PATENT DOCUMENT

Publication Number: US-10750328-B2
Application Number: US-201715653432-A
Country: US
Kind Code: B2

Title: Remote messaging for mobile communication device and accessory

Abstract:
Message notifications to an accessory from a mobile communication device are provided according to some embodiments of the invention. When a message such as a text message, email, and/or voicemail is received at a mobile communication device, the mobile communication device can notify an attached accessory that a message has been received. In response, the accessory can request the full message, media associated with the message, an attachment to the message, and/or an audio/video stream of the message for presentation to a user.

Claims:
What is claimed is: 
     
       1. A method for use in an accessory, the method comprising:
 sending, to a mobile communication device (MCD) through a wireless communication channel that couples the accessory to the MCD, capability information to indicate that the accessory is capable of displaying email messages and to register the accessory with the MCD to receive an email message notification; 
 receiving the email message notification from the MCD based on the capability information, wherein the email message notification includes a listing of a plurality of email messages that the MCD has received, which includes i) a portion of each of the plurality of email messages and ii) an identifier associated with each of the plurality of email messages; 
 in response to receiving the email message notification, providing a message indication by the accessory which indicates that an email message has been received, wherein providing the message indication comprises displaying the portion of each of the plurality of email messages in the listing on an accessory display, wherein the accessory display has a smaller display area than an MCD display of the MCD; 
 receiving a request by the accessory, to access a particular one of the email messages whose portions are displayed; 
 in response to the request, sending a command to the MCD requesting the particular one of the email messages, wherein the command includes the identifier associated with the particular one of the email messages; 
 receiving an entirety of the particular one of the email messages from the MCD; 
 presenting the particular one of the email messages on the accessory display of the accessory; 
 receiving input through an input device of the accessory as a reply to the particular one of the email messages; and 
 in response to receiving the input, sending a reply command to the MCD that requests the MCD to reply to the particular one of the email messages with the received input. 
 
     
     
       2. The method of  claim 1  further comprising
 sending by the accessory a phone-dialing command to the MCD in response to which the MCD samples a signal received from the accessory to detect and recognize a user&#39;s spoken instruction and thereby determine a number to dial. 
 
     
     
       3. The method of  claim 1 , wherein the email message notification includes an email address of a sender. 
     
     
       4. The method of  claim 1  further comprising
 receiving from a user a request to forward an email, and in response sending a command to the MCD to forward an email message. 
 
     
     
       5. The method of  claim 1 , wherein the request to access the particular one of the email messages is received by the accessory as a touch input on the accessory display having the smaller display area. 
     
     
       6. An accessory for use with a mobile communication device (MCD), the accessory comprising a processor and memory having stored therein instructions, wherein the processor upon executing the instructions:
 sends, to the MCD in accordance with a wireless communication protocol, capability information to indicate that the accessory is capable of displaying email messages and to register the accessory with the MCD to receive an email message notification including an email listing having i) a portion of each of a plurality of email messages received by the MCD and ii) an identifier associated with each of the plurality of email messages; 
 receives the email message notification from the MCD based on the capability information and in accordance with the wireless communication protocol; 
 sends a first command to the MCD in response to receiving, via a user interface of the accessory having a smaller area than an MCD display of the MCD, a user indication to present a particular email message, that is associated with the received email message notification; 
 receives further data from the MCD representing the particular email message; 
 presents the particular email message in the accessory; 
 receives input through an input device of the accessory as a reply to the particular email message; and 
 in response to receiving the input, sends a reply command to the MCD that requests the MCD to reply to the particular email message with the received input. 
 
     
     
       7. The accessory of  claim 6 , wherein the processor is to present the user interface on a touch-screen display device of the accessory. 
     
     
       8. The accessory of  claim 6 , wherein the processor, upon executing further instructions stored in the memory, sends a phone-dialing command to the MCD in response to which the MCD samples a signal received from the accessory to detect and recognize a user&#39;s spoken instruction and thereby determine a number to dial. 
     
     
       9. The accessory of  claim 6 , wherein the email message notification includes an email address of a sender. 
     
     
       10. The accessory of  claim 6 , wherein the processor, upon executing further instructions stored in the memory, receives from a user a request to forward an email, and in response sends a command to the MCD to forward an email message. 
     
     
       11. The accessory of  claim 6 , wherein the user indication to present the particular email message is a touch input on the user interface of the accessory having the smaller display area. 
     
     
       12. A mobile communication device (MCD) comprising a processor and memory having stored therein instructions that when executed by the processor:
 receive, from an accessory connected to the MCD through a wireless communication, capability information indicating that the accessory is capable of displaying email messages; 
 determine that the accessory supports email message notifications based on the capability information; 
 register the accessory with the MCD to receive an email message notification; 
 receive a plurality of email messages; 
 send, in response to determining that the accessory supports email message notifications, the email message notification to the accessory through the wireless communication channel for display on a touch-screen display of the accessory, wherein the accessory display has a smaller display area than a display of the MCD, wherein the email message notification indicates that the MCD has received the plurality of email messages and comprises a listing of the plurality of received email messages which includes i) a portion, not all, of each of the plurality of email messages, and ii) an identifier associated with each of the plurality of messages; 
 receive a first command from the accessory that indicates a request for a particular email message to be sent to the accessory, wherein the request includes an identifier associated with the particular email message; 
 send an entirety of the particular email message to the accessory in response to receiving the first command; and 
 receive a second command from the accessory to forward the particular email message to a particular contact. 
 
     
     
       13. The MCD of  claim 12 , wherein a particular email message of the plurality of received email messages includes a multimedia object, and the email message notification includes an indication that the particular email message includes a multimedia object. 
     
     
       14. The MCD of  claim 12 , wherein the email message notification includes an email address of a sender. 
     
     
       15. The MCD of  claim 12 , wherein the memory has stored further instructions that when executed by the processor
 send an audio signal to the accessory. 
 
     
     
       16. The MCD of  claim 12 , wherein the memory has stored further instructions that when executed by the processor
 receive a phone-dialing command from the accessory; and 
 in response to receiving the phone-dialing command, sample an audio signal received from the accessory to detect and recognize a user&#39;s spoken instruction to thereby determine a number to dial. 
 
     
     
       17. The MCD of  claim 12 , wherein the request for the particular email message is a touch input on the accessory display having the smaller display area. 
     
     
       18. A method performed in a mobile communication device (MCD), the method comprising:
 receiving, from an accessory connected to the MCD through a wireless communication, capability information indicating that the accessory is capable of displaying email messages; 
 determining that the accessory supports email message notifications based on the capability information; 
 registering the accessory with the MCD to receive an email message notification; 
 receiving a plurality of email messages; 
 sending, in response to determining that the accessory supports email message notifications, the email message notification to the accessory through the wireless communication channel for display on a touch-screen display of the accessory, wherein the touch-screen display has a smaller display area than a display of the MCD, wherein the email message notification indicates that the MCD has received the plurality of email messages and comprises a listing of the plurality of received email messages which includes i) a portion, not all, of each of the plurality of email messages, and ii) an identifier associated with each of the plurality of messages; 
 receiving, by the MCD, a first command from the accessory that indicates a request for a particular email message to be sent to the accessory, wherein the request includes an identifier associated with the particular email message; 
 sending an entirety of the particular email message to the accessory in response to receiving the first command; and 
 receiving, by the MCD, a second command from the accessory to forward the particular email message to a particular contact. 
 
     
     
       19. The method of  claim 18 , wherein a particular email message of the plurality of received email messages includes a multimedia object, and the email message notification includes an indication that the particular email message includes a multimedia object. 
     
     
       20. The method of  claim 18 , wherein the email message notification includes an email address of a sender. 
     
     
       21. The method of  claim 18  further comprising sending audio signals to the accessory. 
     
     
       22. The method of  claim 18  further comprising
 receiving a phone-dialing command from the accessory; and 
 in response to receiving the phone-dialing command, sampling an audio signal received from the accessory to detect and recognize a user&#39;s spoken instruction to thereby determine a number to dial. 
 
     
     
       23. The method of  claim 18 , wherein the request for the particular email message is a touch input on the touch-screen display having the smaller display area.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a Continuation of U.S. patent application Ser. No. 14/320,183, entitled “Remote Messaging for Mobile Communication Device and Accessory”, filed on Jun. 30, 2014, and a Continuation of U.S. patent application Ser. No. 13/558,217, entitled “Remote Messaging for Mobile Communication Device and Accessory”, filed on Jul. 25, 2012, now issued as U.S. Pat. No. 8,798,652, which is a Divisional of U.S. patent application Ser. No. 12/479,545, entitled “Remote Messaging for Mobile Communication Device and Accessory”, filed on Jun. 5, 2009, now issued as U.S. Pat. No. 8,254,993, which is a Continuation-In-Part of U.S. patent application Ser. No. 12/399,740, entitled “Duplex Audio For Mobile Communication Device And Accessory”, filed on Mar. 6, 2009, now issued as U.S. Pat. No. 8,140,116, and assigned to the assignee of the present application. 
    
    
     BACKGROUND 
     The present disclosure relates in general to mobile communication devices that interoperate with accessories and in particular to interoperation of a mobile communication device with an accessory to provide text message, email and/or voicemail notifications to the accessory. 
     Mobile communication devices, such as cellular phones, have become nearly ubiquitous. Some mobile communication devices, such as the iPhone™ (made by Apple Inc., assignee of the present application), can provide users a variety of services in addition to mobile telephone service; such services can include management and playback of media content (music, videos, audiobooks, photos, etc.); storage of personal data such as calendar, contacts, and notes; Internet access; and the ability to execute various application programs that the user may choose to download and install. 
     Some mobile communication devices are designed to interoperate with various accessory devices (also referred to herein as accessories). For example, a mobile communication device can have a connector with a number of pins that support providing audio and/or video to an accessory, receiving audio and/or video from an accessory, providing serial communication to and/or from the accessory, providing power to and/or receiving power from the accessory, and so on. This connector can be docked or mated with a corresponding connector of an accessory, thereby allowing the exchange of various signals and data between the portable communication device and the accessory. 
     Accessories can provide a number of different services or service enhancements in connection with a mobile communication device. For example, some accessories may include speakers to play audio content received from the mobile communication device and/or video display screens to display video content, text or other media received from the mobile communication device. Some accessories may include a microphone and may provide audio input from the microphone to the mobile communication device, e.g., allowing the mobile communication device to act as a voice recorder. Some accessories may include video and/or still image cameras and may provide video and/or image data to the mobile communication device for storage and/or playback. 
     SUMMARY 
     Certain embodiments of the present invention provide for messaging notifications—text, email, voicemail, SMS and MMS are all example so this concept—to an accessory device from a mobile communication device. A mobile communication device in some embodiments can include devices that can communicate with a mobile communication network, such as, a telephone network and/or the Internet. The mobile communication device can be used to send, receive, display, delete, reply to, forward, and/or take other actions in response to various types of messages. 
     Certain embodiments of the present invention provide improved interoperability of a mobile communication device with an accessory, including viewing and/or playing text messages, emails, and/or voicemails. In some embodiments, when a mobile communication device that is coupled with an accessory (either wired or wirelessly) detects receipt of a message (e.g., text message, voicemail and/or email), the mobile communication device can notify the accessory. The notification, in some embodiments, can include a portion of the message or the entire message. The accessory can notify a user of the mobile communication device&#39;s receipt of the message. 
     In some embodiments, the accessory can request a full message from the mobile communication device and present the full message to the user. In some other embodiments, the accessory can request attachments and/or media associated with the message, and present such to the user. In yet other embodiments, voicemails can be streamed from the mobile communication device to the accessory for presentation to the user. Various other functions, for example, delete, reply to, callback, forward, etc., can also be supported by the accessory. 
     The following detailed description together with the accompanying drawings will provide a better understanding of the nature and advantages of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified illustration of a system according to an embodiment of the present invention. 
         FIG. 2  is a simplified block diagram showing a system according to an embodiment of the present invention. 
         FIG. 3  is a flow diagram of a process for handling an incoming telephone call by a mobile communication device according to one embodiment of the present invention. 
         FIG. 4  is a flow diagram of a process for handling an incoming telephone call by an accessory device according to an embodiment of the present invention. 
         FIG. 5  is a flow diagram of a process for placing a call according to an embodiment of the present invention. 
         FIG. 6  is a flow diagram of a process for handling a telephone call placed using an accessory device according to an embodiment of the present invention. 
         FIG. 7  is a message passing diagram illustrating coordination of audio processing between a mobile communication device and an accessory according to an embodiment of the present invention. 
         FIG. 8  is a flow diagram of a process for handing text messages using an accessory device according to an embodiment of the invention. 
         FIG. 9  is another flow diagram of a process for handing text messages using an accessory device according to an embodiment of the invention. 
         FIG. 10  is a flow diagram of a process for sending text message to an accessory from a mobile communication device according to an embodiment of the invention. 
         FIG. 11  is a flow diagram of a process for handing voicemail using an accessory device according to an embodiment of the invention. 
         FIG. 12  is a flow diagram of a process for sending voicemail to an accessory from a mobile communication device according to an embodiment of the invention. 
         FIG. 13  shows a flow diagram of a process for an accessory to access voicemail through a mobile communication device according to some embodiments. 
         FIG. 14  shows a flow diagram of a process for allowing an accessory to access voicemail through a mobile communication device according to some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Certain embodiments of the present invention provide improved interoperability of a mobile communication device with a speaker accessory, including echo cancellation. In one embodiment, when a mobile communication device that is docked with a speaker accessory detects the beginning of a phone call (e.g., when a call is received or placed), it can notify the speaker accessory and disable its own internal echo cancellation operations. The speaker accessory, which can also have a microphone, can enable its echo cancellation operations, providing clear audio to the parties to the call. 
     In other embodiments, the coordination of echo cancellation between the mobile communication device and the accessory can be applied in phone calls as well as other situations. For example, a number of situations can arise where an accessory is receiving audio signals from the mobile communication device and concurrently delivering audio signals to the mobile communication device, sometimes referred to herein as a “duplex” audio mode. In any such situation, the mobile communication device and the accessory can coordinate the responsibility for various audio processing operations, such as echo cancellation. In one embodiment, the mobile communication device can signal to the accessory to indicate when the accessory should enter or exit duplex audio mode. When in duplex audio mode, the accessory can enable its internal audio processing operations (e.g., echo cancellation) while the mobile communication device disables its corresponding internal operations (or vice versa). When the accessory transitions to a mode other than duplex, the mobile communication device can re-enable its own internal audio processing operations and the accessory can disable its corresponding internal operations. 
     In further embodiments, the accessory may provide user input controls allowing the user to remotely operate the phone functionality of the mobile communication device. For example, the accessory may be able to instruct the mobile communication device to answer or disconnect a call, to place a call to a selected number, to display voice mail notifications or content, or the like. 
     In yet further embodiments, an accessory can provide a messaging interface for a user while coupled with the mobile communication device. For example, the accessory can receive a notification from the mobile communication device that a message has been received. The accessory can alert the user with an audible or a visual notification through a user interface that indicates that the message can be viewed. The message can be provided to the user through accessory. The message, for example, can be text, email, voicemail, MMS, SMS, etc. 
       FIG. 1  is a simplified illustration of a system  100  according to an embodiment of the present invention. System  100  includes a mobile communication device  102  that can be connected to an accessory  104  via a cable  106 . In one embodiment, mobile communication device  102  can be an iPhone™; other mobile communication devices can also be used. Mobile communication device  102  can include a built-in speaker  108  and a built-in microphone  110 . Built-in speaker  108  can produce audible sound in response to a suitable electrical signal, and built-in microphone  110  can generate electrical signals in response to incident sound waves. Mobile communication device  102  can also provide a user interface such as touch-screen display, allowing a user to control mobile communication device  102 . 
     Mobile communication device  102  can support a variety of operations including placing and/or receiving telephone calls, e.g., by communicating with a conventional cellular telephone network, other mobile telephone network, or a data network such as the Internet (e.g., using voice-over-IP technology). During a telephone call, mobile communication device  102  can deliver sounds to the user via speaker  108  and can receive sounds from the user via microphone  110 . Mobile device  102  can implement various audio processing operations to optimize the sound quality. For example, mobile communication device  102  can perform echo cancellation to reduce feedback between sound produced by speaker  108  and sound detected by microphone  110 . As another example, mobile communication device  102  may also perform noise reduction operations and/or automatic gain control operations on signals received via microphone  110 . Those skilled in the art will recognize that a variety of audio processing techniques, including but not limited to techniques presently known in the art, can be used in connection with various embodiments of the present invention; accordingly a detailed description of such techniques has been omitted. 
     Other operations supported by mobile communication device  102  can include, e.g., storage and playback of media assets; access to the Internet, e.g., via wireless connections such as Wi-Fi (referring generally to any standard within the IEEE 802.11 family) and/or advanced wireless data networks using third-generation (“3G”) technology; and execution of various application programs that can be installed on mobile communication device  102  by a user. Some of these application programs may call for mobile communication device  102  to provide audio output and/or accept audio input, as well as performing other operations, and in some embodiments, mobile communication device  102  can use built-in speakers  108  and/or microphone  110  whenever audio operations are needed by a particular application. 
     Mobile communication device  102  can also include a connector  112  that can receive one end connector  113  of cable  106 . Connector  112  can include a number of pins assigned to carry various signals, including audio signals from mobile communication device  102  to accessory  104  (referred to herein as “line-out” or “audio-out” signals) and audio signals from accessory  104  to mobile communication device  102  (referred to herein as “line-in” or “audio-in” signals). Connector  112  can also include pins assigned to carry other signals, such as video signals and/or digital data (including, e.g., commands and other information as described below), as well as pins for providing electrical power and ground connections between mobile communication device  102  and accessory  104 . In one embodiment, a certain pin (or pins) can be assigned to deliver power from mobile communication device  102  to accessory  104  while another pin (or pins) can be assigned to deliver power from accessory  104  to mobile communication device  102 . Thus, either device in system  100  can provide power to the other. 
     Accessory  104  can receive other end connector  115  of cable  106  at an accessory connector  114 . In some embodiments, accessory connector  114  can have a different form factor and/or number of contacts from mobile communication device connector  112 . In other embodiments, the two connectors can be the same, and in still other embodiments, accessory connector  114  can be designed to mate directly with mobile communication device connector  112  so that cable  106  is not required. In further embodiments, some or all communication between mobile communication device  102  and accessory  104  may take place wirelessly, e.g., via Bluetooth or other short-range wireless protocols. 
     Accessory  104  can be a speaker dock or any other accessory that is capable of receiving audio signals from mobile communication device  102  and/or providing audio signals to mobile communication device  102  (e.g., via cable  106 ). In the embodiment shown, accessory  104  includes stereo speakers  122  that can produce sounds in response to audio signals received from mobile communication device  102  and a microphone  124  that can generate electrical signals in response to sounds. Accessory  104  can provide the electrical signals generated by microphone  124 , with or without processing, to mobile communication device  102 , e.g., via cable  106 . In particular, accessory  104  may be capable of concurrently receiving audio signals from and supplying audio signals to mobile communication device  102 ; this mode of operation is referred to herein as “duplex” mode and is contrasted with “simplex” modes in which accessory  104  can be either receiving audio signals or supplying audio signals but not both concurrently. 
     When operating in duplex mode (or simplex mode), accessory  104  can be capable of performing various audio processing operations to optimize sound quality. For example, when operating in either simplex or duplex mode, accessory  104  can implement noise reduction and/or automatic gain control techniques to improve the quality of signals generated by microphone  124 . When operating in duplex mode, accessory  104  can also implement echo cancellation techniques between the signals output to speakers  122  and signals received from microphone  124 . As with audio processing by mobile communication device  102 , a variety of audio processing techniques, including but not limited to techniques presently known in the art, can be used in connection with embodiments of the present invention; a detailed description of such techniques has been omitted. 
     Accessory  104  can also provide user interface components such as volume control  126  and display  128 . In addition or instead, accessory  104  can be equipped with a remote control  130  that can communicate user input to accessory  104  via a wireless channel (e.g., using infrared or radio-frequency (RF) signaling). Remote control  130  can include various controls, e.g., buttons  132 . In some embodiments, remote control  130  can include a display area  134  for providing visual information to the user. Thus, a user can operate accessory  104  by interacting directly with user interface components  126 ,  128  or by interacting with remote control  130 . 
     In some embodiments, user interface components of accessory  104  (including components  126 ,  128  and/or remote control  130 ) can be operated to control various operations of mobile communication device  102 . For example, accessory  104  can generate commands to mobile communication device  102  based on user input received via remote control  130 ; the commands can be communicated to mobile communication device  102  via cable  106 . Mobile communication device  102  can invoke various of its functions in response to these commands. As one example, a user can operate remote control  130  (or interface components  126 ,  128 ) to place and/or receive phone calls on mobile communication device  102 , as described below. 
     It will be appreciated that system  100  is illustrative and that variations and modifications are possible. A variety of mobile communication devices  102  and accessories  104  can be used. The degree to which mobile communication device  102  can be controlled via accessory  104  can be varied as desired. 
       FIG. 2  is a simplified block diagram showing a system  200  according to an embodiment of the present invention. In some embodiments, system  200  can implement system  100  of  FIG. 1 . System  200  includes a mobile communication device (“MCD”)  202  connected to an accessory  204 . 
     MCD  202 , which in some embodiments can implement mobile communication device  102  of  FIG. 1 , includes a processor  206 , a user interface  208 , a storage device  210 , a radio-frequency (“RF”) section  212 , an audio section  214 , a video section  216 , an accessory I/O (“input/output”) interface  218 , a built-in speaker  220  and a built-in microphone (“mic”)  222 . 
     Processor  206 , which can be implemented as one or more integrated circuits (including, e.g., a conventional microprocessor or microcontroller), can control the operation of MCD  202 . For example, in response to user input signals provided by user interface  208 , processor  206  can select and play media assets stored in storage device  210 ; operate RF section  212  to place and/or receive telephone calls; execute various application programs residing on storage device  210 ; and so on. Processor  206  can also manage communication with accessories via accessory I/O interface  218 . 
     User interface  208  can include input controls such as a touch pad, touch screen, scroll wheel, click wheel, dial, button, keypad, or the like, as well as output devices such as a display screen, indicator lights, etc., together with supporting electronics (e.g., digital-to-analog or analog-to-digital converters, signal processors or the like). Although shown separately, built-in speaker  220  and/or built-in microphone  222  can operate as components of user interface  208  to provide sound output to a user and to receive sound input from a user, respectively. A user can operate the various input controls of user interface  208  to invoke the functionality of MCD  202  and can also view and/or hear output from MCD  202  via user interface  208 . 
     Storage device  210  may be implemented, e.g., using disk, flash memory, or any other non-volatile storage medium. In some embodiments, storage device  210  can store media assets such as audio, video, still images, or the like, that can be played by mobile communication device  202 . Storage device  210  can also store metadata describing the media assets (e.g., asset name, artist, title, genre, etc.), playlists (lists of assets that can be played sequentially or in random order), and the like. Storage device  210  can also store information other than media assets, such as information about a user&#39;s contacts (names, addresses, phone numbers, etc.); scheduled appointments and events; notes; and/or other personal information. In still other embodiments, storage device  210  can store one or more programs to be executed by processor  206 , such as video game programs, personal information management programs, programs for playing media assets and/or navigating the media asset database, programs for controlling a telephone interface to place and/or receive calls, and so on. 
     RF section  212  provides an interface to a mobile communication network. In one embodiment, the mobile communication network can be a cellular telephone network or other network capable of carrying a telephone call between mobile communication device  102  and another telephone device (not shown). RF section  212  can include analog-to-digital and/or digital-to-analog circuitry, baseband processing components (e.g., codecs, channel estimators, and the like), modulators, demodulators, oscillators, amplifiers, transmitters, receivers, transceivers, internal and/or external antennas, and so on. As such, RF section  212  can include one or more integrated circuits as desired. In some embodiments, some operations associated with RF section  212  can be implemented entirely or in part as programs executed on processor  206  (e.g., encoding, decoding, and/or other processing in the digital domain), or a dedicated digital signal processor can be provided. In some embodiments, RF section  212  may also be operable to wirelessly access other communication networks such as the Internet, e.g., using 3G, WiFi, Bluetooth, and/or other RF communication technologies. Thus, for example, multiple transmitter, receiver, and/or transceiver chips may be present in RF section  212 , and different chips may use a separate antenna or share an antenna; alternatively, a single chip can support multiple communication channels and/or networks using one or more antennas. 
     Audio section  214  can control the routing of analog and/or digital audio signals within mobile communication device  202  and can also implement audio processing operations such as noise reduction, echo cancellation, gain control, analog-to-digital and digital-to-analog conversion, and the like. (Although shown separately, some or all operations of audio section  214  can be implemented as software executed by processor  206 .) In particular, audio section  214  can select a source to provide input audio signals. In one embodiment, audio section  214  can select between built-in microphone  222  and a “line-in” signal delivered from accessory I/O interface  218 . In another embodiment, MCD  202  can have one or more additional sources of audio signals; for example, MCD  202  may have an external microphone jack, a Bluetooth receiver capable of receiving voice or other audio signals, or the like. Audio section  214  can select incoming audio from any available source, process the audio as desired (e.g., convert analog audio signals to digital, apply noise reduction and/or echo cancellation, etc.) and route it to another destination. For instance, during a phone call, audio section  214  might route incoming audio from built-in microphone  222  to RF section  212 . (A direct connection between audio section  214  and RF section  212  is not shown in  FIG. 2 , but it is to be understood that such direct routing can be implemented if desired.) 
     Similarly, audio section  214  can select a destination to receive output audio signals. In one embodiment, audio section  214  can select between built-in speaker  220  and a “line-out” signal delivered to accessory I/O interface  218 . In another embodiment, MCD  202  can have one or more additional destinations for output audio signals; for example, MCD  202  may have a jack for connecting external speakers or headphones, a Bluetooth transmitter capable of transmitting voice or other audio signals, or the like. Audio section  214  can route audio signals to any available destination. For instance, during a phone call, audio section  214  might route incoming audio signals extracted by RF section  212  to built-in speaker  220 . 
     In some embodiments, the routing and processing decisions made by audio section  214  can be controlled by processor  206 . For example, audio section  214  may have one or more control registers into which processor  206  can write control parameters indicating what audio section  214  should do. Examples of control parameters include: selection of audio source; selection of audio destination; selection of which (if any) signal processing operations to perform on a received audio signal before routing that signal to a destination; various settings to regulate aspects of audio signal processing operations; and so on. In some embodiments, program code executing on processor  206  can include instructions to update some or all of these control parameters, thereby altering the manner in which audio is processed and/or routed by audio section  214 . 
     Video section  216  can control video delivery by MCD  202 . For example, during playback of a video asset stored in storage device  210 , video section  216  can route video signals to a built-in display (not explicitly shown but understood to be part of user interface  208 ) and/or to a “video out” line of accessory I/O interface  218 . In embodiments where MCD  202  is capable of receiving video signals from an external source, video section  216  can select the external source (e.g., a “video in” line from accessory I/O interface  218 ) and direct the video signals to a destination, for instance, processor  206 . Video section  216  in some embodiments can include video processing capability such as image scaling, format conversions, etc. As with audio section  214 , operation of video section  216  can be controlled by processor  206 , e.g., by writing control parameters to control registers of video section  216 . 
     Accessory I/O interface  218  can include a number of signal paths configured to carry various signals between MCD  202  and accessory  204 . In one embodiment, accessory I/O interface  218  includes a 30-pin connector corresponding to the connector used on iPod® and iPhone™ products manufactured and sold by Apple Inc. Alternatively or additionally, accessory I/O interface  218  can include a wireless interface (e.g., Bluetooth or the like). 
     In some embodiments, MCD  202  can also use accessory I/O interface  218  to communicate with a host computer (not explicitly shown) that executes a media asset management program (such as the iTunes® media asset management program distributed by Apple Inc.). In some embodiments, the media asset management program can allow a user to modify the database of media assets stored in storage device  210 ; to update personal data (e.g., calendar, contacts) stored in storage device  210 ; and/or to add, update, or remove application programs on storage device  210 . In other embodiments, MCD  202  can include a wireless interface (not explicitly shown) that can provide communication with a host computer and/or a computer network. 
     Accessory  204 , which in some embodiments can implement accessory  104  of  FIG. 1 , can include a controller  232 , a user interface  234 , an audio section  236 , an MCD I/O interface  238 , a speaker  240 , and a microphone  242 . 
     Controller  232  can include, e.g., a microprocessor or microcontroller executing program code to perform various functions such as digital audio decoding, analog or digital audio and/or video processing, processing of user input, and the like. Controller  232  can also manage communication with an MCD via MCD I/O interface  238 . 
     User interface  234  can include input controls such as a touch pad, touch screen, scroll wheel, click wheel, dial, button, keypad, microphone, or the like, as well as output devices such as a display screen, indicator lights, etc., together with supporting electronics (e.g., digital-to-analog or analog-to-digital converters, signal processors or the like). In some embodiments, user interface  234  can also incorporate a receiver for signals from an associated remote control device (e.g., remote control  130  of  FIG. 1 ). Although shown separately, speaker  240  and/or microphone  242  can operate as components of user interface  234  to provide sound output to a user and to receive sound input from a user, respectively. A user can operate the various input controls of user interface  234  to invoke the functionality of accessory  204  and can view and/or hear output from accessory  204  via user interface  234 . In some embodiments, the user can also operate the various input controls of user interface  234  to invoke functionality of MCD  202  via accessory  204 . For example, in response to user input, controller  232  may generate commands to be sent to MCD  202  via MCD I/O interface  238 . 
     Audio section  236  can receive the “line-out” signal from MCD  202  via MCD I/O interface  238  and can route the signal appropriately. (Throughout this disclosure, the audio signals exchanged between an MCD and an accessory are referred to from the perspective of the MCD; thus, “line-out” or “audio-out” is to be understood as referring generally to an audio signal delivered from the MCD to the accessory, while “line-in” or “audio-in” refers generally to an audio signal delivered from the accessory to the MCD.) For instance, audio section  236  can route the line-out signal to speaker  240  or to an external speaker connection (not explicitly shown). Similarly, audio section  236  can select an audio signal to be delivered as the “line-in” signal to MCD  202  via MCD I/O interface  238 . For instance, audio section  236  can select microphone  242  or an external microphone connection (not explicitly shown) as an audio source. In some embodiments, audio section  236  can also effectively cut off an audio signal; for instance, it can be configured to ignore any received line-out signal from MCD  202  and/or to provide no line-in signal to MCD  202 . 
     In various embodiments, audio section  236  can route signals with or without further processing. For example, audio section  236  can be configured to perform noise reduction, echo cancellation, gain control, and/or other processing on audio signals received from microphone  242  before delivering them to the line-in signal path. 
     Configuration of audio section  236  can be controlled by controller  232 , e.g., by writing control parameter values to control registers of audio section  236 . For example, at a certain time, controller  232  can configure audio section  236  to operate in a duplex mode in which a line-out signal received from MCD  202  is routed to speaker  240  (or an external speaker connection) concurrently with delivering an audio signal received from microphone  242  (or an external microphone connection) as a line-in signal to MCD  202 . At a different time, controller  232  can configure audio section  236  to operate in an output-only simplex mode in which line-out is routed to speaker  240  while line-in is not generated or in an input-only simplex mode in which line-in is generated from microphone  242  while line-out is not routed to any destination (i.e., it is ignored). 
     It will be appreciated that the system configurations and components described herein are illustrative and that variations and modifications are possible. The MCD and/or accessory may have other capabilities not specifically described herein. 
     Accessory I/O interface  218  of MCD  202  and MCD I/O interface  238  of accessory  204  allow MCD  202  to be connected to accessory  204  and subsequently disconnected from accessory  204 . As used herein, MCD  202  and accessory  204  are “connected” whenever a communication channel between accessory I/O interface  218  and MCD I/O interface  238  is open and are “disconnected” whenever the communication channel is closed. Connection can be achieved by physical attachment (e.g., between respective mating connectors of MCD  202  and accessory  204 ), by an indirect connection such as a cable, or by establishing a wireless communication channel. Similarly, disconnection can be achieved by physical detachment, disconnecting a cable, powering down accessory  204  or MCD  202 , or closing the wireless communication channel. Thus, a variety of communication channels may be used, including wired channels such as USB, FireWire, or universal asynchronous receiver/transmitter (“UART”), or wireless channels such as Bluetooth, WiFi, infrared or the like. In some embodiments, multiple communication channels between a media player and an accessory can be open concurrently, or a media player can be concurrently connected to multiple accessories, with each accessory using a different communication channel. 
     Regardless of the particular communication channel, as long as MCD  202  and accessory  204  are connected to each other, the devices can communicate by exchanging commands and data according to a protocol. The protocol defines a format for sending messages between MCD  202  and accessory  204 . For instance, the protocol may specify that each message is sent in a packet with a header and an optional payload. The header can provide basic information such as a start indicator, length of the packet, and a command to be processed by the recipient, while the payload provides any data associated with the command; the amount of associated data can be different for different commands, and some commands may provide for variable-length payloads. The packet can also include error-detection or error-correction codes, e.g., as known in the art. In various embodiments, the protocol can define specific commands to indicate an action to be taken by the recipient; to signal completion of a task, change of state, or occurrence of an error; and/or to identify the nature of the associated data. In some embodiments, the commands may be defined such that any particular command is valid in only one direction. 
     The protocol can define a number of “lingoes,” where a “lingo” refers generally to a group of related commands that can be supported (or unsupported) by various classes of accessories. In one embodiment, a command can be uniquely identified by a first byte identifying the lingo to which the command belongs and a second byte identifying the particular command within the lingo. Other command structures may also be used. It is not required that all accessories, or all MCDs to which an accessory can be connected, support every lingo defined within the protocol or every command of a particular lingo (for instance, different devices might use different versions of a given lingo). 
     In some embodiments, every accessory  204  and every MCD  202  that are designed to be interoperable with each other support at least a “general” lingo that includes commands common to all such devices. The general lingo can include commands enabling the MCD and the accessory to identify themselves to each other and to provide at least some information about their respective capabilities, including which (if any) other lingoes each supports and which capabilities of the other device each intends to use while connected. For example, the accessory may use one or more identification commands to indicate whether it has a microphone or other source of line-in, whether it can receive line-out from MCD  202 , whether it supports duplex mode (using both line-in and line-out capabilities of MCD  202  simultaneously), and/or whether it intends to send commands for remotely controlling operations of MCD  202 . 
     The general lingo can also include authentication commands that the MCD can use to verify the purported identity and capabilities of the accessory (or vice versa), and the accessory (or MCD) may be blocked from invoking certain commands or lingoes if the authentication is unsuccessful. 
     The protocol can also include various Notify commands that can be sent by MCD  202  to accessory  204  upon the occurrence of certain events. Each event may have a different associated Notify command, or fewer Notify commands can be used, with each instance of a Notify command carrying associated data indicative of the particular event. In some embodiments, the protocol can also include one or more Register commands that accessory  204  can use to subscribe to or unsubscribe from receiving particular Notify commands or notifications of particular events. In other embodiments, MCD  202  can determine which notifications accessory  204  should receive based on the identification information provided by accessory  204 . For instance, if accessory  204  indicates that it can operate in a duplex mode, MCD  202  may determine that accessory  204  should receive notifications as to when duplex mode should be entered or exited. In still other embodiments, a combination of accessory-driven subscription and determinations by the MCD can be used to control which notifications are sent to a particular accessory. 
     The protocol can also include commands or groups of commands that support remote control of various operations of MCD  202  by accessory  204  For example, one remote control command can be a ButtonStatus command sendable by accessory  204  to MCD  202 . This command can be sent with associated data in the form of a bitmask indicating the current state of various user-operable controls of accessory  204 . Based on the bitmask, MCD  202  can take various actions. For example, certain bits of the bitmask can be associated with accepting an incoming call (“Answer”), diverting an incoming call to voice mail (“Divert”), or ending a current call (“Hang Up”); thus, accessory  204  can instruct MCD  202  to take any of these actions. 
     Another remote control command can be a DialNumber command sendable by accessory  204  to MCD  202 . The associated data for this command can be, for example, a telephone number. Upon receiving this command, MCD  202  can initiate a telephone call to the specified number. Still other commands can be provided. For example, a VoiceDial command sendable by accessory  204  might be provided. Upon receiving the VoiceDial command, MCD  202  can enable line-in and receive audio from accessory  204 . The user can then speak a name, telephone number, or other words that map to a particular telephone number into microphone  242 ; audio section  236  routes the corresponding audio signal as line-in to MCD  202 . Processor  206  (or another component) of MCD  202  can analyze the sound and determine a number to call. 
     Other remote-control commands can be provided to allow a user of accessory  204  to navigate contacts stored in storage device  210  of MCD  202  by interacting with user interface  234  of accessory  204 . For example, in one embodiment, the user can search for a contact by name or number, or the user can browse a listing of contacts that can be filtered or grouped by name, company name, user-assigned category, or the like. Such navigation commands can include a selection command sendable by accessory  204  to inform MCD  202  of the user&#39;s desired action and a responsive command sendable by MCD  202  to provide information resulting from the action (e.g., a list of contacts or information about the list, such as the number of contacts found) to accessory  204 . In some embodiments, depending on the amount of information sendable by MCD  202 , a user can view the contact information on a display device of accessory  204  and/or on a display device of MCD  202 . The navigational commands can include a DialContact command sendable by accessory  204  to instruct MCD  202  to call a contact selected by the user. 
     It will be appreciated that the protocol described herein is illustrative and that variations and modifications are possible. Specific commands described herein can be replaced with other commands or combination of commands or other types of messages and formats. In addition, it is not required that all of the commands and operations described herein be supported by any particular mobile communication device or accessory. 
     Certain embodiments relate to the use of accessory  204  in conjunction with MCD  202  to provide a speaker phone, allowing a user to place and/or receive calls via MCD  202  by operating accessory  204 . Referring again to  FIG. 2 , during a phone call, the user&#39;s voice can be detected by microphone  242  of accessory  204  and delivered as line-in to MCD  202 . Within MCD  202 , audio section  214  can route the line-in signal (with or without further processing) to RF section  212  to be transmitted across the telephone network, thus allowing the user to speak to the other party (or parties) to the call. Similarly, RF section  212  can receive signals corresponding to the other party&#39;s voice. These signals can be decoded (e.g., in RF section  212  and/or processor  206 ) and delivered as an audio signal to audio section  214 . Audio section  214  can route this signal (with or without further processing) on the line-out path to accessory  204 . Within accessory  204 , audio section  236  can route the line-out signal to speaker  240 , thus allowing the user to hear the other party. During such operations, built-in speaker  220  and built-in microphone  222  of MCD  202  can be disabled. 
     During such a phone call, echo cancellation between speaker  240  and microphone  242  may be desirable to the extent that microphone  242  can pick up sounds from speaker  240 . As described above, both MCD  202  and accessory  204  can have echo cancellation capability; however, it would not be desirable for both to perform echo cancellation on the same signal. Accordingly, some embodiments provide coordinated control of echo cancellation so that echo cancellation is performed by only one device. In embodiments described below, accessory  204  performs the echo cancellation during a phone call; echo cancellation built into accessory  204  can be more readily optimized for the particular characteristics of speaker  240  and microphone  242 . However, other embodiments may provide that MCD  202  performs echo cancellation. 
       FIG. 3  is a flow diagram of a process  300  for handling an incoming telephone call by a mobile communication device according to one embodiment of the present invention. In this embodiment, before the call is received, a mobile communication device (e.g., MCD  202  of  FIG. 2 ) is connected to an accessory (e.g., accessory  204 ) that is operable in a duplex mode but not currently operating in duplex mode. For example, the accessory might be operating as a speaker dock, playing audio content stored on MCD  202 . 
     Process  300  can start when accessory  204  becomes connected to MCD  202 . At block  302 , MCD  202  establishes communication with accessory  204 . In some embodiments, establishing communication can include identification and authentication in accordance with the communication protocol. At block  304 , MCD  202  can obtain capability information from accessory  204 . For example, accessory  204  can indicate whether it provides a microphone, whether it is capable of operating in a duplex mode, and whether it provides echo cancellation; accessory  204  can also provide any other applicable information about its capabilities, including other audio processing capabilities such as noise reduction. In some embodiments, accessory  204  can provide any or all of its capability information as part of establishing communication at block  302 . In some embodiments, process  300  continues only if accessory  204  supports at least duplex mode and echo cancellation. 
     At block  306 , MCD  202  can begin delivering audio signals (line-out) to accessory  204 . For example, a user might operate MCD  202 , either directly or using a remote control feature supported by accessory  204 , to select one or more audio or video tracks for playback. MCD  202  can route the audio portion of the track to accessory  204 . Delivery of audio signals to accessory  204  can continue indefinitely. 
     At block  308 , MCD  202  detects a phone call (in this example, an incoming call) and can generate an alert for the user. For example, MCD  202  can pause the playback of any currently playing track and play a ring tone, display a message, vibrate, and/or take other action to alert a user to an incoming phone call. At block  310 , MCD  202  determines whether the user desires to answer the call. For example, the user can press an “answer” button on MCD  202 . Or in some embodiments, the user can communicate a desire to answer by operating accessory  204 , which can send a remote-control command such as the ButtonStatus command described above to report the user&#39;s desire to MCD  202 . The user can also choose not to answer, e.g., by operating a “divert” control to divert the call to voice mail or by taking no action at all within an allotted period. If the user does not answer the call, MCD  202  can resume playback of the currently playing track, and process  300  can return to step  306  until another incoming call is detected. 
     If, at block  310 , the user chooses to answer the call, then at block  312 , MCD  202  notifies accessory  204  to enter duplex mode and to enable its echo cancellation features. In one embodiment MCD  202  can send a “begin call” notification message to indicate that a phone call is now in progress, and accessory  204  can interpret this message as a signal to enter duplex mode and enable echo cancellation. In another embodiment, MCD  202  can send one or more specific commands to instruct accessory  204  to enter duplex mode and enable echo cancellation. At block  314 , MCD  202  can disable its own internal echo cancellation. In some embodiments, if MCD  202  has not already enabled line-in from accessory  204 , it can do so at block  314 . 
     At block  316 , MCD  202  can deliver received audio content for the phone call to accessory  204  as the line-out signal. As described above, this content may be received via RF section  212  and processed (or not) by audio section  214  prior to delivery as line-out. At block  318 , MCD  202  can process audio content received from accessory  204  via line-in and transmit it to the mobile communication network, e.g., via RF section  212 . Such processing can include conversion to a digital format, modulation, etc., but in this embodiment does not include echo cancellation by MCD  202  (which was disabled at block  314 ). It is to be understood that acts associated with blocks  316  and  318  may be performed simultaneously or concurrently; thus, the user can speak to the caller while hearing anything the caller might say. 
     At block  320 , it is determined whether the call should be disconnected. For example, MCD  202  may detect that the call has been terminated by the mobile communication network (e.g., if the other party hangs up or the connection is lost). MCD  202  may also detect that its user has indicated that the call should end. For instance, in some embodiments, the user can press a “hang up” button on MCD  202 ; in other embodiments, the user can communicate a desire to end the call by operating accessory  204 , which can send a remote-control command such as the ButtonStatus command described above to report the user&#39;s desire to MCD  202 . Until such time as MCD  202  determines that the call should be disconnected, blocks  316  and  318  can continue to be executed. Once MCD  202  determines that the call should be ended, at block  322 , MCD  202  can notify accessory  204  of the end of the call. In one embodiment, MCD  202  can send an “end call” notification message to indicate that the phone call is no longer in progress. Accessory  204  can interpret this notification as a signal to exit duplex mode (e.g., returning to the line-out-only mode) and to disable its echo cancellation. 
     At block  324 , MCD  202  can reset its internal state to the state preceding the phone call, e.g., line-out enabled, line-in disabled. Process  300  can return to block  306 ; for example, MCD  202  can resume playing the track that was paused when the phone call was detected at block  308 . Process  300  can continue indefinitely, e.g., until accessory  204  and MCD  202  become disconnected. 
       FIG. 4  is a flow diagram of a process  400  for handling an incoming telephone call by an accessory device according to an embodiment of the present invention. Process  400  can be executed by accessory  204  while MCD  202  executes process  300 . 
     Process  400  can start when accessory  204  becomes connected to MCD  202 . At block  402 , accessory  204  establishes communication with MCD  202 . Like block  302  of process  300 , block  402  can include identification and authentication in accordance with the communication protocol. At block  404 , accessory  204  can provide capability information to MCD  202 . For example, accessory  204  can indicate whether it provides a microphone, whether it is capable of operating in a duplex mode, and whether it provides echo cancellation; accessory  204  can also provide any other applicable information about its capabilities, including other audio processing capabilities such as noise reduction. In some embodiments, accessory  204  can provide any or all of its capability information as part of establishing communication at block  402 . In some embodiments, process  400  continues only if accessory  204  supports at least duplex mode and echo cancellation. 
     At block  406 , accessory  204  can initialize its audio state, e.g., in line-out simplex mode. In this mode, accessory  204  can receive line-out from MCD  202  (block  408 ) but does not provide line-in to MCD  202 ; in some embodiments, audio section  236  of accessory  204  disables sending of signals onto the line-in path while in line-out simplex mode. Line-out simplex mode supports various operations not requiring two-way audio. For example, as noted above, a user can operate MCD  202  (either directly or using remote-control features supported by accessory  204 ) to play back various media tracks; the audio portion of the playback can be received as line-out by accessory  204 . Process  400  can remain at block  408  indefinitely. 
     At block  410 , accessory  204  receives a notification from MCD  202  that it should enter duplex mode and enable its echo cancellation features. For example, as described above, the notification can be a “begin call” notification message or one or more specific commands directing the accessory to take these actions. At block  412 , accessory  204  responds to the notification by enabling its internal echo cancellation and enabling line-in to MCD  202 , thus entering duplex mode. 
     At block  414 , accessory  204  can play the line-out signal for the user (e.g., on speaker  240 ) while concurrently processing audio input (e.g., from microphone  242 ) and delivering the processed audio input as line-in to MCD  202 . In this embodiment, processing of audio input by accessory  204  includes the echo cancellation that was enabled at block  412 . Process  400  can continue at block  414  for as long as the phone call continues. 
     At block  416 , accessory  204  can receive a notification from MCD  202  that duplex mode should be exited. For example, as described above, the notification can be an “end call” notification message or one or more commands instructing the accessory to take specific actions such as exiting duplex mode. At block  418 , accessory  204  can respond to the notification by disabling its internal echo cancellation and disabling line-in to MCD  202 , thus resuming the line-out simplex mode. Process  400  can then return to block  406 . Thus, like process  300 , process  400  can continue e.g., until accessory  204  and MCD  202  become disconnected. 
     It will be appreciated that processes  300  and  400  are illustrative and that variations and modifications are possible. Steps described as sequential may be executed in parallel, order of steps may be varied, and steps may be modified, combined, added or omitted. For instance, while the embodiment above describes the accessory as operating in a line-in simplex mode when a call is not in progress, other modes can also be used. For example, the accessory can operate in a line-out simplex mode when a call is not in progress, as might be the case if the user is operating the accessory and mobile communication device to record voice or other audio input via a microphone. (In such a case, the accessory&#39;s echo cancellation might not be active prior to the phone call since no signal is being delivered to the accessory&#39;s speaker.) Such recording can be paused when a call is received. In some instances, the accessory might have both line-in and line-out disabled at a time when a call is not in progress, e.g., if the user is simply using the accessory to charge the mobile communication device and is neither listening to nor recording audio. Where this is the case, the accessory can respond to a begin-call notification by enabling both line-in and line-out. 
     Further, the processes described above can be used to manage other types of audio processing in addition to or instead of echo cancellation. In some embodiments, for example, both the accessory and the mobile communication device can be capable of applying noise reduction techniques to an audio signal. Often, applying noise reduction at two stages can actually degrade the signal; thus, it may be desired to coordinate which device performs noise reduction. In one embodiment, the begin-call notification can signal the accessory to enable noise reduction and/or other audio processing in addition to or instead of echo cancellation, and the mobile communication device can disable its internal noise reduction, echo cancellation, or any other audio processing task that is designated to be handled by the accessory during the call. In some embodiments, the capability information exchanged between the mobile communication device and the accessory can include information indicating which audio processing capabilities the accessory does or does not use when in duplex mode. When a call is in progress, the accessory can enable the specified capabilities; when no call is in progress, these capabilities can be enabled or disabled depending on how the accessory is being used at any given time. 
     In addition, the embodiments described above refer to situations in which a phone call is received by MCD  202 . In other embodiments, an accessory and a mobile communication device can interoperate to allow a user to place a call. For example, in process  300 , detecting a call at step  308  can also include detecting that the user is placing a call. In some embodiments, a user can place a call by interacting directly with the user interface of the mobile communication device even while the accessory is connected and can then use the accessory to provide audio input and output for the call as described above. 
     In other embodiments, a user can place a call by interacting with an accessory rather than directly with a mobile communication device.  FIG. 5  is a flow diagram of a process  500  for placing a call according to an embodiment of the present invention. Process  500  can be executed by an accessory (e.g., accessory  204  of  FIG. 2 ) that is connected to a mobile communication device (e.g., MCD  202  of  FIG. 2 ). 
     Process  500  can start when accessory  204  becomes connected to MCD  202 . At block  502 , accessory  204  establishes communication with MCD  202 . As with process  400  described above, block  502  can include identification and authentication in accordance with the communication protocol. At block  504 , accessory  204  can provide capability information to MCD  202 . In particular, accessory  204  can indicate whether it provides a microphone, whether it is capable of operating in a duplex mode, whether it provides echo cancellation, and whether it intends to use remote control commands to control the MCD; accessory  204  can also provide any other applicable information about its capabilities, including other audio processing capabilities such as noise reduction. In some embodiments, accessory  204  can provide any or all of its capability information as part of establishing communication at block  502 . In some embodiments, process  500  continues only if accessory  204  supports duplex mode and echo cancellation and also uses remote control commands. 
     At block  506 , accessory  204  initializes its audio mode, e.g., to line-out simplex mode. In this mode, accessory  204  can receive a line-out signal from MCD  202  (block  508 ) but does not provide a line-in signal to MCD  202 . For example, as noted above, a user can operate MCD  202  (either directly or using remote-control features supported by accessory  204 ) to play back various media tracks; the audio portion can be received on the line-out path by accessory  204 . Process  500  can remain at block  508  indefinitely. (As noted above, other embodiments may use other audio modes such as line-in simplex or audio-off mode.) 
     At block  510 , accessory  204  detects user input requesting initiation of a phone call. For example, accessory  204  may provide user input controls that allow a user to dial a number, and accessory  204  can detect that the user has entered a number to dial. In other examples, accessory  204  may provide voice dialing, and the user can operate a control to indicate the desire to speak a phone number or name to be called. 
     At block  512 , accessory  204  can send an appropriate phone-dialing command to MCD  202 . For example, as noted above, the communication protocol can include a DialNumber command, allowing accessory  204  to provide MCD  202  with a number to be dialed. In the case of voice dialing, accessory  204  can enable line-in to MCD  202 , disable line-out from MCD  202  and send a VoiceDial command to MCD  202 ; in response to the VoiceDial command, MCD  202  can sample the signal received via line-in to detect and recognize the user&#39;s spoken instruction and thereby determine a number to dial. 
     At block  514 , accessory  204  can receive a message from MCD  202  indicating whether the call was successfully connected. In one embodiment, this can include the same begin-call notification as used in processes  300  and  400  described above, and the notification can be sent approximately when MCD  202  begins to place the call. At block  516 , accessory  204  can respond to the begin-call notification by enabling echo cancellation and entering duplex mode (e.g., enabling line-in to MCD  202 ). At block  518 , accessory  204  can play line-out signals received from MCD  202  for the user while processing microphone input and delivering the processed input via line-in to MCD  202 ; this can be similar to block  414  of process  400  described above. 
     In some embodiments, the accessory can enter duplex audio mode while MCD  202  is attempting to place the call. Thus, to the extent that MCD  202  generates audio signals reflecting the progress of placing a call (e.g., sounds indicating the number being dialed or transmitted to the network, a ringback tone while waiting for a called party to answer, etc.), those sounds can be delivered via line-out to accessory  204 , allowing the user to monitor progress of making the call just as if the call had been placed by interacting directly with MCD  202 . 
     Audio processing at block  518  can continue while at block  520  accessory  204  can continually monitor or periodically check to determine if the user has requested that the call should end. For example, the user may operate a “hang up” control on accessory  204 . If the user requests that the call should end, at block  522 , accessory  204  can notify MCD  202  to end the call, e.g., by sending a ButtonStatus command as described above with the bit corresponding to “Hang Up” set or by sending a specific EndCall command or the like. At block  524 , accessory  204  can check for an end-call notification from MCD  202 . MCD  202  may send the end-call notification, e.g., in response to the end-call instruction from accessory  204  at block  522  or in response to termination of the call by the mobile communication network (e.g., if the other party hangs up or the connection is lost). If no end-call notification is received at block  524 , process  500  can return to block  518  to continue duplex-mode audio for the call. 
     Once the end-call notification is received at block  524 , accessory  204  can disable its internal echo cancellation and resume the line-in simplex mode (or other audio mode that was enabled prior to placing the call) at block  526 ; process  500  can return to block  508  to resume playback of audio or other operation that may have been in progress when the call was placed. 
       FIG. 6  is a flow diagram of a process  600  for handling a telephone call placed using an accessory device according to an embodiment of the present invention. Process  600  can be executed by MCD  202  while accessory  204  executes process  500 . 
     Process  600  can start when MCD  202  becomes connected to accessory  204 . At block  602 , MCD  202  establishes communication with accessory  204 . As with other processes described above, block  602  can include identification and authentication in accordance with the communication protocol. At block  604 , MCD  202  can obtain capability and initial state information from accessory  204 . In particular, accessory  204  can indicate whether it provides a microphone, whether it is capable of operating in a duplex mode, whether it provides echo cancellation, and whether it intends to use remote control commands to control the MCD; accessory  204  can also provide any other applicable information about its capabilities, including other audio processing capabilities such as noise reduction. Accessory  204  can also provide initial-state information, e.g., whether it will begin operations in line-out simplex mode or some other mode. In some embodiments, accessory  204  can provide any or all of its capability and initial state information as part of establishing communication at block  602 . In some embodiments, process  600  continues only if accessory  204  supports duplex mode and echo cancellation and also uses remote control commands. 
     At block  606 , MCD  202  can begin delivering audio signals via the line-out path to accessory  204 . For example, a user might operate MCD  202 , either directly or using a remote control feature supported by accessory  204 , to select one or more audio or video tracks for playback. MCD  202  can route the audio portion of the track to accessory  204 . Delivery of audio signals to accessory  204  can continue indefinitely. Delivering line-out to accessory  204  at block  606  is appropriate if accessory  204  initially operates in line-out simplex mode or another mode in which it can receive line-out; in other embodiments, accessory  204  can initialize to a different audio mode, and MCD  202  may signal accessory  204  to enter line-out simplex mode before delivering audio at step  606 . Alternatively, block  606  can involve other audio operations (e.g., recording from accessory  204 ) or simply waiting with both line-in and line-out disabled. 
     At block  608 , MCD  202  can receive a phone-dialing command from accessory  204 . In various embodiments, any of the commands described above or other commands can be received. At block  610 , MCD  202  can send a begin-call notification to accessory  204 ; for instance, any of the notifications described above as signaling that accessory  204  should enter duplex mode can be used. At block  612 , MCD  202  can place the call, and in some embodiments, playback of other audio on line-out to accessory  204  can be paused while the call is placed. MCD  202  can place a call in various ways. For instance, MCD  202  can “dial” a number by transmitting it onto the mobile communication network in the form of a request for a connection to the specified number. MCD  202  can then wait for a telephone connection to be established on the network. In the meantime, at block  614 , MCD  202  can begin directing call-related audio to the line-out path so that it is delivered to the accessory. Thus, for example, MCD  202  can generate audio signals corresponding to “touch-tone” sounds indicating the number being transmitted onto the network and can generate signals corresponding to a ringback tone while waiting for the called party to answer. Such signals can be delivered via line-out to the accessory, allowing the user to hear the progress of the call being placed. Once the call connects, audio signals received via the mobile communication network can be processed and delivered via the line-out path to accessory  204 ; such processing can be similar to block  316  of process  300  ( FIG. 3 ) described above. 
     Once the call connects, MCD  202  can begin processing received audio signals on line-in and transmitting the processed signals to the mobile communication network (block  616 ). Such processing can be similar to block  318  of process  300  described above. It is to be understood that acts associated with blocks  614  and  616  can be performed simultaneously or concurrently, thereby supporting duplex audio. Further, in this embodiment MCD  202  need not perform echo cancellation or any other audio processing that would conflict with processing by accessory  204 . 
     At block  618 , MCD  202  can determine whether the call should be disconnected. In one embodiment, the call can become disconnected without ever being truly connected (e.g., if the network or the called party fails to respond during placing the call at block  612  and the call does not divert to a voice mail or other automated answering system). In other embodiments, MCD  202  can receive a command from accessory  204  indicating that the call should be ended, e.g., as described above. In still other embodiments, MCD  202  can detect that the call has been terminated by the mobile communication network. As long as the call continues, MCD  202  can continue to execute blocks  614  and  616 , allowing the user to speak and listen via accessory  204 . 
     Once MCD  202  determines that the call should end, MCD  202  can send an end-call notification to accessory  204  at block  620 ; any of the notifications described above as signaling that accessory  204  should exit duplex mode can be used. Thereafter, the accessory can revert to line-out simplex mode (or other audio mode it may have been using prior to the call), and process  600  can return to block  606  to provide further audio to accessory  204 . For example, MCD  202  can resume playback of a track that was paused when the call was initiated. 
     It will be appreciated that processes  500  and  600  are illustrative and that variations and modifications are possible. Steps described as sequential may be executed in parallel, order of steps may be varied, and steps may be modified, combined, added or omitted. For instance, as noted above, the accessory can operate in a mode other than line-out simplex mode when a call is not in progress; at the end of a call, the accessory can revert to the mode it was operating in prior to the call. Also as noted above, the techniques described herein can be used to regulate various aspects of audio processing behavior in addition to or instead of echo cancellation so that the accessory and the mobile communication device are in coordination as to what processing is to be done by which device. 
     Other techniques can also be used to place a call. For instance, if accessory  204  and MCD  202  support remote browsing of contacts stored on MCD  202  via the user interface of accessory  204 , a user can operate accessory  204  to select a contact to be called; accessory  204  can send a command to MCD  202  identifying the contact to be called; and MCD  202  can access a database of contact information (e.g., in storage device  210 ) to place the call. In another embodiment, accessory  204  can maintain its own database of contacts, and the user may select a contact to call from that database. 
     Further, techniques similar to those described above can be used to coordinate audio processing between a mobile communication device and an accessory in contexts other than making and/or receiving phone calls. For example, referring again to  FIG. 2 , in another embodiment, accessory  204  and MCD  202  can interoperate to provide a karaoke machine. In one implementation, MCD  202  can play a song while a user sings into microphone  242  of accessory  204  (or an external microphone connected to accessory  204 ). The signal from microphone  242  can be delivered via line-in to MCD  202 , which can mix the line-in signal with the audio signal of the song (e.g., in audio section  214  or processor  206 ) and route the mixed signal to line-out for delivery to speakers  240  of accessory  204 . In some embodiments, MCD  202  can also display song lyrics and/or provide timing prompts to the user (e.g., changing color of the displayed lyrics as the words are to be sung). Similarly, MCD  202  can interoperate with accessory  204  as a mixing board, with accessory  204  providing, via the line-in path, a signal (e.g., corresponding to a voice, instrument, or any other audio source) that is to be mixed with an audio signal generated by MCD  202  and delivered back to accessory  204  as a line-out signal. 
     More generally, in a number of different situations, an accessory device can operate in duplex mode and the line-in signal to a mobile communication device can be looped back onto the line-out path by the mobile communication device, either alone or in combination with another signal. In such situations, embodiments of the present invention can allow the mobile communication device and accessory to coordinate audio processing for optimum sound. 
       FIG. 7  is a message passing diagram illustrating coordination of audio processing between a mobile communication device and an accessory according to an embodiment of the present invention. Left-hand column  702  represents actions taken by a mobile communication device such as MCD  202  of  FIG. 2 ; right-hand column  704  represents actions taken by an accessory device such as accessory  204  of  FIG. 2 . The MCD and the accessory can connect and exchange capability information as described above (not explicitly shown in  FIG. 7 ) to establish an initial operating condition. In some embodiments, the initial operating condition can be a line-out simplex mode in which the MCD sends line-out to the accessory (block  706 ) and the accessory receives the line-out (block  708 ) or a line-in simplex mode in which the accessory sends line-in to the MCD (block  708 ) and the MCD receives the line-in (block  706 ). 
     At some point (block  710 ), the MCD can detect that the accessory should switch to duplex mode. For example, as described above, a phone call may be placed or received, or the user may launch a karaoke application, mixing-board application or other application in which the accessory should operate in duplex mode. Accordingly, at block  712 , the MCD can notify the accessory to enter duplex mode and enable echo cancellation. In some embodiments, the notification at block  712  may also notify the accessory to enable noise reduction and/or any other audio processing that it is desirable for the accessory to perform when in duplex mode. At block  714 , the accessory can respond to the notification by entering duplex mode and enabling echo cancellation (and/or other audio processing), while at block  716 , the MCD disables its own internal echo cancellation (and/or any other audio processing that has been designated to be handled by the accessory when in duplex mode). 
     The MCD and accessory can proceed to operate in duplex mode (blocks  718 ,  720 ), with the MCD receiving an audio signal via the line-in path from the accessory while sending an audio signal via the line-out path to the accessory; conversely, the accessory can send an audio signal via the line-in path to the MCD while receiving an audio signal via the line-out path from the MCD. During duplex-mode operation, the accessory can apply echo cancellation and/or any other audio processing that has been designated to be handled by the accessory while in duplex mode. 
     While operating in duplex mode, the MCD can detect (block  722 ) that duplex mode operation should end. For instance, a phone call may be disconnected, or the user may exit an application program that uses duplex mode such as karaoke or mixing board applications. When duplex mode operation should end, the MCD can signal the accessory (block  724 ) to exit duplex mode and disable echo cancellation (and/or any other audio processing that the accessory performs only in duplex mode). At block  726 , the accessory exits duplex mode. In one embodiment, when duplex mode is exited, the accessory can restore a simplex mode that it was operating in prior to entering duplex mode. Accordingly, the MCD and the accessory can return to the state depicted by blocks  706 ,  708 . In an alternative embodiment, the MCD can signal the accessory to transition to a different audio state upon exiting duplex mode, depending on what activity is expected to occur next. 
     In other embodiments, a user can receive a text message by interacting with an accessory rather than directly with a mobile communication device.  FIG. 8  is a flow diagram of a process  800  for handing text messages using an accessory device according to some embodiments of the invention. Process  800  can be executed by an accessory (e.g., accessory  204  of  FIG. 2 ) that is connected to a mobile communication device (e.g., MCD  202  of  FIG. 2 ). A text message, for example, can be an SMS message and/or an MMS message. 
     Process  800  can start when accessory  204  becomes connected to MCD  202 . At block  802 , accessory  204  establishes communication with MCD  202 . As with process  400  described above, block  802  can include identification and authentication in accordance with the communication protocol. At block  804 , accessory  204  can provide capability information to MCD  202 . In particular, accessory  204  can indicate whether it is capable of receiving and/or displaying text messages. Moreover, accessory  204  can indicate whether it is capable of receiving and/or displaying full text messages, partial text messages, multimedia text messages (MMS), and/or contact information associated with the text message. Accessory can also indicate whether it want to receive text message notifications. For example, an accessory can register with MCD  202  to receive text message notifications. Furthermore, accessory  204  can indicate whether it intends to use remote control commands to control MCD  202 . Accessory  204  can also provide any other applicable information about its capabilities at block  804 . In some embodiments, process  800  continues only if accessory  204  supports text messaging. 
     At block  806 , accessory  204  can receive a text message notification from MCD  202 . A text message notification can indicate to accessory  204  that a text message has been received at MCD  202 . In some embodiments, a text message notification can include an identifier associated with the text message, the phone number from where the text message was sent, at least some contact information, multimedia, a flag indicating multimedia is associated with the text message, the full text message, and/or a portion of the text message. Process  800  can remain at block  806  indefinitely, or until a text message notification is received from MCD  202 . While at block  806 , accessory can perform other tasks, such as media playback, etc. 
     At block  808 , accessory  204  can notify the user that a text message has been received. In some embodiments, such notifications can be turned off at accessory  204  by the user. If the notifications are turned off, in some embodiments, then process  800  can end. In some embodiments, the user can be alerted and queried whether the user would like to view the text message through a user interface (e.g., user interface  234 ). User notifications can also include displaying a text message notice on a display, displaying a portion of the text message on a display, displaying contact information associated with the text message on a display, displaying the phone number associated with the text message on a display, and/or displaying the time the text message was received on a display, etc. In other embodiments, the user can be notified through audible signals such as a ring tone or other sound through a speaker or speakers. In other embodiments, the user can be notified through vibration. Various other sensory notifications can be used. 
     At block  810 , the user can indicate through a user interface (e.g., user interface  234 ) a desire to view the text message. In some embodiments, the user can press a physical button and/or a icon on a touch screen display that indicates a desire to view the text message or not. In some embodiments, a lack of user response can indicate that the user does not desire to view the text message and process  800  can return to block  806  and await a text message notification. If the user wishes to view the text message, then the text message can be displayed at block  812 . In some embodiments, contact information associated with the sender of the text message including name, phone number, and/or photographs can be displayed as well. 
     In some embodiments, a listing of text messages available at MCD  202  can also be requested by the accessory and upon receipt displayed to the user. The user can select a message from the listing of text messages for viewing. In some embodiments, the listing of text messages can include the phone number associated with the text message, the name of the sender of the text message, and/or a portion of the text message. 
     At block  814 , if the text message notification from MCD  202  indicates that the text massage includes multimedia, for example, audio, video, and/or images, etc., then a command can be sent to MCD  202  from accessory  204  requesting the media at block  816 . For example, a GetMedia command can be sent from accessory  204  to MCD  202  that can include a text message identifier and/or a media identifier. As another example, a GetTextMessage command can be sent that includes a text message identifier and/or a bit mask that indicates, by asserting a bit (or bits) within the bitmask, a request for the associated media. In some embodiments, if the text message includes media (e.g., an MMS message) then the user can be queried whether he would like to view or hear the media. The media can be sent from MCD  202  to accessory  204  and then presented to the user through user interface  234  at block  818 . Process  800  can continue indefinitely by returning to block  806  or until accessory  204  and MCD  202  become disconnected. 
     In the embodiments discussed in relation to  FIG. 8 , the text message notification can include the full text message. In some embodiments, the text message notification can include a portion of the text message.  FIG. 9  is a flow diagram of a process  900  for handing a portion of a text messages using an accessory  204  device according to some embodiments of the invention. For example, SMS text messages can include up to 160 characters. In process  800  all characters (e.g., up to 160 characters) are sent to accessory  204  in the text message notification message. In process  900  a lesser portion of the text message can be included in the text message notification message. As an example, the text message notification can include 20, 30, 40, 50, 60, 70, 80, 90 or 100, characters etc. 
     Blocks  902 ,  904 ,  906 , and  908  can be implemented similarly to blocks  802 ,  804 ,  806 , and  808  respectively. At block  910  a partial text message can be displayed at the user interface  234 . Contact information, for example, a phone number and/or contact name associated with a sender of the text message, can also be displayed. At block  912  the user can elect to view the full text message through user interface  234 , if the full text message is not already displayed. In some embodiments, the user can press a physical button and/or an icon on a touch screen display that indicates whether view the full text message should be displayed or not. In some embodiments, the user can simply ignore the notification to indicate that he would not like to view the full text message and process  900  can return to block  906  and await a text notification from MCD  202 . 
     At block  914  the full text message can be requested from MCD  202  by accessory  204 . For example, accessory  204  can send a GetTextMessage command to MCD  202  requesting the full text message. The GetTextMessage command can include a bitmask that indicates that the full text message is requested. The full text message can then be received at accessory  204  at block  916  and displayed to a user through user interface  234  at block  918 . 
     At block  920 , if the text message notification from MCD  202  indicates that the text massage includes multimedia, for example, audio, video, and/or images, etc., then a command can be sent to MCD  202  from accessory  204  requesting the media at block  922 . For example, a GetMedia command can be sent from accessory  204  to MCD  202  that can include the associated text message identifier and/or a media identifier. As another example, the GetTextMessage command can be sent that includes the associated text message identifier and/or a bit mask indicating a request for the associated media. In some embodiments, accessory  204  can request the full text message and the media using a single GetTextMessage command, for example, by asserting the appropriate bit (or bits) in a bitmask associated with receiving the text message and the media. In some embodiments, if the text message includes media (e.g., an MMS message), then the user can be queried whether he would like to view or hear the media. The media can be sent from MCD  202  to accessory  204  and then presented to the user through user interface  234  at block  924 . 
     In some embodiments, accessory  204  can query the user whether he would like to respond to or forward the text message at block  926 . If the user chooses to reply to or forward the text message, then accessory  204  can receive data for replying and/or forwarding at block  928 . For example, if the user elects to reply to the text message, accessory  204  can provide a text entry field on a display and receive text from the user through a keypad and/or a touch screen to send as a reply. As another example, if the user would like to forward the text message, accessory  204  can provide a text entry field on a display for receiving a phone number or for receiving a contact name to forward the text message to. At block  930  a command can be sent to MCD  202  to reply to or forward the text message. For example, the SetTextMessage command can be used with the bits in a bitmask corresponding to either reply to or forward asserted, along with the text message identifier, the text received from the user, the contact name and/or phone number received from the user. 
     At block  932  the user can chose to delete the text message. At block  934  the accessory can send a command to MCD  202  to delete the message. For example, the DeleteTextMessage command can be used with a bit asserted that is associated with deleting the text message along with the text message identifier. Process  900  can then return to block  906  to await notification of a text message or until accessory  204  and MCD  202  become disconnected. 
       FIG. 10  is a flow diagram of process  1000  for sending text messages to an accessory from a mobile communication device according to some embodiments of the invention. In this embodiment, before a text message is received, a mobile communication device can be connected to accessory  204 . For example, accessory  204  might be operating as a speaker dock, playing audio content stored on MCD  202  or performing any number of other functions. 
     Process  1000  can start when accessory  204  becomes connected to MCD  202 . At block  1002 , MCD  202  establishes communication with accessory  204 . In some embodiments, establishing communication can include identification and authentication in accordance with the communication protocol. At block  1004 , MCD  202  can obtain capability information from accessory  204 . For example, accessory  204  can indicate whether it provides a microphone, whether it is capable of operating in a duplex mode, and whether it provides echo cancellation; accessory  204  can also provide any other applicable information about its capabilities, including other audio processing capabilities such as noise reduction. In some embodiments, accessory  204  can indicate whether it supports receiving text messages and/or register with the MCD for such notifications. In some embodiments, accessory  204  can provide any or all of its capability information as part of establishing communication at block  302 . In some embodiments, process  1000  continues only if accessory  204  supports receiving text messages from MCD  202 . 
     At block  1006 , MCD  202  detects a text message (in this example, an incoming text message) and can generate an alert for the user. For example, MCD  202  can pause the playback of any currently playing track and play a ring tone, display a message, vibrate, and/or take other action to alert a user to an incoming phone call. In some embodiments, MCD  202  can exit or suspend operation of an application operating on MCD  202  in order to alert a user. At block  1008  the text message can be stored in memory (e.g., storage device  210 ) and/or associated with a text message identifier. At block  1010  MCD  202  determines whether accessory  204  accepts text messages, for example, as determined from the capability information received from accessory  204  at block  1004 . In other embodiments, at block  1010  MCD  202  can determine whether accessory  204  registered to receive text message notifications. 
     At block  1012  MCD  202  can send a text message notification to accessory  204 . In some embodiments, the text message notification can include a portion of the text message, the sender&#39;s phone number, contact information associated with the text message, the full text message, a text message identifier, an indication that the text message includes media, etc. At block  1014 , in some embodiments, MCD  202  can receive a request for the full text message. In embodiments where the text message notification includes only a portion of the text message, MCD  202  can receive a request for the rest of the text message at block  1014 , retrieve the text message from memory at block  1016 , and send the full text message at block  1018 . Moreover, MCD  202  can also send contact information such as the sender&#39;s name. The sender&#39;s name can be identified by matching the sender&#39;s phone number with a contacts phone number stored in memory. 
     If the text message notification indicates that the text message includes media, at block  1020  MCD  202  can receive a request for the media. If a request is not received, then process  1000  can continue to block  1024 . However, if a request is received at block  1020 , then the media can be sent to accessory  204  at block  1022 . For example, the media can be retrieved from memory using the text message identifier. In some embodiments, the media can include audio and/or video. In such embodiments, the audio and/or video can be streamed to accessory  204  using an audio and/or video connection, if such capability is supported by accessory  204  as indicated in block  1004 . 
     In some embodiments, a user can reply to and/or forward a text message from accessory  204 . If the user elects to reply to and/or forward a text message, then MCD  202  can receive a message indicating that MCD  202  should reply to and/or forward the text message at block  1024 . For example, the SendTextMessage command can be used with the proper bit(s) asserted in a bitmask to indicate whether to reply to and/or forward the text message along with the text message identifier. The SendTextMessage command, for example, can also include a phone number, a contact name, a reply message, etc. A text message can be composed at block  1026 . If the message indicates that the text message should be forwarded, the SendTextMessage command, for example, can specify the name and/or number where the text message should be forwarded. In the event a contact name is specified, MCD  202  can look up the appropriate phone number. If the message indicates that the text message should be replied to, the SendTextMessage command, for example, can specify a reply text message. At block  1028 , the forward and/or reply text message can be sent through the telephone interface (e.g., RF section  212  of  FIG. 2 ). 
     In some embodiments, the user may wish to delete the text message. If so, MCD  202  can receive a message that specifies that the text message should be deleted at block  1030 . For example, the DeleteTextMessage command can be used with the proper bit(s) asserted in a bitmask to indicate that the text message should be deleted. The DeletetextMessage command can also include a text message identifier. Upon receipt of the message, MCD  202  can delete the text message associated with the text message identifier. For example, MCD  202  can delete the text message from memory. Process  1000  can continue indefinitely, e.g., until accessory  204  and MCD  202  become disconnected. 
     While processes  800 ,  900  and  1000  have been described with respect to text messages, similar processes can be implemented for handling e-mail messages. For example, emails can be received from a communication network at the MCD, a notification can be sent from the MCD to the accessory indicating that an email has been received, a request to view at least a portion of the email can be sent to the MCD from the accessory, the email can be sent to the accessory, and viewed at the accessory by a user. In some embodiments, the email address of the sender can be sent to the accessory and/or displayed. In some embodiments, a user can reply to, forward, and/or delete emails using the accessory. 
     In other embodiments, a user can receive a voicemail message by interacting with an accessory rather than directly with a mobile communication device.  FIG. 11  is a flow diagram of process  1100  for handling voicemail using an accessory device according to some embodiments of the invention. Process  1100  can be executed by an accessory (e.g., accessory  204  of  FIG. 2 ) that is connected to a mobile communication device (e.g., MCD  202  of  FIG. 2 ). 
     Process  1100  can start when accessory  204  becomes connected to MCD  202 . At block  1102 , accessory  204  establishes communication with MCD  202 . As with process  400  described above, block  1102  can include identification and authentication in accordance with the communication protocol. At block  1104 , accessory  204  can provide capability information to MCD  202 . In particular, accessory  204  can indicate whether it is capable of receiving and/or playing voicemail messages, for example, by registering with MCD  202  for voicemail notifications. Accessory  204  can also provide any other applicable information about its capabilities at block  1104 . In some embodiments, process  1100  continues only if accessory  204  has registered for voicemail notifications. 
     At block  1106 , accessory  204  can receive a voicemail notification from MCD  202 . A voicemail notification can indicate to accessory  204  that a voicemail has been received at MCD  202 . In some embodiments, a voicemail notification can include an identifier associated with the voicemail, the phone number from where the voicemail was sent, and/or contact information associated with the sender (e.g., the sender&#39;s name). Process  1100  can remain at block  1106  indefinitely, or until a voicemail notification is received from MCD  202 . 
     At block  1108 , accessory  204  can notify the user that a voicemail has been received by MCD  202 . In some embodiments, such notifications can be turned off at accessory  204  by the user. In other embodiments, accessory  204  can register with MCD  202  to receive voicemail notifications. If the notifications are turned off, in some embodiments, then process  1100  ends. In some embodiments, the user can be notified and the user can be queried if he would like to hear the voicemail through a user interface (e.g., user interface  234 ). In other embodiments, such notifications can include displaying a notice on a display, displaying contact information associated with the voicemail on a display, displaying the phone number associated with the voicemail on a display, and/or displaying the time the voicemail was received on a display, etc. In other embodiments, the user can be notified through audible signals such as a ring tone or other sound through a speaker or speakers. In other embodiments, the user can be notified through vibration or other sensory notification. 
     At block  1110 , the user can indicate through a user interface (e.g., user interface  234 ) that he would like to hear the voicemail. In some embodiments, the user can press a physical button and/or a icon on a touch screen display that indicates that a desire to hear the voicemail or not. In some embodiments, the user can simply ignore the notification to indicate that he would not like to view the voicemail and process  1100  can end. If the user elects to hear the voicemail message, at block  1112  accessory  204  can request a voicemail list from MCD  202 . For example, a GetVoicemailList command can be sent to MCD  202  indicating that a listing of voicemails is requested. For example, the GetVoicemailList command can include a bitmask with a bit (or bits) asserted that indicates a listing of available voicemails should be sent to accessory  204 . In some embodiments, a voicemail list can be included in the voicemail notification received at block  1106 . The voicemail list can include a listing of voicemails, the sender&#39;s phone number and/or contact information, date and/or time the voicemail was received, length of the message, and/or a voicemail indicator. At block  1114  a visual representation of the available voicemails from the voicemail list can be displayed on accessory  204 . For example, accessory  204  can display the contact name and the time the message was received. 
     At block  1116  a voicemail can be selected from the listing of voicemail by a user. A voicemail can be selected, for example, through user interface  234 . In some embodiments, block  1116  can repeat indefinitely until the user selects a voicemail message. The voicemail identifier associated with the selected voicemail message can then be sent to MCD at block  1118 . For example, the GetVoicemail command can be used with a bit (or bits) asserted that indicates a voicemail. 
     In some embodiments, an accessory can bypass blocks  1112 ,  1114  and  1116 . That is, at block  1110  the accessory can send the GetVoicemail command indicating that the user would like to hear the voicemail associated with voicemail notification. In this embodiment, a listing of voicemails is not provided. 
     In some embodiments, playback controls can be provided at user interface  234  of accessory  204  at block  1120 . Playback controls can provide a user buttons and/or icons to pause, play, stop, fast forward, rewind, adjust the volume, etc., of a voicemail. At block  1121 , accessory  204  can initialize its audio state, e.g., in line-out simplex mode. In this mode, accessory  204  can receive line-out from MCD  202  but does not provide line-in to MCD  202 ; in some embodiments, audio section  236  of accessory  204  disables sending of signals onto the line-in path while in line-out simplex mode. Line-out simplex mode supports various operations not requiring two-way audio. This line-out mode between MCD  202  and accessory  204  can be used to stream the voicemail from MCD  202  to accessory  204  at block  1122 . The voicemail stream can be played from accessory  204  at block  1124 . For example, the voicemail can be played through speakers and/or headphones at the accessory. 
     The user can modify the playback of the voicemail by using the playback controls displayed at block  1120 . At block  1126  a playback control can be selected. For example, the user can chose to pause, stop, play, fast forward, rewind, slow down, speed up, and/or adjust the volume of the streaming voicemail by sending a message to MCD  202  at block  1128 . For example, the ButtonStatus command can be used to communicate playback control from accessory  204  to MCD  202 . For example, a bit can be asserted to indicate that playback of the voicemail should be paused. Another bit, for example, can be asserted to indicate that playback of the voicemail should be fast forwarded. MCD  202  can provide the required playback control as indicated in the message. 
     A user can also choose to delete a voicemail in the voicemail list, by so indicating though user interface  234 , for example, by pressing or touching a button or icon at block  1130 . If the user chooses to delete a voicemail, the voicemail may be selected by the user in the list or other wise specified by the user. At block  1132  a delete command can be sent to MCD  202  from accessory  204  that includes the voicemail identifier. For example, DeleteVoiceMail command can also be used by asserting the proper bit in a bitmask and including the voicemail identifier. At block  1134 , accessory  204  can then remove the voicemail from the voicemail list that was displayed at block  1114 . In some embodiments, MCD  202  can resend the voicemail list and accessory  204  can redisplay the list in response to deleting a voicemail. 
     At block  1136  the user can choose to call back the phone number from which the voicemail was received. If the user so chooses, at block  1138  a callback command can be sent to MCD  202 , for example, using the DialNumber command. In some embodiments, a notification can be received at the accessory, for example, like the indication discussed at block  514  of  FIG. 5 , indicating whether the call was successfully connected. Accessory  204  can then enter duplex audio mode at block  1140 . If the call is connected by MCD  202 , then audio can be sent and received through user interface  234  at block  1142 , until the call ends at block  1144 . At block  1146  if the voicemail stream has ended, then process  1100  can return to block  1106 , otherwise, process  1100  can return to block  1126 . In some embodiments, even after the voicemail stream has ended, playback control functions, delete functions, and/or call back functions can still be accessed by the user. 
       FIG. 12  is a flow diagram of process  1200  for sending voicemail to accessory  204  from MCD  202  according to some embodiments of the invention. At block  1202 , MCD  202  can establish communication with accessory  204  in a manner similar to those discussed above. At block  1204 , MCD  202  can obtain accessory capability information from accessory  204  as described above. For example, MCD  202  can receive information dictating whether accessory  204  can receive voicemails. 
     At block  1206 , a voicemail is received at MCD  202  and the voicemail can be stored in memory (e.g., in storage device  210 ) at block  1208 . The voicemail can also be associated with a voicemail identifier, which can be associated with the voicemail in memory. Process  1200  can remain at block  1206  indefinitely, or until a voicemail is received. Moreover, various other processes and/or information communicated between accessory  204  and MCD  202  while process  1200  remains at block  1206 . 
     MCD  202  can determine whether accessory  204  has registered with MCD  202  to accept voicemails at block  1210 . If accessory  204  is not configured to accept voicemail messages, then process  1200  ends. If accessory  204  is configured to accept voicemail messages, then a voicemail notification can be sent to accessory  204 . In some embodiments, a voicemail notification can include an identifier associated with the voicemail, the phone number from where the voicemail was sent, and/or some contact information. 
     MCD can then wait until it receives a request for a voicemail list at block  1214 . Process  1200  can remain at block  1214  indefinitely, or until request for a voicemail listing is received. In response to the request for the voicemail listing, at block  1206  MCD  202  can send a listing of the available voicemails that includes, for example, contact information, a voicemail identifier, the time the voicemail was received, etc. 
     MCD can then wait until it receives a request for a specific voicemail within the voicemail list at block  1218 . The request can include the voicemail identifier. For example, the GetVoiceMail command can be used with a bit asserted within a bitmask that indicates a request for a voicemail along with the voicemail identifier. Process  1200  can remain at block  1218  indefinitely, or until request for a specific voicemail is received. In some embodiments, process  1200  can timeout and end after a specific period of time. In response to the request for a voicemail, at block  1219  MCD  202  can retrieve the selected voicemail from memory. At block  1220 , the voicemail can be streamed to accessory  204  using an audio line-out. 
     At block  1221 , MCD  202  can receive a playback control command from accessory  204 . For example, such a command can be issued from accessory  204  at block  1128 . In some embodiments, a playback control command can include, fast-forward, rewind, play, pause, stop, and/or volume commands. For example, the ButtonStatus command can be used with a bit (or bits) associated with playback control asserted. At block  1222 , MCD  202  can respond by controlling playback accordingly. 
     At block  1224 , MCD  202  can receive a call back command from accessory  204 . For example, such a command can be issued from accessory  204  at block  1138 . For example, the VoiceMail command can be used with a bit (or bits) associated with callback asserted. In other embodiments, the DialNumber command can also be used. At block  1227  the phone call is initiated by MCD  202  to the phone number associated with the voicemail over a mobile communication network (e.g., using RF section  212 ). At block  1229  audio line-out to accessory can be established and audio from the phone call can be sent to accessory  204 . At block  1230  audio from accessory  204  can be processed and transmitted to the mobile communication network. Blocks  1229  and  1230  can repeat until the phone call is disconnected at block  1231 . 
     At block  1232 , MCD  202  can receive a delete command from accessory  204 . For example, such a command can be issued from accessory  204  at block  1132 . For example, the DeleteVoiceMail command can be used with a bit (or bits) associated with the delete command asserted. At block  1234 , the voicemail can be removed from memory. In some embodiments, a voicemail can be moved to a deleted voicemail folder rather than being completely removed. 
     At block  1240  if the voicemail stream has ended then process  1200  can return to block  1206  and await another voicemail, otherwise, process  1200  can return to block  1221 . In some embodiments, even after the voicemail stream has ended, playback control functions, delete functions, and/or call back functions can still be performed. 
     In some embodiments, communication-related notifications can be sent to an accessory from a mobile communication device that alerts the accessory that incoming communications are available. In some embodiments, prior to receiving notifications, an accessory can register with the MCD specifying the type of communication-related notifications the accessory wants to receive. In some embodiments, the accessory (often in conjunction with a user) can then respond to the MCD requesting that the MCD forward the message to the accessory and present the communication to the user. 
     In some embodiments, an MCD may not be capable of receiving a voicemail from a mobile communication network. Instead, the MCD can receive a notification from the mobile communication network that a voicemail has been received. The voicemail can be stored by the mobile communication network, (e.g., using a server). In order to hear the voicemail a user can dial his voicemail number and possibly enter a passcode. Following which, the voicemail can be played from a server through the mobile communication network. In some embodiments, an accessory can access a voicemail through the mobile communication network.  FIG. 13  shows a flow diagram of process  1300  for accessing voicemail through the mobile communication network using accessory  204  coupled with MCD  202 . 
     Blocks  1302 ,  1304 ,  1306 , and  1308  can be implemented similarly to blocks  1102 ,  1104 ,  1106 , and  1108 . At block  1310  the user can elect to hear the voicemail. If the user does not elect to hear the voicemail, then process  1300  returns to block  1306  and awaits a voicemail notification. Process  1300  can remain at block  1306  indefinitely or until accessory  204  is disconnected from MCD  202 . If the user elects to hear the voicemail, then accessory  204  can send a request to MCD  202  requesting to hear the voicemail at block  1312  and accessory  204  can enter line-out simplex mode at block  1314  as described above. This line-out mode between MCD  202  and accessory  204  can be used to stream the voicemail from MCD  202  to accessory  204  at block  1316  and/or send dual-tone multi-frequency (DTMF) tones to the MCD. In some embodiments, accessory  204  can enter line-out simplex mode and receive voicemail audio without sending any data to MCD  202 . The voicemail stream can be played from accessory  204  at block  1318 . For example, the voicemail can be played through speakers and/or headphones at the accessory. 
     At block  1318  user input can be entered at the accessory. Typically, during a voicemail call the user can navigate between voicemail options and commands by pressing a button or a series of buttons. Accordingly, if the user presses one or more buttons while listening to the voicemail at block  1320 , then accessory  204  can send the user input to MCD  202  at block  1322 . For example, the accessory can send DTMF tones to MCD  202  that corresponds with telephone buttons. In some embodiments, the ButtonStatus command can be used to communicate data from the accessory. If the voicemail stream ends, as determined at block  1324 , then process  1300  can return to block  1306 , otherwise process  1300  returns to block  1318 . 
       FIG. 14  shows a flow diagram of process  1400  for allowing accessory  204  to access voicemail through MCD  202  according to some embodiments. Process  1400  can be used in conjunction with an accessory executing process  1300 . Blocks  1402  and  1404  can be implemented similarly to blocks  1202  and  1204 . At block  1406  a voicemail notification can be received form a mobile communication network indicating that a voicemail is saved at a server that can be accessed through the mobile communication network. 
     MCD  202  can determine whether accessory  204  has registered with MCD  202  to accept voicemails at block  1410 . If accessory  204  is not configured to accept voicemail messages, then process  1400  can return to block  1406 . If accessory  204  is configured to accept voicemail messages, then a voicemail notification can be sent to the accessory at block  1412 . In response to the voicemail notification, the accessory can send a request to receive and/or call the voicemail (e.g., at block  1312 ), which can be received by MCD  202  at block  1414 . 
     If a request is received from accessory  204 , then MCD  202  can call the voicemail server and communicate voicemail audio to the user through accessory  204 . Blocks  1416 ,  1418 ,  1420 ,  1422 ,  1424 , and  1426  can be implemented similarly as blocks  606 ,  608 ,  610 ,  612 ,  614 , and  616  respectively. In these blocks, a mobile phone connection can be established with a voicemail server and the audio data sent to and from an accessory device through MCD  202 . At block  1428 , if the call is not disconnected, then process  1400  returns to block  1426 . In some embodiments, at block  1420  the MCD can notify the accessory to enter simplex mode. In some embodiments, at block  1420 , the MCD can request that the accessory enable echo cancellation. 
     If user input is received at block  1430 , for example, DTMF data from accessory  204  (e.g., at block  1322 ), then process  1400  can send DTMF data to the voicemail server at block  1432 . In some embodiments, user input may not be DTMF data. For example, user input can be communicated to MCD  202  using the ButtonStatus command. As another example, user data can include a bitmask or byte representing a digit that can be converted into a DTMF tone by MCD  202 . Once received at the server, DTMF data can be used by the server to modify playback of the voicemail. At block  1434 , if the call is disconnected a call-end notification can be sent to the accessory at block  1436 , otherwise process  1400  returns to block  1426 . 
     In some embodiments, a user can place and/or receive a phone call to an MCD using an accessory, as discussed in regard to  FIGS. 3-7 . In some embodiments, a phone call can be made that connects with an automated server that can respond to DTMF responses from a user (e.g., a phone tree). In some embodiments, DTMF signals can be sent to the MCD from the accessory and then to the automated server. In other embodiments, the accessory can send an indication specifying a phone number or a DTMF tone (e.g., sending a byte or bitmask that corresponds with the different tones). In response, the MCD can produce the DTMF tone and send it to the server. 
     While the invention has been described with respect to specific embodiments, one skilled in the art will recognize that numerous modifications are possible. For instance, audio signals can include any signal that provides a representation of sound in any format, including analog or digital formats. Audio signals can represent sound information any encoding desired, provided that the mobile communication device and accessory  204  are equipped with appropriate hardware and/or software for encoding and decoding the audio signals. Further, audio signals referred to as line-in and line-out may include monaural, stereo, and multi-channel (e.g., so-called “5.1” or “7.1”) signals. Audio signal paths can be wired and/or wireless (e.g., using a Bluetooth audio standard). 
     In addition, while certain embodiments make specific reference to echo cancellation, a variety of audio processing techniques can be cooperatively managed in the manner described herein. For example, noise reduction can be performed by accessory  204  or MCD  202 ; in general, one application of noise reduction improves signal quality but two can degrade it. Thus, it can be helpful to coordinate noise reduction so that it is applied exactly once. In some embodiments, the device that has the microphone (e.g., accessory  204  as described in embodiments above) is selected to perform noise reduction while in duplex mode, as the device that has the microphone is likely to provide more optimal noise reduction. Other audio processing features such as gain control can also be designated to be applied by the device that has the microphone. 
     In some embodiments, an accessory can explicitly indicate (e.g., during identification) that it is operable as a speaker phone. In other embodiments, the mobile communication device can use any accessory as a speaker phone, provided that accessory  204  provides a minimum set of features to support speaker phone operation (e.g., line-in and line-out with duplex mode support and echo cancellation capability). 
     In some embodiments, circuits, processors, and/or other components of a mobile communication device and/or accessory may be configured to perform various operations described herein. Those skilled in the art will appreciate that, depending on implementation, such configuration can be accomplished through design, setup, interconnection, and/or programming of the particular components and that, again depending on implementation, a configured component might or might not be reconfigurable for a different operation. For example, a programmable processor can be configured by providing suitable executable code; a dedicated logic circuit can be configured by suitably connecting logic gates and other circuit elements; and so on. Further, while the embodiments described above may make reference to specific hardware and software components, those skilled in the art will appreciate that different combinations of hardware and/or software components may also be used and that particular operations described as being implemented in hardware might also be implemented in software or vice versa. 
     Computer programs incorporating some or all features described herein may be encoded on various computer readable storage media; suitable media include magnetic disk (including “hard” disk) or tape, optical storage media such as compact disk (CD) or DVD (digital versatile disk), flash memory, and the like. Computer readable storage media encoded with the program code may be packaged with a compatible device or provided separately from other devices. In addition, program code may be encoded and transmitted via wired optical, and/or wireless networks conforming to a variety of protocols, including the Internet, thereby allowing distribution, e.g., via Internet download. 
     Thus, although the invention has been described with respect to specific embodiments, it will be appreciated that the invention is intended to cover all modifications and equivalents within the scope of the following claims.

Metadata:
Filing Date: 20170718
Publication Date: 20200818
Grant Date: 20200818
Priority Date: 20090306
Inventors: BOLTON, LAWRENCE G.
RATHI, SHAILESH
Assignee: APPLE INC
CPC Classifications: [{"code": "H04L51/58", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L51/58", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L51/224", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L51/224", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/72412", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/72442", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/72436", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/72412", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/72442", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/72436", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/6041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/6041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W4/12", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W4/12", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W4/12", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L51/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/6041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/7253", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/72552", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/72558", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L51/24", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 42678718