The present disclosure relates generally to connector plugs and jacks and in particular to an audio connector plug and jack that can be used in place of the a standard low profile plug and electronic devices using low profile plug receptacles. The connector plug has a reduced plug length and thickness, an intuitive insertion orientation and a smooth, consistent feel when inserted and extracted from its corresponding receptacle connector. A portion or all of the plug connector may include a flexible material that allows the connector to bend with respect to an insertion axis along which the plug connector is designed to be inserted into a corresponding receptacle connector. A corresponding connector jack may be configured to receive the reduced length and thickness connector plug.

BACKGROUND OF THE INVENTION

The present invention relates generally to connectors such as audio jacks and in particular to an audio connector that can be used in place of the a standard low profile plug receptacles and electronic devices using low profile plug receptacles.

Standard audio connectors or plugs are available in three sizes according to the outside diameter of the plug: a 6.35 mm (¼″) plug, a 3.5 mm (⅛″) miniature plug and a 2.5 mm ( 3/32″) subminiature plug. The plugs include multiple conductive regions that extend along the length of the connectors in distinct portions of the plug such as the tip, sleeve and one or more middle portions between the tip and sleeve resulting in the connectors often being referred to as TRS (tip, ring and sleeve) connectors.

FIGS. 1A and 1Billustrate examples of audio plugs10and20having three and four conductive portions, respectfully. As shown inFIG. 1A, plug10includes a conductive tip12, a conductive sleeve14and a conductive ring16electrically isolated from the tip12and the sleeve14by insulating rings17and18. The three conductive portions12,14, and16are for left and right audio channels and a ground connection. Plug20, shown inFIG. 1B, includes four conductive portions: a conductive tip22, a conductive sleeve24and two conductive rings25and26and is thus sometimes referred to as a TRRS (tip, ring, ring, sleeve) connector. The four conductive portions are electrically isolated by insulating rings27,28and29and are typically used for left and right audio, microphone and ground signals.

When plugs10and20are 3.5 mm miniature connectors, the outer diameter of conductive sleeve14and24and conductive rings16,25, and26is 3.5 mm and the connector is 14 mm long, and for a 2.5 mm subminiature connector the outer diameter of the conductive sleeve is 2.5 mm and the connector is 11 mm long. Such TRS and TRRS connectors are used in many commercially available MP3 players and smart phones as well as other electronic devices. Electronic devices such as MP3 players and smart phones are continuously being designed to be thinner and smaller and/or to include video displays with screens that are pushed out as close to the outer edge of the devices as possible. The diameter and length of current 3.5 mm and even 2.5 mm audio connectors are limiting factors in making such devices smaller, thinner and allowing the displays to be larger.

Some manufacturers have used USB, mini-USB and micro-USB connectors as audio connectors to connect headphones and similar audio components to electronic devices.FIG. 2is an example of a micro-USB connector30, the smallest of the USB connectors. Connector30includes an outer housing32and a metallic shell34that is inserted into a corresponding receptacle connector. Shell34defines an interior cavity38and includes five contacts36formed within the cavity. The insertable shell portion34of connector30is both thinner and shorter than even the 2.5 mm subminiature version of connectors10and20. Connector30, however, suffers from other drawbacks that detract from the overall user experience. For example, connector30must be inserted into its respective receptacle connector in a particular orientation, yet it is difficult for the user to determine when connector30is oriented in the correct insertion position. Also, even when connector30is properly aligned, the insertion and extraction of the connector is not precise, has an inconsistent feel and, even when the connector is fully inserted, has an undesirable degree of wobble that may result in either a faulty connection or breakage. Additionally, cavity38is prone to collecting and trapping debris within the cavity which may interfere with the signal connections.

BRIEF SUMMARY OF THE INVENTION

In view of the shortcomings in currently available audio connectors as described above, the present invention provides an improved audio plug connector having a reduced plug length and thickness, an intuitive insertion orientation and a smooth, consistent feel when inserted and extracted from its corresponding receptacle connector. In some embodiments, a portion or all of the plug connector may include a flexible material that allows the connector to bend with respect to an insertion axis along which the plug connector is designed to be inserted into a corresponding receptacle connector. Additionally, audio plug connectors according to the present invention have external contacts instead of internal contacts and thus do not include a cavity that is prone to collecting and trapping debris.

In one embodiment, a plug connector according to the present invention includes a shell and a sleeve coupled to the shell at its base and having a D-shaped cross section. The sleeve has a ground contact at its distal tip, a plurality of contacts are arranged around a periphery of the sleeve and a plurality of dielectric strips that electrically isolate the plurality of contacts from each other. An insulation ring is positioned between the distal tip and the plurality of contacts and each of the plurality of contacts and plurality of dielectric strips extend from the insulation ring to the shell.

In another embodiment, a plug connector according to the present invention includes a flexible shell and a sleeve coupled to the shell at its base. The sleeve has a D-shaped cross section, a ground contact at its distal tip, a plurality of contacts arranged around a periphery of the sleeve, and a plurality of flexible dielectric strips that electrically isolate the plurality of contacts from each other and an insulation ring between the distal tip and the plurality of contacts and plurality of dielectric strips where each of the plurality of contacts and plurality of dielectric strips extend from the insulation ring to the shell.

In still another embodiment, a connector jack that can be used in conjunction with plug connectors according to the present invention includes a housing that defines an interior cavity into which a plug connector can be inserted. The cavity has a D-shaped cross-section, a ground contact at the rear portion and a plurality of contacts arranged around the walls of the interior cavity to match the locations of the contacts on a corresponding connector plug.

To better understand the nature and advantages of the present invention, reference should be made to the following description and the accompanying figures. It is to be understood, however, that each of the figures is provided for the purpose of illustration only and is not intended as a definition of the limits of the scope of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention pertain to connectors such as audio jacks and in particular to an audio connector that can be used in place of the a standard low profile plug receptacles and electronic devices using low profile plug receptacles. These connectors may be suitable for a multiplicity of electronic devices, including any device with audio out signals (e.g., radio, landline phone, stereo). In some embodiments, the invention is particularly well suited for portable electronic media devices because of its potentially small form factor.

As used herein, an electronic media device includes any device with at least one electronic component that may be used to present human-perceivable media. Such devices may include, for example, portable music players (e.g., Apple's iPod devices), portable video players (e.g., portable DVD players), cellular telephones (e.g., Apple's iPhone devices), video cameras, digital still cameras, projection systems (e.g., holographic projection systems), gaming systems, PDAs, desktop computers, as well as tablet or other mobile computers (e.g., Apple's iPad devices). Some of these devices may be configured to provide audio, video or other sensory output.

FIG. 3is a simplified illustrative block diagram representing an electronic media device100that includes an audio plug receptacle105according to embodiments of the present. Electronic media device100may also include, among other components, connector receptacle110, one or more user input components120, one or more output components125, control circuitry130, graphics circuitry135, a bus140, a memory145, a storage device150, communications circuitry155and POM (position, orientation or movement sensor) sensors160. Control circuitry130may communicate with the other components of electronic media device100(e.g., via bus140) to control the operation of electronic media device100. In some embodiments, control circuitry130may execute instructions stored in a memory145. Control circuitry130may also be operative to control the performance of electronic media device100. Control circuitry130may include, for example, a processor, a microcontroller and a bus (e.g., for sending instructions to the other components of electronic media device100). In some embodiments, control circuitry130may also drive the display and process inputs received from input component120.

Memory145may include one or more different types of memory that may be used to perform device functions. For example, memory145may include cache, flash memory, ROM, RAM and hybrid types of memory. Memory145may also store firmware for the device and its applications (e.g., operating system, user interface functions and processor functions). Storage device150may include one or more suitable storage mediums or mechanisms, such as a magnetic hard drive, flash drive, tape drive, optical drive, permanent memory (such as ROM), semi-permanent memory (such as RAM) or cache. Storage device150may be used for storing media (e.g., audio and video files), text, pictures, graphics, advertising or any suitable user-specific or global information that may be used by electronic media device100. Storage device150may also store programs or applications that may run on control circuitry130, may maintain files formatted to be read and edited by one or more of the applications and may store any additional files that may aid the operation of one or more applications (e.g., files with metadata). It should be understood that any of the information stored on storage device150may instead be stored in memory145.

Electronic media device100may also include input component120and output component125for providing a user with the ability to interact with electronic media device100. For example, input component120and output component125may provide an interface for a user to interact with an application running on control circuitry130. Input component120may take a variety of forms, such as a keyboard/keypad, trackpad, mouse, click wheel, button, stylus or touch screen. Input component120may also include one or more devices for user authentication (e.g., smart card reader, fingerprint reader or iris scanner) as well as an audio input device (e.g., a microphone) or a video input device (e.g., a camera or a web cam) for recording video or still frames. Output component125may include any suitable display, such as a liquid crystal display (LCD) or a touch screen display, a projection device, a speaker or any other suitable system for presenting information or media to a user. Output component125may be controlled by graphics circuitry135. Graphics circuitry135may include a video card, such as a video card with 2D, 3D or vector graphics capabilities. In some embodiments, output component125may also include an audio component that is remotely coupled to electronic media device100. For example, output component125may include a headset, headphones or ear buds that may be coupled to electronic media device100with a wire or wirelessly (e.g., Bluetooth headphones or a Bluetooth headset).

Electronic media device100may have one or more applications (e.g., software applications) stored on storage device150or in memory145. Control circuitry130may be configured to execute instructions of the applications from memory145. For example, control circuitry130may be configured to execute a media player application that causes full-motion video or audio to be presented or displayed on output component125. Other applications resident on electronic media device100may include, for example, a telephony application, a GPS navigator application, a web browser application and a calendar or organizer application. Electronic media device100may also execute any suitable operating system, such as a Mac OS, Apple iOS, Linux or Windows and can include a set of applications stored on storage device150or memory145that is compatible with the particular operating system.

In some embodiments, electronic media device100may also include communications circuitry155to connect to one or more communications networks. Communications circuitry155may be any suitable communications circuitry operative to connect to a communications network and to transmit communications (e.g., voice or data) from electronic media device100to other devices within the communications network. Communications circuitry155may be operative to interface with the communications network using any suitable communications protocol such as, for example, Wi-Fi (e.g., a 802.11 protocol), Bluetooth, high frequency systems (e.g., 900 MHz, 2.4 GHz and 5.6 GHz communication systems), infrared, GSM, GSM plus EDGE, CDMA, quadband and other cellular protocols, VOIP or any other suitable protocol.

In some embodiments, communications circuitry155may be operative to create a communications network using any suitable communications protocol. Communications circuitry155may create a short-range communications network using a short-range communications protocol to connect to other devices. For example, communications circuitry155may be operative to create a local communications network using the Bluetooth protocol to couple with a Bluetooth headset (or any other Bluetooth device). Communications circuitry155may also include a wired or wireless network interface card (NIC) configured to connect to the Internet or any other public or private network. For example, electronic media device100may be configured to connect to the Internet via a wireless network, such as a packet radio network, an RF network, a cellular network or any other suitable type of network. Communication circuitry145may be used to initiate and conduct communications with other communications devices or media devices within a communications network.

Electronic media device100may also include any other component suitable for performing a communications operation. For example, electronic media device100may include a power supply, an antenna, ports or interfaces for coupling to a host device, a secondary input mechanism (e.g., an ON/OFF switch) or any other suitable component.

Electronic media device100may also include POM sensors160. POM sensors160may be used to determine the approximate geographical or physical location of electronic media device100. As described in more detail below, the location of electronic media device100may be derived from any suitable trilateration or triangulation technique, in which case POM sensors160may include an RF triangulation detector or sensor or any other location circuitry configured to determine the location of electronic media device100.

POM sensors160may also include one or more sensors or circuitry for detecting the position orientation or movement of electronic media device100. Such sensors and circuitry may include, for example, single-axis or multi-axis accelerometers, angular rate or inertial sensors (e.g., optical gyroscopes, vibrating gyroscopes, gas rate gyroscopes or ring gyroscopes), magnetometers (e.g., scalar or vector magnetometers), ambient light sensors, proximity sensors, motion sensor (e.g., a passive infrared (PIR) sensor, active ultrasonic sensor or active microwave sensor) and linear velocity sensors. For example, control circuitry130may be configured to read data from one or more of POM sensors160in order to determine the location orientation or velocity of electronic media device100. One or more of POM sensors160may be positioned near output component125(e.g., above, below or on either side of the display screen of electronic media device100).

FIG. 4depicts an illustrative rendering of one particular electronic media device180. Device180includes a click wheel182as an input component and an LED display184as an output component. Device180also includes connector receptacle186and audio plug receptacle188. For simplicity, various internal components, such as the control circuitry, graphics circuitry, bus, memory, storage device and other components are not shown inFIG. 4.

In one particular embodiment, the present invention pertains to connectors that have a single insertion orientation. As an example,FIGS. 5A-5Cillustrate a D-shaped plug connector210that has a ground contact212at its tip and three contacts214a(left audio),214b(right audio) and214c(microphone) that are separated from the tip by an insulation ring216and extend along the length of the connector from insulation ring216to its base. Contacts that extend along the length of the connector from insulation ring216to its base are also referred to as axial contacts. Additional insulation strips218a,218band218cseparate contacts214a-214cfrom each other. The flat surface, upon which contact214cif formed, acts as a keyed feature of connector210, which when aligned with a matching flat surface of a corresponding receptacle connector (shown inFIGS. 7A and 7B) having a matching D-shaped cavity, ensures that plug connector210only can be inserted into the connector jack in a single orientation thus aligning each of the contacts214a-214cwith respective contacts in the receptacle connector. As shown inFIG. 5A-5C, contacts214aand214bmay be curved and formed on a curved surface, while contact214cmay be flat and formed on a flat surface. The lengths of contacts214a-214cmay be longer than their widths.

In other embodiments, contacts do not extend along the full length of the connector from insulation ring216to its base. For example, contacts214a(left audio),214b(right audio) and214c(microphone) may run only a half, a third, a fourth, or another suitable portion of the length of the connector, from the insulation ring to its base. In some embodiments, the ends of the axial contacts may be equidistant from the insulation ring and the base of the connector or shell. In some embodiments, the ends of the axial contacts may not be equidistant from the insulation ring and the base of the connector or shell. In some embodiments, contacts have a different length and are positioned differently between the insulation ring and the base of the connector as compared to at least one other contact.

In one particular embodiment, connector210has an insertion length, X, of about 8 mm; a diameter, Y, of about 2.4 mm; a height, Z, of about 2.0 mm and a volume of about 29.1 mm3.

The geometry of the insertion portion or sleeve of connector210may be selected to create a press fit plug and jack interface that requires specific insertion and extraction forces such that the retention force required to insert connector210into a matching connector jack (shown inFIGS. 7A and 7B) is higher than the extraction force required to remove the plug connector from the jack. Aside from thickness, Z, the dimensions of connector210may be similar to that of the standard audio connector (TRS and TRRS) mentioned above in the “Background of the Invention” section.

In some embodiments, the width of the contacts, insulation strips and rings, and other elements of connector210may be varied as compared to the relative widths illustrated inFIGS. 5A-5C.

In one embodiment, connector210is made exclusively or primarily from rigid and relatively inflexible materials. Contacts212,214a-214ccan be made from a copper, nickel, brass, a metal alloy or any other appropriate conductive material. Thermoplastic polymer or similar material to provide strain relief and insulation, e.g., POM, may be injected around the contacts to create the insulation ring216and insulation strips218a,218band218c. An ABS or similar material can be used to create shell220, which is positioned over and fastened to the base of the connector as shown inFIG. 5A. In some embodiments, Shell220may be thicker than the sleeve, i.e., the dimensions of shell220may be greater than diameter, Y, and height, Z.

In another embodiment, connector210includes a flexible inner member that gives connector210increased flexibility, allowing it to deform in order to prevent breakage. Additional advantages provided by the inclusion of a flexible inner member may include increased ease of insertion for the user as there would be more leeway in the insertion orientation required to successfully insert the connector into a corresponding connector receptacle.FIG. 6Ais top view of the D-shaped connector according to embodiments of the invention wherein a flexible inner member is included whileFIGS. 6B and 6Care simplified cross-sectional views of particular embodiments of the D-shaped connector shown inFIG. 6A. In addition to providing a top view of connector210,FIG. 6Aalso shows an internal element, namely flexible inner member225. Flexible inner member225may be made out of a flexible material, such as nitinol, coated with a conductive layer to carry the ground signal that extends along at least a portion of the length of the connector. The flexible inner member225may be a circular rod, may have a D-shaped cross-section or other appropriate shapes. In some embodiments, contacts214a-214c(shown inFIGS. 5A and 5B) can be brass or other metal contacts formed on flexible elastomer222aso that each axial section serves as a bending plate allowing connector210to bend in order to relieve stress when the connector is inserted or extracted off-axis. Flexible elastomer222amay be polypropylene or polyoxymethylene which is injection molded to capture and insulate components, e.g., contacts214a-214c(shown inFIGS. 5A and 5B). In another embodiment, contacts214a-214c(shown inFIGS. 5A and 5B) and dielectric material may all be part of a flex circuit that is slid over flexible inner element225. This arrangement allows connector210to flex relatively evenly along much of its length. Also, insulation strips218a-218c(shown inFIGS. 5A and 5B) may be made from a flexible elastomer and contacts214a-214c(shown inFIGS. 5A and 5B) may be flex circuits that are adhered to flexible inner member225or adhered to elastomer that is injection molded around the inner member. The shell220(shown inFIGS. 5A and 5B) of connector210can be overmolded with a thermoplastic elastomer to give it elastic properties as well.

In one particular embodiment, flexible inner member225is a sheet of superelastic material, such as nitinol (an alloy of nickel and titanium present in roughly equal amounts) and the flexible contacts are part of a flex circuit adhered to the superelastic sheet. Nitinol alloys exhibit elasticity some 10-30 times that of ordinary metal which enables it to flex under very high strain without breaking. The flex circuit may include, for example, metal contacts214a-214cscreen printed on a thin polymide or PEEK (polyether ether ketone) layer. The flex circuit may be made from two separate pieces each of which is directly adhered to one side of the nitinol sheet or may be a single piece wrapped around the perimeter of the nitinol sheet or made into a sleeve that fits over the nitinol sheet.

The invention is not limited to the use of any particular superelastic material and can instead use any material that deforms reversibly to very high strains and returns to its original shape when the load is removed without requiring a change of temperature to regain its original shape. Also, some embodiments of the invention may use flexible materials for flexible inner member225that are not superelastic. For example, flexible inner member225can be made from an elastomer or polyurethane in some embodiments.

In another embodiment contacts214a-214c(shown inFIGS. 5A and 5B) can be surrounded by flexible elastomer222bso that each axial section serves as a bending plate allowing connector210to bend in order to relieve stress when the connector is inserted or extracted off-axis. Flexible elastomer222bmay be polypropylene or polyoxymethylene which is injection molded to capture and insulated components, e.g., contacts214a-214c(shown inFIGS. 5A and 5B). In these embodiments, flexible elastomer222breplaces the need for insulation strips218a-218c. In order to injection mold flexible elastomer222bwhere insulation strips are not present, contacts214a-214c(shown inFIGS. 5A and 5B) may be positioned in a frame or mold until flexible elastomer222bis injection molded around the contacts. Thus, elastomer222bmay provide structural support as well as to capture and insulate components, e.g., contacts214a-214c(shown inFIGS. 5A and 5B). In these embodiments, as well as previously mentioned embodiments employing injection molding, vacuum injection molding may be used and may minimize trapped air or gases that may lead to defective connectors.

In some embodiments, when connector plug210is engaged with a corresponding receptacle connector (shown inFIG. 7B) and extracted at an angle to the insertion axis, more force is applied to the base of the connector than at its tip. To address this discrepancy, in some embodiments the flexibility of flexible inner member225varies along the length of the member so that, for example, it is more flexible near the base portion or proximal end of the connector and less flexible near the distal end of the connector. Flexibility can be varied in this manner by, among other techniques, varying the materials along the length of the connector, varying the thickness of flexible inner member225along its length or varying the shape of flexible inner member225along its length or any combination of these approaches. For example, in one embodiment flexible inner member225may include a superelastic sheet near its base and a polyurethane sheet near its distal end. The superelastic and polyurethane sheets may overlap and be adhered together in an area between the proximal and distal ends. In one particular embodiment, flexible inner member225includes two sheets of polyurethane near the distal end of connector210and a single sheet of nitinol near the base of connector210. At a point approximately one third of the length of the connector from the distal end, the nitinol sheet is sandwiched between the two polyurethane sheets for a portion of the length.

In other embodiments, connector210may not only have variable flexibility about its length, but it may also alternate between rigid and flexible throughout its length in a myriad of combinations. For example, a hybrid rigid-flexible connector may be implemented in some circumstances.

In some embodiments, connector210is designed to break when side-loaded at a certain tension after it is inserted into a matching connector jack (shown inFIGS. 7A and 7B). It is preferable that connector210breaks as opposed to the connector jack because if the connector jack breaks, the electronic device in which it is housed may no longer be usable. To this end, in some embodiments, plug connectors according to the present invention are made from flexible materials such as elastomers or polymide dielectric materials to reduce strain when side-loaded under high levels of force and the like. As an example, when fully inserted, a rigid portion and a portion of a flexible portion of connector210may be inserted within a matching connector jack (shown inFIGS. 7A and 7B). When connector210is extracted from a matching connector jack (shown inFIGS. 7A and 7B) with a force that intersects its insertion axis, connector210bends or deforms the flexible portion which reduces the risk the connector will bind within or break the connector jack (shown inFIGS. 7A and 7B).

FIG. 7Ais a simplified perspective view of a matching connector jack (connector receptacle)400according to embodiments of the invention.FIG. 7Aillustrates connector jack400according to the present invention including a housing402that defines an interior cavity404into which a plug connector, such as connector210, can be inserted. Also shown inFIG. 7Aare contacts414cand414athat may be electrically coupled to corresponding contacts214cand214b(shown inFIGS. 5A-5C). Connector jack400aligns axial contact214cwith overhead contact414cas illustrated inFIG. 7A, allowing connector210to be operatively coupled to connector jack400. Similar connector jack contacts may be implemented for the other contacts of connector210, e.g., contact214bmay have a corresponding contact on connector jack400—similar to the contact414a.

FIG. 7Bis a cross-sectional view of the jack connector ofFIG. 7Aand a side view of a complementary plug to mate with jack connector400.FIG. 7Billustrates connector210inserted in connector jack400according to one embodiment of the present invention. Also shown are contact414cand contact portion412aof movable ground contact412bwhich engage corresponding contact214cand ground contact212. Similar corresponding contacts may exist for contacts214aand214b. The rear element416aforms an angled face416bat an angle corresponding to that of the oblique face of ground contact212so that when the connector210is fully inserted into the jack connector400, the oblique face of ground contact212is flush with angled face416b.

In some embodiments, connector210may have a retention feature that holds it firmly in place when fully inserted within corresponding connector jack400. The retention feature may be mechanical or magnetic.

In an example of a mechanical embodiment, movable ground contact412bmay initially be held by stopping element418in a position wherein spring element412cof movable ground contact412bonly is partially compressed. When connector210is inserted with sufficient force to further compress spring element412c, it may further compress movable ground contact412binto the position shown inFIG. 7B; this allows full insertion of connector210and provides a retention force as connector210is pressed against angled face416bby the spring portion412cof movable ground contact412b. This retention force provides the retention feature. Connector210may be extracted from connect jack400when sufficient extraction force is applied to connector210to compress spring element412c.

In one example of a magnetic connector system, each of the plug connector and receptacle connector have a magnetic element. A magnetic element in the plug connector may be attracted to a magnetic element in the receptacle connector such that the plug connector may be magnetically held in place when mated with the receptacle. In a specific example, magnets in the receptacle may be arranged in proximity to each other with opposing polarities. With this arrangement, field lines originating in one magnet in the receptacle connector may pass through the ferromagnetic element in the plug connector and terminate in another magnet in the receptacle. Mechanical retention systems may also be used which may implement a cantilevered spring or detent to hold the connector plug in place.

FIGS. 7A and 7Balso illustrate the space saving feature of the D-shaped connector implementation, wherein an electronic device may be made slimmer or have additional internal components by virtue of the D-shaped connector's smaller thickness.

In other embodiments of the invention, the connector plug may have a differently shaped cross-section.FIGS. 8A-8Care simplified cross-sectional views of connector plugs according to embodiments of the invention. The cross-section of the connector plug may be shaped like a non-regular polygon (non-equilateral and non-equiangular polygon), including a non-equilateral triangle (shown inFIG. 8A), a non-regular octagon (shown inFIG. 8B), a non-regular hexagon (shown inFIG. 8C) or other shapes wherein a plurality of axial contacts and a plurality of axial insulation strips may be integrated. An inherent feature of a connector plug with a non-regular polygon cross section is that it will have a single insertion orientation when mated with a receptacle connector having a matching cavity. In other words, these embodiments may be described in terms of whether the cross-section of the connector plug has rotational symmetry—a cross section that looks the same after rotating the orientation of the cross-section less than 360 degrees in any direction. In embodiments of the invention, the cross-section of the connector plug does not have rotational symmetry. Connector plug with axial contacts have a required insertion orientation that may be dependent on the positions of the contacts. Thus, the connector plug (specifically its cross section) may be designed to only have one insertion rotation compatible with the shape of the connector receptacle in order for the contacts to be able to mate properly without additional design modifications.

As will be understood by those skilled in the art, the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. For example, while embodiments of the invention were discussed above with respect to audio plugs having four contacts, the invention is not limited to any particular number of contacts. Some embodiments of the invention may have as few as two contacts while other embodiments can have thirty or even more contacts. As one example of a variation with additional contacts, an additional insulation ring may be implemented so as to split each of the contacts214a,214band214cinto halves, thereby doubling the number of contacts. In other embodiments, the location of the contacts, insulation strips, insulation rings, and grounds may be interchangeable—creating additional variations of the present invention.

Additionally, while the invention was described with respect to an audio connector, it is not limited to any particular type of signal and can be used to carry video and/or other signals instead of audio-related signals or in addition to audio-related signals. Also, in some embodiments, connectors according to the present invention can carry both analog and digital signals. As an example, connector210and its flexible version can be modified to include one or more fiber optic cables that extend through the connector and can be operatively coupled to receive or transmit optical signals between a mating connector jack. Those skilled in the art will recognize, or be able to ascertain, using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.