a different circuit configuration results. The plug outer shell 28&#34; is configured to function like the outer shell of a BNC plug as aforedescribed except that it does not contact the outer spring terminals 80, 82. This can be accomplished by making at least the end portion 90 of the plug shell 28&#34; of non-conductive material. Like plug E of FIG. 2, the plug D of FIG. 3 has an extra cylindrical shaped contact 72&#34; which slides over and makes contact with cylindrical shaped intermediate contact 50&#34; of the jack, and this provides the terminal for one wire of a twisted wire pair of the cable connected to the plug. The other wire of the twisted pair is connected to a pin 26&#34; of the plug which engages the central conductor contact 22&#34; of the jack. Accordingly, one twisted pair conductor is connected via 26&#34; to contact 22&#34; and thus to terminal 36&#34; of the transformer while the other twisted pair wire is connected via 72&#34; and 50&#34; to the other terminal 40&#34; of the transformer, and neither contact 80 or 82 is electrically engaged. If the twisted pair cable is shielded, at least part of the element 28&#34; is made of metal and provides a contact to ground at 42&#34; via the outer barrel 20&#34; of the jack. It will be appreciated that, if desired, one of the switch elements 60 or 62 of FIG. 2 could operate isolated from the intermediate barrel 50 and connected similarly to element 80 of FIG. 3. 
     FIG. 4 shows the various ways in which standard BNC plugs A can be used with a standard BNC jack B or the jack C of FIG. 2 or the jack F of FIG. 3 to provide coaxial cable connections. Similarly, that figure shows the plug E of FIG. 2 , coupled with the jack C of that figure and the plug D of FIG. 3 coupled with the jack F of FIG. 3 to accommodate wire pair (such as shielded or unshielded twisted wire pairs) systems. 
     For illustrative purposes, the driver/receiver is shown transformer coupled to facilitate balanced or unbalanced operation. It will be understood that this would not be needed in all cases, especially where the driver/receiver is of the type that sense whether barrel connection 38, 38&#39; or 38&#34; is grounded or not and automatically switches between unbalanced and balanced operations. 
     In summary, the foregoing examples illustrate ways in which a fundamental principle of the invention can be carried into effect. That principle is that a hybrid jack can be provided that will mate with a BNC plug as if it were a BNC jack and thus provide a coaxial type unbalanced circuit connection, and that the same hybrid jack can mate with a special plug designed for it to provide a twisted pair type balanced circuit connection, the hybrid jack having a third contact for this purpose and switch means to connect that third contact alone or the outer BNC--fitting part of the jack in circuit with an output terminal in response to a conductive difference or length difference in the hybrid plug as compared to the BNC plug, which difference co-acts with the hybrid jack to make or break a circuit connection.