Patent Publication Number: US-2015072666-A1

Title: Teleconferencing with multiple headsets coupled to a single mobile telephone

Description:
BACKGROUND 
     A Bluetooth®-equipped mobile telephone may be paired with another Bluetooth® device such as a hands-free car kit, or a headset for more convenient calling. These devices are examples of a user interface for the telephone which communicate audio signals between the user and the telephone. Device profiles defining the requirements for these classes of device are contained in the Bluetooth® specification, version 1.1. For each class of supported device, the profiles define options and parameter ranges corresponding to each protocol in the Bluetooth® protocol stack. 
     A hands-free car kit may be used to make and receive calls without physically interacting with the mobile telephone itself. The kit consists of an earpiece and a microphone, and typically uses the audio system of a car for incoming audio signal. It also includes capabilities for dialing and telephone book management using voice commands. A headset, on the other hand, typically consists only of an earpiece and microphone and associated hardware and/or software, and the mobile telephone itself must be used for dialing. 
     Although the Bluetooth® specification allows for a master device to maintain simultaneous connections with more than one slave device, a mobile telephone typically supports only a single hands-free device or headset at one time. This limits the number of calls that can be made simultaneously to one call per mobile telephone. Further, only one user can speak on the line per mobile telephone. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like reference numerals indicate corresponding, analogous or similar elements, and in which: 
         FIG. 1  is a schematic diagram showing multiple external audio devices coupled to a single mobile telephone that can support multiple concurrent telephone calls with call multiplexing; 
         FIGS. 2A and 2B  are a flowchart showing an exemplary method for pairing multiple headsets to a single mobile telephone with call multiplexing; 
         FIG. 3  is an example of a dialog screen that may be displayed to the user of the mobile telephone when more than one headset is coupled to the mobile telephone and a call is being placed or received; 
         FIG. 4  is an example of a menu that may be associated with the phone application in the mobile telephone; 
         FIG. 5  is an example of a configuration screen that may be displayed to the user; 
         FIG. 6  is another example of a menu that may be associated with the phone application in the mobile telephone; 
         FIGS. 7A and 7B  are schematic diagrams showing multiple external audio devices coupled to a single mobile telephone that can support conferencing among the users of the external audio devices and another party to the telephone call; 
         FIG. 8  is a flowchart showing an exemplary method for pairing multiple headsets to a single mobile telephone in a conferenced format; 
         FIG. 9A  is a block diagram of exemplary software, firmware and hardware blocks in a mobile telephone that may implement the methods described herein; 
         FIG. 9B  is a block diagram of exemplary software, firmware and hardware blocks in a Bluetooth® headset that may implement the methods described herein; 
         FIG. 10  is a diagram showing audio inputs to an exemplary audio subsystem such as is shown in  FIG. 9A ; 
         FIG. 11  is a block diagram of an exemplary mobile telephone that is able to support the methods described herein; and 
         FIG. 12  is a schematic diagram showing multiple external audio devices coupled to a single mobile telephone that can support conferencing among the users of the external audio devices and another party to the telephone call, and that can also support multiple concurrent telephone calls. 
     
    
    
     It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. 
     DETAILED DESCRIPTION 
     In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of embodiments. However it will be understood by those of ordinary skill in the art that the embodiments may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the embodiments. 
     The ability to pair more than one Bluetooth® slave device to a single master device is possible according to the Bluetooth® specification. If the master device is a mobile telephone, and the slave devices are hands-free devices and/or headsets, then if the mobile telephone is enabled with appropriate hardware, firmware and/or software capabilities, multiple independent calls may be supported concurrently on the slave devices, using the single mobile telephone to make the calls. Alternatively, multiple parties could speak on the same call in a conferenced format without the requirement of sharing a single specialized conferencing telephone. Until recently, supporting multiple headsets on a single mobile telephone has not been technically feasible due to protocol and hardware limitations. However, these limitations are being overcome as higher throughput radio protocols and faster processor speeds become available. 
     An exemplary situation where a single mobile telephone may be used to support multiple concurrent telephone calls is as follows:
         (1) Jack&#39;s battery has just died on his mobile telephone;   (2) Bob&#39;s mobile telephone supports multiple headsets and multiple concurrent calls;   (3) Bob needs to call Ned, and Jack needs to call Sandy;   (4) Bob lets Jack pair his wireless headset with Bob&#39;s mobile telephone while Bob&#39;s wireless headset is also paired to it;   (5) Bob uses the mobile telephone to start a telephone call with Ned;   (6) Jack then uses the mobile telephone to start a telephone call with Sandy.       

     The two telephone calls are concurrently supported by a single mobile telephone, but are maintained separately from each other using a call multiplexing strategy. 
     An exemplary situation where a single mobile telephone may be used to support multiple participants in a single conference call is as follows:
         (1) Mike and Jim want to talk to Krishna;   (2) They may use a specialized conference telephone to support a conference call, or they may choose to use Mike&#39;s mobile telephone which supports multiple-headset conferencing;   (3) Mike&#39;s wireless headset is already paired with his telephone. Mike lets Jim additionally pair his wireless headset with Mike&#39;s telephone;   (4) Mike dials Krishna and starts a conversation with him;   (5) Mike starts a conference call, enabling Jim&#39;s headset as an active participant in the conversation.       

     Although the method for supporting multiple headsets in multiple separate conversations and the method for supporting multiple headsets in a single conference call have been presented separately, it is to be understood that both methods may be supported concurrently on the same mobile telephone. An example situation where this might be useful is as follows:
         (1) Mary, John, and Ralph are traveling together by car to visit a customer;   (2) Mary, John and Ralph have all paired their headsets to Ralph&#39;s mobile telephone;   (3) Mary, John and Ralph all join a conference call with the customer&#39;s sales representative, Alex, in preparation for the meeting;   (4) Alex mentions that the customer&#39;s most recent order has been shipped but has not yet arrived at the customer&#39;s site;   (5) John drops off the conference call;   (6) John starts a new call on Ralph&#39;s mobile telephone to the shipping department to determine the status of the order while Mary and Ralph continue the conference call with Alex;   (7) John ends the call to the shipping department, and rejoins the conference call to update the others on the order&#39;s status.       

     In general, various methods for using external audio devices with a single mobile telephone are proposed, where the external audio devices have audio input functionality and audio output functionality. 
     To support conferencing, audio data of a single telephone call involving the mobile telephone is communicated with two or more external audio devices. In this manner, two or more users are able to provide audio input for the telephone call and receive audio output of the telephone call via external audio devices that are coupled to the mobile telephone. If two users have external audio devices coupled to the mobile telephone for use in the same telephone call, the result is a 3-way call involving only two telephones. The telephone call involves an external communications server (for example, a mobile switching station or an Internet Protocol (IP) public branch exchange (PBX) using the session initiation protocol (SIP)). Incoming audio data from two or more of the external communications server and the external audio devices is mixed, and the mixed audio data is provided as audio output to the external communications server and to the external audio devices. The mobile telephone may reduce a noise component of the communicated audio data. 
     To support separate telephone calls that are concurrent for at least a period of time, audio data of a first telephone call involving the mobile telephone is communicated with one or more first external audio devices, and audio data of a second telephone call involving the mobile telephone is communicated with one or more second external audio devices. If there are two or more first external audio devices, then the first telephone call is a conference call. The mobile telephone may reduce a noise component of the communicated audio data. 
     Any of the external audio devices may be a wireless device. For example, the mobile telephone and the wireless device may be compatible with the same wireless personal area network (WPAN) standard, such as Bluetooth®, ZigBee™, ultra wide-band (UWB), and the like. If two or more of the external audio devices are wireless devices, the mobile telephone will establish and maintain a separate wireless communication session with each of the wireless devices. Establishing a wireless communication session between the wireless device and the mobile telephone may require that the wireless device and the mobile telephone be paired. 
     An external audio device such as an earbud, headset, hands-free set, microphone or speaker, may be coupled via a wired connection to the mobile telephone. 
       FIG. 1  is a schematic diagram showing multiple external audio devices coupled to a single mobile telephone  102  that can support multiple concurrent telephone calls with call multiplexing. Mobile telephone  102  communicates with wireless headsets  104  and  106  through wireless communication links  114  and  116 , respectively. Wireless communication links  114  and  116  are created according to a wireless personal area network (PAN) standard, for example, Bluetooth®, ZigBee™, ultra wide-band (UWB), and the like. Mobile telephone  102  communicates with a wired headset  108  through a wired communication link  118 . 
     Mobile telephone  102  has the capacity to support multiple concurrent telephone calls  124 ,  126 , and  128 , each of which may correspond to a different headset. In the example shown in  FIG. 1 , a first telephone call  124  corresponds to headset  104  and to a wireless communication link  134 . A second telephone call  126  corresponds to headset  106  and to a wireless communication link  136 . A third telephone call  128  corresponds to headset  108  and to a wireless communication link  138 . Telephone calls  124 ,  126  and  128  are concurrent for at least a period of time. Wireless communication links  134 ,  136  and  138  may connect mobile telephone  102  to an external communications server. For example, if mobile telephone  102  is using cellular technology to handle the telephone calls, then the external communications server may be a mobile switching station for GSM and CDMA calls. In another example, if mobile telephone  102  is using Voice over IP (VoIP) technology and wireless local area network (WLAN) technology to handle the telephone calls, the external communications server may be an IP PBX using SIP. Any other suitable intermediary communications device may be used instead. 
     In this example, and throughout the application, a hands-free set, or any external audio device having audio input functionality and audio output functionality, could take the place of any of the headsets. Moreover, although this example describes three concurrent telephone calls, two or more than three concurrent telephone calls may be handled in other examples. 
       FIGS. 2A and 2B  show an exemplary method for supporting multiple concurrent telephone calls on a single mobile telephone such as is shown in  FIG. 1 . Many variations in the order of activities of this method are feasible, as long as a headset is paired or otherwise coupled to the mobile telephone prior to its use. 
     At  202 , headset  104  is paired to mobile telephone  102  in preparation for a telephone call by a first user. At  204 , headset  106  is paired to mobile telephone  102  in preparation for a telephone call by a second user. At  206 , headset  108  is plugged into mobile telephone in preparation for a telephone call by a third user. 
     At  208 , the first user dials a first party using mobile telephone  102 . This may be accomplished, for example, by using user interface elements of mobile telephone  102  such as a keyboard, trackball, thumbwheel and the like. At  210 , headset  104  and mobile telephone  102  establish a wireless communication session. Alternatively, this session may be established before the first user dials the first party, thus enabling the dialing to be done via a voice command provided by the first user to audio input functionality of headset  104 . At  212 , mobile telephone  102  establishes a telephone call # 1  with the telephone of the first party. This telephone call is established via an external communications server. Once the telephone call has been established, audio data of the telephone call is communicated by mobile telephone  102  with headset  104  at  214  via wireless link  114 . Mobile telephone  102  receives audio data originating at headset  104  and transmits to headset  104  audio data of the telephone call arriving at mobile telephone  102  via the external communications server. 
     At  216 , the second user dials a second party using mobile telephone  102 . This may be accomplished, for example, by using user interface elements of mobile telephone  102  such as a keyboard, trackball, thumbwheel and the like. At  218 , headset  106  and mobile telephone  102  establish a wireless communication session. Alternatively, this session may be established before the second user dials the second party, thus enabling the dialing to be done via a voice command provided by the second user to audio input functionality of headset  106 . At  220 , mobile telephone  102  establishes a telephone call # 2  with the telephone of the second party. This telephone call is established via an external communications server. Once the telephone call has been established, audio data of the telephone call is communicated by mobile telephone  102  with headset  106  at  222  via wireless link  116 . Mobile telephone  102  receives audio data originating at headset  106  and transmits to headset  106  audio data of the telephone call arriving at mobile telephone  102  via the external communications server. 
     At  224 , the third user dials a third party using mobile telephone  102 . This may be accomplished, for example, by using user interface elements of mobile telephone  102  such as a keyboard, trackball, thumbwheel and the like. Alternatively, this may be accomplished via a voice command provided by the third user to audio input functionality of headset  108 . At  226 , mobile telephone  102  establishes a telephone call # 3  with the telephone of the third party. This telephone call is established via an external communications server. Once the telephone call has been established, audio data of the telephone call is communicated by mobile telephone  102  with headset  108  at  228  via wired link  118 . Mobile telephone  102  receives audio data originating at headset  108  and transmits to headset  108  audio data of the telephone call arriving at mobile telephone  102  via the external communications server. 
     The three concurrent telephone calls are carried on independently on mobile telephone  102  using a call multiplexing algorithm. 
     The telephones of the first, second and third parties may be any suitable communication device including, for example, a landline telephone, a cordless telephone, a cellular telephone, a smart phone, an Internet Protocol (IP) phone, a computer equipped with a VoIP application, and the like. 
     There are limitless possibilities for the user interface (UI) presented to a user of the mobile telephone, depending on the order of the activities in the method. 
       FIG. 3  is an example of a dialog screen  300  that may be displayed to the user when more than one headset is coupled to the mobile telephone and a call is being placed or received. When a telephone call is outgoing or incoming, dialog screen  300  asks the user to select which of the connected devices to route the call to. For example, dialog screen may be displayed to the user in connection with the first user dialing the first party at  208 , in connection with the second user dialing the second party at  216 , and in connection with the third user dialing the third party at  224 . 
     Alternatively, selection of the headset to which a call is to be routed may involve a menu.  FIG. 4  is an example of a menu  400  that may be associated with the phone application in the mobile telephone. A menu item  402  indicates which headset the mobile telephone is routing the call to, and menu items  404 ,  406  and  408  enable the user to cause the mobile telephone to route the call to a different headset. In this example, three different wireless headsets are paired to the mobile telephone and a wired headset is connected to the mobile telephone. 
     The UI may include a configuration screen indicating which headsets will be activated for all future calls.  FIG. 5  is an example of a configuration screen  500  that may be displayed to the user. Configuration screen  500  enables the user to specify which headset is the primary headset and includes checkboxes  504 ,  506  and  508  to enable the user to specify which other headsets will be activated for future calls. Routing decisions are then limited to one of the active headsets. In this example, the wireless headset with the device name “Jim” is not active. 
       FIG. 6  is an example of a menu  600  that may be associated with the phone application in the mobile telephone. Menu  600  differs from menu  400  of  FIG. 4  in that menu item  406  is omitted. Since the wireless headset with the device name “Jim” has been configured as not active, the user is unable to switch the routing of an incoming or outgoing call to that headset. 
     The issue of receiving calls when different headsets are paired or otherwise coupled to the mobile telephone, and deciding which headset to route the call to is a UI problem, which can be addressed either on the mobile telephone&#39;s UI or by using a possibly dedicated button on the headset and/or using speech recognition. One possible UI solution is that when a call comes into a mobile telephone with N headsets coupled to it, all N headsets alert their respective users, and the first headset which answers the call receives the call. 
       FIGS. 7A and 7B  are schematic diagrams showing multiple external audio devices coupled to a single mobile telephone  702  that can support conferencing among the users of the external audio devices and another party to the telephone call. In  FIG. 7A , mobile telephone  702  communicates with wireless headsets  104  and  106  through wireless communication links  714  and  716  respectively. Wireless communication links  714  and  716  are created according to a WPAN standard, for example, Bluetooth®, ZigBee™ UWB, and the like. In  FIG. 7B , wireless headset  106  is absent and in its stead, mobile telephone  702  communicates with a wired headset  108  through a wired communication link  718 . 
     Mobile telephone  702  allows headsets  104  and  106  (or  104  and  108 ) to participate simultaneously in a single telephone call  724  using a conferenced format. Additional headsets (not shown) may be supported in this conversation up to some pre-determined maximum number of supportable devices. 
     In the example shown in  FIGS. 7A and 7B , telephone call  724  corresponds to a wireless communication link  734 , which connects mobile telephone  702  to an external communications server. For example, if mobile telephone  702  is using cellular technology to handle the telephone calls, then the external communications server may be a mobile switching station for GSM and CDMA calls. In another example, if mobile telephone  702  is using VoIP technology and WLAN technology to handle the telephone calls, the external communications server may be an IP PBX using SIP. Any other suitable intermediary communications device may be used instead. 
       FIG. 8  shows an exemplary method for supporting a conference call with multiple headsets on a single mobile telephone such as is shown in  FIGS. 7A and 7B . Many variations in the order of activities of this method are feasible, as long as a headset is paired or otherwise coupled to the mobile telephone prior to its use. At  802 , headset  104  is paired to mobile telephone  702  in preparation for participation in a telephone call by a first user. At  804 , headset  106  is paired to mobile telephone  702  in preparation for participation in the same telephone call by a second user. 
     At  806 , the first user (or alternatively, the second user) dials another party using mobile telephone  702 . This may be accomplished, for example, by using user interface elements of mobile telephone  702  such as a keyboard, trackball, thumbwheel and the like. At  808 , headset  104  and mobile telephone  702  establish a wireless communication session, and at  810 , headset  106  and mobile telephone  702  establish a wireless communication session. The establishment of a wireless communication session between mobile telephone  702  and headset  104 / 106  may occur before the other party is dialed, thus enabling the dialing to be done via a voice command provided by the first (second) user to audio input functionality of headset  104  ( 106 ). 
     In the case of  FIG. 7B , where only one of the headsets is a wireless device, pairing the second headset and establishing a wireless communication session between the mobile telephone and the second headset are omitted, and instead, there is a step of coupling headset  108  to mobile telephone  702 . 
     At  812 , mobile telephone  702  establishes a telephone call with the telephone of the other party. This telephone call is established via an external communications server. Once the telephone call has been established, the second user (or alternatively, the first user) may join the telephone call at  814 . 
     At  816 , mobile telephone  702  communicates audio data of the telephone call with headset  104  and with headset  106  ( 108 ). 
     There are limitless possibilities for the UI presented to a user of the mobile telephone, depending on the order of the activities in the method. For example, a possible UI solution for getting a paired or otherwise coupled headset to join into an ongoing call is to have the headset recognizing a voice command, a particular button press or a unique sequence of button presses that would be interpreted as the “join call” command on the headset device. For instance, the user could say “join”. The voice command would be interpreted by the headset or by the mobile telephone, whichever is configured to do the speech recognition. 
     This UI solution is to be distinguished from a possible UI solution for getting a paired or otherwise coupled headset to start a new call while another call (conferenced or otherwise) is currently in progress. For instance, the user could say “new call”, and recite the telephone number to dial into the headset. The voice command and telephone number would be interpreted by the headset or the mobile telephone, whichever is configured to do the speech recognition. Alternatively, a particular button press or a unique sequence of button presses could be interpreted as the “new call” command on the headset device. 
     It is obvious to a person of ordinary skill how to extend the examples described with respect to  FIGS. 7A ,  7 B and  8  to more than two external audio devices all participating in a single telephone call. 
       FIG. 9A  is a block diagram of exemplary software, firmware and hardware blocks in a mobile telephone that may implement the methods described herein. Telephone user interface (UI) software  902  interfaces with a telephone application module  903 , which in turn, interfaces with a telephone Application Programming Interface (API) module  904 . Telephone API module  904  provides a front end to a software block  906  which is responsible for telephone logic. Block  906  coordinates signaling to a Bluetooth® API module  908  and an audio API module  914 . Bluetooth® API module  908  interfaces with a Bluetooth® services module  910 , which in turn, interfaces with a Bluetooth® radio  912 . Audio API module  914  interfaces with an audio subsystem  916 , which in turn, interfaces with audio headset hardware  918 . For example, audio headset hardware  918  may have a direct connection to a microphone/headset earbud (not shown) via wire. Audio subsystem  916  also interfaces with a cellular audio software block  920 . Cellular audio software block  920  interfaces with a cellular radio  922 . Cellular radio  922  and cellular audio software block  920  interface with a cellular services block  924 . Cellular services block  924  interfaces with phone network APIs  926  to communicate with telephone logic block  906 . 
       FIG. 9B  is a block diagram of exemplary software, firmware and hardware blocks in a Bluetooth® headset that may implement the methods described herein. Many of the blocks of  FIG. 9A  are repeated in this diagram, and will not be discussed again. Headset UI software  952  interfaces with a headset application  953 . The UI elements of the headset may comprise one or more buttons and possibly a microphone if speech recognition of voice commands is involved. 
     Headset application  953  interfaces with Bluetooth® API module  908  and audio API module  914 . An optional speech recognition module  954  may interface with audio API module  914  and headset application  954 . 
     The mobile telephone&#39;s configuration application typically does the pairing operation between the mobile telephone and wireless devices. However, in this case, it is possible that telephone application module  903  does the pairing operation out of convenience, or proxies the operation through the configuration application. Ultimately, whichever application does the pairing, Bluetooth® API module  908  is invoked to pair the mobile telephone to the wireless headset. From there, the Bluetooth® services module  910  runs the Bluetooth® radio  912 , which invokes communication with the Bluetooth® headset. 
     During telephone calls, telephone application module  903  may instruct phone logic block  906  to start full duplex audio communication between the headset and the mobile telephone. Telephone API module  904  may trigger phone logic block  906  to start the Bluetooth® services for an asynchronous audio connection with the Bluetooth® headset. If handshaking with the Bluetooth® headset is successful, the audio packets will flow between the devices, thereby creating the audio link required for the telephone call. 
     The telephone call gets established by the telephone application through the telephone network APIs  926 . There may be separate telephone network APIs for different types of cellular user (e.g. one for GSM, one for CDMA, one for IDEN, etc.) and separate telephone network APIs for VoIP (of which there can be multiple flavours, e.g. SIP, skinny, H323). The user may pre-select from a list of available options which telephone network to use. The software or configuration may limit the possibilities to a manageable number. The current state of the art is about two possibilities, namely SIP, VoIP and 3G. The telephone application chooses the appropriate software API to invoke to properly route the call. In short, the telephone UI and the telephone application resolve which network to use. 
     In order to communicate audio data to the Bluetooth® headset, the incoming data to the mobile telephone is digital in nature. When using the wired headset in conjunction with the Bluetooth® headset, the data from the wired headset&#39;s microphone must be digitized through the use of a digital-to-analogue converter. After passing through a digital mixer, as in  FIG. 10  below, the audio data packets of digital audio information are fed to the Bluetooth® audio buffer(s) for each of the participating wireless headsets through the Bluetooth® API  508 . These packets are sent to the Bluetooth® headset. 
     The mixed digital audio output is also routed to the wired headset (if it is participating on the call) and also back out to the telephone line output (i.e. line out to the cellular network and/or SIP PBX). 
       FIG. 10  is a diagram showing audio inputs  1002 ,  1004 ,  1006 ,  1008 ,  1009  and  1010  to audio subsystem  916  during a single telephone call. Input  1002  corresponds to audio data from a cellular telephone connection. Alternatively, if a VoIP connection is being used for the telephone call, input  1010  corresponding to incoming VoIP data from the Internet to the mobile telephone may replace input  1002 . Inputs  1004 ,  1006 , and  1008  correspond to voice data received from the microphones of connected wireless headsets. Input  1004  corresponds to a first wireless headset, input  1006  corresponds to a second wireless headset, and input  1008  corresponds to an Nth wireless headset, where N is the total number of connected wireless headsets. Audio subsystem  916  receives all these inputs and mixes them into an output signal  1020  for distribution to all the speakers and headsets corresponding to the connected wireless devices and also for output on the cellular or VoIP connection. Audio subsystem  916  may add noise-gates and/or echo cancellers to the inputs and outputs to reduce noise and improve the signal. Alternatively or additionally, other digital signal processing algorithms for noise reduction may be applied. 
       FIG. 11  is a block diagram of an exemplary mobile telephone that is able to support the methods described herein. Mobile telephone  1100  comprises a processor  1102  coupled to audio subsystem  516 , and a memory  1104  coupled to processor  1102 . 
     Mobile telephone  1100  comprises a communication interface  1110  coupled to processor  1102  and to an antenna  1112 . Communication interface  1110  comprises a baseband controller  1114  coupled to a radio  1116 , which in turn is coupled to antenna  1112 . Communication interface  1110  is compatible with a WPAN standard, such as Bluetooth®, ZigBee™, UWB, and the like. 
     Mobile telephone  1100  also comprises a WLAN communication interface  1120  coupled to processor  1102  and to an antenna  1122 . WLAN communication interface  1120  comprises a baseband controller  1124  coupled to a radio  1126 , which in turn is coupled to antenna  1122 . Communication interface  1120  is compatible with a WLAN standard, such as IEEE 802.11, ETSI HiperLAN, and the like. 
     Mobile telephone  1100  also comprises a wireless wide area network (WWAN) communication interface  1130  coupled to processor  1102  and to an antenna  1132 . WWAN communication interface  1130  is compatible with a cellular communications standard, such as GSM, CDMA, and the like. 
     Mobile telephone  1100  may include other components that, for clarity, are not shown. Other mobile telephones may comprise only one of WLAN communication interface  1120  and WWAN communication interface  1130 . 
       FIG. 12  is a schematic diagram showing multiple external audio devices coupled to a single mobile telephone  1202  that can support conferencing among the users of the external audio devices and another party to the telephone call, and that can also support multiple concurrent telephone calls. Mobile telephone  1202  communicates with wireless headsets  104  and  106  through wireless links  1214  and  1216 , respectively. Wireless communication links  114  and  116  are created according to a WPAN standard, for example, Bluetooth®, ZigBee™, UWB, and the like. Mobile telephone  1202  communicates with a wired headset  108  through a wired communication link  1218 . 
     Mobile telephone  1202  allows headsets  104  and  108  to participate simultaneously in a single telephone call  1224  using a conferenced format. Additional headsets (not shown) may be supported in this conversation up to some pre-determined maximum number of supportable devices. Telephone call  1224  corresponds to a wireless communication link  1234 , which connects mobile telephone  1202  to an external communications server. For example, if mobile telephone  1202  is using cellular technology to handle the telephone calls, then the external communications server may be a cellular base station. In another example, if mobile telephone  1202  is using VoIP technology and WLAN technology to handle the telephone calls, the external communications server may be an access point. Any other suitable intermediary communications device may be used instead. 
     Mobile telephone  1202  allows headset  106  to participate in another telephone call  1226  which is concurrent with telephone call  1224  for at least a period of time. Telephone call  1226  corresponds to a wireless communication link  1236 , which connects mobile telephone  1202  to an external communications server. Call multiplexing functionality in mobile telephone  1202  keeps the control and audio for the different telephone calls separate. Audio mixing functionality in mobile telephone  1202  is used to mix audio input for telephone call  1224  from headset  104 , headset  108  and the external communications server, and to output the mixed audio to headset  104 , headset  108  and the external communications server. 
     Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.