Patent Publication Number: US-9854343-B2

Title: Headset connector

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/847,103, filed Mar. 19, 2013, and entitled “Headset Connector,” which is a continuation of U.S. patent application Ser. No. 11/824,444, which was filed on Jun. 28, 2007, and entitled “Headset Connector,” which application claims benefit under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 60/879,177, which was filed on Jan. 6, 2007, and entitled “Wireless Headset,” and U.S. Provisional Patent Application No. 60/879,195, which was filed on Jan. 6, 2007, and entitled “Connector with Magnetic Detent,” all of which are incorporated by reference as if fully disclosed herein. 
     Commonly assigned Terlizzi U.S. patent application Ser. No. 13/460,228, filed Apr. 30, 2012, entitled “Wireless Headset Having Adaptive Powering” is hereby incorporated by reference in its entirety. 
     Commonly assigned DiFonzo et al. U.S. patent application Ser. No. 11/235,873, filed Sep. 26, 2005, entitled “Electromagnetic Connector for Electronic Device” is hereby incorporated by reference in its entirety. 
     Commonly assigned Rohrbach et al. U.S. patent application Ser. No. 11/235,875, filed Sep. 26, 2005, entitled “Magnetic Connector for Electronic Device” is hereby incorporated by reference in its entirety. 
     Commonly assigned Andre et al. U.S. patent application Ser. No. 11/456,833, filed Jul. 11, 2006, entitled “Invisible, Light-Transmissive Display System” is hereby incorporated by reference in its entirety. 
     Commonly assigned Andre et al. U.S. patent application Ser. No. 11/551,988, filed Oct. 23, 2006, entitled “Invisible, Light-Transmissive Display System” is hereby incorporated by reference in its entirety. 
     Commonly assigned Sanford et al. U.S. patent application Ser. No. 11/651,094, filed Jan. 6, 2007, entitled “Antenna and Button Assembly for Wireless Devices” is hereby incorporated by reference in its entirety. 
     Commonly assigned Terlizzi et al. U.S. patent application Ser. No. 11/650,130, filed Jan. 5, 2007, entitled “Systems and Methods for Determining the Configuration of Electronic Connections” is hereby incorporated by reference in its entirety. 
     Commonly assigned Rabu et al. U.S. patent application Ser. No. 11/620,669, filed Jan. 6, 2007, entitled “Apparatuses and Methods that Facilitate the Transfer of Power and Information Among Electrical Devices” is hereby incorporated by reference in its entirety. 
     Commonly assigned Terlizzi et al. U.S. Provisional Patent Application No. 60/878,852, filed Jan. 5, 2007, entitled “Systems and Methods for Multi-State Switch Networks,” is herein incorporated by reference in its entirety. 
     Commonly assigned Forstall U.S. Patent Application No. 60/936,965, filed Jun. 22, 2007, entitled “Single User Input Mechanism for Controlling Electronic Device Operations,” is herein incorporated by reference in its entirety 
    
    
     FIELD OF INVENTION 
     The present invention can relate to headsets. More particularly, the present invention can relate to headsets for communicating with an electronic device. 
     BACKGROUND OF THE INVENTION 
     Headsets for providing hands-free communications are known in the art. Such headsets typically can be used in conjunction with a cellular telephone or a computer (e.g., Voice over IP). Some existing headsets include a microphone, a speaker (also referred to as a receiver), electronics for controlling the headset and communicating with another device (e.g., a cellular telephone), a battery and a connector for re-charging the battery. 
     There are many aspects involved in the design of headsets. For example, the size and weight of headsets can be key issues because of how they typically mount to a user&#39;s ear. A heavy or large headset can pull on a user&#39;s ear, creating an uncomfortable fit. The shape of headset earpieces (e.g., earbuds) may also be an important design consideration to take into account as it is desirable for earpieces to fit comfortably in, on, or over a wide range of different sizes and shapes of ears. 
     Additionally, the acoustic performance of headsets, such as receiver sound generation quality and microphone sound reception quality (e.g., ability to pick up a user&#39;s voice without undue background noise), can be important design considerations. Achieving desired receiver and microphone acoustic performance can become increasingly difficult as the size of a headset decreases. 
     Another example of an important design consideration can be the user interface of a headset. It may be desirable for a user interface to be intuitive for a first-time user, yet convenient for an experienced user. 
     Aesthetics may be yet another important design consideration for headsets. 
     Further still, ease of manufacturing headsets can be another design consideration. For example, it can be desirable to design a headset that can be mass produced in an affordable fashion. 
     In view of the foregoing, there is a need for an improved headset that addresses one or more of the above-identified considerations. 
     SUMMARY OF THE INVENTION 
     In accordance with one embodiment of the present invention, a headset that includes a tube housing and a magnetic connector fixed within the tube housing is provided. The magnetic connector can include a mating face and a plurality of electrical contacts disposed within the mating face. 
     In accordance with another embodiment of the present invention, an engaging connector assembly that includes a housing, a magnetic array structure, and a plurality of spring biased contact members is provided. The housing can have a mating side. The magnetic array structure can be fixed within the housing and constructed to house a plurality of spring biased contact members. The plurality of spring biased contact members can be housed within the magnetic array structure. The spring biased contact members can include tips that extend out of the mating side. 
     In accordance with yet another embodiment of the present invention, a connector that includes at least one magnetic component, a mating face, at least two contacts, and circuitry is provided. The mating face can be proximal to the at least one magnetic component. The at least two contacts can be disposed in the mating face. The circuitry can be electrically coupled to the at least two contacts. The mating face can be angled with respect to a plane passing lengthwise through the connector. 
     In accordance with yet another embodiment of the present invention, a connector that includes at least one triangle shaped magnetic component and at least one contact disposed adjacent to the at least one triangle shaped magnetic component is provided. 
     In accordance with yet another embodiment of the present invention, a system that includes a headset connector and an engagement connector is provided. The headset connector can include at least one electrical contact housed within a connector plate having an angled headset mating surface. The engagement connector can include at least one spring biased connector member having a tip portion that is electrically coupled to the at least one electrical contact when the angled headset mating surface is in close proximity to an angled engagement connector mating surface. 
     In accordance with yet another embodiment of the present invention, a system that includes a headset assembly and a headset engaging assembly is provided. The headset assembly can include a magnetic connector having an angled mating face. The connector can include a plurality of electrical contacts disposed within the angled mating face. The headset engaging assembly can include a magnetic component. The magnetic component can include at least one angled surface and at least one spring biased contact member. Each contact member can include a tip that extends beyond the at least one angled surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be apparent upon consideration of the following detailed description, taken in conjunction with accompanying drawings, in which: 
         FIG. 1  is a simplified block diagram of a headset in accordance with an embodiment of the present invention; 
         FIG. 2  is a simplified block diagram of a headset connector system in accordance with an embodiment of the present invention; 
         FIG. 3  is a simplified cross-sectional illustration of a connector assembly in accordance with an embodiment of the present invention; 
         FIG. 4  is a simplified cross-sectional illustration of another connector assembly in accordance with an embodiment of the present invention; 
         FIG. 5  is a simplified block diagram of a headset in accordance with an embodiment of the present invention; 
         FIG. 6A  is a simplified cross-sectional illustration of a portion of a headset in accordance with an embodiment of the present invention; 
         FIG. 6B  is a simplified cross-sectional illustration of a screw in accordance with an embodiment of the present invention; 
         FIG. 7  is a simplified block diagram of a display system in accordance with an embodiment of the present invention; 
         FIG. 8  is a simplified block diagram of a power distribution system in accordance with an embodiment of the present invention; 
         FIG. 9  is a simplified block diagram of another power distribution system in accordance with an embodiment of the present invention; 
         FIGS. 10A and 10B  are illustrations of a headset in accordance with an embodiment of the present invention; 
         FIG. 11  is an exploded view of a headset in accordance with an embodiment of the present invention; 
         FIG. 12  is an exploded view of a headset in accordance with another embodiment of the present invention; 
         FIG. 13  is a simplified diagram showing how software in a Bluetooth device is organized in accordance with an embodiment of the present invention; 
         FIG. 14  is a simplified block diagram of the electrical system of a headset in accordance with an embodiment of the present invention; 
         FIG. 15  is a simplified block diagram of the core processor of a headset in accordance with an embodiment of the present invention; 
         FIG. 16  is a simplified schematic diagram of a power distribution system in accordance with an embodiment of the present invention; 
         FIGS. 17A-17C  are illustrations of a traditional circuit board and distribution of electrical components in a headset; 
         FIG. 18  is a simplified block diagram of a circuit board with an improved distribution of electrical components in a headset in accordance with an embodiment of the present invention; 
         FIGS. 19A and 19B  are illustrations comparing the traditional circuit board of  FIGS. 7A-7C  to a circuit board with an improved distribution of electrical components in a headset in accordance with an embodiment of the present invention; 
         FIG. 20A-20C  are illustrations of an improved distribution of electrical components in a headset in accordance with an embodiment of the present invention; 
         FIG. 21A  is an illustration of a headset earbud in accordance with an embodiment of the present invention; 
         FIG. 21B  is a simplified exploded view of a headset earbud in accordance with an embodiment of the present invention; 
         FIGS. 22-25  and  FIG. 26A  are simplified illustrations of a headset earbud in various states of assembly in accordance with some embodiments of the present invention; 
         FIG. 26B  is a simplified cross-sectional view of an audio receiver in accordance with an embodiment of the present invention; 
         FIG. 27A  is a simplified cross-sectional view of a partially assembled headset earbud in accordance with an embodiment of the present invention; 
         FIG. 27B  is a simplified cross-sectional view of a fully assembled headset earbud in accordance with an embodiment of the present invention; 
         FIG. 28  is an exploded view of an attachment system in accordance with an embodiment of the present invention; 
         FIG. 29  is a flowchart of an illustrative process for assembling a portion of a headset in accordance with an embodiment of the present invention. 
         FIGS. 30A and 30B  are illustrations of a tool that can be used to assist in assembly of a portion of a headset in accordance with an embodiment of the present invention; 
         FIG. 30C  is an illustration of the tool of  FIGS. 30A and 30B  being used in accordance with an embodiment of the present invention; 
         FIG. 31  is a cross-sectional view of a “finished” tube in accordance with an embodiment of the present invention; 
         FIG. 32  is a cross-sectional view of an initially manufactured tube in accordance with an embodiment of the present invention; 
         FIG. 33  is a perspective view of a cross section of the tube of  FIG. 31  in accordance with an embodiment of the present invention; 
         FIG. 34  is an illustrative die and stamper for modifying the initially manufactured tube of  FIG. 32  in accordance with an embodiment of the present invention; 
         FIG. 35  is a cross-sectional view of the tube of  FIG. 34  once the stamper and die are removed from the tube in accordance with an embodiment of the present invention; 
         FIG. 36  is a perspective view of the tube of  FIG. 35  once the tube is machined to create an internal wall in accordance with an embodiment of the present invention; 
         FIG. 37  is a cross-sectional view of an illustrative tube formed using a single impact extrusion in accordance with an embodiment of the present invention; 
         FIG. 38  is a perspective view of the tube of  FIG. 37  once the tube is machined to create an internal wall in accordance with an embodiment of the present invention; 
         FIG. 39  is a cross-sectional view of an illustrative tube formed using a double impact extrusion in accordance with an embodiment of the present invention; 
         FIG. 40  is a perspective view of the tube of  FIG. 39  once the tube is machined to create an internal wall in accordance with an embodiment of the present invention; 
         FIG. 41  is a cross-sectional view of an illustrative tube formed using a progressive deep draw process in accordance with an embodiment of the present invention; 
         FIG. 42  is a perspective view of a cross section of the tube of  FIG. 41  in accordance with an embodiment of the present invention; 
         FIG. 43  is a perspective view of the tube of  FIGS. 41 and 42  once the tube is machined to create an internal wall in accordance with an embodiment of the present invention; 
         FIG. 44  is a flow chart of an illustrative process for forming an extruded tube with a feature on the internal surface of the tube with using a die and stamper in accordance with an embodiment of the present invention; 
         FIG. 45  is a flow chart of an illustrative process for forming a tube with a feature on the internal surface of the tube using a single impact extrusion in accordance with an embodiment of the present invention; 
         FIG. 46  is a flow chart of an illustrative process for forming a tube with a feature on the internal surface of the tube using a impact extrusion on both ends of the tube in accordance with an embodiment of the present invention; 
         FIG. 47  is a flow chart of an illustrative process for forming a tube with a feature on the internal surface of the tube using a progressive deep draw process in accordance with an embodiment of the present invention; 
         FIG. 48  is a cross-sectional view of a visual indicator system in accordance with an embodiment of the present invention; 
         FIG. 49  is an illustration of a visual indicator system of a headset in accordance with an embodiment of the present invention; 
         FIGS. 50A and 50B  are illustrations of a headset in accordance with an embodiment of the present invention; 
         FIG. 51  is an illustration of a connector in accordance with an embodiment of the present invention; 
         FIG. 52  is an exploded view of a connector in accordance with an embodiment of the present invention; 
         FIG. 53  is an illustration of a microphone boot in accordance with an embodiment of the present invention; 
         FIG. 54  is a cross-sectional view of a connector in accordance with an embodiment of the present invention; 
         FIGS. 55A-55D  are illustrations of a headset in accordance with an embodiment of the present invention; 
         FIG. 56  is a cross-sectional view of an electrical contact assembly coupled to a circuit board in accordance with an embodiment of the present invention; 
         FIGS. 57A and 57B  are illustrations of an electrical contact assembly in accordance with an embodiment of the present invention; 
         FIGS. 58A-58C  are illustrations of an electrical contact assembly in accordance with an embodiment of the present invention; 
         FIGS. 59A and 59B  are illustrations of electrical contacts in accordance with an embodiment of the present invention; 
         FIGS. 60A and 60B  are illustrations of a connector plate in accordance with an embodiment of the present invention; 
         FIGS. 61A and 61B  are illustrations of magnetic components of a connector in accordance with an embodiment of the present invention; 
         FIGS. 62A and 62B  are illustrations of a connector in accordance with an embodiment of the present invention; 
         FIGS. 63A and 63B  are illustrations of a connector in accordance with an embodiment of the present invention; 
         FIG. 64  is an illustration of a headset coupling with a complementary connector in accordance with an embodiment of the present invention; 
         FIG. 65  is a simplified graph of magnetic and spring forces involved in the coupling of a headset with a complementary connector in accordance with an embodiment of the present invention; 
         FIG. 66  is an illustration of a docking device that can receive a headset in accordance with an embodiment of the present invention; 
         FIG. 67A  is an illustration of a connector in accordance with an embodiment of the present invention; 
         FIG. 67B  is an illustration of a headset coupling with a complementary connector in accordance with an embodiment of the present invention; and 
         FIG. 68  is a chart listing exemplary modes and functions of a communications system in accordance with an embodiment of the present invention. Detailed Description of the Invention 
     
    
    
     The present invention relates to headsets and methods for manufacturing the same. Headsets are communication devices that are worn on a user&#39;s head in order to allow hands free data and/or voice communication with a host device such as a computer, phone handset, cellular phone, an automobile and/or the like. Headsets can include one or more speakers (in proximity to one or both ears) for audio output and/or one or more microphones for audio input. 
     Headsets can come in a variety of form factors or shapes. In some cases, headsets can be embodied as an earpiece that serves as the primary support mechanism for wearing the headset. For example the headset may be supported on the head by an earpiece worn over or in the ear. Alternatively, the headset may be supported by a frame or band that fits on or over the user&#39;s head. The headset may include a fixed or movable boom that places the microphone closer to the user&#39;s mouth (wraps around the face). Alternatively, the headset may be boomless such that the microphone is integrated with the earpiece thereby forming a more compact device (e.g., smaller, lighter, more aesthetically pleasing, etc.). 
     According to one aspect of the invention, the headset can be embodied as a small compact unit including a primary housing and an earbud member extending therefrom. The earbud member may be attached to or integrally formed with the primary housing. Various components can be placed at the surface of or within the confines of the earbud member and the primary housing. In fact, both of them can include one or more components depending on the needs of the device. The components contained within each of these can be widely varied. Examples of operational components can include speakers, microphones, antennas, connectors, buttons, displays, indicators, battery, and associated processors, controllers and circuitry. Generally, the earbud member includes at least a speaker while the primary housing includes at least a microphone (although this is not a requirement). Depending on their size, each of these members can include additional components of the headset. In one embodiment, the primary housing includes an antenna, user interface button, indicator or display (e.g., LEDs), battery, microphone, and/or a connector along with any accompanying circuitry while a speaker, a processor, and its accompanying circuitry can be located in the earbud. The button can be located on one end of the main housing. A user can interface with this button to perform various functions (e.g., terminating calls). 
     The shape and size and orientation of the earbud member and primary housing can be widely varied. In one embodiment, the earbud member is configured for insertion into the ear such that it supports the remaining portions of the headset (e.g., primary housing) proximate the user&#39;s head. In one embodiment, the primary housing can be configured as a longitudinal member (e.g., a tube). In one example, an earbud member, which contains a speaker, perpendicularly protrudes away from one end of a longitudinally extending primary housing, which includes a microphone at an opposite end of the longitudinally extending primary housing. Furthermore, the earbud member can expand outwardly and then inwardly from a neck portion that couples to the primary housing in order to form a bud that fits into an ear. 
     The primary housing can include a tube that forms a housing and receives internal components through an open end. The tube can be manufactured using one of several processes in order to reduce costs and increase speed and efficiency. In one embodiment, the tube can be manufactured to include features on the inner surface of the tube for supporting electronic components of the headset. Processes for creating such a tube can include applying a die and stamp to an extruded tube, single or double impact extrusion, or a progressive deep draw process. 
     The headset can include a hollow neck between the earbud and the primary housing in order to allow electrical wires to connect sets of discrete electronics disposed within the earbud and primary housing. In one embodiment, dual threaded inserts can be used to structurally reinforce the hollow neck without adding size to the device. 
     Small compact headsets have limited surface area for placing components. Therefore, one aspect of the invention relates to integrating multiple components into the same surface area of the headset in order to help form a small compact headset. Put another way, multiple components can be built into the same location on the headset in order to achieve the desired level of functionality without impacting a desired small size of the headset. The components may for example be selected from connectors, microphones, speakers, buttons, indicators, displays and/or the like. In one embodiment, an antenna and a button function at the same location of the headset. In another embodiment, a microphone and connector function at the same location of the headset. Other embodiments can also be realized. For example, a button can function at the same location of a speaker (e.g., at an earbud) or an indicator can function at the same location of a microphone. 
     Small compact headsets also have limited internal volume for placing internal components. Therefore one aspect of the invention relates to dividing/separating internal electronic assemblies into small multiple components that can be positioned at different locations (discretely) within the headset. By way of example, the electronics that would normally be embodied on a single large circuit board may be divided/separated out and placed on multiple smaller circuit boards, each of which can be positioned at different locations within the headset. The smaller circuit boards can be more easily placed within various small internal pockets found in a small compact device. Flexible wires and possibly wireless protocols can be used to operatively couple the electronics and/or discrete circuit boards together. In other words, a first portion of the electronics may be separated from a second portion of the electronics, and further the first portion may be positioned at a first location within the headset while the second portion may be positioned at a second location within the headset. Note that, two portions is not a limitation and the electronics can be divided into any number of smaller discrete portions. 
     Along a similar vein, another aspect of the invention relates to electronic assemblies that are partially flexible or bendable such that the assemblies can be folded into a small compact form in order to fit inside tightly spaced internal volumes. By way of example, the electronics that would normally be embodied on a single rigid circuit board may be placed on multiple rigid circuit boards that are interconnected by flexible or bendable circuit board portions that can be bent around various internal shapes and/or folded over itself while still functioning properly. 
     Another aspect of the invention relates to acoustical paths, ports and volumes that are built through a small compact headset in order to improve acoustical performance of the microphone and/or speaker (with limited impact on the form factor of the headset). In one embodiment, in order to control the flow of air through an earbud, acoustic ports can be integrated into one or more electronic components disposed therein and/or the earbud housing. In another embodiment, at least some of the ports that pass through the various housings are substantially hidden from view thereby enhancing the aesthetic appearance of the headset. For example, the ports may be positioned within a seam between two interfacing external surfaces of the headset. In one example, a first external surface is provided by the open end of a tube of the primary housing and the second external surface is provided by an end member disposed within the open end of the tube of the primary housing. The end member may for example include a connector assembly thereby integrating a connector with a microphone into the same surface area. 
     In accordance with one aspect of the invention, the connector assembly can include contacts for the transfer of power and data. The connector can be located on the end of the primary housing opposite a user interface button. The connector can have a symmetrical configuration so that it can be coupled with complementary connectors in more than one interface orientation (e.g., 90 degree symmetry, 180 degree symmetry, etc.). In one embodiment, switching circuitry can be included in order to accommodate this symmetry. Such circuitry can, for example, measure the polarity of data and/or power lines from the complementary connector to determine its interface orientation and route the data and/or power lines based on the determined orientation. In some embodiments, the connector assembly can be at least partially made of a ferromagnetic material, which can serve as an attraction plate for one or more magnets on a complementary connector in another device (e.g., a headset charger). 
     In accordance with another aspect of the invention, the headset can include an indicator that is hidden from view when inactive and that is in view when active. This can for example be accomplished with micrometer sized holes, called microperforations, that can be drilled into the wall of primary housing and/or earbud member. Through these holes, light sources on the inside of the primary housing and/or earbud member can create visual indicators for a user. A light diffuser can be used in combination with such microperforations so that the indicator can be illuminated with evenly distributed light. 
     Headsets may communicate with the host device via a wired and/or wireless connection. Wired connections may for example occur through a cable/connector arrangement. Wireless connections on the other hand can occur through the air (no physical connection is needed). The wired and wireless protocols may be widely varied. Wired protocols may for example be based on Universal Serial Bus (USB) interfaces, Firewire interfaces, conventional serial interfaces, parallel interfaces, and/or the like. Wireless protocols may, for example, be based on short range transmissions of voice and/or data. The wireless protocols may further be used to create personal area networks between the headset and a nearby host device such as a cellular phone. Some examples of wireless protocols that can be used include Bluetooth, Home RF, iEEE 802.11, IrDA, Wireless USB, and the like. The communication electronics may be embodied as a system on a chip (SOC). 
     Although other wireless protocols may be used, according to one aspect of the invention, the headset can include communication electronics based on the Bluetooth wireless protocol. The communication electronics may, for example, include or correspond to a Bluetooth System-on-a-Chip (SoC). The SoC can include circuitry for performing functions other than wireless communications. For example, in some embodiments, circuitry for communicating using wired Universal Serial Bus (USB) interfaces and conventional serial interfaces can be integrated into the SoC. 
     For increased functionality, according to one aspect of the invention, the headset can include power distribution circuitry. Such circuitry can operate the headset according to several different modes depending, for example, on the charge level of the battery or the availability of an external power source. In one mode, the power distribution circuitry can supply power to limited parts of the SoC while simultaneously charging the battery. The battery charging process can be further improved by using temperature detection circuitry (e.g., a thermistor) to monitor the battery temperature. This process can extend the battery life by charging it only when the monitored temperature is at, or below, a predetermined threshold. In another mode, the power distribution circuitry can selectively power various electronic components using the battery while other electronic components may be powered by an external power source. 
     Aspects and embodiments of the invention are discussed below with reference to  FIGS. 1-68 . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes as the invention extends beyond these limited embodiments. 
       FIG. 1  is a simplified block diagram of headset  10  in accordance with one embodiment of the present invention. Headset  10  can be configured to be a small compact unit in the form of a simple earpiece that can be placed in the ear. The headset can include a primary housing  11  and an earbud  12  that extends from the primary housing. Earbud  12  can fit into an ear thereby placing the primary housing next to a user&#39;s face. Each of these members can surround and protect various internal components and can also support thereon various external components associated with operating the headset. The components may be a plurality of electrical components that provide specific functions for the electronic device. For example, the components may generally be associated with generating, receiving, and/or transmitting data associated with operating the device. 
     Headset  10  includes processor  20  for controlling the headset&#39;s functions. In the illustrated embodiment, processor  20  can be provided in earbud  12 . In other embodiments, processor  20  can be located anywhere in headset  10 . Processor  20  can be electrically coupled to the other components of headset  10  through circuit boards and/or cables. Processor  20  may facilitate wireless communications with a host device. For example, processor  20  can generate signals for wireless transmission and process received wireless signals. In addition to wireless communications, processor  20  may coordinate the operation of the various components of headset  10 . For example, processor  20  may control the charging of a battery or the operation of a display system. 
     Headset  10  also includes speaker system  13  for distributing audio information from earbud  12 . Speaker system  13  can include an audio port at the end of the earbud and a receiver (e.g., a speaker) disposed at the end of the audio port. The audio port may be covered with a grill. Speaker system  13  may also include various ports internal and external to the earbud. For example, speaker system  13  may include acoustical paths inside the earbud and acoustical paths that pass through the surfaces of the earbud. 
     Headset  10  also includes one or more input mechanisms for providing inputs to the headset. The input mechanism may be placed at the primary housing and/or the earbud. The input mechanisms may be widely varied and may include for example slide switches, depressible buttons, dials, wheels, navigation pads, touch pads, and/or the like. For simplicity purposes, the headset may only include a single input mechanism. Furthermore, for aesthetical reasons, the input mechanism may be placed at a select location. In other embodiments, two or more input mechanisms may reside on the headset. 
     In one embodiment, headset  10  includes single button  14  located at one end of primary housing  11 . Placing button  14  at the end preserves the side surfaces of primary housing  11 . This can also be accomplished by configuring earbud  12  as a button (e.g., the earbud is depressible relative to the primary housing). Earbud  12  may also be configured to tilt, rotate, bend and/or slide in order to provide inputs while preserving the side surfaces of primary housing  11 . 
     Headset  10  also includes a communication terminal for communicating with a host device. The communication terminal may be configured for wired or wireless connections. In the illustrated embodiment, the communication terminal is antenna  15  that supports wireless connections. Antenna  15  may be located internal to the primary housing or earbud. If the primary housing or earbud is not formed from a radio transparent material then a radio transparent window may need to be provided. In the illustrated embodiment, antenna  15  is located at one end of the headset. Placing antenna  15  and the accompanying radiotransparent window at the end preserves the side surfaces of primary housing  11 . In one embodiment, button  14  and antenna  15  are integrated at the same end. 
     Headset  10  may also include one or more connectors  16  for transferring data and/or power to and from the headset. A data connection allows data to be transmitted to and received from a host device. A power connection, on the other hand, allows power to be delivered to the headset. The connectors may for example connect to a corresponding connector in a dock or cable in order to connect to a power source for charging and/or a data source for downloads or uploads. Although the location of the connector can be widely varied, in the illustrated embodiment, connector  16  is located at one of the ends in order to preserve the side surfaces of the primary housing. 
     In some embodiments, connector  16  and corresponding connectors may be shaped such that the two connectors can mate in two or more different interface orientations. To compensate for this possibility, headset  10  can include switching circuitry that is coupled to connector  16 . Such switching circuitry can determine how connector  16  is coupled with a corresponding connector (e.g., how the connectors are physically orientated). Switching circuitry can determine this by measuring, for example, the polarity of data and/or power lines from the complementary connector. Switching circuitry can then route the data and/or power from the connector to other circuitry in headset  10  appropriately. In some embodiments, at least a portion of connector  16  can be magnetic or magnetically attractive. For example, connector  16  may include a ferromagnetic material that biases it to magnetic connectors. Such magnetic interactions can assist a user in coupling connector  16  with corresponding connectors and help prevent the connectors from uncoupling. 
     Headset  10  also includes microphone  17  for capturing speech provided by a user. The microphone is typically located internal to the primary housing. One or more acoustical ports may be configured into the primary housing in order to provide an acoustical path from outside the primary housing to the microphone. The location of the acoustical ports can be widely varied. In one embodiment, the acoustical ports are located at one end of the primary housing in order to preserve the sides of the primary housing. In one embodiment, the connector assembly and acoustical ports are integrated at the same end. Furthermore, the acoustical port may be configured to be substantially hidden from view by selective placement of the ports. For example, the ports may be placed at the seam between the connector assembly and the primary housing. 
     Headset  10  also includes display system  18  for providing visual feedback. The display system may be a complex display system comprising an LCD or other related display device capable of displaying graphical information and/or it may be an indicator assembly that only provides simple visual feedback as for example via an LED assembly. In one embodiment, the display system only comprises an indicator assembly that provides visual feedback along the side walls of the primary housing. In order to preserve the side walls, however, the indicator assembly may be hidden when inactive. This can be accomplished, for example, through microperforations through the primary housing. The microperforations allow light to pass through, but are so small that they are undetectable to a user. 
     Headset  10  also includes battery  19 . Battery  19  may provide electrical power to components of headset  10 . Charging circuitry may also be provided to charge battery  19  when an external power supply is connected to headset  10 . 
     Headset  10  can also include support circuitry for the aforementioned components. For example, this may include circuit boards, various electrical components, processors and controllers. The support circuitry can be placed inside the primary housing and/or the earbud. In one embodiment, the support circuitry can be split or divided between the two locations in order to make a more compact device, i.e., the various electronics are distributed among volumes as needed. In order to further save space, the electronics may be stackable. In one embodiment, the electronics are placed on a circuit board with one or more flexible portions so that a stack is created by folding or bending the circuit board. 
     Although earbud  12  and primary housing  11  can be integrally formed, in the illustrated embodiment, the primary housing and earbud are separate housing members that are attached together. Any suitable means can be used to attach the two parts together including but not limited to screws, glues, epoxies, clips, brackets, and/or the like. 
     The position of the earbud relative to the primary housing may be widely varied. For example, the earbud may be placed at any external surface (e.g., top, side, front, or back) of the primary housing. In one embodiment, the earbud is located on a planar front side near one of the ends of the primary housing. In one embodiment, the earbud may be configured to move relative to the primary housing so that its position can be adjusted. 
     Each of the earbud  12  and primary housing  11  can be configured to surround its internal components at a peripheral region thereof so as to cover and protect the internal components. They can also be configured to support components externally if needed. Each of earbud  12  and primary housing  11  help define the shape and form of the headset. That is, their contours embody the outward physical appearance of the headset. Such contours may be rectilinear, curvilinear or both. In one embodiment, earbud  12  is formed as an outwardly extending protruding member while primary housing  11  is formed as a longitudinally extending member. For example, earbud  12  may be coupled to primary housing  11  through a neck, which can be a portion of the primary housing, earbud or a separate piece altogether. The axis of earbud  12  and primary housing  11  can be transverse, and more particularly perpendicular. The shapes of earbud  12  and primary housing  11  may be widely varied. In one embodiment, earbud  12  is formed as a reverse rounded circular conical member and primary housing  11  is configured with a pill shaped cross section. It is understood however that these are not limitations and that the form, shape, and orientation may vary according to the specific needs or design of the headset. By way of example, earbud  12  and primary housing  11  may have various cross-sectional shapes including for example, circular, square, rectangular, triangular, oval, and/or the like. In addition, their form may be such that they do not have a typical straight axis. 
     Earbud  12  and primary housing  11  may be formed by one or more members. In one embodiment, primary housing  11  may include an integrally formed member. By integral, it is meant that the member is a single complete unit. By being integrally formed, the member can be structurally stronger than conventional housings, which include two parts that are fastened together. Furthermore, unlike conventional housings that have a seam between the two parts, the member has a substantially seamless appearance. Moreover, the seamless housing can prevent contamination and can be more water resistant than conventional housings. The primary housing may, for example, be formed as a tube that defines a cavity therethrough between a first open end and second open end located opposite the first open end. In order to seal the ends of the tube, the primary housing can additionally include a pair of end caps. Each of the end caps can be configured to cover one of the open ends thereby forming a fully-enclosed housing system. The end caps may be formed from similar or different materials as the tube. Furthermore, the end caps may be attached to the tube using a variety of techniques, including but not limited to, fasteners, glues, clips, brackets, and/or the like. The end caps can also be movably attached, and be configured to carry operational components of the headset. 
     It is understood that the inner cross sectional shape of primary housing  11  may be the same or different from the external cross-sectional shape of the primary housing. For example, it may be desirable to have a pill shaped external and a rectangularly shaped interior, etc. In addition, although not a requirement, the front and back surface of primary housing  11  may be substantially planar. 
     In one embodiment, primary housing  11  can be formed via an extrusion or related process. The extrusion process is capable of producing an integral tube without seams, crack, breaks, etc. As is generally well known, extrusion is a shaping process where a continuous work piece is produced by forcing molten or hot material through a shaped orifice, i.e., the extrusion process produces a length of a particular cross-sectional shape. The cross-sectional shape of the work piece is controlled at least in part on the shaped orifice. As the shaped work piece exits the orifice, it is cooled and thereafter cut to a desired length. The extrusion process is a continuous high volume process that produces intricate profiles and that accurately controls work piece dimensions (which can be a necessity for smaller parts). Furthermore, because extrusion has low tooling costs, it is relatively inexpensive when compared to other forming or manufacturing processes. 
     Primary housing  11  may be formed from a variety of extrudable materials or material combinations including but not limited to metals, metal alloys, plastics, ceramics and/or the like. By way of example, the metals may correspond to aluminum, titanium, steel, copper, etc., the plastic materials may correspond to polycarbonate, ABS, nylon, etc, and the ceramic materials may correspond to alumina, zirconia, etc. Zirconia may, for example, correspond to zirconia oxide. 
       FIG. 2  shows headset connector system  200  in accordance with an embodiment of the present invention. System  200  can include headset  210  and headset engaging connector  220 . In some embodiments, headset  210  may correspond to headset  10  of  FIG. 1 . Headset  210  can include any number of headset connector contact regions (see e.g., regions  211 ,  212  and  213 ) disposed within face  214  of the headset. Face  214  can mate with headset engaging connector  220  such that a corresponding number of headset engaging contact regions disposed in the headset engaging connector (see e.g., regions  221 ,  222  and  223 ) electrically couple with the headset connector contact regions. Moreover, headset  210  can include switching circuitry  215  that is electrically coupled with each of the headset connector contact regions. Switching circuitry  215  can be operative to determine an interface orientation between the headset connector contact regions and headset engaging contact regions. For example, switching circuitry  215  can determine the interface orientation in which headset  210  is mated with headset engaging connector  220 . Switching circuitry  215  can determine this by measuring the polarity of data and/or power lines from headset engaging connector  220 . After having determined the interface orientation, switching circuitry  215  can route signals received on the headset connector contact regions based on the determined orientation. It is understood that switching circuitry can be provided in connector  220  to provide functionality similar to switching circuitry  215 . For example, switching circuitry in connector  220  can determine the interface orientation of headset  210  and route electrical signals to contact regions based on the determined orientation. 
     In some embodiments, at least a portion of headset  210  and/or headset engaging connector  220  (e.g., a portion or all of housing  224 ) can be magnetically attractive. Moreover, headset engaging contact regions (see e.g., regions  221 ,  222 , and  223 ) may be biased to protrude from housing  224  of connector  220 . In such embodiments, headset  210  can be magnetically attracted to headset engaging connector  220  such that the magnetic forces can cause the headset engaging contact regions (see e.g., regions  221 ,  222 , and  223 ) to press against the headset connector contact regions (see e.g., regions  211 ,  212 , and  213 ). 
       FIG. 3  shows electronic device  300  in accordance with an embodiment of the present invention. In some embodiments, device  300  may be an electronic headset (see e.g., headset  10  of  FIG. 1 ), but it is to be understood that device  300  is not limited to electronic headsets. Device  300  can include housing  310  and connector assembly  320 . At least a portion of connector assembly  320  may be disposed in housing  310 . Connector assembly  320  may include port  322 , microphone  324  and channel  326  that fluidically couples the microphone to the port. Connector assembly  320  may also include one or more contacts (see e.g., contacts  321 ,  323 ,  325  and  327 ) for electrically coupling with another device. Port  322  may be provided in a location such that the contacts of connector assembly  320  are on the same exterior surface as the port or located nearby. In some embodiments, port  322  may be located between two contacts (see e.g., contacts  323  and  325 ). 
       FIG. 4  shows electronic device  400  in accordance with another embodiment of the present invention. Like device  300 , device  400  may be an electronic headset in some embodiments (see e.g., headset  10  of  FIG. 1 ) but it is to be understood that device  400  is not limited to electronic headsets. Device  400  can include housing  410  and joint connector and microphone assembly  420 . Microphone  430 , boot  440  and connector plate  450  may be provided in joint connector and microphone assembly  420 . Microphone  430  may include one or more side surfaces and a top surface with microphone port  432 . Microphone boot  440  may be mounted to the microphone such that the boot forms a seal with at least a portion of the top surface and the side surfaces. This seal can surround microphone port  432 . Microphone boot  440  can further include a portion for sealing to connector plate  450  and an aperture for fluidically connecting microphone port  432  to connector port  452 . Connector plate  450  may include one or more contacts (see e.g., contacts  451 ,  453 ,  455  and  457 ) for electrically coupling with another device. Connector port  452  may be provided in a location such that the port is in the same exterior surface as the contacts of connector assembly  420  or located near the contacts. In some embodiments, port  452  may be located between two contacts (see e.g., contacts  453  and  455 ). 
       FIG. 5  shows headset  500  in accordance with an embodiment of the invention. Headset  500  may correspond to an electronic headset (see e.g., headset  10  of  FIG. 1 ) and may include primary housing  510  and earbud  520 . Primary housing  510  may correspond to primary housing  11  and earbud  520  may correspond to earbud  12 , for example. Earbud flexible circuit board  522  may be provided in earbud  520 . Receiver  524  and processing circuitry  526  can be mounted on the earbud flexible circuit board  522 . Earbud flexible circuit board  522  may be flexible such that it can fold upon itself or bend. Such flexibility may allow earbud flexible circuit board  522  to fit in smaller or less traditionally-shaped earbuds. 
     Primary housing  510  may be fixed to earbud  520 . Primary housing  510  may include primary housing flexible circuit board  512  and microphone  514 . Like earbud flexible circuit board  522 , primary housing flexible circuit board  512  may be flexible such that it can fold upon itself or bend. Such flexibility may allow primary housing circuit board  512  to bend around other components in the primary housing (e.g., circuitry, antennas, or batteries) so as to conserve interior space inside the primary housing. For example, conserving interior space may result in more room to accommodate a larger battery. In another example, conserving interior space may result in a smaller primary housing. Earbud flexible circuit board  522  and microphone  514  can be electrically coupled to primary housing flexible circuit board  512 . In some embodiments, such as the one shown in  FIG. 5 , earbud flexible circuit board  522  may extend into primary housing  510  such that it can couple with primary housing flexible circuit board  512 . In other embodiments, primary housing flexible circuit board  512  may extend into earbud  520  such that it can couple with earbud flexible circuit board  522 . It is to be understood that although primary housing flexible circuit board  512  and earbud flexible circuit board  522  are described as being flexible, one or both circuit boards may include both flexible and rigid portions. For example, each circuit board may include one or more rigid portions upon which electrical components (e.g., receiver  524 , processing circuitry  526 , or microphone  514 ) can be easily and stably mounted. 
       FIG. 6A  shows headset device  600  in accordance with an embodiment of the present invention. Headset device  600  can include earbud housing  610 , threaded neck  620 , and primary housing  630 . Headset device  600  can correspond to headset  10  of  FIG. 1  such that, for example, earbud housing  610  corresponds to earbud  12  and primary housing  630  corresponds to primary housing  11 . Earbud housing  610  can include earbud through-hole  612  and neck engaging surface  614 . Threaded neck  620  can include first neck surface  622  that can mate with the earbud housing&#39;s neck engaging surface  614 . First neck surface  622  and neck engaging surface  614  may include one or more features (e.g., protrusions, tabs, slots or notches) such that they can only be coupled in a certain orientation (with respect to each other). 
     Primary housing  630  can include primary housing through-hole  632  and neck engaging surface  634 . Threaded neck  620  can further include second neck surface  624  that can mate with the primary housing&#39;s neck engaging surface. Second neck surface  624  and neck engaging surface  634  may include one or more features (e.g., protrusions, tabs, slots or notches) such that they can only be coupled in a certain orientation (with respect to each other). 
       FIG. 6B  shows screw  690  for use with headset device  600  in accordance with the present invention. Screw  690  can be used as both an earbud screw and a primary housing screw. Screw  690  can include hollow channel  692  running through the center of the screw. Screw  690  may also include features  694  (e.g., notches) such that a tool can interface with the features and rotate the screw. As an earbud screw, screw  690  can be inserted into earbud through-hole  612  and tightened such that it fastens neck engaging surface  614  to first neck surface  622 . As a primary housing screw, screw  690  can be inserted into primary housing through-hole  632  and tightened such that it fastens neck engaging surface  634  to second neck surface  624 . 
       FIG. 7  shows display system  700  in accordance with an embodiment of the present invention. Display system  700  can, for example, correspond to display system  18  of  FIG. 1 . System  700  can include housing  710 , light source  720 , diffuser  730  and control circuitry  740 . Housing  710  can have signal indicator region  712  disposed therein. Signal indicator region  712  may be, for example, one or more apertures•(e.g., microperforations) for transmitting light. Signal indicator region  712  may be configured to output a signal of a certain shape or form. Housing  710  can also include internal wall  714 . Diffuser  730  can be located between light source  720  and internal wall  714 . 
     Control circuitry  740  may be electrically coupled with light source  720  to control when light source  720  emits light. 
     Diffuser  730  may be operable to diffuse light from light source  720  such that all of the light exiting the diffuser has an equal intensity or brightness. For example, diffuser  730  may be operable to evenly illuminate signal indicator region  712  with the light from light source  720 . Diffuser  730  may be composed of a mixture of different particles that cause light diffusion. For example, diffuser  730  can include mainly clear particles with translucent particles distributed throughout. The translucent particles can cause light to be deflected from its original course so that the light is distributed throughout the diffuser. Accordingly, light exiting from any portion of the diffuser will have substantially even illumination. 
       FIG. 8  shows power distribution system  800  in accordance with an embodiment of the present invention. Power distribution system  800  can be employed in an electronic device (see e.g., headset  10  of  FIG. 1 ) and can include switch  810 , bus  820 , first power regulating circuitry  822 , core processing circuitry  824 , battery  830 , second power regulating circuitry  832 , RF processing circuitry  834 , and control circuitry  840 . Core processing circuitry  824  may include circuitry for handling low-level, core functions of the electronic device, and RF processing circuitry  834  may include circuitry for handling RF communications for the electronic device. To power core processing circuitry  824  and RF processing circuitry  834 , power distribution system  800  can include both bus  820  and battery  830  as potential power sources. 
     Bus  820  can be coupled to receive power from a source external to the system. For example, bus  820  may be coupled to a connector such that the bus can receive power through the connector. First power regulating circuitry  822  may be electrically coupled to bus  820  and core processing circuitry  824 . First power regulating circuitry  822  may be operable to, for example, convert power from bus  820  into a condition suitable for core processing circuitry  824  (e.g., by changing the voltage or regulating the current flow). 
     Battery  830  can be a device that stores chemical energy and makes it available in an electrical form. Battery  830  may be rechargeable. Second power regulating circuitry  832  may be electrically coupled to battery  830  and RF processing circuitry  834 . Second power regulating circuitry  832  may be operable to, for example, convert power from bus  820  into a condition suitable for core processing circuitry  824  (e.g., by changing the voltage or regulating the current flow). 
     Switch  810  may be electrically coupled to both core processing circuitry  824  and RF processing circuitry  834 . Switch  810  may be controlled by the presence of an external power source on bus  820 . For example, switch  810  may be activated when the voltage of bus  820  goes below a predetermined threshold. When switch  810  is activated, first power regulating circuitry  822 , core processing circuitry  824 , RF processing circuitry  834 , and second power regulating circuitry  832  may be electrically coupled such that both core processing circuitry and RF processing circuitry can share power. 
     Control circuitry  840  can be electrically coupled to bus  820 , first power regulating circuitry  822 , core processing circuitry  824 , and second power regulating circuitry  832 . Control circuitry  840  may be able to selectively active first power regulating circuitry  822  and second power regulating circuitry  832  based on bus  820 , core processing circuitry  824 , and/or any other signals in the electronic device. 
       FIG. 9  shows wireless headset  900  in accordance with an embodiment of the present invention. Headset  900  can be an electronic headset for communications (see e.g., headset  10  of  FIG. 1 ). Headset  900  can include processor circuitry  910  that has a first power consumption portion  912  and a second power consumption portion  914 . First power consumption portion  912  can, for example, include the core circuitry of an electronic device (e.g., boot-up circuitry), while second power consumption portion  914  can include the device&#39;s auxiliary circuitry (e.g., circuitry for RF communications). Headset  900  can further include power distribution circuitry  920 . 
     Power distribution circuitry  920  can selectively power first power consumption portion  912  independent of whether second power consumption portion  914  is powered. In some embodiments, power distribution circuitry  920  can selectively power any combination of first power consumption portion  912  and second power consumption portion  914  based on one or more monitored conditions of headset  900 . For example, power distribution circuitry  920  can monitor if an external power source is present and/or the charge level of an internal battery in order to determine which power consumption portions to activate. 
       FIGS. 10A and 10B  show perspective views of an illustrative headset in accordance with an embodiment of the present invention. Headset  1000  can correspond to headset  10  of  FIG. 1 . For example, primary housing  1010  can correspond to primary housing  11  and earbud  1020  can correspond to earbud  12 . 
     Headset  1000  can include a housing that encloses the electronic and other elements of the headset. The housing can incorporate several pieces that are assembled using any suitable process (e.g., adhesive, screws, or press fit). In the example of  FIGS. 10A and 10B , headset  1000  can include earbud  1020 , neck  1030 , primary housing  1010 , antenna cap  1011  and connector  1040 . Earbud  1020  can include perforations (e.g., acoustic ports)  1021  and  1022  for allowing air to pass into and out of the earbud  1020 . Front port  1021  can allow sound waves from a receiver located in earbud  1020  to reach a user&#39;s ear and/or the outside environment. Side ports  1022  can provide a path for acoustic pressure to vent to the outside environment. Earbud  1020  can be attached to primary housing  1010  by neck  1030 . 
     Attached to one end of primary housing  1010  is antenna cap  1011 . Antenna cap  1011  can have button  1012  disposed at least partially therethrough. A user can interface with button  1012  to control the headset. Primary housing  1010  can include display  1013  which can correspond to display system  700  of  FIG. 7  or display system  18  of  FIG. 1 . In some embodiments, display  1013  may include microperforations such as those discussed in more detail below in connection with  FIGS. 48 and 49 . Located at the connector end of primary housing  1010 , connector  1040  includes at least one port (not shown in  FIG. 10A ) for enabling a microphone inside housing  1010  to receive acoustic signals (e.g., a user&#39;s voice), and at least one contact  1042  for receiving power, data, or both from an external source. Connector  1040  may correspond to contact regions  211 ,  212 , and  213  of  FIG. 2 , for example. 
     Earbud  1020 , neck  1030 , primary housing  1010 , antenna cap  1011  and connector  1040  can be constructed from any suitable material including, for example, metal, plastic, silicone, rubber, foam, or combinations thereof. For example, earbud  1020  can be formed from a plastic element surrounded by a silicone seal and primary housing  1010  can be formed from aluminum. Earbud  1020 , neck  1030 , primary housing  1010 , antenna cap  1011  and connector  1040  can be manufactured using any suitable process (e.g., molding, casting or extrusion). In some embodiments, earbud  1020 , neck  1030 , primary housing  1010 , antenna cap  1011  and connector  1040  can be post processed to provide texture and other features on the inner or outer surfaces of the bodies. For example, a bead blast and anodization process can be used to apply a desired surface texture to primary housing  1010 . 
       FIG. 11A  is an exploded view of headset  1100  in accordance with an embodiment of the present invention. Headset  1100  can correspond to headset  10  of  FIG. 1  or headset  1000  of  FIGS. 10A and 10B , for example. In one embodiment of the present invention, earbud housing  1120  can contain earbud circuit board  1122 . Earbud circuit board  1122  can, for example, correspond to earbud circuit board  522  of  FIG. 5 . Earbud circuit board  1122  can be a flexible circuit board on which one or more of the following components are electrically and/or mechanically mounted: processor  1123  (which can be used to control the functions of headset  1100 ), receiver  1124 , and other circuitry and components. The flexible nature of earbud circuit board  1122  can enable it to be folded onto itself, providing layers of circuitry that can be packed into earbud housing  1120 , thereby occupying space within earbud housing  1120  that may otherwise be empty and unused. The flexible portions of earbud circuit board  1122  can replace the need for separate wires connecting different circuit boards, which might cause a substantial increase in size because, for example, each wire might involve a pair of connectors. Additionally, the flexible nature of circuit board  1122  can advantageously reduce the area or footprint required by circuit board  1122 . That is, compared to another circuit board having similar circuitry and components disposed thereon but in an unfolded layout, circuit board  1122  can occupy less area. In addition, circuit board  1122  further can reduce the footprint or size requirements of other components of headset  1100 , such as primary housing  1110  and antenna cap  1111 , by incorporating within earbud housing  1120  electronics and other components that traditionally are located elsewhere within a headset. Earbud housing  1120  and the circuitry and components contained therein are discussed in more detail below in connection with  FIGS. 18-27B , for example. 
     Earbud housing  1120  can be coupled to primary housing  1110  by neck  1130 . Earbud housing  1120 , primary housing  1110 , and neck  1130  can correspond, respectively, to earbud housing  610 , primary housing  630 , and neck  620  of  FIG. 6 . Neck  1130  can be constructed with a double threaded screw insert to receive screw member  1131  (associated with earbud housing  1120 ) and screw member  1132  (associated with primary housing  1110 ). Neck  1130  can connect earbud housing  1120  and primary housing  1110  in a manner that can reduce the likelihood of earbud housing  1120  and primary housing  1110  rotating independently of each other. That is, when headset  1100  is in use and the user adjusts its position by, for example, pulling primary housing  1110  down, the earbud housing  1120  can rotate in conjunction with primary housing  1110 . However, in some embodiments, pulling primary housing  1110  down may cause the housing to rotate with respect to earbud housing  1120  so as to trigger a switch and signify a user input. A more detailed discussion of headset necks and their assembly can be found below in connection with  FIGS. 28-30 , for example. 
     In addition to earbud circuit board  1122 , headset  1100  also can include primary housing circuit board  1115  on which additional electronic components  1113  can be electrically and/or mechanically mounted. Primary housing circuit board  1115  may, for example, correspond to primary housing circuit  512  of  FIG. 5 . Primary housing circuit board  1115  can be electrically coupled with the earbud circuit board by one or more wires, cables, flexible circuit boards, and the like. The arrangement of electronic components in both earbud circuit board  1122  and primary housing circuit board  1115  can advantageously reduce the size of headset  1100 . The arrangement of the electronic components in headset  1100  will be discussed in more detail below in connection with  FIGS. 18-200 , for example. 
     A user can control the functions of headset  1100  using button  1112 , which can be electrically coupled with primary housing circuit board  1115 . Button  1112  can extend from antenna cap  1111  such that it appears as a discrete user interface easily activated by a user. Button  1112  can be configured to move in any suitable manner including, for example, bending with respect to primary housing  1110 , translating in and out of antenna cap  1111 , rotating around an axis passing through connector plate  1141  and button  1112 , or any combination thereof. 
     In one embodiment, button  1112  can include a switch such as a dome switch, which can be activated when a user depresses button  1112 . Button  1112  can have a button guide structure. The button guide structure can have one or more guide channels to facilitate user actuation of the button with respect to the rest of headset  1100 . In one embodiment of the present invention, the guide channel(s) can be provided in the form of a hole through the button guide structure. The switch actuation member can have a stem that is supported and guided by the guide channel. When pressed by a user, the switch actuation member moves along the guide channel towards the switch. Raised structures (e.g., ribs) can be used to ensure that the switch actuation member reciprocates smoothly within the guide channel. 
     Button  1112  and antenna cap  1111  can be constructed from a dielectric material such as plastic. Antenna  1118  can be formed by mounting an antenna resonating element within antenna cap  1111  (e.g., along an inner surface of antenna cap  1111 ) or on a portion of the button guide structure. Constructing button  1112  and antenna cap  1111  from a dielectric material can reduce or eliminate potential signal interference that can disrupt the proper operation of antenna  1118 . In addition, a dielectric button  1112  can allow for smaller clearance between the antenna resonating element and conductive structures (e.g., primary housing circuit board  1115 ) in headset  1100 . 
     Antenna  1118  can be electrically coupled with primary housing circuit board  1115  so that it can send and receive wireless (e.g., radio) signals. 
     Antenna  1118  can include any suitable antenna resonating element for communicating between headset  1100  and an electronic device (e.g., a cellular telephone or a personal media device). The antenna resonating element can be formed from a flex circuit containing a strip of conductor. The flex circuit can be attached to the button guide structure using, e.g., adhesive. For example, the flex circuit can contain registration holes that mate with corresponding registration bosses on the button guide structure. One or more of the bosses can be heat staked to the flex circuit. 
     Details about the operation and design of an antenna and button system similar to antenna  1118  and button  1112  can be found, e.g., in U.S. patent application Ser. No. 11/651,094 entitled “Antenna and Button Assembly for Wireless Devices,” which is incorporated herein. 
     Appendages  1117  can be incorporated into antenna cap  1111  in order to mount the antenna cap to headset  1100 . Appendages  1117  can, for example, fasten to primary housing  1110  or one or more brackets  1116  which will be discussed in more detail below. 
     Battery pack  1119  can be located within primary housing  1110 . Battery pack  1119  can contain one or more suitable batteries including, for example, lithium ion, lithium ion polymer (Li-Poly), nickel metal hydride, or any other type of battery. Battery pack  1119  can be electrically coupled with circuit board  1115  for powering electronic components in headset  1100 . Additionally, circuitry that is typically packaged within standard battery packs (e.g., charging or fuse protection circuitry) can be moved to primary housing circuit board  1115 . Advantageously, the distribution of circuitry into earbud housing  1120  and the layout of circuit board  1115  can permit battery pack  1119  to occupy a substantial portion of the internal space of primary housing  1110 . This can increase the energy storage capacity of headset  1100  (e.g., allow headset  1100  to operate for longer period of time in between charges) without increasing the size of primary housing  1110  and headset  1100 . 
     Headset  1100  can include connector  1140  for enabling headset  1100  to electrically connect to other devices. An opening or port can be included in connector  1140  so that acoustic signals (e.g., speech from a user) can reach the microphone inside microphone boot  1144 . Connector  1140  can, for example, correspond to assembly  320  of  FIG. 3  or assembly  420  of  FIG. 4 , for example. The microphone can be electrically coupled with circuit board  1115  in any suitable manner. Microphone boot  1144  can be placed inside the end of primary housing  1110  that is farthest from earbud housing  1120 . This end may be referred to herein as the microphone or connector end of headset  1100 , and is also the portion of headset  1100  that is closest to the user&#39;s mouth when in use. The arrangement of the microphone boot  1144  with respect to connector  1140  and accompanying parts is discussed in more detail below in connection with the description accompanying  FIGS. 50A-54 . 
     Connector  1140  can include connector plate  1141  in which contacts  1142  and accompanying casing  1143  can reside. As such, contacts  1142  can facilitate the electrical coupling of headset  1100  with another device. Accompanying casing  1143  can be made from a non-conductive material (e.g., a polymeric material). Casing  1143  can surround contacts  1142  to prevent the contacts from electrically coupling with connector plate  1141 . Contacts  1142  and casing  1143  can be substantially flush with the surface of connector plate  1141  so that the combination of the contacts, casing and plate creates a substantially flat surface for mating with other connectors. Connector plate  1141  can be made of a ferromagnetic material so that it is biased to magnetic connectors, such as those discussed in connection with  FIGS. 62A-67B , for example. The design of connector plate  1141 , contacts  1142 , casing  1143  and complementary magnetic connectors will be described in more detail below in connection with the discussion of  FIGS. 55A-67B . 
     Headset  1100  can include one or more brackets  1116  to couple connector  1140  with appendages  1117  of antenna cap  1111 . Brackets  1116  can prevent connector plate  1141  and antenna cap  1111  from moving axially away from each other or separating from primary housing  1110 . Alternatively, connector plate  1141  and antenna cap  1111  can be coupled to one or more brackets that are secured to the inner surface of primary housing  1110 . 
     As a matter of design choice, a seam can be included in between the peripheral surface of connector plate  1141  and the inner surface of primary housing  1110 . That is, in addition to the predefined port for providing an acoustic pathway between the microphone and the outside environment, gaps can exist. These gaps can advantageously enable the microphone to receive acoustic signals in the event the predefined acoustic pathway is blocked (e.g., by a foreign object such as dirt). In other embodiments, an adhesive may be applied to provide a substantially airtight seal between connector plate  1141  and primary housing  1110 . In yet another embodiment, a gasket may be used to provide a seal. 
       FIG. 12  shows a view of headset  1200  in accordance with another embodiment of the present invention. Headset  1200  can be similar to headset  1100 , but with some substantial differences between the two. For example, headset  1200  can use a different attachment technique to couple connector  1240  to primary housing  1210 . Connector  1240  can include tabs  1242  which can be used to couple with features (e.g., wall  1212 ) on an interior surface of primary housing  1210 . Such a method might be advantageous to using the brackets  1116  in headset  1100 . For example, the tabs  1242  can attach to the near end of primary housing  1210  which might provide connector  1240  with higher structural integrity than, for example, the method of using brackets to attach to a structure (e.g., antenna cap) on the other end of the primary housing. Headset  1200  can also include light diffuser  1244  which can be used in conjunction with a visual indicator system as discussed in connection with  FIGS. 48 and 49 . Additionally, headset  1200  can include antenna  1218  which can wrap around button guide  1217  in some embodiments. 
     The fundamental basics of the Bluetooth protocol are well known in the art, and discussed briefly below. For a more detailed discussion, please see Bluetooth Specification Version 2.0+EDR, Vol. 0, Nov. 4, 2004, which is hereby incorporated by reference in its entirety. Bluetooth wireless technology is based on an international, open standard for allowing intelligent devices to communicate with each other through wireless, low power, short-range communications. This technology allows any sort of electronic equipment, from computers and cell phones to keyboards and headphones, to make its own connections, without wires or any direct action from a user. Bluetooth is incorporated into numerous commercial products including laptop computers, PDAs, cell phones and printers, and is likely to be used in future products. 
     Bluetooth can be referred to as a frequency hopping spread spectrum (FHSS) radio system that operates in the 2.4 GHz unlicensed band. Bluetooth transmissions change frequencies based on a sequence which is known to both the transmitter and the receiver. According to one known standard, Bluetooth transmissions use 79 different frequencies ranging from 2.404 GHz to 2.480 GHz. Bluetooth&#39;s low power transmissions allow a typical range of about 10 meters or roughly 30-40 feet. This range can vary from about 1 meter to 100 meters depending on the amount of power used by the device for Bluetooth transmissions. 
     Bluetooth devices connect to each other to form networks known as piconets. A piconet includes two or more devices which are synchronized to a common clock signal and hopping sequence. Thus, for any device to connect to a given piconet, that device may need to have the same clock signal and hopping sequence. The synchronized clock and hopping sequence can be derived using the clock signal of one of the devices on the piconet. This device is often referred to as the “master” device while all other devices on the piconet are referred to as “slave” devices. Each piconet can include one master device and up to seven or more slave devices. Moreover, Bluetooth devices can belong to more than one piconet. The term “scatternet” is used to define Bluetooth networks which are made up of multiple, overlapping piconets. In the case where one Bluetooth device is on two or more piconets, all of the devices are on a single scatternet. Devices from one of the piconets can communicate with devices from another piconet by using the shared device to relay the signals. 
     When two Bluetooth devices initially connect, they first share some general information (e.g., device name, device type) with each other. In order to enhance the connection, the devices can establish a trusted relationship by using a secret passkey. This passkey is typically provided by a user or stored on memory in a device. According to a known Bluetooth standard, the process of establishing this trusted relationship is called pairing. Once two devices are paired, they typically share information and accept instructions from one another. 
     Bluetooth devices can operate with a maximum data throughput of approximately 2.1 Mbit/s (Megabits-per-second), but it is understood that such limitations change as technology advances, and that embodiments of the present invention may operate at other rates. This maximum throughput is shared among all devices on a piconet, meaning that if more than one slave device is communicating with the master, the sum of all communications is less than the maximum data throughput. 
     The Bluetooth standard includes a published software framework. The shared framework is called the Bluetooth Protocol Stack and includes different software applications to implement Bluetooth communications.  FIG. 13  is a simplified schematic diagram of an exemplary Bluetooth Protocol Stack  1300  in accordance with an embodiment of the present invention. Low-level software is included in Lower Stack  1302 . This section includes code to generate/receive radio signals, correct transmission errors and encrypt/decrypt transmissions, among other things. The Host Controller Interface (HCI)  1304  is a standardized interface between the low-level Bluetooth functions and applications. The HCI layer represents a division between the Lower Stack  1302  functions handled by a dedicated Bluetooth processor and the rest of the functions handled by an application-specific processor. 
     The Extended Synchronous Connection-Oriented (eSCO)  1306  layer is used to implement dedicated communication channels, commonly used for voice data, in between the Lower Stack  1302  and high-level applications. The Logical Link Control and Adaptation Protocol (L2CAP)  1308  layer combines and repackages the data transmitted and received by the multiple higher-level applications. The L2CAP  1308  layer combines all of these different communications into one data stream that can interface with Lower Stack  1302  the RFCOMM  1310  layer emulates the protocol used by serial connections. This allows software designers to easily integrate Bluetooth into existing applications which previously used a serial connection. The Service Discovery Protocol (SDP)  1312  layer is used by devices to provide information about what services (or functions) each device offers and how other devices can access those services through Bluetooth. 
     The Profiles  1314  layer allows a device to identify itself as a member of a generic group of devices with a predefined set of functions. For example, a device complying with the headset profile may support predefined methods relating to audio communications. The Application Layer  1316  contains programs that implement the useful tools created by all of the other layers. By writing different programs for Application Layer  1316 , software developers can focus on new uses of the Bluetooth functionality without having to rewrite the code which controls the underlying communication tasks. 
       FIG. 14  shows a simplified block diagram of exemplary electronic system  1400  of a headset in accordance with an embodiment of the present invention. The system of  1400  can be implemented in, for example, headset  10  of  FIG. 1  or headset  1000  of  FIGS. 10A and 10B . System  1400  can include processor circuitry  1410 , interface circuitry  1420 , power distribution circuitry  1430 , switching circuitry  1440  and 4-pin symmetrical magnetic connector  1455 . 
     Processor circuitry  1410  can include processor  1411  and auxiliary circuitry that operates in connection with processor  1411 . Processor  1411  can coordinate all of the operations in system  1400 , including, for example, Bluetooth transmissions, battery charging and processing (e.g., encoding and decoding) of acoustic signals. Processor  1411  can drive receiver  1412  to provide acoustic signals that may be heard by a user. Reset circuit  1413  can detect when system  1400  is connected to another device and subsequently instruct processor  1411  to reset. Power FET  1414  can be used with the power supply circuitry inside processor  1411  and will be discussed in more detail below in connection with the discussion of  FIG. 15 . Antenna  1415  can be used to send wireless signals to and receive wireless signals from another device (e.g., a phone or portable media device). UART multiplexer  1416  can be electrically coupled with processor  1411  and can route data signals to different parts of processor  1411 . This routing can reduce unwanted effects, such as inductance, in unused data lines. 
     Interface circuitry  1420  can include a microphone isolation LDO  1421 , a micro-electro-mechanical (MEMs) microphone  1422 , LED driver  1424  and switch  1423 . Microphone isolation LDO  1421  can be electrically coupled with MEMs microphone  1422 . Microphone isolation techniques and MEMs microphones are well known, and a person of ordinary skill in the art will appreciate that these elements can be replaced by other equivalent microphone configurations without deviating from the spirit of the present invention. LED driver  1424  can be configured to drive a LED display unit based on one or more outputs of processor  1411 . Details about the design and function of circuitry similar to LED driver  1424  can be found in U.S. Patent Application No. 60/878,852 entitled “Systems and Methods for Compact Multi-State Switch Networks,” which is incorporated herein. Switch  1423  can represent the electrical behavior of button  1012  of  FIG. 10B . A user can interface with this switch to input commands to the headset. For example, a user can depress switch  1423  to initiate a telephone call, terminate a call, or both. In one embodiment, switch  1423  can be a single-pole, single-throw switch with a spring to bias it to an open position. 
     Power distribution circuitry  1430  can include over-voltage protection and fuse  1431 , battery protection circuitry  1432  and thermistor  1433 . Over-voltage protection and fuse  1431  can protect system  1400  in the event that an unsafe amount of voltage is applied to one or more inputs. The fuse in the protection circuitry can be an over-current protection device which disconnects the inputs of the headset if an over-current condition is detected. Battery protection circuitry  1432  can include circuitry to prevent the malfunction of a battery (e.g., a li-poly battery) which could result in a dangerous overheating situation. Battery protection circuitry  1432 , in contrast to conventional headsets which has such circuitry integrated into the battery pack, can be separated from the battery pack and located elsewhere within a headset according to the invention. Thermistor  1433  can be located in the proximity of a battery (see e.g., battery pack  1119  of  FIG. 11 ) and may change its resistance based on the battery&#39;s temperature. One or more inputs of processor  1411  can be electrically coupled with thermistor  1433  to monitor the temperature of the battery. Processor  1411  can be programmed to charge the battery differently depending on the detected battery temperature. For example, processor  1411  may charge the battery at a faster rate when the monitored battery temperature is low than when the temperature is high. By regulating the charging in this manner, the time required to completely charge a battery can be decreased without damaging the battery. 
     Symmetrical magnetic connector  1455  can allow system  1400  to connect to other devices and systems for communicating data or transmitting power. Connector  1455  represents the electrical behavior of connector  16  of  FIG. 1 , for example. 
     Switching circuitry  1440  can enable connector  1455  to connect and communicate with many different types of devices and in many interface orientations. Switching circuitry  1440  can, for example, correspond to switching circuitry  215  of  FIG. 2 . Switching circuitry  1440  can include power polarity switch circuit  1441  and data polarity switch circuit  1442 . The two circuits can, for example, determine the type of communication interface being used and route the corresponding data and/or power lines to the correct pathways (e.g. internal electrical traces) for the detected interface. The two circuits can also determine the interface orientation of a connection with another device, for example, and route the corresponding data and/or power lines to the correct pathways (e.g., internal electrical traces) for the detected orientation. A detailed description of the design and function of exemplary circuits similar to switch circuits  1441  and  1442  can be found in U.S. patent application Ser. No. 11/650,130 entitled “Systems and Methods for Determining the Configuration of Electronic Connections,” which is incorporated herein. 
       FIG. 15  shows processor  1500  which can be used as the core processor or application processor of a headset in accordance with an embodiment of the present invention. Processor  1500  can, for example, correspond to processor  20  of  FIG. 1 . Processor  1500  can also be referred to as a System on a Chip (SoC) because it can be a single integrated circuit capable of a diverse range of functions. Processor  1500  can be a CSR BC04 Audio Processor with integrated Flash Memory that fully supports the Bluetooth v2.0+EDR specification. An oscillator  1510  and clock generation circuitry  1511  can be used in conjunction with a timing crystal to establish a timing signal (or clock) which processor  1500  can use to coordinate its activities. RF circuitry  1520  can be used to input and output RF signals for wireless communications. Baseband circuitry  1530  can coordinate communications so that they conform with the a communications protocol (e.g., a Bluetooth protocol). Flash memory  1531  can store, for example, software and configuration information for processor  1500 . Random access memory (RAM)  1532  can temporarily store data for Baseband circuitry  1530  and microprocessor  1533 . RISC microprocessor  1533  can be programmed to perform various functions, such as monitoring a thermistor (see e.g., thermistor  1433  of  FIG. 14 ) and coordinating battery charging as previously described, for example. 
     Full speed USE controller  1540  and UART circuitry  1541  can facilitate wired communication interfaces so that processor  1500  can share data with another device through a physical interface (e.g., connector contacts  1042  of  FIG. 10A ). In one embodiment, processor  1500  can support both full speed USE and simplified RS-232 serial interfaces. A simplified RS-232 interface can include, for example, three lines: transmit data, receive data, and ground. In order to accommodate more than one interface over a limited number of data lines, USB controller  1540  and UART circuitry  1541  can be coupled to a switch (e.g., UART Multiplexer  1416  of  FIG. 14 ). This switch can route data lines to the circuitry, within processor  1500 , that corresponds to the communication interface being used. A more detailed discussion of similar systems and methods for using more than one communications interface over a limited number of data lines can be found in U.S. patent application Ser. No. 11/650,130 entitled “Systems and Methods for Determining the Configuration of Electronic Connections,” which is incorporated herein. Processor  1500  can also support other interfaces in addition to those discussed above without deviating from the spirit of the present invention. For example, processor  1500  can include circuitry for supporting a proprietary communications interface. 
     Processor  1500  can include differential microphone input amplifier  1551  and differential speaker output amplifier  1552 . Both the input amplifier  1551  and the output amplifier  1552  can be electrically coupled with Audio CODEC  1550  to process (e.g., encode and decode) audio signals. Power control and regulation circuitry  1560  can include low-dropout regulator (LDO)  1561 , battery charger  1562  and switch mode power supply (SMPS)  1563 . The power needed for the various subsystems of processor  1500  can be regulated by LDO  1561  or SMPS  1563  depending on both the charge level of the battery and any external power sources that might be connected. This will be described in more detail below in connection with the discussion of  FIG. 16 . Battery charger  1562  can output a controllable current between 25 and 100 milliamps to charge a battery (see e.g., battery pack  1119  of  FIG. 11 ). In accordance with an embodiment of the present invention, this controllable current can vary based on various factors (e.g., the detected temperature of the battery). 
     Programmable I/O  1570  can include LED driver  1571  and analog-to-digital converter (ADC)  1572 . LED driver  1571  can use signals from other circuitry in processor  1500  to generate signals with sufficient current to illuminate one or more indicator LEDs. The design and operation of exemplary circuitry similar to LED driver  1571  can be found in U.S. Patent Application No. 60/878,852 entitled “Systems and Methods for Compact Multi-State Switch Networks,” which is incorporated herein. Analog-to-Digital Converter (ADC)  1572  can accept inputs from analog circuitry and convert them to digital signals to be used by other circuitry in processor  1500 . For example, ADC  1572  can monitor the current running through a thermistor (see e.g., thermistor  1433  of  FIG. 14 ) to determine the temperature of a battery. Circuitry in processor  1500  can use this temperature information to determine an appropriate charging current for battery charger  1562  to provide. Moreover, it is understood that ADC  1572  can process multiple analog signals concurrently. For example, in addition to the temperature information above, ADC  1572  can also process voltage information about the current charge level of a headset&#39;s battery. 
     While the processor described above and shown in  FIG. 15  is a CSR BC04 Audio Processor, other processors with other configurations and functionality can be used in a headset without deviating from the spirit of the present invention. 
       FIG. 16  shows a simplified schematic of power distribution system  1600  for the subsystems of processor  1605  in accordance with an embodiment of the present invention. System  1600  can, for example, correspond to system  800  of  FIG. 8  and headset  900  of  FIG. 8 . Moreover, processor  1605  can correspond to processor  1500  of  FIG. 15 . Processor  1605  can include both low-dropout regulator (LDO)  1620  and switch mode power supply (SMPS)  1625  as options for regulating power for processor  1605 . SMPS  1625  can output power with a higher efficiency than LDO  1620 , but can require the installation of several additional components, such as a relatively large capacitor and inductor, which can increase the cost (and size) of system  1600 . In addition, SMPS  1625  may require an input voltage that meets, or exceeds, a predetermined voltage level to operate. Therefore, it may be a matter of design choice as to which power supply is used. For example, in low voltage applications, it may be advantageous to use LDO  1620 . In other embodiments, such as the one shown in  FIG. 16 , LDO  1620  and SMPS  1625  can both be used to provide functionality over a wide range of input voltages and high power efficiency. 
       FIG. 16  shows processor  1605  which includes core circuitry  1610  and radio circuitry  1615  in accordance with an embodiment of the present invention. Radio circuitry  1615  can include, for example, circuitry related to RF communications. Additional functions (e.g., low-level system functions, firmware updates) can be executed by core circuitry  1610 . Additionally, core circuitry  1610  can monitor and control other circuitry in system  1600  using, for example, input line  1614  and output lines  1611 ,  1612  and  1613 . 
     Power distribution system  1600  can include circuitry for interfacing with two power sources. In  FIG. 16 , an internal battery is represented by BAT  1655 , and an external power supply is represented as BUS  1650 . From herein, the voltage of BAT  1655  will be referred to as VBAT. BUS  1650  can, for example, represent the power provided by a battery charger that is connected to system  1600 . BUS  1650  can be electrically coupled with LDO  1620  such that the LDO draws power from an external source through BUS. Therefore, LDO  1620  operates when an external power supply is connected to system  1600 . Similarly, SMPS  1625  can be electrically coupled with BAT  1655  so that it draws power from the battery. 
     Other circuitry in power distribution system  1600  can include Power FET  1640 , Analog-to-Digital Converter (ADC)  1630  and logic gates  1661 ,  1631  and  1632 . Button  1660  can represent, for example, a signal from an on/off switch or other circuitry that can signal processor  1605 . 
     An illustrative operation of system  1600 , in which BAT  1655  is the only source of power, is now discussed. An absence of power on BUS  1650  prevents LDO  1620  from supplying power and causes FET  1640  to turn on, thereby effectively coupling nodes  1641  and  1642 . System  1600  may be turned on when button  1660  is activated and outputs a high voltage. Activation of button  1660  can cause the button input of gate  1661  to go HIGH, which can cause the output of the gate  1661  to go HIGH. This HIGH signal can cause gate  1632  to assert a HIGH signal on its output. When gate  1632  outputs a high voltage, SMPS  1625  is activated and can begin providing power, if VBAT is at or above the predetermined voltage level (e.g., BAT  1655  has sufficient power to run SMPS  1625 ). Because power FET  1640  is on, the power provided by SMPS  1625  can be transmitted to radio circuitry  1615  and core circuitry  1610 . As core circuitry  1610  begins to boot up, it can output a HIGH signal on line  1613  so that gate  1632  continues to output a HIGH signal after button  1660  is released. System  1600  can operate with full functionality at this point because both core circuitry  1610  and radio circuitry  1615  are receiving power. However, when VBAT drops below the predetermined voltage level (e.g., BAT  1655  is dead), SMPS may no longer be able to produce reliable power and system  1600  may begin to shut down. 
     An illustrative operation of system  1600  receiving power from an external power source on BUS  1650  is now discussed. The power on BUS  1650  can provide supply power to LDO  1620  and cause power FET  1640  to turn OFF or remain turned OFF, effectively decoupling nodes  1641  and  1642 . Additionally, the power on BUS  1650  can cause gates  1661 ,  1631  and  1632  to output HIGH signals. When gate  1631  generates a HIGH signal, LDO  1620  can begin supplying power. Power from LDO  1620  may be provided to core circuitry  1610 , but not to radio circuitry  1615 , because power FET  1640  is not conducting. When core circuitry  1610  receives power, it can output a HIGH signal on line  1611  which causes the output of gate  1631  to maintain a HIGH signal so that LDO  1620  can continue operating. 
     SMPS  1625  may not be able to operate until VBAT has risen to or above the predetermined voltage level. Core circuitry  1610  can instruct battery charging circuitry (not shown) to begin using power from BUS  1650  to charge BAT  1655 . Core circuitry  1610  can receive signals (e.g., digital signals) from ADC  1630  over line  1614 . ADC  1630  can be electrically coupled with BAT  1655 . ADC  1630  can convert a signal with a varying voltage (e.g., VBAT) into a digital signal that can be processed by core circuitry  1610 . When VBAT has met or exceeded the predetermined voltage level, SMPS  1625  may now be able to operate and provide radio circuitry  1615  with power. Note that in some embodiments, SMPS  1625  may be powered ON substantially immediately when an external power service is connected to BUS  1650 . Using ADC  1630 , core circuitry  1610  can detect when SMPS turns on and coordinate the functions of processor  1605  accordingly. For example, when radio circuitry  1615  is powered, core circuitry  1610  can begin sending communications data to radio circuitry  1615 . In this manner, processor  1605  can operate with full functionality before BAT  1655  is fully charged. 
     While BAT  1655  is charging, core circuitry  1610  can perform various other functions, regardless of whether VBAT has met or exceeded the predetermined voltage level. For example, core circuitry  1610  can run boot up processes, communicate over wired interfaces and run user interfaces. In this manner, core circuitry  1610  can, for example, handle auxiliary processes (e.g., downloading firmware updates via a wired interface and installing the updates) before processor  1605  has full functionality. 
     Several benefits may be realized by power distribution system  1600  in the manner discussed above. For example, the core circuitry  1610  can turn ON before the battery has reached a minimum charge threshold. This enables core circuitry  1610  to handle boot up processes in advance, thereby enabling headset to begin working immediately once the battery is charged to the minimum level. In effect, certain components may be powered independent of BAT  1655  when an external power supply is connected to BUS  1650 . 
     Additionally, system  1600  limits the unnecessary use of BAT  1655 . Traditionally, known headset circuitry is powered through a battery even if an external power supply is present. The power drained from the battery is then recharged using power from the external power supply. This charging and recharging can shorten a battery&#39;s lifespan. System  1600  allows core circuitry  1610  to draw power independent of BAT  1655  and directly from an external supply (if present), extending the life of BAT  1655 . 
     To provide additional functionality, output line  1612  can be included in core circuitry  1610  so that the core circuitry can shut down system  1600 . Line  1612  can be coupled with node  1633  such that line  1612  can drive node  1633  to a LOW signal. Therefore, if core circuitry outputs LOW signals to lines  1611 ,  1612  and  1613 , the output of gates  1631  and  1632  go LOW, turning off both LDO  1620  and SMPS  1625 , which causes core circuitry  1610  and radio circuitry  1615  to turn off. 
     While the previous discussion described a method and system for separately powering on core and RF radio circuitries, the same techniques can be applied to other electronic subsystems which, for example, might be unrelated to RF communications. 
       FIGS. 17A-17C  show different views of known headset circuit boards, with particular emphasis on how circuitry and components are distributed therein. Electrical components  1796 , including processor  1792 , may be mounted on two sides of circuit board  1790 . As can be appreciated by one of skill in the art, circuit board  1790  may occupy a relatively large, undistributed area. Such circuit boards can limit the amount that other components (e.g., batteries, buttons, antennas) are spatially integrated with the electronics. Thus, known headsets have to be relatively large to accommodate such boards and other components. 
       FIG. 18  is a simplified schematic system diagram of a headset showing a circuit board arrangement in accordance with an embodiment of the present invention. System  1800  can correspond to headset  500  of  FIG. 5 , for example. System  1800  can be divided into two independent and separately arranged circuit boards  1810  and  1820 . That is, when boards  1810  and  1820  are installed in a headset according to an embodiment of the present invention, the boards may be electronically coupled to each other, but the boards themselves are discrete. Circuit board  1810  corresponds to earbud circuit board  522  of  FIG. 5  and earbud circuit board  1122  of  FIG. 11A  and can include, for example, Bluetooth processor  1812 , circuitry that requires placement close to the processor, balance RF filter circuitry  1814  and coaxial connector (see e.g., connector  2752  of  FIG. 27B ). Examples of circuitry required close proximity to processor  1812  can include a timing crystal, charging inductors, capacitors, field effect transistors and resistors. 
     Circuit board  1820  corresponds to primary housing circuit board  512  of FIG. Sand primary housing circuit board  1115  of  FIG. 11A  and can, for example, include RF Antenna  1822 , interface circuitry  1823 , power distribution circuitry  1824 , switching circuitry  1825 , 4-pin symmetrical magnetic connector  1826 , RF matching circuitry  1821  and coaxial connector (see e.g., connector  2752  of  FIG. 27B ). 
     Circuit boards  1810  and  1820  can be electrically coupled using, for example, co-ax cable  1830  and bus  1832 . In the embodiment shown in  FIG. 18 , bus  1832  includes ten lines, but one of ordinary skill in the art will appreciate that the number of lines in the bus can vary. 
     Balance RF filter circuitry  1814  and RF matching circuitry  1821  can adjust RF signals to compensate for the specific effects of circuit board  1810 , co-ax cable  1830 , circuit board  1820  and antenna  1822 . The functions of elements of additional circuitry in circuit board  1810  and  1820  have been described in more detail in the above discussion relating to  FIG. 14 . 
       FIGS. 19A and 19B  compare respective top and bottom views of earbud circuit board  1920  according to an embodiment of the present invention to respective top and bottom views of the known circuit boards shown in  FIGS. 17A-17C . In addition,  FIGS. 19A and 19B  show that selected components of known circuit board  1990  can be arranged on earbud circuit board  1920 . For example, as shown, the encircled circuit and components such as components  1996  and processor  1992  can be placed on one or more sides of earbud circuit board  1920 . The remaining electronic components such as components  1996  can be placed on primary housing circuit board (see e.g., circuit board  1115  of  FIG. 11 ) which may be located inside the headset&#39;s primary housing. 
     Earbud circuit board  1920  can include a layer made from a flexible substrate that enables circuit board  1920  to bend onto itself, thereby effectively reducing the area needed to install circuit board  1920  into a headset according to the invention. The flexible layer of circuit board  1920  can include one or more layers of electrical traces for electrically coupling processor  1922  and electronic components  1926 , for example. The flexible layer of circuit board  1920  can, for example, extend over the entire footprint of the circuit board, or be limited to predetermined portions of circuit board  1920 . 
     Circuit board  1920  can include relatively rigid sections  1923 ,  1925  and  1927  which have increased structural strength and are easier to mount electrical components to. Rigid circuit board sections  1923 ,  1925 , and  1927  can be fabricated by attaching rigid circuit board pieces to one or more outer surfaces of the flexible layer of circuit board  1920 . Rigid pieces can be attached to a flexible layer using any suitable process, such as applying an adhesive, for example. Contacts can be included on complementary surfaces of the rigid pieces and the flex layer so that electrical traces can be routed across the different layers. One or more layers of electrical traces can be included in the rigid circuit board pieces so that the combination of rigid and flex layers can provide two or more layers of electrical traces. In the embodiment shown in  FIGS. 19A and 19B , a flex circuit layer with two levels of traces can be located in between two rigid, single-trace layers such that the resulting rigid sections of circuit board  1920  include four layers of traces. In flexible sections of circuit board  1920 , such as connector lead  1921 , the absence of rigid pieces can result in two levels of traces. 
     Rigid sections  1925  and  1927  can have substantially circular footprints with different radii. Various electrical components, such as capacitors and resistors, for example, can be mounted on both sides of rigid section  1925 . Rigid section  1927  can have a larger footprint than section  1925  in order to accommodate the mounting of processor  1922  on a first side and receiver  1924  on a second side of section  1925 . Connector  1928  can be mounted to rigid section  1923  to enable earbud circuit board  1920  to electrically couple with a primary housing circuit board (see e.g., circuit board  1115  of  FIG. 11 ). 
       FIGS. 20A and 20B  show side and perspective views of earbud circuit board  2020  in a folded configuration in accordance with an embodiment of the present invention. Earbud circuit board  2020  may, for example, correspond to earbud circuit board  1920 . The folded configuration may correspond to the configuration of circuit board  2020  when installed within a headset, or more particularly, the earbud of the headset, as shown in  FIG. 20C . Top rigid section  2027  can be folded over middle rigid section  2025  so that both sections can fit in the earbud of a headset. Processor  2022 , receiver  2024  and various other electronic components  2026  may be mounted to earbud circuit board  2020 . Electronic components  2026  can include resistors, capacitors, transistors, amplifiers and other types of both passive and active electronic components, for example. It is to be understood that the term electronic components, as used herein, does not include interconnect devices (e.g., wires, traces, connectors, etc.). Earbud circuit board  2020  can further include rigid section  2023  and connector  2028  mounted thereon. Connector  2028  can be used to electrically couple earbud circuit board  2020  with a circuit board in a headset&#39;s primary housing (see e.g., circuit board  1115  or circuit board  2011 ). 
     Referring now to  FIG. 20C , which shows earbud circuit board  2020  and primary housing circuit board  2011  installed in a possible configuration within headset  2000  in accordance with an embodiment of the present invention. Circuit board  2020  can be folded in a configuration similar to that of  FIGS. 20A and 20B  and inserted into earbud  2014 . Primary housing circuit board  2011  can include a combination of rigid and flexible sections that are similar, in composition but not necessarily shape, to the rigid and flexible sections of circuit board  2020 . Circuit board  2011  can be folded to provide a cavity  2012  for a battery (see e.g., battery pack  1119  of  FIG. 11 ). Circuit board  2011  can include connector  2018  which may connect to connector  2028  of earbud circuit board  2020 . During installation, circuit board  2011  can be inserted through one of the open ends of primary housing  2010 . Connector lead  2021  can be fed through headset neck  2013  so connector  2028  can mate with connector  2018  when circuit board  2011  has been inserted into primary housing  2010 . 
     This distribution of electronics, where processor  2022  and other circuitry (e.g., receiver  2024  and other electronic components  2026 ) are located inside earbud  2014 , advantageously allows for a generally smaller and more comfortable headset. Although the discussion above is related to an embodiment in which a certain distribution of electronic components is used, other distributions can be used without deviating from the spirit of the present invention. For example, a battery can be placed inside the earbud and a processor can be placed in the primary housing. 
       FIG. 21A  shows a perspective view of earbud housing  2100  and neck  2110  in accordance with an embodiment of the present invention. Bezel  2130  can cover the top of earbud housing  2100 . One or more acoustic ports  2102  can be located in the wall of the earbud to allow pressure to vent out of earbud housing  2100 . 
       FIG. 21B  shows an exploded view of earbud housing  2100  of  FIG. 21A  in accordance with an embodiment of the present invention. Screens  2131  and  2132  can be located on top of bezel  2130 . Screens  2131  and  2132  can, for example, provide dust protection and acoustic resistance. Top gasket  2134  can be attached to the underside of bezel  2130  to create a seal with receiver  2124 , and bottom gasket  2123  can be attached to section  2127  (a rigid section) of circuit board  2120 . Bracket  2135  can be used to mount circuit board  2120  inside earbud housing  2100 . Mesh can cover acoustic ports  2102  and can, for example, impose acoustic resistance on air passing through those ports. Screw  2112  can be used to mount earbud housing  2100  to neck  2110 . Gaskets  2134  and  2123  can be made of, for example, foam, rubber, or any other compressible material so that the gaskets can form acoustic (e.g., substantially air-tight) seals with surrounding parts. 
       FIG. 22  shows an interior view of empty earbud housing  2200  in accordance with an embodiment of the present invention. Mesh  2204  can be located on the inner wall of housing  2200  to control the flow of air through one or more acoustic ports  2202  and prevent foreign objects (e.g., dirt) from entering housing  2200 . Mesh  2204  can, for example, be affixed to housing  2200  using an adhesive. Mesh  2204  can be made of nylon, plastic, or any other suitable material. Mesh  2204  can provide acoustic resistance to the passage of air between an acoustic volume inside housing  2200  and the outside environment when the earbud is assembled. Even though only one acoustic port is shown in  FIG. 22 , any number of acoustic ports can be used in accordance with the principles of the present invention. 
       FIG. 23  shows rigid section  2327  of an earbud circuit board mounted inside earbud housing  2300  in accordance with an embodiment of the present invention. Acoustic port  2328  can be provided in circuit board section  2327  to permit air flow through the circuit board. The size, shape and location of acoustic port  2328  can vary depending on, for example, the acoustic properties of the earbud and the desired sound output. If desired, more than one acoustic port may be provided. Although not shown in  FIG. 23 , a second rigid portion of the earbud circuit board, such as rigid section  2025  of  FIG. 20 , may too include one or more acoustic ports. Though such port(s) may not be necessary if sufficient air gaps exist between the inside wall of housing  2300  and the second rigid portion. 
       FIG. 24  shows bottom gasket  2440  mounted onto circuit board section  2427  in accordance with an embodiment of the present invention. Bottom gasket  2440  can include an combination of, for example, acoustic mesh  2430 , adhesive, and foam  2441 . Foam  2441  of gasket  2440  can be shaped to fit around receiver (see e.g., gasket  2740  and receiver  2724  of  FIG. 27A ) and acoustic port  2428 . Mesh  2430  can be shaped to cover port  2428 . In this manner, acoustic mesh  2430  can cover acoustic port  2428  even though foam  2441  does not. Mesh  2430  can be made of nylon, plastic, or any other suitable material that can provide acoustic resistance to the passage of air through port  2428  which couples the acoustic volume under circuit board section  2427  (see e.g., acoustic volume  2796  of  FIG. 27 ) with the acoustic volume where the receiver is located (see e.g., acoustic volume  2794  of  FIG. 27 ). 
       FIG. 25  shows the underside of bezel  2530  in accordance with an embodiment of the present invention. Bezel  2530  can include rim  2536  which extends from the bottom of bezel  2530 . Rim  2536  can be of sufficient height to compress bottom gasket  2440  of  FIG. 24  against circuit board section  2427  of  FIG. 24  when bezel  2530  is mounted to the top of the earbud housing, thereby creating an acoustic seal between the rim and the circuit board. Gasket  2534  can be, for example, a layer of foam that is affixed to the underside of bezel  2530  using adhesive. Gasket  2534  can be shaped so that it can form a seal with the top of the earbud&#39;s receiver when bezel  2530  is mounted to the earbud. Bezel  2530  includes acoustic port  2533  for sound to exit an earbud. Screen  2531  can be located on the topside of bezel  2530  so that the screen completely covers acoustic port  2533 . Screen  2531  can apply an acoustic resistance to air passing through acoustic port  2533 . 
       FIG. 26A  shows the underside of bezel  2630  with receiver  2620  installed in accordance with an embodiment of the present invention. Receiver  2620  can be placed inside rim  2636  so that the front output of receiver  2620  is encircled by the seal formed between the top of the earbud&#39;s receiver and the top gasket (see e.g., top gasket  2134  of  FIG. 21B ). Receiver  2620  can include spring contacts  2622  and  2624 . Spring contacts  2622  and  2624  can, for example, be made from a metal or an alloy. Springs contact  2622  and  2624  can electrically couple with circuitry in a headset in order to input audio signals to receiver  2620 . 
       FIG. 26B  shows a cross-sectional view of receiver  2620  in accordance with an embodiment of the invention. Receiver  2620  can include spring contacts  2622  and  2624  which can connect receiver  2620  with a source of electrical signals (e.g., earbud circuit board  1115  of  FIG. 11 ). Contacts  2622  and  2624  can include tips  2623  and  2625  to facilitate the physical contact with a contact on a circuit (e.g. a flex circuit board). 
       FIG. 27A  shows a cross-sectional view of earbud housing  2700  with receiver  2724  and circuit board  2720  installed in accordance with an embodiment of the present invention. Bezel  2730  is mounted on top of earbud housing  2700 . Bezel  2730  can be attached to housing  2700  using a notch and rib configuration  2738  or any other suitable method of attachment, such as adhesive, for example. In an alternative embodiment of the present invention, bezel  2730  can be integrally formed with earbud housing  2700 . Neck  2710  can be coupled to the bottom of earbud housing  2700 . Earbud circuit board  2720  can be located inside the earbud and extend through lumen  2716  of neck  2710 . 
     Located on the top of bezel  2730 , screens  2731  and  2732  can cover audio port  2733 . Audio port  2733  can allow air to pass between the external environment  2798  and front volume  2792  of receiver  2724 . Top gasket  2734  and bottom gasket  2740  can create acoustic seals around receiver  2724  so that receiver volume  2794  is created. Acoustic port  2728  can allow air to pass through top rigid section  2727  of circuit board  2720  so that a port between receiver volume  2794  and rear earbud volume  2796  is created. Acoustic port  2702  can be located in earbud housing  2700  so that air can pass between rear earbud volume  2796  and the external environment  2798 . Mesh (see e.g., mesh  2204  of  FIG. 22 ) can be applied to the inner wall of earbud housing  2700  to cover acoustic port  2702  such that some resistance is applied to air passing through the port. 
     In one embodiment of the present invention, receiver  2724  can form at least part of a wall defining front volume  2792  and at least part of a wall defining receiver volume  2794 . Rim  2736  of bezel  2730  can extend from the bezel into the interior of the earbud and compress against bottom gasket  2740 , thereby also forming at least part of a wall defining receiver volume  2794 . In one embodiment of the present invention, top rigid section  2727  of circuit board  2720  can be disposed between receiver volume  2794  and rear earbud volume  2796 , thereby forming at least part of a wall defining receiver volume  2794  and at least part of a wall defining rear earbud volume  2796 . To ensure the desired acoustic seal between receiver volume  2794  and rear earbud volume  2796 , top rigid section  2727  of circuit board  2720  can be rigidly coupled to earbud housing  2700 , directly or indirectly. In contrast, in one embodiment of the present invention, middle rigid section  2725  of circuit board  2720 , which can be disposed within rear earbud volume  2796 , can be flexibly coupled to the earbud housing, directly or indirectly (e.g., via top rigid section  2727  and flexible section  2729  of circuit board  2720 ). As used herein, when a component forms part of a wall defining an acoustic volume, the component can do so directly or indirectly. For example, the component can directly form part of a wall defining an acoustic volume when part of the component is open to the acoustic volume. The component can indirectly form part of a wall defining an acoustic volume when the component is incorporated into another component open to the acoustic volume. 
     In order to prevent sound from exiting rear earbud volume  2796  through lumen  2716 , a substance, such as silicon glue, can be used to fill the inside of neck  2710 . It is advantageous to prevent sound from receiver  2724  leaking into the headset&#39;s primary housing (see e.g., primary housing  11  of  FIG. 1 ) because the microphone is located therein. If sound from the receiver is picked up by the microphone, a potentially undesirable echo may be created. 
       FIG. 27B  shows a cross-sectional view of earbud housing  2700  with coaxial cable  2750  and conductive stopper  2760  installed in accordance with an embodiment of the present invention. Coaxial cable  2750  can couple to rigid section  2725  of circuit board  2720  using connector  2752 , for example. Coaxial cable  2750  can be used to couple a processor in earbud housing  2700  with an antenna provided in a headset&#39;s primary housing (see e.g., antenna  1218  in primary housing  1210 ). Coaxial cable  2750  can include, for example, an insulated wire surrounded by a conductive shield and an outer insulator. In some embodiments, the outer insulator may be removed from at least a portion of cable  2750 . For example, insulator can be removed to create exposed portion  2754  of the cable such that the insulator can be electrically coupled with (e.g., grounded to) insert  2712 . Insert  2712  can be grounded to neck  2710  through the insert&#39;s threads and the neck can be grounded to a headset&#39;s primary housing (see e.g., housing  11  of  FIG. 1 ). By grounding the insulator of cable  2750 , electromagnetic interference and other negative effects may be reduced thereby increasing the wireless performance of a headset. 
     Conductive stopper  2760  can be installed in the lumen  2716  of insert  2712 . In some embodiments, conductive stopper  2760  can be made of silicone and filled with silver. Conductive stopper  2760  can include a slit for circuit board  2720  and coaxial cable  2750  to pass through lumen  2716 . Providing conductive stopper  2760  in neck  2710  can have several benefits. For example, conductive stopper  2760  can help isolate any sounds in acoustic volume  2796  from a headset&#39;s primary housing. In some embodiments, conductive stopper  2760  can also press exposed portion  2754  of cable  2750  against the wall of insert  2712  such that the cable&#39;s insulator is always electrically coupled with (e.g., grounded to) the insert. In other embodiments, stopper  2760  can be made from a conductive material such that the stopper can electrically coupled exposed portion  2754  of the cable with insert  2712 . 
       FIG. 28  shows a view of unassembled pieces of attachment system  2800  that can be used to attach earbud housing  2820  to primary housing  2810  in accordance with an embodiment of the present invention. The configuration described below can allow for a mechanically robust connection which prevents housing  2820  from rotating with respect to primary housing  2810 . An additional benefit of this design is the open lumen that can be used to run wires (or flexible printed circuit boards) between the earbud and primary housing. Attachment system  2800  can, for example, correspond to device  600  of  FIGS. 6A and 68 . 
     Attachment system  2800  can include insert  2840 , earbud housing  2820 , neck  2830 , insert  2850  and primary housing  2810 . In order to simplify manufacturing, inserts  2840  and  2850  can be substantially similar and can both include features  2841 , (e.g., notches), threads  2842  and a through-hole. Features  2841  can be arranged in a pattern to promote proper interface with certain tools. A custom tool which can interface with inserts  2840  and  2850  is described in more detail in the discussion below corresponding to  FIGS. 30A-30C . 
     Primary housing  2810  can include through hole  2814 . Insert  2850  can be located in primary housing  2810  so that the threaded part of insert  2850  protrudes through through-hole  2814 . A through-hole can be provided through neck  2830 , and the interior can be threaded so the neck can couple with inserts  2850  and  2840 . Earbud housing  2820  can include an through-hole (see e.g., through-hole  612  of  FIG. 6 ) through which insert  2840  can pass to couple with neck  2830 . 
     The top surface of neck  2830  can include one or more protrusions  2831  (e.g., tabs) which can interface with one or more slots (e.g., notches) in the bottom of housing  2820  to prevent the two parts from rotating independently of each other when coupled together. The slots in the bottom of housing  2820  are not shown in  FIG. 28 , but slots similar to slots  2816  can be provided on the neck engaging surface of earbud housing  2820  in accordance with an embodiment of the present invention. Earbud housing  2820  can have a curved exterior surface that can form a nearly seamless transition with the curved exterior surface of neck  2830 . 
     The bottom surface of neck  2830  can include protrusions that interface with one or more slots  2816  in housing  2810  to prevent the two parts from rotating independently of each other when coupled together. The protrusions on the bottom surface of neck  2830  are not shown in  FIG. 28 , but protrusions similar to protrusions  2831  can be provided on the bottom surface of neck  2830  in accordance with an embodiment of the present invention. Primary housing  2810  can include recessed region  2818  so that the bottom surface of neck  2830  can be recessed below the primary exterior surface of the housing. Moreover, the exterior of neck  2830  can be shaped to provide a nearly seamless transition from earbud housing  2820  to primary housing  2810 . 
     Neck  2830  and inserts  2840  and  2850  can be made from any suitable material (e.g., metals or polycarbonates). For example, neck  2830  can be made from aluminum and inserts  2840  and  2850  can be made from steel. The choice of materials for neck  2830  and inserts  2840  and  2850  can depend on factors such as structural strength, weight, price, ability to be machined, and cosmetic appearance. 
       FIG. 29  shows a flowchart of process  2900  for connecting a headset earbud with a primary housing (e.g., a tube) in accordance with an embodiment of the present invention. Note that the protrusions and slots of  FIG. 28  are referred to, respectively, as tabs and notches in process  2900 . At step  2901 , a bottom insert (such as insert  2850  of  FIG. 28 ) can be inserted into a primary housing. The bottom insert can be inserted from either side of the primary housing and manipulated so that the threaded end is protruding from a through hole in the wall of the primary housing. At step  2902 , thread-locking glue can be applied to the threads of the bottom insert. The glue can be applied so that it covers a complete circular path around the threads of the insert. Alternatively, the glue can be applied to just one section of the threads. The glue can be selected in order to prevent the insert from unscrewing itself due to external forces (e.g., vibration). In one embodiment, a sufficient quantity of glue may be applied to the threads of the insert to prevent moisture and other harmful elements from entering the inside of a headset through a seam which may exist between the neck and the primary housing. At step  2903 , a neck (such as neck  2830  of  FIG. 28 ) can be screwed onto the insert to a predetermined level. At step  2904 , the neck can be aligned to the primary housing so that one or more tabs (e.g., protrusions  2831 ) on the neck fit within one or more notches on the primary housing. At step  2905 , a custom tool can be used to turn the bottom insert while the neck is rotationally fixed to the primary housing. At step  2906 , the bottom insert can be tightened to a predetermined torque. This torque measurement can be estimated by hand or performed with a calibrated torque wrench. At step  2907 , an earbud housing can be mounted to the neck so that one or more tabs on the neck fit within one or more notches on the earbud housing. At step  2908 , thread-locking glue can be applied to the top insert threads. The glue used on the threads of the top insert can be the same as the glue used on the threads of the bottom insert and can be applied in a similar manner. At step  2909 , the top insert can be screwed into the neck. At step  2910 , the top insert can be tightened to a predetermined torque. 
       FIGS. 30A and 30B  show custom tool  3000  that can be used to manipulate an insert (e.g., insert  2840  or insert  2850 ) with respect to a neck (e.g., neck  2830 ) in accordance with an embodiment of the present invention. Tool  3000  can include two members  3010  and  3020  which can be coupled together by fastener  3030 . Fastener  3030  can allow members  3010  and  3020  to rotate (or pivot) independently around the faster. 
     Members  3010  and  3020  can include appendages  3011  and  3021  which can be used by a user to control tool  3000 . Appendages  3011  and  3021  can be an ergonomic size and shape. For example, appendages  3021  can be curved to accommodate an average human hand. Appendages  3011  and  3021  can include plastic covers  3012  and  3022  with ridges  3013  and  3023  such that a user can easily grip the appendages with his/her hands. A spring  3040  can be coupled with appendages  3011  and  3021  such that the appendages are biased to separate from each other. 
     Members  3010  and  3020  may control the movement of manipulators  3014  and  3024 , which can interface with a part, such as an insert. For example, when appendages  3011  and  3021  are squeezed together, manipulators  3014  and  3024  may be forced apart. Manipulators  3014  and  3024  can include narrow sections  3015  and  3025  and tips  3016  and  3026 . 
       FIG. 30B  shows a detailed view of the shape of tips  3016  and  3026  in accordance with an embodiment of the present invention. Tips  3016  and  3026  can include outward facing tabs  3017  and  3027  which can interface with features (see e.g., features  2841  of  FIG. 28 ) of inserts in order to manipulate (e.g., screw into place) the inserts. Tabs  3017  and  3027  can form the outer surface of narrow sections  3015  and  3025 . 
       FIG. 30C  shows custom tool  3000  coupling neck  3090  with primary housing  3092  in accordance with step  2905  of  FIG. 29  according to an embodiment of the present invention.  FIG. 30C  illustrates how the narrow section of the manipulators can be of sufficient length so that tabs  3017  and  3027  can interface with features on the insert (see e.g., features  2841  of  FIG. 28 ). Note that to preserve the structural strength of the manipulators, the narrow section may not be constructed to be substantially longer than necessary. 
     Extruded tubes with internal features for securing elements are useful for electronic devices. For example, such tubes can be used as a primary housing (see e.g., housing  11  of  FIG. 1 ) or an earbud housing (see e.g., earbud  12  of  FIG. 1 ). The following discussion describes different processes for creating a tube having an internal wall, for example, for supporting circuitry or electronic components. It will be understood, however that the processes and devices described can be used to create any suitable feature on the inner surface of a tubular structure. 
       FIG. 31  is a cross-sectional view of a tube having an internal wall  3104  in accordance with an embodiment of the present invention. Tube  3100  has a wall thickness  3102 , and includes internal wall  3104  that extends inward perpendicular from the elongated axis of the tube. Internal wall  3104  has a thickness  3106  and a height  3108  (as measured from the outer surface of the tube). The discussion accompanying  FIGS. 32-33, 34-36, 37-28, 39-40 , and  41 - 43  respectively relate to various methods for creating tube  3100  in accordance with some embodiments of the present invention. 
     Known extrusion processes are unable to extrude tubes with internal features such as an internal wall (e.g., internal wall  3104 ). For example, known extrusion processes involve forcing a molten material through an aperture in order to create an object with a cross-sectional shape that is similar to the shape of the aperture. This type of process is incapable of producing tubes with discreet internal features because such a tube will have a cross-sectional shape that varies along the length of the tube. To overcome this limitation, existing processes require manufacturing a tube having a wall thickness equal to the required height of the feature (e.g., height  3108 ), and subsequently removing excess material around the feature using a machining process so that the final wall thickness meets the desired specification (e.g., thickness  3102 ).  FIG. 32  is a cross section of an illustrative tube manufactured with a wall thickness that is thicker than the desired end product wall thickness in accordance with an embodiment of the present invention. Tube  3200  may be formed from any material (e.g., metal, plastic, or composite) using any suitable process (e.g., extrusion, impact extrusion, or progressive deep draw). Wall thickness  3202  may be selected based on the features that will be carved into tube  3200 . 
       FIG. 33  is a perspective view of a cross section of the illustrative tube of  FIG. 32  once the tube has been machined to include an internal wall in accordance with an embodiment of the present invention. To form internal wall  3204  in tube  3200 , the entire inner surface  3201  of tube  3200  is machined to remove excess material around the internal wall and to reduce tube thickness  3202  to a desired wall thickness. This machining step may be time consuming, expensive, and difficult to implement, as it requires an experienced machinist and expensive tools. Furthermore, machining may also leave marks on the part, which may be undesired (e.g., for aesthetic reasons). Also, some features may include geometry or aspects that cannot be manufactured by machining (e.g., sharp angles not directly accessible from either end of the tube) or features that cannot be manufactured within the required tolerances (e.g., due to the inherent size of the machining tools). 
     To overcome the limitations of an entirely machined tube, a number of approaches may be used.  FIG. 34  is an illustrative die and stamper for modifying the internal aspect of a tube in accordance with an embodiment of the present invention. Tube  3400  is extruded with the desired final thickness  3402  required for the tube. Tube  3400  is extruded to a slightly longer length  3403  than required for the final product, as the longer portion may be part of a cold-worked process that is used to create the internal wall. A die  3410  may be inserted in a first end of tube  3400  and inserted such that die end  3412  is aligned with a desired location of internal wall  3404  (see  FIG. 36 ). Die  3410  may fit flush against the inside wall of tube  3400  and may be operative to maintain wall thickness  3402  when stamper  3420  is used to cold-work the tubing not in contact with die  3410 . Stamper  3420  is then inserted into the second end of tube  3400 , and a stamping force is applied to cold work the portion of tube  3400  located between the second end and die  3410 . Stamper  3420  causes the wall thickness  3422  of tube  3400  to increase in the cold worked portion of tube  3400  by forcing the excess tube length to be cold-worked into the internal wall. The shape of stamper  3420  and the distance between the second end of tube  3400  and die end  3412  may be set to obtain the desired thickness for internal wall  3404 . 
       FIG. 35  is an cross-sectional view of the tube of  FIG. 34  after stamper  3420  and die  3410  are removed from tube  3400  in accordance with an embodiment of the present invention. After stamping, tube  3400  includes two thicknesses, thickness  3402  which is the expected final thickness of the tube, and thickness  3422 , which corresponds a maximum possible height of any internal wall that may be machined from the thicker portion. 
     To create internal wall  3404 , portions of inner surface  3401  of tube  3400  may be machined.  FIG. 36  is a perspective view of the tube of  FIG. 35  when the tube is machined to create an internal wall in accordance with an embodiment of the present invention. The portions of inner surface  3401  having thickness  3422  may be machined to thickness  3402  such that internal wall  3404  remains in tube  3400 . 
     Surface  3430  of  FIG. 36  can identify the surfaces that are machined to complete tube  3400 . An advantage of this process over the process described in  FIGS. 32 and 33  is that the amount of machining required for the tube can be greatly reduced, as are costs. 
     Another approach for forming features in a tube may include impact extrusion of one end of the tube.  FIG. 37  is a cross section of an illustrative tube formed using impact extrusion in accordance with an embodiment of the present invention. Tube  3700  having wall thickness  3702  is formed using impact extrusion. Impact extrusion creates an indentation that extends to surface  3710 , which corresponds to the surface of internal wall  3704  ( FIG. 38 ) of tube  3700 . The end of tube  3700  remains closed by material  3722 . 
     To complete tube  3700  and construct internal wall  3704 , material  3722  may be machined.  FIG. 38  is a perspective view of the tube of  FIG. 37  when tube  3700  is machined to create an internal wall in accordance with an embodiment of the present invention. Material  3722  may be machined to leave inner surface  3701  of tube  3700  with thickness  3702 , and with internal wall  3704  extending from inner surface  3701 . Surface  3730  may represent the surface that is machined to create wall  3704 . Similar to the process of  FIGS. 34-36 , this process is advantageous over the process described in  FIGS. 32-33  because the amount of machining required for the tube can be greatly reduced. 
     Another approach for forming features in a tube may include impact extrusion of both ends of a tube.  FIG. 39  is a cross section of an illustrative tube  3900  formed using impact extrusion in accordance with an embodiment of the present invention. Tube  3900  having final wall thickness  3902  is formed using multiple impact extrusions. The impact extrusions create a first indentation  3910  that extends to surface  3912  with surrounding interior surface  3901  and a second indentation  3914  that extends to surface  3916  with surrounding interior surface  3921 . The thickness of tube  3900  left by first indentation  3910  is thickness  3902 , which may be the expected final thickness of the tube. The thickness of tube  3900  left by second indentation  3914  is thickness  3922 . The difference between thickness  3902  and thickness  3922  may correspond to height  3908  of internal wall  3904 . 
     In some embodiments, if internal wall  3904  is configured to be constrained between surfaces  3912  and  3916 , the distance between surfaces  3912  and  3916  may correspond to the thickness  3906  of internal wall  3904 . 
     In embodiments where internal wall  3904  is constrained between surfaces  3912  and  3916 , thickness  3922  may be the same as thickness  3902  (i.e., substantially the expected final thickness of tube  3900 ) because internal wall  3904  having height  3908  (as shown in  FIG. 40 ) may be machined from the material left between surfaces  3912  and  3916 . In such embodiments, height  3908  of internal wall  3904  may be determined by the machining process. 
     To complete tube  3900  and construct internal wall  3904 , material between surface  3912  and  3916  may be machined. Material may also be machined from interior surface  3921 .  FIG. 40  is a perspective view of the tube of  FIG. 39  once the tube is machined to create an internal wall in accordance with an embodiment of the present invention. In some embodiments, material may be machined to leave interior surface  3921  with thickness  3902 , and with internal wall  3904  extending from interior surfaces  3901  and/or  3921 . Surface  3930  of  FIG. 40  identifies the surface that may be machined to complete tube  3900 . Similar to the processes of  FIGS. 34-36 and 37-38 , this process is advantageous over the process described in  FIGS. 32-33  because the amount of machining required for the tube can be greatly reduced. 
     Yet another approach for forming features in a tube may include a progressive deep draw process.  FIG. 41  is a cross section of an illustrative tube formed using a progressive deep draw process in accordance with an embodiment of the present invention. Tube  4100  is constructed to have two consecutive indentations  4110  and  4114  having distinct wall thicknesses. Indentation  4110  has wall thickness  4102 , which may be the expected final thickness of tube  4100 , and indentation  4114  has wall thickness  4122 . Tube  4100  may transition from indentation  4110  to indentation  4114  at plane  4112 , which may correspond to the location of internal wall  4104  ( FIG. 43 ) configured to be constructed in inner surface  4101  ( FIG. 43 ) of tube  4100 . 
       FIG. 42  is a perspective view of a cross section of the tube of  FIG. 41  in accordance with an embodiment of the present invention. As shown in  FIG. 42 , tube  4100  is closed at the end of indentation  4114  by material  4124 . To complete tube  4100  and construct internal wall  4104 , material  4124  may be machined to open tube  4100 , and indentation  4114  may be machined to reduce thickness  4122  to the thickness  4102  (e.g., the final expected thickness) while leaving internal wall  4104 . 
       FIG. 43  is a perspective view of the tube of  FIGS. 41 and 42  after the tube is machined to create an internal wall in accordance with an embodiment of the present invention. Surface  4130  of  FIG. 43  identifies the surfaces that are machined to complete tube  4100 . Similarly to the process of  FIGS. 34-36 , this process is advantageous over the process described in  FIGS. 32-33  because the amount of machining required for the tube can be greatly reduced. 
     The following flow charts illustrate methods for forming a tube with a feature on the internal surface of the tube using embodiments of the invention described above. Internal features may include, for example, a wall, a protrusion, an aperture, a snap, a shelf, or any other suitable feature.  FIG. 44  is a flow chart of an illustrative process for forming an extruded tube with a feature on the internal surface of the tube using a die and stamper in accordance with an embodiment of the present invention. Process  4400  begins at step  4410 . At step  4410 , a tube is extruded and cut to a length that is slightly longer than the desired finished length. At step  4420 , a die is inserted in one end of the tube, such that the end of the die placed in the tube extends to a desired location where the feature is intended to exist in the tube. 
     At step  4430 , a stamper is inserted in the second end of the tube. At step  4440 , a force is applied to the stamper to force excess material into the tube, thus cold working the tube to increase the thickness of the tube in the region adjacent the stamper. At step  4450 , the tube is machined to form the feature. Process  4400  then ends at step  4450 . 
       FIG. 45  is a flow chart of an illustrative process for forming a tube with a feature on the internal surface of the tube using a single impact extrusion in accordance with an embodiment of the present invention. Process  4500  begins at step  4510 . At step  4510 , an indentation is formed in the material of the tube by impact extrusion such that the end of the indentation aligns with a desired location of the feature in the tube. At step  4520 , the closed end of the material is machined to form the tube and the feature. Process  4500  then ends a step  4520 . 
       FIG. 46  is a flow chart of an illustrative process for forming a tube with a feature on the internal surface of the tube using a impact extrusion on both ends of the tube in accordance with an embodiment of the present invention. Process  4600  begins at step  4610 . At step  4610 , a first indentation is formed in the material of the tube using a first impact extrusion. At step  4620 , a second indentation opposing the first indentation is formed in the material using a second impact extrusion. The ends of the first and second indentations may be configured to align with the boundaries of the feature. At step  4630 , the feature is machined in the material remaining between the first and second indentations. Process  4600  then ends at step  4630 . 
     In an alternative embodiment of the present invention, steps  4610  and  4620  can be combined into one step, as indicated by the dotted line around steps  4610  and  4620  in  FIG. 46 . That is, the first and second indentations can be formed using a single impact. Advantageously, this can be more efficient than forming first and second indentations from two impacts. 
       FIG. 47  is a flow chart of an illustrative process for forming a tube with a feature on the internal surface of the tube using a progressive deep draw process in accordance with an embodiment of the present invention. Process  4700  begins at step  4710 . At step  4710 , first and second indentations are formed consecutively using a progressive deep draw process. The interface between the first and second indentations may be configured such that the feature is located at the interface. At step  4720 , the material closing the tube (i.e., not removed by the progressive deep draw process) is removed. At step  4730 , the feature is machined in the inner surface of the tube. 
     Process  4700  then ends at step  4730 . 
     It is understood that any of the processes described above in connection with providing a wall in the inner surfaces of a tube may be used to form any other suitable feature on the inner surface of a tube. In addition, it is understood that these processes may be used for non-extruded and non-tubular components. It is also understood that any of the processes described above can be applied to a component formed from injection molded plastic or any other material. 
     In order to convey information, such as device status, visual indicator systems can be included in a headset. One type of indicator system can emit different colors of light to indicate what a device is doing. For example, a system in a headset can emit a green light if it is in a telephone conversation and a blinking red light if the battery power is low. 
       FIG. 48  shows a simplified cross-sectional view of a visual indicator system  4800  for a headset in accordance with an embodiment of the present invention. Visual indicator system  4800  can, for example, correspond to display system  18  of  FIG. 1 , system  700  of  FIG. 7 , or display  1013  of  FIG. 10 . One or more light sources  4821  and  4822  can be integrated into system  4800 . Light sources  4821  and  4822  can be, for example, LEDs that each emit a different color of light. Each color or combination of colors can be used to signify different information (e.g., the mode of a headset or a function the headset is performing). Light sources  4821  and  4822  can be mounted onto circuit board  4820 . Through circuit board  4820 , the light sources can be electrically coupled with driver circuitry (see e.g., LED driver  1424  of  FIG. 14 ) that is operable to activate each source individually or in combination. A detailed description of circuitry with this functionality can be found in U.S. Patent Application No. 60/878,852 entitled “Systems and Methods for Compact Multi-State Switch Networks,” which is incorporated herein. 
     It is understood that, while the embodiment shown in  FIG. 48  uses two separate light sources (e.g., light sources  4821  and  4822 ), any number of light sources can be provided without deviating from the spirit and scope of the present invention. In some embodiments, a single light source device can be provided that includes two LEDs such that the device can emit light from either of the LEDs or a combination of the two LEDs. For example, a light source device can be provided that includes a green LED and a red LED. Such a light source device may, for example, emit green light when activating only the green LED, red light when activating only the red LED, and amber light when activating both LEDs in combination. 
     Microperforations  4812  can be provided in housing  4810  so that light sources  4821  and  4822  are visible to a user. Outer apertures  4814  of microperforations can have a small diameter so that they are imperceptible to a user when light sources  4821  and  4822  are off. The diameter of inner apertures  4816  can be of a larger size so that they can guide more light through the microperforations. A detailed description of microperforations and their fabrication can be found in U.S. patent application Ser. Nos. 11/456,833 and 11/551,988 which are both entitled “Invisible, Light-Transmissive Display System,” and which are both incorporated herein. For the purposes of illustration, only five microperforations are shown in  FIG. 48 , however a much larger number of microperforations can be used without deviating from the spirit of the present invention. It is further understood that none of the elements of  FIG. 48 , including microperforations  2402 , are drawn to scale. 
     While the incorporated U.S. patent application Ser. Nos. 11/456,833 and 11/551,988, both entitled “Invisible, Light-Transmissive Display System,” describe microperforations for use with display systems, microperforations can also be used as acoustic ports in accordance with the present invention. For example, one or more microperforations can be provided such that acoustic pressure can pass through the microperforations and exit a volume. For example, acoustic ports  1021  and  1022  of  FIGS. 10A and 10B  may be composed of a plurality of microperforations in earbud  1020 . 
     Light diffuser  4830  can be located between circuit board  4820  and an inner wall of housing  4810 . Light diffuser  4830  can, for example, be made of a polycarbonate with sections of varying opacity. Outer core  4832  of diffuser  4830  can be made from a substantially opaque material such that light from light sources  4821  cannot pass through the core. Outer core  4832  can be substantially opaque in that it can transmit 0% to 20% of light. For example, if outer core  4832  is substantially opaque it can deflect light back into inner core  4834  such that the light doesn&#39;t exit the sides of the diffuser. 
     Inner core  4834  can be located within the inner wall of outer core  4832 . The inner core  4834  of diffuser  4830  can be made from, for example, a combination of substantially transparent or translucent substrate  4835  and diffusing particles  4836  such that the particles are suspended in the substrate. In some embodiments, substrate  4385  can be substantially transparent in that it can transmit 80% to 100% of light. In other embodiments, substrate  4385  can be translucent such that it transmits any 0% to 100% of light. Both substrate  4835  and particles  4836  can be, for example, made from polycarbonate materials of different opacities. Particles  4836  can be made from an opaque or translucent material that alters the path of light through inner core  4834 . Particles  4836  can have any form (e.g., a sphere, a cylinder, a cube, a prism, or an uneven form). In some embodiments, each of particles  4836  can have a different form to simplify manufacturing. The combination of substrate  4835  and particles  4836  can thoroughly diffuse light from the light sources when it exits the top of inner core  4834 . That is, the light from light sources  4821  and  4822  can be evenly spread across the top surface of inner core  4834  so that a user detects an even intensity of light exiting microperforations  4812 . 
     It is understood that other diffusion means can be used without deviating from the spirit and scope of the present invention. For example, surface textures, coatings or labels can be applied to a light transmissive material such that any light passing through the material is substantially diffused. 
     Inner core  4834  can have a sufficient width  4890  so that it surrounds the footprint of light sources  4821  and  4822 . In one embodiment, inner core width  4890  can be approximately 1.7 millimeters (e.g., between 1.5 millimeters and 1.9 millimeters), and the width  4892  of outer core  4832  can be approximately 2.8 millimeters (e.g., between 2.6 millimeters and 3.0 millimeters). In some embodiments, the width of the end of the diffuser proximal to circuit board  4820  can be different from the width of the end of the diffuser proximal to housing  4810 . For example, diffuser  4830  can be in shape similar to a cone such that the width of the end of the diffuser proximal to housing  4810  is smaller than the width of the diffuser proximal to circuit board  4820 . In other words, diffuser  4830  can, for example, be in the shape of a cone having a flattened top. 
     The bottom surface of outer core  4832  can extend below the bottom surface of inner core  4834  so that the outer core can be mounted to circuit board  4820  without the inner core damaging light sources  4821  and  4822 . The outer core  4832  can be attached to circuit board  4820  using, for example, an adhesive or any other suitable material. 
     In  FIG. 48 , light source  4822  is activated and emitting light  4860 . Because of the effect of light diffuser  4830 , light  4862  can be evenly distributed as it exits the diffuser, thereby making it difficult for a person to discern whether the light is being generated by light source  4821  or light source  4822 . 
       FIG. 49  shows the exterior of an embodiment of headset  4910  that includes visual indicator  4913  in accordance with an embodiment of the present invention. Headset  4910  may correspond to headset  10  of  FIG. 1 , for example. The embodiment shown in  FIG. 49  uses LEDs  4921  and  4922  as light sources and includes a cylindrical light diffuser. Visual indicator  4913  can include microperforations  4912  which allow a user to see light being emitted from LEDs  4921  and  4922 . A light diffuser can be included between the LEDs and microperforations  4912  so that the diffused light seen by a user is equally distributed over the microperforations. The diameter  4990  of the microperforated area can be substantially similar to or smaller than the diameter of the diffuser&#39;s inner core. Diameter  4990  can be, for example, approximately 1.7 millimeters (e.g., between 1.5 millimeters and 1.9 millimeters). 
     Alternatively, the size and shape of the microperforated area could be different from that of the light diffuser. For example, a microperforated area with a noncircular shape can be placed over a light diffuser so that a noncircular indicator is generated. Similarly, the shape of the light diffuser can be non-cylindrical. Moreover, the light diffuser can be larger than the microperforated area so that it can cover the footprint of any other light sources that might be included. 
     Numerous light sources of different colors can be used in conjunction with a light diffuser as described above in order to present a visual indicator to a user. Because of the effect of the material in the light diffuser, light from each different source may appear evenly distributed over an area. In this manner, the entire indicator can appear to change colors as different light sources are activated. 
       FIG. 50A  includes a side view of headset  5000  in accordance with an embodiment of the present invention. Connector  5040  can include primary housing  5010 , connector plate  5041 , contacts  5043 , casing  5044  and microphone port  5050 . Connector plate  5041  can include recessed groove  5042  which runs around the perimeter of connector plate  5041 . Groove  5042  can also be referred to as a recessed step in connector plate  5041 . At the top of connector plate  5041 , a microphone port  5050  can be located in groove  5042 . 
     There are many benefits associated with placing microphone port  5050  along the edge of connector plate  5041 . By including the microphone port near the connector plate, the microphone can be embedded in the connector which saves space inside the headset housing. The space that is saved can be used to incorporate other functionality or decrease the overall size of the headset. Moreover, locating the microphone port in the groove around the edge of the connector can hide it from view which increases the overall aesthetic appearance of the headset 
       FIG. 40B  shows a detailed view of the microphone port area of a connector in accordance with an embodiment of the present invention. The dimensions of port  5050  can include, for example, a width  5090  of approximately 2.5 millimeters and a height  5092  of approximately 0.3 millimeters. These dimensions are merely illustrative and it is understood that other dimensions may be practiced. 
       FIG. 51  shows a view of connector  5140  with the primary housing removed in accordance with an embodiment of the present invention. Connector  5140  can, for example, correspond to connector  16  of  FIG. 1 , assembly  320  of  FIG. 3 , assembly  420  of  FIG. 4 , connector  1040  of  FIG. 10 , or connector  1140  of  FIG. 11 . Connector  5140  can be mounted up primary housing circuit board  5115 , for example. 
     Connector  5140  can include connector plate  5141 , contacts  5143  and accompanying casing  5144  to prevent the contacts from electrically coupling with the connector plate. Microphone port  5150  can be included in the top of connector plate  5141  to allow sound to reach microphone boot  5120 . Microphone boot  5120  and a microphone contained therein can be located behind connector plate  5141 . The microphone can be contained within microphone boot  5120  to, for example, protect the microphone from damage and control the flow of air into the microphone. 
       FIG. 52  shows an exploded view of connector  5140  of  FIG. 51  which can include, for example, connector plate  5240 , microphone boot  5220 , microphone  5222 , contacts  5243 , casing  5244 , bracket  5248  and screws  5249  in accordance with an embodiment of the present invention. Microphone  5222  can be a MEMs microphone and can be electrically coupled with circuit board  5215 . Circuit board  5215  is similar to primary housing circuit board  1115  of  FIG. 11 . Microphone boot  5220  can mount over microphone  5222 . Microphone boot  5220  can, for example, be made of silicon so that it can seal with surrounding parts when connector  5200  is assembled. Contacts  5243  can be included in casing  5244 . 
     Casing  5244  can be made of a non-conductive material (e.g., polymeric) so that contacts can not be electrically coupled with connector plate  5240 . 
     Casing  5244  can be mounted onto circuit board  5215  and include conductive elements (see e.g., shank  5707  and contact segment  5708  of  FIG. 57B ) which can electrically couple contacts  5243  with circuit board  5215 . Bracket  5248  can couple with connector plate  5240  in order to hold connector  5200  together. Upward pressure from bracket  5248  can compress microphone boot in order to create an acoustic (e.g., substantially air-tight) seal for the passage of air into and out of microphone  5222 . Circuit board  5215 , casing  5244  and bracket  5248  can include one or more apertures for mounting to connector plate  5240 . 
     Screws  5249  can be inserted through these apertures and screwed into threaded cavities (see e.g., cavities  6046 ) on the back of connector plate  5240 . 
       FIG. 53  shows a view of microphone boot  5320  which can include input aperture  5325  in accordance with an embodiment of the present invention. Microphone boot  5320  can, for example, correspond to microphone boot  5220  of  FIG. 52 . Air that flows into a headset by going around microphone boot  5320  can cause a noticeable loss in the quality of the audio signals picked up by a microphone in the boot. Therefore, microphone boot  5320  can include sealing surface  5326  to prevent air from leaking through any seams along the edge of the microphone boot. Sealing surface  5326  can be a horizontal surface of boot  5320  that extends to the perimeter of the boot&#39;s footprint. Sealing seams in this manner can direct the flow of air into aperture  5325  which can result in higher sound quality being received by the microphone. 
     Traditionally, the roof of a microphone boot creates a seal with the surfaces of surrounding parts. This can require a thicker roof which is structurally robust enough to support the pressure required to make an adequate seal. Because boot  5320  uses horizontal sealing surface  5326  (instead of roof  5327 ) to seal with surrounding parts, roof  5327  does not need to be very thick. This reduced thickness saves space in a housing and can result in a generally smaller or thinner headset. 
       FIG. 54  shows a perspective, cross-sectional view of connector plate  5440  which includes microphone boot  5420  and microphone  5422  in accordance with an embodiment of the present invention. Connector plate  5440 , boot  5420  and microphone  5422  can, respectively, correspond to connector plate  5240 , booth  5220  and microphone  5222  of  FIG. 52 , for example. The components shown in  FIG. 54  can fit together so that air can pass through microphone port  5450 , into boot aperture  5425  and reach microphone input  5421 . Microphone port  5450  may, for example, be a cut-out in the recessed step of connector plate  5440 . Because of other elements in the connector assembly (e.g., circuit board  5215  and bracket  5248 ), microphone  5422  and microphone boot  5420  can be pushed up against connector plate  5440  when installed in a headset. The pressure from this force can cause surface  5426  to form a seal with surface  5445  of connector plate  5440 . This seal can prevent air from passing through seam  5490  in between connector plate  5440  and microphone boot  5420 . 
     In some embodiments, porous plug  5428  may be provided in boot aperture  5425 . Plug  5428  may be, for example, made from a porous foam (e.g., sintered polyethylene or super high-density polyethylene). 
     Plug  5428  can help filter out high-frequency noises such as those generated by wind blowing into microphone port  5450 . The acoustical performance of plug  5428  can be a factor of its porosity which can be controlled by manufacturing. For example, plug  5428  can be manufactured by melting particles of polyethylene together. The porosity of the resulting plug can be a function of how long the particles are melted, what temperature is used to melt the particles, and the particles size. In some embodiments, it may be advantageous to only use polyethylene particles of a certain size when forming plug  5428 . For example, particles with a diameter between 177 microns and 250 microns may be melted to form plug  5428 . 
       FIGS. 55A and 55B  show views of the connector of headset  5500  in accordance with an embodiment of the present invention. Four contacts  5561 ,  5562 ,  5563  and  5564  can be integrated into the connector. The contacts can be of a substantially flat shape so that they are flush with the face of connector plate  5540 . The contacts can, for example, be of an oval shape. The outer contacts  5561  and  5564  can be configured for coupling to either a power supply line or a ground line. The remaining inner contacts  5562  and  5563  can be configured for receiving and transmitting data. 
     Connector plate  5540  can be located within primary housing  5510  and can include recessed groove  5542 . Height  5580  of primary housing  5510  can be approximately 5 millimeters or can be from a range between 4.7 and 5.3 millimeters. Height  5581  of the interior cavity of primary housing  5510  can be approximately 4 millimeters or can be from a range between 3.7 and 4.3 millimeters. Height  5582  of the raised face of connector plate  5540  can be approximately 3.3 millimeters or can be from a range between 3.0 and 3.6 millimeters. Heights  5580 ,  5581  and  5582  can be advantageous because they can provide a headset having a small form-factor yet large enough to adequately couple with a complementary connector. Heights  5581  and  5582  can also provide an adequate groove for sound from a user&#39;s voice to reach a microphone embedded in connector plate  5540  (see e.g., microphone  17  of  FIG. 1 ). It is understood that these dimensions are merely illustrative. It is also understood that connector plate  5540  and the aperture in primary housing  5510  are angled with respect to the axis of primary housing  5510 , and heights  5580 ,  5581  and  5582  reference the orthogonal heights of the corresponding elements. 
     Connector plate  5540  can include four contacts  5561 ,  5562 ,  5563  and  5564  which can be separated by pitch  5583 , which can be approximately 2 millimeters or from a range between 1.75 and 2.25 millimeters. Pitch can be defined as the distance from the centerline of a contact to the centerline of the nearest contact. Pitch  5583  can be advantageous because it can allow contacts on complementary connectors (see e.g., connector  6200  of  FIGS. 62A and 62B ) to be sufficiently spaced apart such that magnetic components can be provided between the contacts. 
     Each contact can have a width  5584 , which can be approximately 0.7 millimeters or from a range between 0.5 and 0.9 millimeters. The ring of exposed casing can have a width  5586  of approximately 0.2 millimeters or can be from a range between 0.12 and 0.3 millimeters. All of the rings of exposed casing can have the same width (e.g., width  5586 ). Width  5586  can be advantageous because it is large enough to prevent contacts  5561 ,  5562 ,  5563  and  5564  from shorting with connector plate  5540 , but small enough to not impact the size of connector plate  5540 . The contacts can be arranged on the face of connector plate  5540  so that they are symmetrical about the centerline of headset  5500 . Dimension  5585 , which represents the distance from the centerline of each contact to the centerline of the headset, can be approximately 1 millimeter. The dimensions of contacts  5561 - 5564  can be advantageous because the dimensions can provide a sufficient surface for coupling with a corresponding connector while maintaining a small form-factor headset. For example, if the contacts were much larger, the size of housing  5510  may need to increase. 
       FIG. 55C  includes a side view of headset  5500  in accordance with an embodiment of the present invention. The angle between the face of connector plate  5540  and the axis of primary housing  5510  can be represented by angle  5587 , which can be approximately 55 degrees or from a range between 10 and 80 degrees. Angle  5587  can be advantageous because it can provide a suitable angle for mating headset  5500  with a corresponding connector. Angle  5587  may also provide an appropriate angle for reflecting sound from a user&#39;s mouth to the microphone of headset  5500  (see e.g., microphone  17  of  FIG. 1 ). Angle  5587  can also be provided to block outside sounds from the microphone of headset  5500 . 
     As measured along the surface of connector plate  5540 , the height  5588  of each contact can be approximately 1.5 millimeters. Height  5588  can be advantageous because it provides a substantial surface area for headset  5500  to couple with corresponding headsets but does not necessarily cause an increase in the size of housing  5510 . 
     The connector plate  5540  can be recessed in primary housing  5510  by a depth  5589  of approximately 0.25 to 0.3 millimeters. This depth can be determined by measuring the distance between the face of connector plate  5540  and a plane defined by the end of primary housing  5510  (e.g., a plane including three points on the connector end of primary housing  5510 ). Depth  5589  can be advantageous because it can provide a sufficient depth to strengthen the mechanical link between headset  5500  and a corresponding connector, but not be of such a large depth that it becomes difficult to align the headset with such a connector. 
       FIG. 55D  includes a top view of headset  5500  in accordance with an embodiment of the present invention. Width  5590  of primary housing  5510  can be approximately 12.3 millimeters or can be from a range between 10 and 14 millimeters. Width  5591  of the interior cavity of primary housing  5510  can be approximately 11.1 millimeters or can be from a range between 7 and 13 millimeters. Width  5592  of the raised face of connector plate  5540  can be approximately 10.3 millimeters or can be from a range between 5 and 11 millimeters. Widths  5590 ,  5591 , and  5592  can be advantageous because they can provide a large enough area for headset  5500  to securely couple with a complementary connector, while not being so large so as to prevent headset  5500  from having a small form-factor. The dimensions given above apply to the embodiments shown in  55 A,  55 B,  55 C and  55 D and it is understood that other dimensions can be used without deviating from the scope of the present invention. 
       FIG. 56  illustrates an assembly of electrical contacts for connector  1040  in accordance with an embodiment of the present invention. Assembly  5601  can include plurality of electrical contacts  5602  disposed in non-conductive (e.g., polymeric) casing  5603 . Casing  5603  can include protruding members such that each protruding member can extend through a cavity in a connector plate. In  FIG. 52 , for example, casing  5244  includes four protruding members and connector plate  5240  includes four cavities (or apertures). When casing  5244  is coupled with connector plate  5240 , the casing&#39;s protruding members will fill those cavities. Accordingly, each protruding member can be referred to as a protruding cavity member as well. Electrical contacts  5602  can extend through at least a portion of depth  5690 . In an assembled headset, each electrical contact  5602  can have a portion disposed in electrical contact with electrical contact  5604  of circuit board  5605 , which can be flexible or rigid. 
       FIGS. 57A and 57B  illustrate an assembly of electrical contacts in accordance with one embodiment of the present invention. Assembly  5701  can include plurality of electrical contacts  5702  disposed in non-conductive casing  5703 . Each electrical contact  5702  can have first portion  5705  and second portion  5704 , each of which are manufactured independently and assembled together thereafter. 
     First portion  5705  can have head  5706  and shank  5707 . Head  5706  can have an exposed surface for engagement with an external electrical contact of, for example, a connector on a charging dock or cable. In one embodiment of the present invention, the exposed surface on head  5706  can have a conductive, durable finish that also is aesthetically appealing, for example, nickel, tin cobalt, or a blackened finish. Shank  5707  can be integrally formed with head  5706  or formed independently and then attached to head  5706  using adhesive material (e.g., glue, solder, weld, surface mount adhesion material, etc.). For example, during manufacturing, first portion  5705  can be formed from a cylindrical block of conductive material, turned to create shank  5707 , and stamped or milled to shape head  5706 , for example, into an oval shape. 
     Second portion  5704  can have engagement segment  5709  and contact segment  5708 . Engagement segment  5709  can have a hole configured for accepting shank  5707  of first portion  5705  during assembly of electrical contact  5702  to casing  5703 . Conductive adhesive material can be applied during manufacturing to mechanically and electrically couple first portion  5705  and second portion  5704  of electrical contact  5702 . Contact segment  5708  can have an internal surface for engagement with electrical contact  5604  on circuit board  5605  (see  FIG. 56 ) when in an assembled headset. The engagement surface of contact segment  5708  also can have a finish (e.g., gold-plating) that has good properties for adhering electrical contact  5702  to circuit board  5605 , storage, and corrosion-resistance. 
     In one embodiment of the present invention, the center of the internal contact surface of second portion  5704  can be offset from the center of the external surface of first portion  5705  when considered in a plane substantially defined by the external contact surface of first portion  5705 . This can be useful when design constraints require electrical contacts  5702  to electrically couple electronic components that are not co-linearly aligned, as in one embodiment of the present invention illustrated in  FIG. 56 . In one embodiment of the present invention, second portion  5704  can have a hook-shape to position the internal contact surface of second portion  5704  in an offset configuration with respect to shank  5707 . In manufacturing, second portion  5704  can be stamped from sheet metal, machined from a solid block of conductive material, molded, or formed using a different method known in the art or otherwise. In one embodiment of the present invention, second portion  5704  can be stamped from sheet metal in high volume production situations to save valuable time and money. 
       FIGS. 58A-58C  illustrate an assembly of electrical contacts in accordance with another embodiment of the present invention. Assembly  5801  can include plurality of electrical contacts  5802  disposed in non-conductive casing  5803 . Similar to the embodiment illustrated in  FIGS. 57A-57B , each electrical contact  5802  can have first portion  5805  and second portion  5804 , each of which are manufactured independently and assembled together thereafter. 
     First portion  5805  can have an exposed surface for engagement with an external electrical contact of, for example, a connector on a charging dock or cable. In one embodiment of the present invention, the exposed surface on first portion  5805  can have a conductive, durable finish that also is aesthetically appealing. 
     Second portion  5804  can have engagement segment  5806 , shank  5807 , and contact segment  5808 . Engagement segment  5806  can be electrically and mechanically coupled to first portion  5805  using, for example, surface mount technology, solder, weld, or another conductive adhesive. Shank  5807  can couple engagement segment  5806  to contact segment  5808 . Contact segment  5808  can have an internal surface for engagement with electrical contact  5604  on circuit board  5605  (see  FIG. 56 ) when headset assembly  5801  is installed in a headset (e.g., headset  10  of  FIG. 1 ). The engagement surface of contact segment  5808  also can have a finish that has good properties for soldering, storage, and corrosion-resistance. 
     In one embodiment of the present invention, the center of the internal contact surface of contact segment  5808  can be offset from the center of the external surface of first portion  5805  when considered in a plane substantially defined by the external contact surface of first portion  5805 . In one embodiment of the present invention, second portion  5804  also can have a hook-shape to position the internal contact surface of second portion  5804  in an offset configuration with respect to the external contact surface of first portion  5805 . 
       FIG. 58C  illustrates how assembly  5801  can be manufactured in accordance with one embodiment of the present invention. Initially, second portions  5804  of one or more electrical contacts  5802  can be stamped from single piece of sheet metal  5809  and folded into, e.g., a hook-shape as described above. This can create fingers  5810  in sheet metal  5809  that mechanically and electrically couple all electrical contacts  5802 . 
     First portions  5805 , which also can be stamped in a separate operation, then can be adhered to engagement segments  5806  of each second portion  5804 . This assembly then can be placed in an injection molding machine to injection-mold casing  5803  around the assembly. Once the injection molding procedure is complete, a blade can sever second portions  5804  of electrical contacts  5802  from the rest of sheet metal  5809 , thereby mechanically and electrically decoupling each electrical contact  5802  from the other electrical contacts. Advantageously, because first portions  5805  and second portions  5804  can be formed from a stamping process, assembly  5801  can be used in high volume production situations by saving valuable time and money. 
       FIGS. 59A and 59B  illustrate electrical contacts in accordance with further embodiments of the present invention. Electrical contacts  5901  and  5905  can be similar to that described above with respect to  FIGS. 57A-58C , except that electrical contacts  5901  and  5905  can be formed as one unitary piece. 
     Electrical contact  5901  can have external contact portion  5902 , shank  5903 , and internal contact portion  5904 . External contact portion  5902  can have an external surface for engagement with an external electrical contact of, for example, a connector on a charging dock or cable. Shank  5903  can couple external contact portion  5902  to internal contact portion  5904 . Internal contact portion  5904  can have an internal surface for engagement with electrical contact  5604  on circuit board  5605  (see  FIG. 56 ) when electrical contact  5901  is installed in a headset (e.g., headset  10  of  FIG. 1 ). As in the above-described embodiments, the center of the internal contact surface of internal contact portion  5904  can be offset from the center of external contact portion  5902  when considered in a plane substantially defined by the external contact surface of external contact portion  5902 . Electrical contact  5901  also can have a hook-shape to position the internal contact surface of internal contact portion  5904  in an offset configuration with respect to the center of external contact portion  5902 . In one embodiment of the present invention, electrical contact  5901  can be machined from a single block of conductive material. 
     Similar to electrical contact  5901 , electrical contact  5905  also can have external contact portion  5906 , shank  5907 , and internal contact portion  5908 . Rather than being machined from a conductive material, however, electrical contact  5905  can be stamped from sheet metal and folded to form the hook-shape. Again, because the electrical contact can be manufactured using a stamping procedure, it can be used in high volume production situations. 
       FIGS. 60A and 60B  show two views of connector plate  6040  of a headset connector in accordance with an embodiment of the present invention. Recessed step  6042  can run around the edge of connector plate  6040  in order to create a groove when the plate is installed in a primary housing (see e.g., primary housing  1110  of  FIG. 11 ). Microphone port  6050  can be cut out of step  6042  in order to create an opening for sound to reach cavity  6051  where a microphone or microphone boot (see e.g., microphone boot  5220 ) can be located. In  FIG. 60B , surface  6045  of connector plate  6040  can be used to compress the perimeter of a microphone boot so that an airtight seal is made. 
     Tabs  6047  and threaded cavities  6046  can be used to mount other elements onto connector plate  6040 . For example, tabs  6047  can mate with a bracket that wraps around the entire connector assembly (see e.g., bracket  5248  of  FIG. 52 ). This same bracket can include apertures for use in conjunction with threaded cavities  6046  so that inserts (e.g., screws) can fix the bracket against connector plate  6040 . Bracket  5248  of  FIG. 52  is an example of a bracket that is suitable for use with connector plate  6040 . 
     In accordance with one aspect of the present invention, connector plate  6040  can be made of a material with magnetic properties. By incorporating magnetic properties into connector plate  6040 , magnetic effects can be used to enhance the coupling between connector plate  6040  and a complementary connector (see e.g.,  FIG. 62B ). Connector plate  6040  can include, for example, a ferromagnetic material such as a steel alloy. In another embodiment, connector plate  6040  can include a permanent rare-earth magnet that produces a magnetic field. Moreover, an embodiment of connector plate  6040  can include an electromagnet which produces a magnetic field as a result of the application of electric current. In the electromagnetic embodiment, the magnetic field can be controlled (e.g., through the application of an electric current) so that it is only present when necessary. In the embodiments where connector plate  6040  includes a permanent magnet or an electromagnet, a complementary connector (see e.g.,  FIG. 62B ) can include a ferromagnetic material or a complementarily positioned permanent magnet or electromagnet. 
       FIG. 61A  shows array  6180  of magnetic components which can be embedded in a connector in accordance with an embodiment of the present invention. Array  6180  can include components  6181 ,  6182 ,  6183 ,  6184  and  6185  which can be made of, for example, a permanent rare-earth magnetic material. An example of a suitable material for magnetic components  6181 - 6185  is magnetized Neodymium and, more specifically, N50 magnets. The magnetic components  6181 - 6185  can be shaped so that a substantially flat mating face  6186  is formed along one side. This mating face  6186  can, for example, be at an angle complementary to the angle of a headset&#39;s connector plate (see e.g., angle  5587  of  FIG. 55 ). 
       FIG. 61B  shows a view of how connector plate  6140  can be used in combination with array  6180  of magnetic components in accordance with an embodiment of the present invention. If connector plate  6140  is made of a ferromagnetic material and array  6180  includes permanent magnets, the magnetic fields of array  6180  will generate magnetic forces biasing connector plate  6140  and array  6180  together. If array  6180  is embedded within a connector that mates with connector plate  6140 , these magnetic forces can reinforce the connection. 
     In order to maximize the magnetic field generated by array  6180 , it can be advantageous to arrange components  6181 - 6185  (e.g., magnets) so that the polarity of each component is in a particular orientation. For example, the components can be arranged so that the south pole of the outer two magnets are closest to the mating face, and the north pole of the inner three magnets are closest to the mating face. In this configuration, if one were to list the polarities encountered when passing horizontally over the mating face, the list would read south-north-north-north-south. This maximization of the magnetic field is one reason why it might be desirable to use an array of magnets as opposed to one large magnet. 
     While the embodiments described above include a ferromagnetic connector plate and an array of permanent magnets embedded in a complementary connector (see e.g.,  FIG. 62B ), it is contemplated that any other magnetic configurations can be used without deviating from the spirit of the present invention. For example, an electromagnet element can be included in the connector plate and a ferromagnetic material can be located in a complementary connector. A detailed discussion about the use of electromagnetic and magnetic elements in connectors can be found in U.S. patent application Ser. No. 11/235,873 entitled “Electromagnetic Connector for Electronic Device” and U.S. patent application Ser. No. 11/235,875 entitled “Magnetic Connector for Electronic Device,” which are both incorporated herein. 
       FIGS. 62A and 62B  show connector  6200  that is complementary to and capable of mating with connector  1040  of  FIG. 10A  in accordance with an embodiment of the present invention. Connector  6200  can, for example, correspond to headset engaging connector  220  of  FIG. 2 . Connector  6200  can be integrated into, for example, a charger (see e.g., docking station  6400  of  FIG. 64 , device  6600  of  FIG. 66 , and docking station  6700  of  FIG. 67 ) which charges a battery in a headset or other apparatus that facilitates the charging of the headset (such as an apparatus discussed in U.S. patent application Ser. No. 11/620,669 entitled “Apparatuses and Methods that Facilitate the Transfer of Power and Information Among Electrical Devices” which is incorporated herein). 
     The view of connector  6200  in  FIG. 62A  does not include connector housing  6210  so that magnetic array  6280  and contacts  6290 ,  6292 ,  6294  and  6296  can be seen. Array  6280  can be installed in connector  6200  such that it forms a magnetic array structure, and each magnet of the array can be separated by a gap of predetermined size. Array  6280  of magnetic components can be embedded in connector housing  6210  so that the surface of components  6282 ,  6283  and  6284  can be flush with mating face  6286 . These exposed components can extended all of the way to the surface of a corresponding connector plate so that the strongest magnetic forces are generated. However, a connector can have no exposed magnetic elements without deviating from the spirit of the present invention. For example, it can be desirable to recess magnetic components  6281  and  6285  in order to create a smaller connector. 
     Contacts  6290 ,  6292 ,  6294  and  6296  can be included in connector  6200 . In order to integrate the contacts with the array  6280  of magnetic components, each contact can be placed in the gaps between magnetic components. In this manner, contact  6290  can be located in between magnetic components  6281  and  6282 , contact  6292  can be located between components  6282  and  6283 , etc. This integrated distribution of contacts can allow for a smaller connector. This is another example of a reason why it might be desirable to use multiple magnetic components that are spaced apart as opposed to a single, large magnetic component. 
     Each contact can include a spring mechanism, such as coil  6297  of contact  6296 . Coil  6297  can bias contact tip  6296  to extend out of connector housing  6210 . The coils  6291 ,  6293 ,  6295  and  6297  included in the contacts can be substantially planar or flat. A flat coil can allow for minimal spacing between magnetic components  6281 - 48815 . This reduced spacing can result in a generally smaller connector. However, other types of coils and contacts can be used in accordance with the principles of the present invention. For example, a cylindrical spring biasing a cylindrical contact, commonly called a “pogo pin,” can be used without deviating from the spirit of the present invention. 
     Contacts  6290 ,  6292 ,  6294  and  6296  can be position to electrically couple with, for example, the contacts located on the face of a connector plate of a headset. Connector housing  6210  can include an elevated face  6212  which can, for example, fit into a cavity in a complementary connector. For example, if connector  6200  were to mate with headset  1000  of  FIGS. 10A and 10B , the elevated face  6212  can fit against recessed connector plate  1041  while the edge of primary housing  1010  can fit against the recessed perimeter  6214  of connector  6200 . In this mating configuration, contacts  6290 ,  6292 ,  6294  and  6296  can be electrically coupled with contacts  1042  of headset  1000 . 
     Connector  6200  can include contacts or wires (not shown) on the rear of housing  6210  so that the connector can be electrically coupled with other circuitry. For example, connector  6200  can be mounted onto a circuit board that includes power supply circuitry (such as circuitry discussed in U.S. patent application Ser. No. 11/620,669 entitled “Apparatuses and Methods that Facilitate the Transfer of Power and Information Among Electrical Devices” which is incorporated herein) that can be used to transmit power to a headset through one or more contacts. 
       FIGS. 63A and 63B  show connector  6300  that is complementary to and capable of mating with connector  1040  of  FIG. 10A  in accordance with an embodiment of the present invention. Connector  6300  is substantially similar to connector  6200  in  FIGS. 62A and 62B . For example, magnetic components  6382 ,  6383  and  6384  of  FIG. 63A  are similar, respectively, to magnetic component  6282 ,  6283 , and  6284  of  FIG. 62A . 
     Connector  6300  can include four contact tips  6390 ,  6392 ,  6394  and  6396  that can be biased to extend from housing  6310 . Each contact tip can have a width  6303  of approximately 0.5 millimeters. 
     Width  6303  may be advantageously sized to be large enough to easily connect with connectors on headsets (e.g., connector  16  of  FIG. 1 ) while not being so large that contact tips  6390 ,  6392 ,  6394 , and  6396  are stiff and cannot be depressed by a headset coupling with connector  6300 . 
     The centerline of each contact tip can be separated from the centerline of an adjacent contact tip by pitch  6302 . Pitch  6302  can be chosen so that the contacts of connector  6300  are capable of electrically coupling with the contacts of a headset connector (e.g., connector  1040  of  FIG. 10A ). Accordingly, pitch  6302  can be approximately 1.97 millimeters so that it corresponds to pitch  5583  shown in  FIG. 55A . Moreover, pitch  6302  can be selected from a range between 1.75 and 2.25 millimeters. The size of pitch  6302  may also be advantageous for placing magnetic components (e.g., components  6382 ,  6383 , and  6384 ) in between the contacts of connector  6300 . The centerline of outer contact tips  6390  and  6396  can be separated by width  6301 , which can be approximately 5.1 millimeters or from a range between 4.7 millimeters and 5.4 millimeters. 
     Width  6301  can be selected such that contact tips  6390  and  6394  can couple with the outer contacts of a headset (see e.g., contacts  5561  and  5564  of  FIG. 55 ). In some embodiments, the outer contacts of a headset may be configured to receive power, and a connector, similar to connector  6300  but not including contact tips  6392  and  6394 , can be provided to transmit only power to the headset. Such a connector may be easier to manufacture and cheaper than connector  6200 . 
     Connector  6300  can have a raised face  6312  that is capable of coupling with a headset connector (e.g., connector  1040  of  FIG. 10A ). The housing  6310  of connector  6300  can have a total height  6304 , which can be approximately 5.1 millimeters or from a range between 4.9 millimeters and 5.3 millimeters. The total height  6304  of a connector may be advantageously selected to corresponding with the total height of a headset&#39;s primary housing (see e.g., height  5580  of  FIG. 55 ) such that connector  6300  can receive a headset&#39;s primary housing. The raised face  6312  of housing  6310  can have a height  6305 , which can be approximately 3.43 millimeters or from a range between 3.2 and 3.7 millimeters. Height  6305  can be selected such that it is less than the height of an internal cavity inside of a headset&#39;s primary housing (see e.g., height  5581 ) such that connector  6300  can easily couple with a headset. In summary, heights  6304  and  6305  can be selected in order to complement heights  5580  and  5581  of  FIG. 55B . Thereby allowing headset  5500  to mate with connector  6300 . It is understood that the mating face of connector  6300  is angled with respect to the rest of the connector. This angle can, for example, range from ten to thirty degrees. Heights  6304  and  6305  reference the orthogonal heights of the corresponding elements. This is similar to the radial dimensions that are shown in  FIG. 55B . 
     In order to apply pressure to the contacts of a complementary connector, the contact tips  6390 ,  6392 ,  6394  and  6396  can be biased to extend from connector housing  6310 . When no complementary connector is present, contact tips  6390 ,  6392 ,  6394  and  6396  can extend from the housing by distance  6306  of approximately 0.7 millimeters. Distance  6306  can be selected such that the contact tips can advantageously apply enough pressure to a headphone&#39;s contacts such that the tips can reliably couple with the headphone&#39;s contacts. 
     Connector  6300  can also include contacts or wires (not shown) that allow the connector to route electrical signals from contact tips  6390 ,  6392 ,  6394  and  6396  to other circuitry. The dimensions given above apply to the embodiments shown in  63 A and  63 B and it is understood that other dimensions can be used without deviating from the scope of the present invention. 
       FIG. 64  shows a view of headset  6498  coupled with connector  6499  in accordance with an embodiment of the present invention. Headset  6498  can be substantially similar to headset  1000  of  FIGS. 10A and 10B  and can include the features shown on connector  1040 . Connector  6499  can be installed in, for example, docking station  6400  which can include a socket in which a headset can be inserted. Docking stations substantially similar to or the same as docking station  6400  are discussed in U.S. patent application Ser. No. 11/620,669 entitled “Apparatuses and Methods that Facilitate the Transfer of Power and Information Among Electrical Devices” which is incorporated herein. The socket in docking station  6400  can be shaped to align headset  6498  properly with respect to connector  6499 . 
     Connector  6499  can include raised face  6412  and lower perimeter  6414  to further align headset  6498 . Raised face  6412  can extend into the cavity created by a recessed headset connector while the headset&#39;s primary housing abuts perimeter  6414 . 
     This alignment can result in the contacts of headset  6498  (see e.g., contacts  1042  of  FIG. 10A ) being approximately centered over the tip of contact  6490 . Contact  6490  can be biased to extend beyond raised face  6412  by coil  6491 . This bias can be represented by a force exerted in the direction of arrow  6401 . Additionally, arrow  6402  can represent the magnetic force generated by the proximity of the connector plate of headset  6498  (see e.g., connector plate  1041  of  FIG. 10A ) to the array of magnetic components of connector  6499  (see e.g., array  6180  of  FIG. 61 ). This magnetic force can cause contact  6490  to electrically couple with a contact on headset  6498 . Connector  6499  can include additional contacts (see e.g., contacts  6290 ,  6292 ,  6294  and  6296 ) which can couple with the remaining contacts of headset  6498 . Connector  6499  can be mounted on circuit board  6480  in docking station  6400  such that circuit board  6480  can route signals to and from headset  6498  when it is coupled with connector  6499 . 
       FIG. 65  shows graph  6500  which depicts the approximate change of the two forces described above as the separation between the magnetic components and the connector plate varies in accordance with an embodiment of the present invention. In graph  6500 , x-axis  6502  can represent the approximate force, and y-axis  6504  can represent the distance between the magnetic components and the connector plate. The separation where the x-axis intercepts the y-axis is zero, and this point can represent when the connector plate is in contact with the magnetic components. As the separation increases, approximate force  6508  from spring contacts pushing on a connector plate in a headset can decrease linearly because of the substantially linear nature of coil springs. While the spring force decreases linearly, the approximate magnetic force  6506  can decrease exponentially due to the behavior of magnetic materials. 
     It can be desirable to choose magnetic components (e.g., magnets, connector plates) and design spring components (e.g., contact coils) such that the magnetic force biasing a headset&#39;s connector plate to a complementary connector is greater than the force of the spring contacts pushing back on the connector plate at all possible distances of separation between the two parts. If there are situations where the spring force is greater than the magnetic force, it might be necessary to apply an external force in order to properly couple a headset with a complementary connector. Applying this external force might require intervention from a user, and therefore, it can be desirable to design a connection system so that the magnetic force is always greater that the spring force. 
       FIG. 66  shows charging device  6600  that can be used in conjunction with a headset in accordance with an embodiment of the present invention. In some embodiments, connector  6601  can be integrated into device  6600 , thereby allowing device  6600  to be electrically coupled with a headset. Connector  6601  is similar to the connectors discussed in connection with  FIGS. 61-65 . 
     In some embodiments, auxiliary connector  6610  can be integrated into charging device  6600 . As such, auxiliary connector  6610  can be used to couple an additional device, such as a cellular phone which can be used with a headset, to device  6600 . In order to connect a headset or additional device to an external power supply (e.g., wall outlet or computer), device  6600  can include cable  6620 . Circuitry  6630  can be integrated into device  6600  to facilitate charging of both a headset and an additional device. 
     Circuitry  6630  can also provide a communications interface for data to be shared between a headset and an additional device. An example of a charging device similar to device  6600  is discussed in detail within U.S. patent application Ser. No. 11/620,669 entitled “Apparatuses and Methods that Facilitate the Transfer of Power and Information Among Electrical Devices,” which is incorporated herein. 
       FIGS. 67A and 67B  show connector  6710  in accordance with an embodiment of the present invention. The face of connector  6710  can be shaped to include peak  6711 . By incorporating peak  6711  into the connector face, connector  6710  is capable of mating with a headset in two different interface orientations (e.g., physical orientations). When connector  6710  is installed in docking station  6700  (see  FIG. 67B ), peak  6711  creates cavities  6702  and  6704  which can each accept the long side  6721  of headset  6720 . In the interface orientation shown in  FIG. 67B , side  6721  of headset  6720  is in cavity  6704 . However, if headset  6720  were inserted in another orientation, long side  6721  of the headset may be in cavity  6702 . In either of these orientations, the contacts of connector  6710  can be electrically coupled with the contacts on headset  6720 . 
     In some embodiments, switching circuitry can be included in headset  6720  to compensate for these different interface orientations. Such switching circuitry can determine the interface orientation of headset  6720  and connector  6710  and route signals received from the connector to pathways inside the headset (e.g., electrical traces) based on the determined orientation. In other embodiments, switching circuitry can be provided in docking station  6700  that can determine the interface orientation of connector  6710  and headset  6720  and route signals to the connector based on the determined orientation. A detailed discussion of similar switching circuitry can be found in U.S. patent application Ser. No. 11/650,130 entitled “Systems and Methods for Determining the Configuration of Electronic Connections,” which is incorporated herein. 
     Similar to the elevated face  6212  and recessed perimeter  6214  shown in  FIG. 62B , raised face  6712  and recessed perimeter  6714  can be advantageous when coupling a headset (see e.g., headset  1000  of  FIGS. 10A and 10B ) to connector  6710 . For example, raised face  6712  and recessed perimeter  6714  can provide structural features that strengthen the mechanical coupling of connector  6710  and a headset. 
       FIG. 68  shows chart  6800  listing exemplary modes and functions of a communications system in accordance with an embodiment of the present invention. With regards to chart  6800 , a communications system can include a headset (e.g., headset  10  of  FIG. 1 ) and a host device (e.g., a cellular telephone, a laptop computer, etc.). Further defining the communications system referenced in chart  6800 , the headset can be in communication with the host device and the host device can be communicating with other devices through a cellular network or other communications network (e.g., Voice over Internet Protocol). 
     Chart  6800  includes rows describing exemplary modes and functions of the system and columns identifying inputs and outputs that correspond to each mode or function. Some of the functions listed in column  6810  typically occur when a system is in a certain mode, and therefore, these functions can be listed under their respective modes. For example, the answer call function  6812  and the reject call function  6813  are typically executed when a system is in incoming call mode  6811  and chart  6800  can reflect this by listing functions  6812  and  6813  directly under incoming call mode  6811 . 
     For each row corresponding to a function, column  6820  can be used to identify an input that can cause that function to occur. For example, column  6820  may identify a manner in which a user can press a single button on a headset (see e.g., button  14  of  FIG. 1 ) to initiate a corresponding function. It is understood that the initiated function may further depend on the mode in which a headset is in. For example, a long button press may initiate the reject call function  6813  if a system is in incoming call mode  6811 , while the same type of button press may initiate function  6814  if the system is in another mode. Examples of using a single button to control an electronic device can be found in U.S. Provisional Patent Application No. 60/936,965 entitled “Single User Input Mechanism for Controlling Electronic Device Operations,” which is incorporated herein. 
     Outputs can be associated with each mode or function so that, for example, a user can be aware of a system&#39;s operation. Such outputs may be provided through a headset display system (see e.g., display system  18  of  FIG. 1 ), a headset audio system (e.g., speaker system  13  of  FIG. 1 ), and/or host device user interface (UI). A display screen and a speaker on a host device can, for example, be part of a host device UI used to provide outputs. Column  6830  lists outputs that can be provided by a headset display system to correspond with modes or functions listed in column  6810 . For example, if a headset&#39;s display system includes an indicator that can output different colors using LEDs, column  6830  can include different colors and/or flashing patterns that the indicator can output based on the communication systems mode or function. Column  6840  lists outputs that can be provided by a headset audio system (e.g., a speaker) based on the communication system&#39;s mode or function. Column  6840  can, for example, include beeps, tones, or other noises that can be used to notify the operation of the communications system. Column  6850  lists outputs that can be provided by a Host Device UI. For example, column  6850 , may include outputs that can be presented through a display screen on a host device. 
     In summary, chart  6800  identifies the inputs and outputs corresponding to various exemplary modes and functions of a communications system in accordance with an embodiment of the present invention. For example, when a communications system is in incoming call mode  6811 , the system&#39;s headset (e.g., headset  10  of  FIG. 1 ) can display a slow blinking green light and output two beeps while the system&#39;s host device can display an incoming call screen (e.g., a graphic displaying information about the incoming call). Continuing the example, if a user presses a button on the headset (e.g., button  14  of  FIG. 1 ) for a short amount of time, the system can answer the call while the headset displays a green light and outputs a short low tone followed by a short high tone. While the system is answering the call, the host device can display a call answer screen. It is understood that the modes and functions shown in  FIG. 68  and discussed above are merely exemplary and that communication systems can operate using other modes and functions without deviating from the spirit and scope of the present invention. 
     Although particular embodiments of the present invention have been described above in detail, it will be understood that this description is merely for purposes of illustration. Alternative embodiments of those described herein are also within the scope of the present invention. For example, while one embodiment can include a Bluetooth headset, one or more features of the present invention also can be incorporated into headsets employing other wired and/or wireless communication protocols. Also, while some embodiments of the present invention can include headsets configured for communication with a cellular phone and/or personal media device (e.g., a portable media player similar to that sold under the trademark iPod® by Apple Inc. of Cupertino, Calif.), one or more features of the present invention can also be incorporated into headsets configured for communication with any electronic device. Furthermore, while one embodiment illustratively described above can include a headset and methods for fabricating the same, one or more features of the present invention can also be incorporated into other electronic devices that require, e.g., circuit boards distributed within small acoustic volumes, symmetric connectors, extruded housings having one or more internal features, microperforations, co-located microphones and connectors, magnetic connectors, or any combination thereof. 
     Various configurations described herein may be combined without departing from the present invention. The above described embodiments of the present invention are presented for purposes of illustration and not of limitation. The present invention also can take many forms other than those explicitly described herein. Accordingly, it is emphasized that the invention is not limited to the explicitly disclosed methods, systems and apparatuses, but is intended to include variations to and modifications thereof which are within the spirit of the following claims.