Patent Publication Number: US-2010128888-A1

Title: Automatic Audio Processing Mode Control

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. application Ser. No. 12/276020, filed Nov. 21, 2008, the contents of which are incorporated by reference herein for all purposes. 
    
    
     BRIEF DESCRIPTION OF THE INVENTION 
     This invention relates to telecommunications (telecom) in general, and more particularly, to methods and apparatus for automatically enabling and disabling audio processing modes in telecom headsets and headset adapters. 
     BACKGROUND 
     In full duplex telephony, “sidetone” comprises a form of intentional feedback to the user of a telecom device, such as a telephone handset or headset, that enables the user to hear his own voice and thereby ascertain that a connection, or communication circuit, is open between the user and a far-end respondent, and also as a means for modulating the volume and speech formatives of the user&#39;s voice for effective communication. When the user speaks, his voice is sensed by the microphone of the device and introduced (at a reduced level) into the earpiece of the device so that the user hears himself speaking. Without sidetone, users cannot hear their own voice in the earpiece, and may conclude that the device is not working, or may speak either too softly or too loudly for effective communication. 
     Digital telecom devices typically lack the mechanical acoustics and circuitry that are present in older analog telephones for creating sidetone and therefore typically include electronic circuitry that generates the sidetone. An example of such a sidetone generator can be found in, e.g., U.S. Pat. No. 7,330,739 to S. Somayajula, which is incorporated by reference herein for all purposes. 
     In voice-over-internet-protocol (VOIP) telephony, headsets coupled via, e.g., a universal serial bus (USB) connection to a host computer, typically a personal computer (PC) acting as a telephone host, constitute the telecom devices of choice. Special USB adapters are also available that can be used to couple conventional corded analog telecom headsets to a suitably programmed PC telephone host. These headsets and adapters are typically marketed as both VOIP and hi-fidelity computer audio devices, i.e., as “multifunction” devices that can be used for both telephony and pure listening activities, such as the audition of music, e.g., MP3 files, or multimedia presentations. 
     By default, these devices have sidetone turned on at all times. This does not present a problem if the user of the headset is engaged exclusively in VOIP telephonic activities, where, as above, sidetone is a desirable feature. However, if the user is listening to music or simply sitting idly, the user may not want to have background noise or his own voice injected into the headset earpiece(s). If the user does not want sidetone on, the sidetone of the device must be turned off manually. This requires the user to open the audio mixer console of the PC&#39;s operating system (OS), e.g., Windows, and manually turn the sidetone off. Then, when sidetone in the device is wanted again, the user must turn it back on manually, again using the OS mixer console. 
     In a similarly related problem, headsets or headset adapters may utilize different algorithms depending on the type of application. For example, different algorithms may be used to enhance a VoIP telephone call, such as an acoustic echo cancellation algorithm, telephony specific EQs, versus a multimedia presentation, in which telephony-specific algorithms may be disabled and high fidelity EQs may be enabled. However, in order to switch between a telephony mode and a multimedia mode, the user must typically have specific software installed and must manually switch between the modes. The process of manually navigating the OS mixer or audio mode processing switch is time consuming and not intuitive to technically unsophisticated users, and can result in missed calls and degraded listening experiences. 
     SUMMARY 
     In accordance with the present disclosure, an automatic audio processing mode control feature of a telecom device, such as a headset or headset adapter that is coupled to a telephone host device, such as a PC or a digital phone, is operable to sense when the transmit (TX) channel between the two devices is active and to automatically enable telephony specific algorithms of the device, and additionally, to automatically disable telephony specific algorithms and enable multimedia specific algorithms of the device when the TX channel is not active. 
     In one example embodiment, a telecommunications device, system, and method for automatically controlling an audio processing mode are provided. In one embodiment, the device comprises a transmit (TX) channel; a receive (RX) channel; and a signal processor configured to detect when the TX channel of the device has been placed in an active state and to apply a telephony-specific or multimedia-specific audio processing algorithm to the RX channel depending upon a state of the TX channel. 
     A better understanding of the above and many other features and advantages of the novel sidetone control feature of the present disclosure may be obtained from a consideration of the detailed description of some example embodiments thereof below, particularly if such consideration is made in conjunction with the several views of the appended drawings, wherein like elements are referred to by like reference numerals throughout. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an example embodiment of an adapter for coupling an analog telecommunications headset to a host device in accordance with the present disclosure; 
         FIG. 2  is a perspective view of an example embodiment of a telecom headset that may be used for both telecommunication and listening-only activities; 
         FIG. 3  is a hardware block diagram of an adapter for coupling an analog telecommunications headset to a host device in accordance with the present disclosure; 
         FIG. 4  is a diagram of the DSP firmware signal flow in an adapter for coupling an analog telecommunications headset to a host device in accordance with the present disclosure; 
         FIG. 5  is a table illustrating a user configurable state of a telecom device incorporating the example sidetone control apparatus; 
         FIG. 6  is a logic flow diagram of an example embodiment of a method for automatically controlling sidetone in a telecommunication headset in accordance with the present disclosure; 
         FIG. 7  is a diagram of the DSP firmware signal flow in an adapter for coupling an analog telecommunications headset to a host device in accordance with another embodiment of the present disclosure; 
         FIG. 8  is a table illustrating a user configurable state of a telecom device incorporating the example audio processing mode control apparatus; 
         FIG. 9  is a logic flow diagram of an example embodiment of a method for automatically controlling audio processing modes in a telecommunication headset in accordance with the present disclosure; and 
         FIG. 10  illustrates an embodiment of another method for automatically controlling audio processing modes in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In accordance with an embodiment of the present disclosure, an automatic sidetone control feature of a telecom device, such as a digital headset or an analog headset adapter coupled to a digital telephone host device, such as a PC or a digital telephone, is operable to detect when the TX channel between the two devices is either active or inactive and to automatically turn the sidetone of the telecom device on and off, respectively, in response thereto without need for manual intervention by the user. 
       FIG. 1  is a perspective view of an example embodiment of one type of telecom device, viz., an adapter  100  for coupling a conventional analog telecom headset to a host digital computer or digital telephone (not illustrated) in accordance with the present disclosure.  FIG. 2  is a perspective view of an example embodiment of another type of telecom device, viz. a headset  200  that, in the case of a digital headset, may be directly coupled to a host digital computer or digital telephone (not illustrated), and in the case of a conventional analog headset, may be coupled thereto through the adapter  100  of  FIG. 1 . In either case, a headset may be used for both bidirectional telephony and listening-only activities.  FIG. 3  is a hardware block diagram of a telecommunication system  300  incorporating an example embodiment of an automatic sidetone generator and control apparatus in accordance with the present disclosure. 
     With reference to  FIGS. 1 and 2  the headset adapter  100  includes a main body  102  housing circuitry which is adapted to, inter alia, couple an analog headset  200 , such as the example headset of  FIG. 2 , to a host computer or digital telephone or other host device  400 , as described in more detail below. As illustrated in  FIG. 2 , the analog headset  200  comprises a microphone  202 , at least one audio speaker or earpiece  204  (also referred to as a receiver), and an apparatus  206 , such as the resilient headband, for holding the headset on a user&#39;s head such that the microphone  202  is disposed adjacent to the user&#39;s mouth and at least one earpiece is disposed adjacent to one of the user&#39;s ears. Other known types of headset holding mechanisms, such as ear loops and neck bands, can also be used. Referring to  FIG. 3 , the microphone  202  comprises a transducer, such as a dynamic, electret or piezoelectric transducer, that is operable to detect acoustic signals, such as the sounds of a user&#39;s voice, to convert the acoustic signals to corresponding electrical signals, and to couple the electrical signals onto a TX channel  303  for ultimate transmission to a far-end respondent. The earpiece transducer  204  is operable to receive electrical signals via an RX channel  304 , to convert the electrical signals to corresponding audible acoustic signals, and to output the acoustic signals to one of the user&#39;s ears. 
     The adapter body  102  may contain a printed circuit board (not illustrated) on which one or more active circuit devices, such as integrated circuits (ICs) and one or more digital signal processors (DSPs)  305  are mounted and interconnected. In one advantageous embodiment, substantially all of the active circuitry may be embodied in a single, dedicated signal processing chip. The adapter firmware of DSP  305  controls circuitry for generating and controlling a sidetone signal in the headset  200 , which, as discussed above, can be implemented in a variety of known ways, by coupling at least a portion of a TX signal from the microphone  202  to speaker(s)  204 . 
     As those of skill in the art will appreciate, the particular example adapter  100  and associated analog headset  200  illustrated in  FIG. 2  can comprise a monophonic system, or the adapter  100  and headset  200  may easily be augmented with a second RX channel  304  and earpiece  204 , as illustrated in  FIG. 2 and 3 , to form a binaural or stereophonic system. In a stereophonic system, each of two RX channels and earpieces are respectively dedicated to the right and left channels of the system. Although conventional VOIP telephony is universally monophonic in nature, the addition of a second channel to the system enables the headset  200  to function not only as a telecom device, but also as a means for delivering high fidelity stereophonic sound to a user. 
     With reference to  FIG. 3 , since the microphone  202  and earpiece transducers  204  of the headset  200  are typically analog in nature, the communication path  302  between the headset  200  and the adapter  100  is also typically analog in nature. Further, since the host device  400  is inherently digital in nature, the communication path  304  between the host device  400  and the adapter  100  is also digital in nature, and accordingly, the adapter circuitry further includes circuitry for converting a digital RX signal from the digital host device  400  to an analog RX signal for output to the analog speakers or earpiece(s)  204  of the headset  200 , as well as circuitry for converting an analog TX signal from the microphone  202  of the headset  200  to a digital TX signal and outputting it to the host device  400 . This signal converting circuitry may respectively include suitable digital-to-analog (D/A)  314  and analog-to-digital (A/D) converters  312  and/or audio coderdecoders (codecs) of a known type, and additionally, may be either off-the-shelf, standalone devices, or alternatively, may be integrated into a single DSP device in the adapter, such as those commercially available from Micronas, UAC 3556B. 
     The example headset adapter  100  further includes a connector  108  for coupling the adapter to the host device  400  via a digital communication protocol, as well as one or more connectors  110  for attaching the headset  200 , such that the headset is coupled to the host device  400  through the adapter  100 . In the particular example embodiment of  FIGS. 1 and 3 , the adapter  100  communicates with the host device  400  via the universal serial bus (USB) protocol at USB interface  308  and controller  306 , and accordingly, the host connector  108  in this illustrative embodiment comprises a conventional USB connector. 
     However, it should be understood that the particular data communication protocol by which the adapter  100  communicates with the host device  400  is not limited to the USB protocol, and the adapter may instead communicate with the host device  400  by means of another digital communication protocol, such as pulse code modulation (PCM), Microsoft AC &#39;97, IEEE 1394 (Firewire), AES/EBU (AES3), S/PDIF, MADI (AES10), Intel High Definition Audio (HD Audio), mlan, mp3, and WAV protocols, or another digital protocol, and accordingly, the connector  108  may comprise a correspondingly appropriate alternative connector type. The plug(s) (not illustrated) of the analog headset  200  may be comprised, of one or more conventional analog plugs, e.g. ⅛ inch analog plugs, including one each for the microphone  202  and the speaker(s) or earpiece(s)  204  thereof. Alternatively, the headset may incorporate a single, integrated plug through which the TX and RX signals  303 ,  304  are coupled into/from the headset  200 . Still further, one or both of the links between the adapter  100  and the host device  400  and the headset  200  may be a wireless link, and the adapter  100  may be integrated with the host device  400  or the headset  200 . 
     Referring now to  FIG. 4 , illustrated is the signal flow of a particular USB embodiment of the invention. In the USB communication protocol, all data transmissions travel to or from a device “endpoint” via a software “pipe” established between the device and the host at the time of system power-up (“enumeration”) or when the device is later connected to the host. Endpoint  0 , for example, is a default bidirectional control point, always accessible. Industry standard USB Specification 2.0 describes the bus attributes, protocol definitions, types of transactions and programming interface for USB devices. USB Device Class Definition for Audio Devices 1.0 defines USB audio transport mechanisms. Both specifications are incorporated by reference herein. Other endpoints are uniquely identifiable portions of a USB device that are the terminus of communication flow between the host and device. 
     Following the TX path signal flow  303 , an audio signal from microphone  202  of the headset  200  is converted to a digital stream by A/D  312  and the signal is directed to digital TX amplifier  419 . Amplifier  419  can be used as a volume control for the TX signal path. Output from amplifier  419  is provided to the USB interface  308 . This function is defined as “endpoint  1 ”. Thus, endpoint  1  is allocated to the TX function addressable by the host device  400  to initiate the transfer of audio data from the headset  200  to the host device  400  under the host&#39;s control, and endpoint  1  is the terminus of the TX communication with host device  400 . To effect an audio TX path from the headset  200  to the host, the host requests a change for endpoint  1  and its pipe from “alternate  0 ” (closed channel with zero bandwidth assigned) to “alternate  1 ” (open channel of appropriate bandwidth on the bus). That is, endpoint  1  is toggled from a “0” or “inactive” mode to a “1” or “active” mode. In the inactive mode, the headset  200  is incapable of transmitting audio data to the host device  400 , and in the active mode, the headset  200  transmits packets of audio data to the host device  400  isochronously and without error correction under the control of the host device  400 . 
     Referring again to  FIG. 4 , the host device  400  provides a digital RX signal  304  at the USB interface  308  defined as “endpoint  2 ”. This data stream of digital signal  304  can carry monaural or stereo audio information. The data is input to RX amplifier  417 , which can be configured as a volume control that allows a user to set RX level via controller  306 . Data flows from amplifier  417  to digital mixer  415 . Mixer  415  then provides RX signal  304  to D/A(s)  314  which in turn drive speaker(s)  204 . Endpoint  2  is the terminus of the RX signal from the host device  400  to the adapter  100  addressable by the host device  400  to initiate the transfer of audio data from the host device  400  to the speaker(s)  204  under the host&#39;s control. 
     When endpoint  1  and its pipe are open, analog signals from microphone  202  of headset  200 , after conversion to a digital stream by A/D converter  312 , also flow to digital amplifier  416 . Amplifier  416  provides a level control of the digital TX signal  303  input to mixer  415  under the command of controller  306 . Amplifier  416  can adjust the feedback level of TX signal  303  from zero (no sidetone) to a nominal value representing a desired sidetone level. Mixer  415  then mixes the desired TX signal with the RX signal  304  from digital amplifier  417 . 
     In accordance with this embodiment of the invention, controller  306  is programmed to monitor the status of the TX channel. If the TX channel is in an open condition (endpoint  1  in active mode), amplifier  416  is set to nominal gain by the controller  306  and a desired level of the TX signal  303  is mixed with the RX  304  signal in mixer  415 . This combined signal is sent through D/A  314  to the speakers  204  and the headset wearer hears sidetone. When the TX channel is closed by the host device  400  (endpoint  1  in inactive mode), amplifier  416  is set to 0 gain level by controller  306  and mixer  415  has no TX signal input. Only the RX signal  304  from the host device  400  is present at the output of mixer  415  and the headset wearer will hear no sidetone. Thus, headset adapter  100  provides an automatic sidetone control function, which in this embodiment, comprises logic and circuitry for detecting when the TX channel  303  of the adapter has been placed in an open or active mode by the host device  400  and for enabling a sidetone path  420  between the TX and RX channels  303  and  304  in response thereto, as well as logic and circuitry for detecting when the TX channel  303  from the headset has been placed in the closed or inactive mode and for disabling the sidetone path in response thereto. In the example USB adapter of  FIGS. 3 and 4 , this function is affected by logic (firmware) incorporated in the programming of the adapter&#39;s controller  306 . 
       FIG. 5  is a logic table used in the sidetone generating and path controller portion  306  of the circuitry of the adapter  100  to detect a change in the alternate mode of the TX endpoint of the system and to automatically enable or disable the sidetone path  420  ( FIG. 4 ) in response thereto. As shown in  FIG. 6 , the example method  500  may comprise a subroutine executed within a main processing loop  502  of the adapter  100 &#39;s processor during operation. 
     Thus, in step  504  of the sidetone controller method  500  of  FIG. 6 , the processor of the adapter  100  or headset  200  checks to determine whether the endpoint  1  alternate mode has changed, i.e., from a 0 to a 1 or vice versa, since the last processor cycle. If it determines that no change has occurred, i.e., a “No” determination, the balance of the subroutine is bypassed via the branch  506  and the processor proceeds with the main processing loop  502 . However, if the endpoint alternate mode has changed, i.e., a “Yes” determination, then at step  508 , the processor determines whether the TX endpoint mode has been changed to 0, i.e., the disabled mode. If a Yes determination is made, the method proceeds via branch  510  to step  512 , at which the processor disables the sidetone path  420 , so that no sidetone is coupled onto the RX channel  304 , and hence, no sidetone is heard by the user, whereupon the processor continues with the main processing loop  502 , as above. 
     On the other hand, if a “No” determination is made at step  508 , then the method  500  proceeds via branch  514  to step  516 , where a determination is made as to whether the user has manually muted sidetone, e.g., through a telephony or listening application program running on the host device  400 , or by manually actuating a sidetone muting switch  118  on the headset adapter  100  or a sidetone muting switch on the headset. If a “Yes” determination is made at step  516 , the method proceeds via branch  518  to step  512 , where, as above, the processor disables the sidetone path  420 , and then continues with the main processing loop  502 . However, if a “No” determination is made at step  516 , i.e., the user has not manually muted sidetone, then the method proceeds via branch  520  to step  522 , at which the processor enables the sidetone path  420 , so that sidetone from the microphone  202  is coupled onto the RX channel  304 , and hence, is heard by the user through the earpiece  204  of the headset  200 , then continues on with the main processing loop  502 . 
     As may be seen from the foregoing, the TX channel  303  is defined as “active” or “open” when the host device  400  requests audio data from the microphone  202 . This occurs, for example, when a VoIP phone call is either initiated or received by the user. When the host device  400  wants microphone audio data, it sends a control transfer instruction to the adapter  100  via the digital audio communication path  304  that tells the adapter  100  to supply the microphone audio. When the processor of the adapter  100  receives this command, it begins supplying microphone audio data to the host device  400  via the USB interface  308 , and at the same time, controller  306  enables the sidetone path  420 . At all other times, the controller disables the sidetone path. These two states are illustrated in the sidetone control logic table of  FIG. 5 . 
     An example use case of the automatic sidetone controller is one in which a user is initially listening to music on a host device  400  (e.g. a personal computer) with an analog telecom headset  200  coupled to the host device  400  via a USB headset adapter  100  equipped with the novel automatic sidetone controller. In such a case, no distracting sidetone is present in the headset, because the TX channel  303  of the system is inactive. The user may then receive a VoIP phone call via, e.g., the Skype service. The user may then quickly switch to the call, causing the TX channel  303  of the adapter  100  to become active. As above, the sidetone controller  306  portion of the adapter&#39;s processor immediately detects this change in mode, and in response, automatically enables the sidetone path  420  of the adapter  100 , as above. After the user completes the call, i.e., “hangs up,” the TX  303  channel becomes inactive, i.e., in the USB example, the “end-point  1 ” alternate mode is set to 0, or inactive. The sidetone controller detects this change, and automatically disables the sidetone path  420 , so that the user may resume listening to the music without having to access the audio mixer function of the host device  400 . 
     As described above, for additional functionality, the adapter  100  may include a mechanism, such as a switch  118  ( FIG. 3 ), manually operable by the user for selectively activating and deactivating the automatic sidetone generator via the controller  306 . When active, the sidetone generator and controller  306 &#39;s operation is as described above and illustrated in  FIGS. 5 and 6 . However, when sidetone is muted by the user, i.e., when the sidetone generator is manually deactivated by the user, its operation reverts to the default operation described above, in which sidetone is manually activated or deactivated by the user through the audio mixer function of the host device  400 . 
     The primary advantages of the automatic sidetone generator and controller  306  is that sidetone is present only when the user wants it to be and that its presence or absence is invoked automatically, without the need for manual intervention by the user. 
     Referring now to  FIGS. 7-9  in conjunction with  FIGS. 1-3 , an embodiment for automatically controlling audio processing modes is disclosed. In accordance with an embodiment of the present disclosure, an automatic audio processing mode control feature of a telecom device, such as a digital headset or an analog headset adapter coupled to a digital telephone host device, such as a PC or a digital telephone, is operable to detect when the TX channel between the two devices is either active or inactive and to automatically select a telephony specific or multimedia specific audio processing algorithm of the telecom device in response thereto without need for manual intervention by the user. 
     As similarly described above,  FIG. 1  is a perspective view of an example embodiment of one type of telecom device, viz., an adapter  100  for coupling a conventional analog telecom headset to a host digital computer or digital telephone (not illustrated) in accordance with the present disclosure.  FIG. 2  is a perspective view of an example embodiment of another type of telecom device, viz. a headset  200  that, in the case of a digital headset, may be directly coupled to a host digital computer or digital telephone (not illustrated), and in the case of a conventional analog headset, may be coupled thereto through the adapter  100  of  FIG. 1 . In either case, a headset may be used for both bidirectional telephony, such as through VoIP, and listening-only activities, such as listening to music or viewing multimedia applications.  FIG. 3  is a hardware block diagram of a telecommunication system  300  incorporating an example embodiment of an audio processing mode control apparatus in accordance with the present disclosure. Features and elements of  FIGS. 1-3  are applicable in this embodiment of the present disclosure, and repetitive descriptions of the same or similar elements as those described above may not be fully included here although applicable to this embodiment of the present disclosure. 
     Adapter body  102  may contain a printed circuit board (not illustrated) on which one or more active circuit devices, such as integrated circuits (ICs) and one or more digital signal processors (DSPs)  305  are mounted and interconnected. In one advantageous embodiment, substantially all of the active circuitry may be embodied in a single, dedicated signal processing chip. The adapter firmware of DSP  305  controls circuitry for selecting and applying audio processing algorithms in the headset  200  dependent upon whether the transmit (TX) channel between the headset and host is active. 
     Referring now to  FIG. 7  in conjunction with  FIG. 3 , the signal flow of a particular USB embodiment of the invention is illustrated. Following the TX path signal flow  303 , an audio signal from microphone  202  of the headset  200  is converted to a digital stream by A/D  312  and the signal is directed to digital TX amplifier  602 . Amplifier  602  can be used as a volume control for the TX signal path. Output from amplifier  602  is provided to DSP  605  which is configured to apply telephony-specific or multimedia-specific algorithms to the TX signal depending upon the state of the transmit (TX) channel between the headset and the host. When the TX channel is active, telephony-specific algorithms of the device are enabled, and when the TX channel is not active, telephony-specific algorithms are disabled and multimedia-specific algorithms of the device are enabled. Applicable telephony-specific algorithms include but are not limited to acoustic echo cancellation, telephony-specific EQs, multiband compression, and expansion. 
     The processed TX signal from DSP  605  is then provided to the USB interface  308  ( FIG. 3 ). This function is again defined as “endpoint  1 ”. Thus, endpoint  1  is allocated to the TX function addressable by the host device  400  to initiate the transfer of audio data from the headset  200  to the host device  400  under the host&#39;s control, and endpoint  1  is the terminus of the TX communication with host device  400 . To effect an audio TX path from the headset  200  to the host, the host requests a change for endpoint  1  and its pipe from “alternate  0 ” (closed channel with zero bandwidth assigned) to “alternate  1 ” (open channel of appropriate bandwidth on the bus). That is, endpoint  1  is toggled from a “0” or “inactive” mode to a “1” or “active” mode. In the inactive mode, the headset  200  is incapable of transmitting audio data to the host device  400 , and in the active mode, the headset  200  transmits packets of audio data to the host device  400  through DSP  605  under the control of the host device  400 . For example, when a host computer wants microphone audio USB data, the host may send a USB command to the USB adapter or headset to tell the adapter or headset to supply the microphone audio. When the adapter or headset interprets this command, it begins supplying the microphone audio to the host via USB and at the same time, the adapter or headset may automatically switch to a telephone audio processing mode. At all other times, it may be assumed that the user is not on a telephone call and the audio processing algorithm may be set to a multimedia audio processing mode. 
     Referring again to  FIG. 7  in conjunction with  FIG. 3 , the host device  400  provides a digital RX signal  304  at the USB interface  308  ( FIG. 3 ) again defined as “endpoint  2 ”. This data stream of digital signal  304  can carry monaural or stereo audio information. The data is input to RX amplifier  608 , which can be configured as a volume control that allows a user to set RX level via controller  306  ( FIG. 3 ). Data flows from amplifier  608  to DSP  605 , which again is operable to apply telephony-specific or multimedia-specific algorithms to the RX signal depending upon the state of the transmit (TX) channel between the headset and the host. When the TX channel is active, telephony-specific algorithms of the device are enabled, and when the TX channel is not active, telephony-specific algorithms are disabled and multimedia-specific algorithms of the device are enabled. The processed RX signal  304  from DSP  605  is then provided to D/A(s)  314  which in turn drive speaker(s)  204 . Endpoint  2  is the terminus of the RX signal from the host device  400  to the adapter  100  addressable by the host device  400  to initiate the transfer of audio data from the host device  400  to the speaker(s)  204  under the host&#39;s control. 
     In accordance with this embodiment of the invention, controller  306  ( FIG. 3 ) is programmed to monitor the status of the TX channel. If the TX channel is in an open condition (endpoint  1  in active mode), DSP  605  is configured to apply telephony-specific algorithms to the TX and RX signals. At all other times (no microphone audio USB data requested and endpoint  1  in inactive mode), DSP  605  is configured to apply multimedia-specific algorithms to the RX signals). Thus, headset adapter  100  provides an automatic control function over audio processing algorithms, which in this embodiment, comprises logic and circuitry for detecting when the TX channel  303  of the adapter has been placed in an open or active mode by the host device  400  and for applying particular audio processing algorithms to the TX and RX channels  303  and  304  in response thereto, as well as logic and circuitry for detecting when the TX channel  303  from the headset has been placed in the closed or inactive mode and for applying alternative audio processing algorithms to the TX and RX channels in response thereto. In the example USB adapter of  FIGS. 3 and 7 , this function is affected by logic (firmware) incorporated in the programming of the adapter&#39;s controller  306 . 
     In another embodiment of the present disclosure, the internal audio processing sample rate may also be adjusted when the audio processing mode is switched. For example, algorithms used for telephony-specific audio processing are resource intensive, requiring a relatively large number of MIPs, and thus these algorithms may be implemented at a lower sampling rate (e.g., 16 Ks instead of 48 Ks). However, for listening to music or other multimedia applications it is desirable to have audio bandwidths greater than telephony audio (e.g., 48 Ks instead of 16 Ks), and thus these algorithms may be implemented at a higher sampling rate than in the telephony mode. Accordingly, the internal audio processing sample rates of the adapters or headsets may automatically switch sampling rate based upon the audio processing mode. 
       FIG. 8  is a logic table used in the controller portion  306  of the circuitry of the adapter  100  to detect a change in the alternate mode of the TX endpoint of the system and to automatically enable or disable an audio processing algorithm in response thereto. 
     As shown in  FIG. 9 , an example method  700  may comprise a subroutine executed within a main processing loop  702  of the adapter  100 &#39;s processor during operation. In step  704  of the audio processing mode controller method  700 , the processor of the adapter  100  or headset  200  checks to determine whether the endpoint  1  alternate mode has changed, i.e., from a 0 to a 1 or vice versa, since the last processor cycle. If it determines that no change has occurred, i.e., a “No” determination, the balance of the subroutine is bypassed via the branch  706  and the processor proceeds with the main processing loop  702 . However, if the endpoint alternate mode has changed, i.e., a “Yes” determination, then at step  708 , the processor determines whether the TX endpoint mode has been changed to 0, i.e., the disabled mode. If a Yes determination is made, the method proceeds via branch  710  to step  712 , at which the processor disables telephony-specific algorithms and either selects the multimedia-specific algorithm or returns to a default multimedia-specific algorithm to apply to the RX channel  304 , whereupon the processor continues with the main processing loop  702 , as above. 
     On the other hand, if a “No” determination is made at step  708 , then the method  700  proceeds via branch  714  to step  716 , where a determination is made as to whether the user has manually disabled the telephony mode, e.g., through a telephony or listening application program running on the host device  400 , or by manually actuating a switch  118  on the headset adapter  100  or on the headset  200 . If a “Yes” determination is made at step  716 , the method proceeds via branch  718  to step  712 , where, as above, the processor disables the telephony-specific algorithms and either selects the multimedia-specific algorithms or returns to a default multimedia processing mode, and then continues with the main processing loop  702 . However, if a “No” determination is made at step  716 , i.e., the user has not manually disabled telephony mode, then the method proceeds via branch  720  to step  722 , at which the processor enables the telephony-specific algorithms to be applied to the TX and RX channels  303 ,  304  and then continues on with the main processing loop  702 . 
     As may be seen from the foregoing, the TX channel  303  is defined as “active” or “open” when the host device  400  requests audio data from the microphone  202 . This occurs, for example, when a VoIP phone call is either initiated or received by the user. When the host device  400  wants microphone audio data, it sends a control transfer instruction to the adapter  100  via the digital audio communication path  304  that tells the adapter  100  to supply the microphone audio. When the processor of the adapter  100  receives this command, it begins supplying microphone audio data to the host device  400  via the USB interface  308 , and at the same time, controller  306  enables telephony-specific algorithms to be applied. At all other times, the controller disables the telephony mode. These two states are illustrated in the telephony control logic table of  FIG. 8 . 
     An example use case of the automatic audio processing mode controller is one in which a user is initially listening to music on a host device  400  (e.g. a personal computer) with an analog telecom headset  200  coupled to the host device  400  via a USB headset adapter  100  equipped with the novel automatic audio processing mode controller. In such a case, multimedia-specific algorithms, such as high fidelity EQ, is applied to the audio because the TX channel  303  of the system is inactive. The user may then receive a VoIP phone call via, e.g., the Skype service. The user may then quickly switch to the call, causing the TX channel  303  of the adapter  100  to become active. The controller  306  portion of the adapter&#39;s processor immediately detects this change in mode, and in response, automatically switches to a telephony mode in which telephony-specific algorithms are applied to the received and transmitted audio signals. After the user completes the call, i.e., “hangs up,” the TX  303  channel becomes inactive, i.e., in the USB example, the “endpoint  1 ” alternate mode is set to 0, or inactive. The controller detects this change, and automatically disables the telephony algorithms and switches back to a multimedia mode, so that the user may automatically resume listening to the music with high fidelity EQ without having to access the audio mixer function of the host device  400 . 
     As described above, for additional functionality, the adapter  100  may include a mechanism, such as a switch  118  ( FIG. 3 ), manually operable by the user for selectively activating and deactivating the telephony mode and/or the multimedia mode via the controller  306 . 
     Referring now to  FIG. 10 , a flowchart is shown illustrating another method of automatically controlling audio processing modes via software located outside of the adapter or headset. For example, the functionality of the adapter or headset to detect a state or mode of the TX channel may be in the host device (e.g., a middleware application on a PC), where the middleware application is configured to send control commands to the audio device for setting changes to the audio processing mode depending upon the state of the TX channel. At step  802 , the host initiates a TX audio channel (e.g., a softphone call is started). At step  804 , the middleware application, for example located on a PC host, detects the TX audio channel initiation. At step  806 , the middleware application sends a command to the audio device (e.g., a headset or adapter) to change an audio processing mode from a multimedia mode to a telephony mode such that different audio processing algorithms are applied to the audio signals. 
     The primary advantages of the automatic audio processing mode controller  306  is that in either a telephony application or a multimedia application, the audio processing algorithms will be optimized for those applications automatically without the need for manual intervention by the user. 
     As those of skill in the art will appreciate, although the methods and apparatus of the present disclosure have been described and illustrated herein with reference to certain specific example embodiments thereof, a wide variety of modifications and variations may be made to them without departing from the spirit and scope of the invention. For example, it should be understood that the functionality of the adapter  100  described above, including the automatic audio processing mode controller  306 , may be incorporated directly into the headset  200 , such that the adapter is eliminated and the resulting “digital” headset then comprises an integrated telecom device that connects directly to the host device  400  via, e.g., a USB or other digital type of connection. Furthermore, although various endpoints and channels of communication have been described, various other endpoints and/or channels may be used for bidirectional communication and monitoring for audio mode processing. 
     In light of the foregoing, the scope of the present invention should not be limited to that of the specific example embodiments described and illustrated herein, but rather, should be commensurate with that of the claims appended hereafter and their functional equivalents.