AU2011101205B4 - Accessory and mobile computing device communication using an application communication protocol - Google Patents

Abstract

Embodiments of the present invention provide various communication techniques for communication between a mobile computing device and an accessory. An accessory protocol that is generic to the mobile computing device can be used for some communication. An application executing at the mobile computing device can communicate with the accessory using an application communication protocol. In some embodiments, the application communication protocol can be different from the accessory communication protocol. In other embodiments the application protocol may only be recognized by the application and the accessory. In some embodiments, messages conforming to an application protocol can be communicated between the application and the accessory by packaging the messages inside a message conforming to the accessory communication protocol.

Description

Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION INNOVATION PATENT Invention Title: Accessory and mobile computing device communication using an application communication protocol The following statement is a full description of this invention, including the best method of performing it known to us: 1000014903 ACCESSORY AND MOBILE COMPUTING DEVICE COMMUNICATION USING AN APPLICATION COMMUNICATION PROTOCOL BACKGROUND 5 [0001] The present disclosure relates generally to communication between an accessory and a mobile computing device and in particular to using accessory and/or application specific protocols for such communications. [0002] Mobile computing devices have become ubiquitous. Various companies have created TM T mobile computing devices, such as the iPhone , iPod Touchim , various BlackBerry® devices, D and smart phones compatible with Google's AndroidTM platform, to name a few. Mobile computing devices often include web browsers, word processors, email applications, maps, telephone services, games, audio applications, video applications, etc. Moreover, accessories have also been created for use with mobile computing devices. Such accessories can communicate with a mobile computing device using one or more connectors and/or ports. Such 5 accessories can be used to control features of the mobile computing device or used by the mobile computing device to interact with users and/or the environment. [0002A] Reference to any prior art or background information in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that this prior art or background information forms part of the common general knowledge in Australia or any other 20 jurisdiction; or that this prior art or background information could reasonably be expected to be ascertained, understood and regarded as relevant by a person skilled in the art. [0002B] As used herein, except where the context requires otherwise, the term "comprise" and variations of the term, such as "comprising", "comprises" and "comprised", are not intended to exclude further additives, components, integers or steps. 25 BRIEF SUMMARY [0003] In an aspect of the present invention, a method is provided that includes communicating, by an accessory device, with an operating system executing at a mobile

IA

1000014903 computing device using an accessory communication protocol. The accessory communication protocol provides a global standard to enable communication between any accessory device and the mobile computing device. The method also includes, communicating, by the accessory device to the operating system executing on the mobile computing device, information that is 5 usable by the mobile computing device to identify an application communication protocol supported by the accessory device. The information is communicated using the accessory communication protocol, wherein the application communication protocol is distinct from the accessory communication protocol and is specific to a particular application on the mobile computing device. The method further includes communicating, by the accessory device, with an 0 application executing on the mobile computing device using the application communication protocol. [0003A] Also described herein, according to various embodiments, an accessory may communicate with an application executing on a mobile computing device using an accessory specific communication protocol and/or an application specific communication protocol. For 5 example, when an accessory couples with a mobile computing device it may perform initialization, identification, and/or authentication procedures using an accessory protocol defined by the mobile computing device. The accessory may also communicate information indicating one or more application protocols that may be used by an application executing on the mobile computing device to communicate with the accessory. In some embodiments, an 0 application protocol can be different from the accessory protocol, while in other embodiments an application protocol can be the same as the

IB

accessory protocol. In some embodiments, an application protocol packet can be nested within portions of an accessory protocol packet. [0004] Various embodiments disclosed herein describe methods for creating communication sessions between accessories and applications. Some embodiments 5 describe how an accessory provides the proper information for the mobile computing device to open a communication session using an application protocol. Other embodiments describe various schemes at the mobile computing device for selecting an application protocol, opening communication streams, downloading a preferred application, communicating with an accessory, nesting application protocol packets within 10 an accessory protocol packet, etc. In some embodiments, an application manager executing at a mobile computing device can be used to abstract the communication between an accessory and an application. [00051 The following detailed description, together with the accompanying drawings, will provide a better understanding of the nature and advantage of the embodiments 15 disclosed herein. BRIEF DESCRIPTION OF THE DRAWINGS [0006] FIG. IA shows a mobile computing device coupled with an accessory device according to some embodiments of the invention.. [00071 FIG. I B shows an accessory device wirelessly coupled with a mobile computing 20 device according to some embodiments of the invention. [0008] FIG. 2 shows a block diagram of a mobile computing device coupled with an accessory according to one embodiment. [0009] FIG. 3 is a block diagram showing various modules and processes within a mobile computing device according to some embodiments of the invention. 25 [00101 FIG. 4 is a simplified diagram further illustrating communication between an application and an accessory according to some embodiments of the invention. [00111 FIGs. 5A-5C illustrate an example of packaging an application protocol message within an accessory communication protocol command according to some embodiments of the invention. 2 [0012] FIG. 6 illustrates a path for commands of the accessory communication protocol in the embodiment of FIG. 4 according to some embodiments of the invention. [00131 FIG. 7 is a flow diagram of a process for identifying an accessory and compatible application according to some embodiments of the invention. 5 [00141 FIG. 8 shows a connected protocol list and a supported-protocol table usable to associate compatible applications and accessories according to some embodiments of the invention. [00151 FIG. 9 illustrates a technique for formulating a query usable to locate a compatible application for an accessory according to some embodiments of the invention. 10 [00161 FIG. 10 is a flow diagram of a process that can be executed by an application to initiate communication with an accessory according to some embodiments of the invention. [00171 FIG. 11 illustrates an application on a mobile computing device concurrently interacting with two different accessories according to some embodiments of the 15 invention. [00181 FIG. 12 illustrates two applications on a mobile computing device concurrently interacting with two different accessories according to some embodiments of the invention. [0019] FIG. 13 illustrates two applications on a mobile computing device concurrently 20 interacting with the same accessory according to some embodiments of the invention. [00201 FIG. 14 illustrates the flow of data between an application, the application manager and the hardware transport layer of a mobile computing device according to some embodiments of the invention. [00211 FIG. 15 is a flow diagram of a process that can be executed by an application 25 manager at a mobile computing device according to some embodiments of the invention. [00221 FIG. 16 is another flow diagram of a process that can be executed by an application manager at a mobile computing device according to some embodiments of the invention. 3 [00231 FIG. 17 is a flow diagram of a process that can be executed by an accessory coupled with a mobile computing device to open communication with an accessory according to some embodiments of the invention. [00241 FIG. 18 is a flow diagram of a process that can be executed by an application at a 5 mobile computing device to open a communication with an accessory according to some embodiments of the invention. DETAILED DESCRIPTION [00251 Various embodiments of the invention disclosed herein are directed toward various aspects of communication between accessory devices and a mobile computing 10 device. In some embodiments, an accessory can communicate with a mobile computing device using an accessory communication protocol. An accessory communication protocol can specify communication commands, transport links, authentication routines, identification processes, lingoes, packet structures, data types, or any other suitable command or data that can be used to communicate between an accessory device and a 15 mobile computing device. [00261 An application executing on a mobile computing device can also communicate with the accessory using an application communication protocol. In some embodiments, an application communication protocol can specify communication commands, packet structures, data types, lingoes, message formats, etc., for communication between the 20 application and the accessory. In some embodiments, at least some of the communication commands, packet structures, data types, lingoes, message formats specified by the application communication protocol can be different from those specified by the accessory communication protocol. In other embodiments, at least some of the communication commands, packet structures, data types, lingoes, message formats specified by the 25 application communication protocol can be the same as those specified by the accessory communication protocol. [00271 In some embodiments, the application protocol can use the transport link specified by the accessory communication protocol. An application communication protocol can be developed, for example, by the developer of the application and/or 30 accessory. In some embodiments, an application communication protocol can include application and/or accessory specific commands, data structures, etc. Furthermore, the 4 terms "application communication protocol" and "application protocol" can be used interchangeably. The terms "accessory communication protocol", "accessory communication protocol", "general communication protocol", and "general protocol" can also be used interchangeably. 5 [0028] FIG. IA shows a mobile computing device 102 coupled with an accessory device 113. Cable 111 is used to couple mobile computing device 102 with accessory device 113. Cable 111 can include connector 108 to connect with mobile computing device 102 and connector 110 to connect with accessory device 113. FIG. 1B shows accessory device 113 wirelessly coupled with mobile computing device 102. 10 [00291 The mobile computing device shown in FIGs. 1A and lB, can be any type of mobile computing and/or communication device without limitation. For example, an iPod TouchTm, an iPhoneTm, an Android compatible device and/or a Blackberry device can be used. Moreover, mobile computing device 102 can provide media player capability, networking, web browsing, email, word processing, data storage, application execution, 15 and/or any other computing or communication functions. [00301 Accessory 113 can be any device capable of communicating with mobile computing device 102 such as, for example, an external speaker system; an external video device; a multimedia device; a consumer electronic device; a test instrument; a home appliance (e.g., refrigerator or dishwasher); exercise equipment; a security system; a home 20 or office automation system; a camera; a user input device (e.g., keyboard, mouse, game controller); a measurement device; a medical device (e.g., glucose monitor or insulin monitor); a point of sale device; an automobile; an automobile accessory (e.g., a car stereo system or car navigation system); a radio (e.g., FM, AM and/or satellite); an entertainment console on an airplane, bus, train, or other mass transportation vehicle; etc. Any type of 25 device that can be used in conjunction with a mobile computing device can be used as an accessory device. [00311 FIG. 2 shows a block diagram of mobile computing device 200 (e.g., implementing mobile computing device 102 of FIG. IA or I B) coupled with an accessory 202 (e.g., implementing accessory 113 of FIG. IA or 1B) according to one embodiment. 30 Mobile computing device 200 can include processor 230, storage device 225, user interface (UI) 235, network interface 236, and accessory input/output (I/O) interface 205. 5 [00321 Processor 230, which can be implemented as one or more integrated circuits (including, e.g., a conventional microprocessor or microcontroller), can control the operation of mobile computing device 200. For example, in response to user input signals provided by user interface 235, processor 206 can perform various tasks such as selecting 5 and playing media assets that may be stored in stored in storage device 225; accessing various networks (e.g., a mobile telephone network, the Internet, local area network, or the like) to send and/or retrieve data using network interface 236; executing various application programs (Apps) 226 residing on storage device 225; and so on. Processor 230 can also manage communication with accessories via accessory I/O interface 205. 10 [00331 User interface 235 can include input controls such as a touch pad, touch screen, scroll wheel, click wheel, dial, button, keypad, microphone, etc., as well as output devices such as a display screen, indicator lights, speakers, headphone jacks, etc., together with supporting electronics (e.g., digital-to-analog or analog-to-digital converters, signal processors or the like). A user can operate the various input controls of user interface 235 15 to invoke the functionality of mobile computing device 200 and can also view and/or hear output from mobile computing device 200 via user interface 235. [0034] Storage device 225 may be implemented, e.g., using disk, flash memory, or any other non-volatile storage medium. Storage device 225 can store application programs 226 that are executable by processor 230, system programs and other program code (not 20 explicitly shown), and various data such as protocol table 227 that can be used in managing communication with various accessories, as described below. In some embodiments, storage device 225 can also store media assets such as audio, video, still images, or the like, that can be played by mobile communication device 200, along with metadata describing the media assets (e.g., asset name, artist, title, genre, etc.), playlists 25 (lists of assets that can be played sequentially or in random order), and the like. Storage device 225 can also store any other type of information such as information about a user's contacts (names, addresses, phone numbers, etc.); scheduled appointments and events; notes; and/or other personal information. [00351 Application programs (also referred to herein as "applications" or "apps") 226 30 can include any program executable by processor 230. In some embodiments, certain applications can be installed on mobile computing device 200 by its manufacturer, while other applications can be installed by a user. Examples of application programs can 6 include 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. Certain application programs 226 may provide communication with and/or control of accessory 202, and 5 certain application programs 226 may be responsive to control signals or other input from accessory 202; examples are described below. [00361 Network interface 236 can provide an interface to one or more communication networks. For example, network interface 236 can incorporate a radio-frequency (RF) transceiver and suitable components for communicating via a mobile communication 10 network such as a mobile telephone network. Additionally or instead, network interface 236 can incorporate a wireless connection to the Internet (e.g., a WiFi transceiver, 3G transceiver or the like), to a personal area network (e.g., a Bluetooth network), or any other network. In still other embodiments, a wired network connection (e.g., Ethernet) may be provided. In some embodiments, the same hardware can be used to support 15 connections to multiple networks; thus, network interface 236 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. In some embodiments, some operations associated with network connectivity can be 20 implemented entirely or in part as programs executed on processor 230 (e.g., encoding, decoding, and/or other processing in the digital domain), or a dedicated digital signal processor can be provided. [00371 Accessory I/O interface 205 can include a number of signal paths configured to carry various signals between mobile computing device 200 and accessory 202. In one 25 embodiment, accessory I/O interface 205 includes a 30 pin connector corresponding to the connector used on iPod® and iPhoneT" products manufactured and sold by Apple Inc.; other connectors can also be used. Alternatively or additionally, accessory I/O interface 205 can include a wireless interface (e.g., Bluetooth or the like). [0038] In some embodiments, mobile computing device 200 can also use accessory I/O 30 interface 205 to communicate with a host computer (not shown) that executes an asset management program that can provide media and/or applications for a mobile computing device (for example, iTunes* or Microsoft's application store). The asset management 7 program can enable a user to add media assets and/or applications to mobile computing device and/or remove media assets from mobile computing device 200. The user can update metadata associated with media assets on mobile computing device 200. In some embodiments, the user can also interact with the asset management program to create and 5 update playlists and/or applications as well as other documents. In one embodiment, the host computer maintains a master database of media assets and/or applications and can access other databases, for example, through the Internet (including associated metadata and playlists), and the asset management program synchronizes the master database with the database maintained on storage device 225 of mobile computing device 200 10 automatically whenever mobile computing device 200 connects to the host computer. In other embodiments, mobile computing device 200 can use network interface 236 to communicate with a host computer and/or directly with various other servers to acquire applications, media assets and/or other data. [00391 Accessory 202 can include controller 260, user interface 255, mobile computing 15 device I/O interface 250, memory 265, and accessory specific hardware 275. [00401 Mobile computing device 1/0 interface 250 can include a number of signal paths configured to carry various signals between accessory 202 and mobile computing device 200. In one embodiment, mobile computing device I/O interface 250 can include a connector adapted to mate with the 30-pin connector used on iPod* and iPhone"m products 20 manufactured and sold by Apple Inc. Other connectors can also be used; for example, mobile computing device 1/0 interface 250 can include a standard USB or FireWire connector or the like. Alternatively or additionally, mobile computing device I/O interface 250 can include a wireless interface (e.g., Bluetooth or the like). [00411 Controller 260 can include, e.g., a microprocessor or microcontroller executing 25 program code to perform various functions such as digital audio decoding, analog or digital audio and/or video processing, processing of user input, controlling of accessory functionality and the like. Controller 260 can also manage communication with a mobile computing device via mobile computing device I/O interface 250. [0042] User interface 255 can include input controls, such as a touch pad, touch screen, 30 scroll wheel, click wheel, dial, button, keypad, microphone, probes, etc., as well as output devices, such as a video screen, indicator lights, speakers, headphone jacks or the like, together with supporting electronics (e.g., digital-to-analog or analog-to-digital converters, 8 signal processors or the like). A user can operate the various input controls of user interface 255 to invoke the functionality of accessory 202 and can view and/or hear output from accessory 202 via user interface 255. In addition, in some embodiments, a user can operate mobile computing device 200 (or applications executing thereon) via accessory 5 user interface 255. [00431 Memory 265 can be implemented using any type of memory, disk, or other storage medium that can store program code for controller 260 and/or data. For example, memory 265 can store accessory specific software 280 that can provide instructions for controller 260 to interact with accessory specific hardware 275, and/or user interface 255. 10 In some embodiments, accessory 202 can receive information (e.g., user input, metadata, and/or application data) from mobile computing device 200, and such information can also be stored in memory 265. [0044] Accessory specific hardware 275 can represent any hardware needed to enable desired functionality of accessory 202. For example, accessory specific hardware 275 can 15 include one or more data gathering devices, such as any type of sensor or meter. In some embodiment, accessory specific hardware 275 can include an electrical meter that generates data representing electrical characteristics (resistance, voltage difference, or the like); a light sensor that detects light and/or patterns of light; a motion sensor; a temperature sensor; a humidity sensor; a pressure sensor; a chemical sensor that responds 20 to the presence of selected chemicals (e.g., potentially toxic gases such as carbon monoxide); and so on. Accessory specific hardware 275 can also include one or more medical device such as a glucose meter, respiratory meter, heart rate and/or heart function monitor, blood pressure monitor, or the like. [0045] In some embodiments, accessory specific hardware 275 that includes a 25 data-gathering device can provide one or more electrical signals (e.g., voltage, resistance, and/or current) that correspond to or represent the physical data. Analog and/or digital signals in a variety of formats may be used. Accessory specific hardware 275 can also include signal processing components that process the signal before sending it to controller 260; in some embodiments, accessory specific hardware 275 can send the 30 electrical signal directly to controller 260, which can process the signal. For example, if accessory specific hardware 275 includes a thermometer implemented using a thermocouple, resistance data from the thermocouple can be converted into temperature 9 data by accessory specific hardware 275, by controller 260, or both. Further, signals representing data gathered by accessory specific hardware 275 can be sent (with or without processing by controller 260) to an application executing on mobile computing device 200, e.g., using an application protocol as described below; thus an application 5 executing on mobile computing device 200 can also process data gathered using accessory specific hardware 275. [00461 In some embodiments, accessory specific hardware 275 can include one or more computer-controllable devices. Examples of computer-controllable devices include motors, actuators, lights, cameras, valves, speakers, display screens, printers, and/or any 10 other equipment that is controllable by controller 260. In some embodiments, an application executing on mobile computing device 200 can send control signals to accessory 202, and controller 260 can operate accessory specific hardware 275 in response to the control signals. 100471 In some embodiments, accessory specific hardware 275 can include components 15 of user interface 255. Thus, an application executing on mobile computing device 200 can receive user input from accessory 202, provide output to a user via accessory 202, and/or control, interact with, or respond to any operation accessory 202 is capable of performing. [0048] In some embodiments, accessory specific hardware 275 can include network and/or communication interfaces. For example, accessory specific hardware 275 can 20 include an RF receiver (e.g., for FM, AM, satellite radio, and/or other bands) and/or an RF transmitter (e.g., a short-range transmitter for personal use). In other embodiments, accessory specific hardware 275 can include a communication interface to a personal area network, such as a Bluetooth transceiver or other short-range wireless communication interface. In still other embodiments, accessory specific hardware 275 can include a 25 telephone interface, GSM, CDMA, and/or other voice and/or data network interfaces. [00491 Accordingly, accessory specific hardware 275 can encompass any hardware component for which interoperability with a mobile computing and/or communication device may be desirable. [00501 It will be appreciated that the system configurations and components described 30 herein are illustrative and that variations and modifications are possible. The mobile computing device and/or accessory may have other capabilities not specifically described herein. While accessory 202 and mobile computing device 200 are described herein with 10 reference to particular blocks, it is to be understood that the blocks are defined for convenience of description and are not intended to imply a particular physical arrangement of component parts. Further, the blocks need not correspond to physically distinct components. 5 [0051] Accessory I/O interface 205 of mobile computing device 200 and mobile computing device I/O interface 250 of accessory 202 allow mobile computing device 200 to be connected to accessory 202 and subsequently disconnected from accessory 202. As used herein, mobile computing device 200 and accessory 202 are "connected" whenever a communication channel between accessory 1/0 interface 205 and mobile computing 10 device I/O interface 250 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 mobile computing device 200 and accessory 202), by an indirect attachment such as a cable, or by establishing a wireless communication channel. Similarly, disconnection can be achieved by physical detachment, disconnecting a cable, 15 powering down accessory 202 or mobile computing device 200, or closing the wireless communication channel. Thus, a variety of communication channels may be used, including wired channels such as Universal Serial Bus ("USB"), FireWire (IEEE 1394 standard), or universal asynchronous receiver/transmitter ("UART"), or wireless channels such as Bluetooth (a short-range wireless communication standard developed by the 20 Bluetooth SIG and licensed under the trademark Bluetooth*), WiFi (adhering to any of the IEEE 802.11 family standards), wireless personal area network, infrared, or the like. In some embodiments, communication can occur using both a wired and a wireless channel. In some embodiments, multiple communication channels between a mobile computing device and an accessory can be open concurrently, or a mobile computing device can be 25 concurrently connected to multiple accessories, with each accessory using a different communication channel. [00521 Regardless of the particular communication channel, as long as mobile computing device 200 and accessory 202 are connected to each other, the devices can communicate by exchanging commands and data as specified by an accessory 30 communication protocol. The accessory communication protocol can define a format for sending messages between mobile computing device 200 and accessory 202. For instance, the accessory communication protocol may specify that each message is sent in a packet with a header, a payload, and/or a tail. The header can provide basic information such as a I I 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 a tail that may provide 5 error-detection or error-correction codes, e.g., as known in the art, and/or other information as desired. In various embodiments, the accessory communication 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 1o that any particular command is valid in only one direction. [00531 The accessory communication protocol can also specify one or more physical transport links usable for transmitting signals between devices. For example, the transport link can be a USB link, a UART link, a FireWire link, a Bluetooth link, a WiFi link, a parallel link, a serial link, etc. At this level, the accessory communication protocol can 15 specify, e.g., start bytes, sync bytes, stop bytes, and/or other auxiliary signals. In some embodiments, the accessory communication protocol can provide for multiple alternative transport links; thus a single mobile computing device can support communication over a variety of physical links including wired and/or wireless links. [00541 The accessory communication protocol can define a number of "lingoes," where 20 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 mobile computing 25 devices to which an accessory can be connected, support every lingo defined within the accessory communication protocol or every command of a particular lingo (for instance, different devices might use different versions of a given lingo). [00551 In some embodiments, every accessory 202 and every mobile computing device 200 that are designed to interoperate with each other support at least a "general" lingo that 30 includes commands common to all such devices. The general lingo can include commands enabling the mobile computing device and the accessory to identify themselves to each other and to provide at least some information about their respective capabilities, 12 including which (if any) other lingoes each supports and which capabilities of the other device each intends to use while connected. [0056] The general lingo can also include authentication commands that the mobile computing device can use to verify the purported identity and capabilities of the accessory 5 (or vice versa), and the accessory (or mobile computing device) may be blocked from invoking certain commands or lingoes if the authentication is unsuccessful. For example, an authentication manager (not shown) within mobile computing device 200 can communicate with an authentication controller (also not shown) within accessory 202 to perform an authentication procedure, e.g., based on public key cryptography and a store of 10 digital certificates maintained within the authentication manager of mobile computing device 200. [00571 The general lingo or another lingo of the accessory communication protocol can also include "tunnel" commands that allow an exchange of arbitrary information between an application 226 executing on mobile computing device 200 and accessory 202. For 15 example, a TunnelToAcc command can be defined as being sendable by mobile computing device 200 to accessory 202. The payload of this command can be any data, control signals, or other information that an application 226 executing on mobile computing device 200 can generate and send to accessory 202. Similarly, a TunnelToHost command can be defined as being sendable by accessory 202 to mobile computing device 200. The 20 payload of this command can be any data, control signals, or other information that accessory 202 can generate and send to an application 226 executing on mobile computing device 200. These tunnel commands can be defined such that the accessory communication protocol is agnostic as to the payload content. Examples of techniques for managing communication such that a particular application sends data, control signals or 25 other information only to accessories capable of processing it (and vice versa) are described below. [0058] In some embodiments, the accessory can communicate with an API associated with one or more applications at the mobile computing device using the application communication protocol. For example, such communication can use the "tunnel" 30 command discussed above. In some embodiments,, the accessory can communicate with an API associated with one or more application using the accessory communication protocol. In other embodiments, the accessory can also communicate with the mobile 13 computing device operating system using either or both of the accessory communication protocol and/or the application communication protocol. Thus, embodiments disclosed herein can be used to facilitate communication from an accessory to an application, API, and/or an operating system at the mobile computing device using either or both of an 5 application communication protocol and/or an accessory communication protocol. [00591 An accessory communication protocol supported by a mobile computing device and an accessory can include various other lingoes, such as a simple remote lingo that allows the accessory to send a command indicating a function of the mobile computing device to be invoked, a remote user interface lingo that can be used to communicate 10 commands and data related to replicating all or part of a user interface of the mobile computing device on the accessory (thereby supporting a more advanced remote control), a tuner lingo that allows a user to control a tuner accessory by operating the mobile computing device, a storage lingo that allows the accessory to store data on the mobile computing device, and so on. Any lingo or combination of lingoes or other commands or 15 groups of commands can be used in connection with embodiments described herein. [00601 It will be appreciated that the accessory communication 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 20 of the commands and operations described herein be supported by any particular mobile communication device or accessory. [0061] As noted above, application 226 executing on mobile computing device 200 and accessory 202 can exchange arbitrary data, control signals, and/or other information (also referred to herein as "messages"). These messages can relate to a wide variety of 25 circumstances. For example, messages relating to user input events, detected external conditions, received data or any other events or conditions that may occur at mobile computing device 200 can be communicated to accessory 202. Conversely, messages relating to user input events, detected external conditions, received data or other events or conditions that may occur at accessory 202 can be communicated to mobile computing 30 device 200. [00621 For example, in some embodiments, mobile computing device 200 can process input events from a user, for example, through user interface 255, such as touch screen 14 events, button presses, scroll wheel events, etc. Mobile computing device 200 can provide data representative of input events to an application running on mobile computing device 200, to accessory 202, or to both. Accessory 202 can interpret such data as input for controlling, for example, accessory specific hardware 275 and/or for processing at 5 controller 260. For example, touch screen data can be collected by mobile computing device 200 for use by an application, accessory 202, or both; in some embodiments, touch screen data can include data representing taps and/or movements such as swipes, pinches, drags, and other gestures. In some embodiments, touch screen data can be sent in raw data format (e.g., a sequence of coordinates representing where pressure corresponding to a 10 finger movement was detected). In other embodiments, touch screen data can be converted into processed data, such as gesture events (e.g., a tap, a swipe or drag from one point to another, a pinch, etc.) prior to being sent to an accessory. In some embodiments, raw keyboard data can be sent to an accessory and/or processed keyboard data can be sent to an accessory. In some embodiments, some or all types of user input data can be 15 communicated to accessory 202 using an application and application protocol, e.g., as described below; in other embodiments, some or all types of user input data can be communicated using the accessory communication protocol to whatever extent the accessory communication protocol supports sending user input data of a particular type. [0063] Mobile computing device 200 can also send information other than user input to 20 accessory 202. For example, in some embodiments mobile computing device 200 can include various sensors and/or data gathering devices in addition to user input devices; examples can include accelerometers, gyroscopes, compass, location-determining devices (e.g., a Global Positioning System receiver or telephonic triangulation system), light sensors, infrared sensors, camera, network interfaces (e.g., telephone, WiFi, Bluetooth), or 25 the like. Mobile computing device 200 can provide any or all of this data to accessory 202, e.g., in response to a specific request from accessory 202. In some embodiments, some or all of this data can be communicated to accessory 202 using an application and application protocol, e.g., as described below; in other embodiments, some or all of this data can be communicated using the accessory communication protocol to whatever extent 30 the accessory communication protocol supports sending information of a particular type. [00641 In another example accessory 202 can receive input events from mobile computing device 200. Such events can correspond to user input and/or other data detected at mobile computing device 200, including but not limited to any of the data 15 types described above. In some embodiments, such input events can be processed by controller 260 at accessory 202 to control accessory specific hardware 275. For example, touch screen or other user input events at mobile computing device 200 can be sent to accessory 202 to turn on, change the state of, receive data from, provide data to, turn off, 5 and/or set settings for, accessory specific hardware 275. Touch screen data, for example, can be sent in raw data format or as interpreted events (e.g., press, swipe, pinch). In some embodiments, accessory specific software 280 can include instructions to receive and/or interpret raw touch screen data. In some embodiments, accessory specific software 280 can include instructions to translate raw touch screen data into commands and/or controls 10 for accessory specific hardware 275. In another embodiment, the touch screen data can be provided in raw format to an application executing on mobile computing device 200, which can interpret the data and send corresponding commands and/or information to accessory 202. [00651 Moreover, input events received at accessory 202 from mobile computing device 15 200 can be processed by controller 260 executing accessory specific software 280. In some embodiments, accessory specific software 280 can interact with accessory specific hardware 275 in response to input events received from mobile computing device 200. [0066] Further, in some embodiments, accessory specific hardware 275 can also be controlled by mobile computing device 200 via a connection with accessory 202. For 20 example, an application executing on mobile computing device 200 can include program code that when executed by processor 230, can control, interface with, interoperate with, and/or receive signals from the accessory specific hardware 275 at accessory 202. In some embodiments, the application executing on mobile computing device 200 can exchange messages with a control program executing on controller 260 of accessory 202, thereby 25 instructing controller 260 to communicate with and/or control operation of accessory specific hardware 275. Such messages can be exchanged using an application protocol, e.g., as described below. [0067] In some embodiments, accessory specific hardware 275 can provide input data to controller 260. For example, accessory specific hardware 275 can include a measurement 30 sensor that can convert physical characteristics into data (or electronic signals representing data; the terms are used interchangeably) that can be sent to controller 260 and/or stored in memory 265. Controller 260 can process the data (e.g., applying calibration corrections, 16 reducing noise, and/or other data-processing operations). The processed data can be sent from accessory 202 to mobile computing device 200. At mobile computing device 200 an application can further process the data and/or provide the data to a user through the user interface. Moreover, the application can perform any number of functions in response to 5 the data. [00681 In some embodiments, an accessory and an application can exchange any messages desired, where the term "message" refers generally to any type of control signal, event, data, status or configuration information or any other type of information available to the sender. To facilitate exchange of messages, an accessory and an application can use 10 a mutually agreed-upon application protocol. The application protocol can specify a universe of accepted formats for messages that can be exchanged. Devices or programs adhering to a particular application protocol can structure the messages they send in accordance with the application protocol's universe of accepted formats and can interpret messages they receive in accordance with the application protocol's universe of accepted 15 formats. For instance, in the case of binary digital communication, the application protocol can specify how the bits comprising the message are to be interpreted by the recipient. Thus, like the accessory communication protocol, an application protocol can specify packet structures; commands; lingoes; payload formats; and/or other formats, data structures, semantics or rules of interpretation such that a particular message sent by one 20 participant will be correctly interpreted by the recipient. Indeed, in some embodiments, portions of the accessory communication protocol can be directly adopted as all or part of an application protocol for a particular accessory and/or application. [00691 In certain embodiments described herein, accessory protocol messages can be sent between devices by encapsulating, wrapping, or packaging the messages within 25 packets conforming to the accessory communication protocol, e.g., using tunneling commands as described above. Thus, the transport link specified by the accessory communication protocol can be used, and it is not necessary for an application protocol to specify a physical transport link. [00701 It is contemplated that an unlimited range of accessories and applications that use 30 a variety of different application protocols can be created for use with a particular mobile computing device (or line of mobile computing devices). In some embodiments, mobile computing device 200 can be configured with application protocol management capability 17 (e.g., using an application manager) that includes tracking the application protocol(s) used by each connected accessory and the application protocol(s) used by each executing and/or installed application. For example, mobile computing device 200 can provide system services to facilitate identifying an appropriate application to be used with a particular 5 accessory and/or identifying whether a suitable accessory is available for a particular application. These services can be provided without requiring the system services of mobile computing device 200 to implement or communicate according to any application protocol. [00711 FIG. 3 is a block diagram showing various modules and processes within mobile io computing device 200 according to an embodiment of the present invention. The various modules shown can correspond to programs executing on processor 230 of FIG. 2, programs executing on other processors within mobile computing device 200, application-specific integrated circuits, or other implementations. In some embodiments, multiple processor chips or multiple processor cores within a single chip can be used to 15 implement the various modules and processes described herein. Some or all of the processors can be programmable general-purpose processors executing software and/or firmware programs; others can be digital signal processors, state machines with built-in functionality, or any combination thereof. [00721 Ports 305-307 provide communication channels for accessories 300-302 20 respectively. Each of ports 305-307 can be a physical and/or logical port supporting a specific communication channel. For example, port 305 can be a physical port associated with a wired channel such as USB or UART and can incorporate hardware elements (e.g., USB-compatible driver circuits and/or pins) along with suitable control software. Port 306 can be a logical port (e.g., a virtual serial port) associated with a wireless channel such as 25 Bluetooth. In some embodiments, each port 305-307 can send and receive messages conforming to the accessory communication protocol as applied to the particular physical transport or channel associated with that port. While three ports are shown, it is understood that a mobile computing device can be designed to support any number of physical and/or logical ports in any combination. Further, as described below, a single 30 accessory can connect to multiple ports in some embodiments. [00731 Protocol manager 310, which can be, e.g., a firmware or software module executed by processor 230, can receive mobile computing device-protocol messages (also 18 referred to as commands) from ports 305-307 and begin the process of interpreting the messages. In some embodiments, protocol manager 310 or an associated protocol daemon (not shown) associated with protocol manager 310 can also create or define ports 305-307 and connect them to suitable communication hardware, such as connector pins and driver 5 circuits, wireless transceivers, etc. In one embodiment, protocol manager 310 (or its associated protocol daemon) can extract inbound mobile computing device-protocol messages received on the various ports and deliver the extracted messages to support layer 315 or to other components within mobile computing device 200. Thus the upper levels of the process stack of FIG. 3 can be independent of a particular transport link. 10 [00741 In another embodiment, protocol manager 310 can receive outbound information (e.g., a message that has been structured according to an application protocol by application 404 that created the message) intended for a connected accessory (e.g., any of accessories 300-302) from support layer 315, package the outbound message into a mobile computing device-protocol packet, and deliver the packet to the one of ports 305-307 that 15 is connected to the desired accessory. [0075] In some embodiments, protocol manager 310 (or an associated protocol daemon) can also support and/or control opening and closing of ports. For example, in the case of a virtual port, protocol manager 310 can create a set of virtual ports at startup and open and/or close the ports as connections are requested and/or terminated. 20 [0076] Protocol manager 310 can maintain a dynamic port map 325 that associates specific application protocols with specific ports. For example, when an accessory such as accessory 300 establishes a connection to mobile computing device 200 on a particular port such as port 305, accessory 300 can identify the application protocol(s) it supports (e.g., AP3 in the case of accessory 300) to protocol manager 310, e.g., by providing a 25 protocol name string via port 305. Protocol manager 310 can store an association between the application protocol name and the port in port map 325. When the accessory is subsequently disconnected, the association can be removed from port map 325. Thus, port map 325 can provide a list of application protocols that are currently available for use by applications. As described below, such a list facilitates routing of communications 30 between accessories and applications, as well as notifying compatible applications when compatible accessories are connected. 19 [00771 Software support layer 315 can act as an intermediary between protocol manager 310 (and optionally other low-level device functions) and applications 320-322 that can be executed on mobile computing device 200. For example, software support layer 315 can provide an application program interface (API) via which applications can invoke device 5 functionality. Software support layer 315 can provide an extra level of device independence to applications 320-322; however, those skilled in the art will appreciate that not all layers shown in FIG. 3 are required. For instance, in some embodiments, protocol manager 310 can communicate directly with applications 320-322. [00781 In the embodiment shown, support layer 315 can provide accessory information 10 lookup table 330. In one embodiment, accessory information table 330 can include information about each connected accessory such as accessory type, accessory identifier, and/or the name(s) of one or more application protocols supported by the accessory. Accessory information table 330 can be populated and updated in response to information provided by protocol manager 310 as accessories connect and disconnect. 15 [00791 Applications 320-322 can be concurrently or sequentially executing applications and can be implemented as program code executable, e.g., by processor 230. Various applications 320-322 can provide various forms of user interaction with mobile computing device 200 and/or connected accessories 300-302. For example, an application can provide a user interface to a connected measurement probe accessory. In response to user 20 input, the application can instruct the measurement probe to begin recording measurement data and stop recording measurement data. The application can also present measurement data to a user. The application can convert data into various forms and/or provide further user interactions, such as viewing a record of measurements over time, performing analysis operations on the data (e.g., averaging, trend analysis, graphical analysis, or the 25 like), and so on. [00801 An executing application (e.g., any of applications 320-322) can query accessory information table 330 at any time to determine whether a compatible accessory (i.e., an accessory that supports an application protocol used by the application) is connected. If a compatible accessory is connected, the application can communicate with the accessory 30 using the application protocol. For example, as described below, the application can initiate a communication session with the accessory. 20 [00811 It will be appreciated that the modules described herein are illustrative and that variations and modifications are possible. Mobile computing device 200 can support any type of application, and applications can be launched or exited under control of a user or another process. Certain modules, such as support layer 315 and protocol manager 310, 5 can be implemented in software and/or firmware and configured to be automatically started at device power-up and to terminate only on power down or when various abnormal conditions are detected; applications 320-322 may start and terminate in response to user input or other input. In some embodiments, an application may automatically be launched when a corresponding accessory is connected, e.g., as described 10 below. The various modules or processes may go into inactive states to minimize resource consumption when not in use. Further, not all of the layers and modules shown herein are required; for instance, in some embodiments, applications might communicate directly with the protocol manager, bypassing support layer 315. In other embodiments, modules or layers shown as separate in FIG. 3 can be combined, or additional modules or layers 15 can be provided, such as the protocol daemon and/or modules associated with various system services of mobile computing device 200 (e.g., audio and/or video playback, network connections, and the like). [0082] It is also to be understood that an accessory can implement modules, layers, and other components similar to those shown in FIG. 3, or any variation or modification 20 thereof. As long as the accessory is capable of exchanging information with a mobile computing device according to an accessory communication protocol, the internal implementation can be varied as desired. [0083] As shown in FIG. 3, mobile computing device 200 in some embodiments can maintain multiple concurrently executing applications 320-322 and/or concurrent 25 connections to multiple accessories 305-307. The applications and/or accessories can support different (and potentially incompatible) application protocols, and each application protocol can be assigned a name (e.g., a unique string) to distinguish it from all other application protocols. For example, in the embodiment of FIG. 3, application 320 and accessory 301 support application protocol API; application 321 and accessory 302 30 support application protocol AP2; and application 322 and accessory 300 support application protocol AP3. 21 [00841 It is contemplated that third parties will be able to independently develop applications and/or accessories. If two accessories (or applications) associate the same accessory protocol name with application protocols that are in fact not compatible, this can create a name conflict, e.g., if both accessories attempt to connect to the same mobile 5 computing device concurrently. To avoid such conflicts, it may be desirable to provide centralized namespace management for application protocol names. In some embodiments, a central namespace manager (e.g., the manufacturer of the mobile computing device) can assign names to application protocols upon request from developers thereof. In another embodiment, the central namespace manager can simply 10 define a naming convention that, if adhered to, should prevent name conflicts, and developers of accessories and/or applications can avoid conflicts by adhering to the convention. [0085] In one embodiment, a reverse domain name convention is adopted for managing the application protocol namespace. Conventional domain names provide, from left to 15 right, lower level domains to top level domains. For example, in the domain name: "help.example.com", the term "com" is the top level domain and the term "example" is a lower level domain, and the term "help" is the lowest level domain. As another example, the domain name "mac.apple.com" from left to right specifies the lowest level domain "mac", the middle domain "apple", and the top level domain "com". Reverse domain 20 names, on the other hand, would provide "com.apple.mac". [00861 The reverse domain name convention can be used to specify application protocols used by a specific company. That is, the reverse domain name "com.companyl.accessoryl" specifies that the "accessoryl" protocol is associated with the company (or other developer) companyl ". Thus, in general, a company can 25 implement a protocol using the reverse domain name convention, where the first portion of the reverse domain name references the company ("com.company ") and is associated with the company's (or other developer's) Internet domain name. The second portion of the reverse domain name ("accessory 1") specifies a specific protocol. To the extent that the different developers of accessories and/or applications are associated with different 30 Internet domain names, a reverse domain name convention allows developers to distinguish applications and/or protocols and/or accessories from others by naming their protocols based on the reverse of their Internet domain name. This convention allows developers to independently name their protocols without concern for the naming 22 conventions of other developers. Moreover, if there is a conflict between two developers using the same names, a simple check of who owns the corresponding Internet domain name should determine which developer has rights to a particular reverse domain name. [00871 In some embodiments, reverse domain names can be appended to include a 5 global identifier that is specific to all devices in a class of devices. For instance, all serial pass through type devices can include an identifier appended to the reverse domain name. For example, such a reverse domain name may have the following format: "com.company l.accessory I.serialpass" or "serialpass.com.company l.accessoryl." With such a convention, different companies can produce serial pass through devices and yet 10 the mobile computing device can recognize such devices despite manufacturer differences. This reverse domain name convention is only one example of how application protocols can be identified. Any type of convention can be used. [0088] Accordingly, when an accessory is connected with a mobile computing device, the accessory can provide the mobile computing device with a list of its supported 15 application protocols by supplying the name that was assigned to each supported protocol using the reverse domain name convention. An accessory can support a single application protocol or multiple application protocols. Based on the received information, mobile computing device 200 of FIG. 3 can populate port map 325, accessory information table 330 and/or other lookup tables with information such as accessory type, accessory 20 identifier, application protocol name, and/or communication port identifier. As described below, applications 320-322 can use these lookup tables to determine whether a compatible accessory is available, and support layer 315 and/or protocol manager 310 can use the lookup tables to route communications without having to understand any of the application protocols. 25 [0089] For example, mobile computing device 200 can be wirelessly connected with a thermometer and also connected with a camera using a cable. (For instance, in FIG. 3, accessory 302 can be a thermometer and port Z a wireless port while accessory 300 can be a camera and port X a wired port.) Upon connection, the thermometer can identify its supported application protocol by sending the reverse domain name 30 "com.temprus.thermometerl ". This reverse domain name can be sent to the mobile computing device using the accessory communication protocol. At the mobile computing device, this reverse domain name can be stored as an application protocol name in a 23 lookup table (e.g., port map 325 and/or accessory information table 330); in some embodiments, the reverse domain name can be stored in conjunction with an accessory identifier for the thermometer and/or the wireless port where the thermometer can be accessed. Similarly, upon connection, the camera can identify its supported application 5 protocol by sending the following reverse domain name "com.camerasrus.camera l", again using the accessory communication protocol. This reverse domain name can also be stored in the lookup table (e.g., port map 325 and/or accessory information table 330), e.g., in conjunction with an accessory identifier for the camera and/or the port where the camera can be accessed. 10 [00901 Mobile computing device 200 can execute a temperature application (e.g., application 321) that communicates with a thermometer using the application protocol "com.temprus.thermometerl" to make temperature readings. During execution, the temperature application can access the lookup table to see if a compatible application protocol is present, e.g., by searching for the protocol name "com.temprus.thermometerl". 15 When the temperature application finds "com.temprus.thermometerl", the application has a match and can begin communicating with the thermometer using the com.temprus.thermometerl application protocol. The communication is routed through the associated port, e.g., by using tunneling commands of the accessory communication protocol. The application protocol can specify commands, packet information, data, etc., 20 that can be different from what is specified in the accessory communication protocol. Moreover, the company providing the application and/or the accessory (for example, the TempRUs company) can implement any communication protocol for communication between applications and accessories. [00911 FIG. 4 is a simplified diagram further illustrating communication between an 25 application and an accessory according to some embodiments of the invention. Mobile computing device 400 can be connected to accessory 402, allowing application 404 executing on mobile computing device 400 to communicate with accessory 402 using an application protocol. [00921 In the embodiment shown in FIG. 4, application 404 has already determined that 30 accessory 402 is a compatible accessory and has created a session 406 by invoking appropriate function calls to support layer 408. Session 406 can be, e.g., a software object created by application 404 using an API call to support layer 408. Session 406 can be 24 associated with the application 404 that created it as well as a particular accessory and/or application protocol specified by application 404 when it creates the session. Session 406 can provide, among other things, an input stream and an output stream whose contents are, respectively, received from and delivered to application 404. (Creation of a session is 5 described below.) [00931 To communicate a message (e.g., control signals and/or other information) to accessory 402 using the application protocol, application 404 generates the message and writes it as data to an output stream of session 406. In this embodiment, application 404 is solely responsible for formatting the message in accordance with the application protocol; 10 other intermediary processes on mobile computing device 400 do not alter the data that is written to the output stream. [00941 Session 406 detects the presence of data in the output stream and sends a corresponding send (SND) instruction to protocol manager 410. The SND instruction provides the accessory and accessory protocol identifiers associated with session 406 and 15 a "bundle" that represents data from the output stream. In some embodiments, the bundle can correspond to all of the message data; however, depending on the length of the message and constraints that might be imposed on packet length by the accessory communication protocol, a bundle may also correspond to only a portion of the message data. Conversely, in some embodiments, a single bundle might include multiple 20 application protocol messages. [0095] Protocol manager 410 can use the accessory and accessory protocol identifiers provided by session 406 along with port map 412 to select a port for transmission of the bundle. Protocol manager 410 can also package the bundle within a command of the accessory communication protocol, e.g., a TunnelToAcc command as described above. 25 The accessory communication protocol command is sent to port 414 for transmission. (While only one port is shown in FIG. 4, it is understood that mobile computing device 400 can have multiple ports.) [00961 FIGs. 5A-5C illustrate an example of packaging (or wrapping) an application protocol message within an accessory communication protocol command according to 30 some embodiments of the invention. FIG. 5A shows an example of an accessory protocol packet 500. As shown, packet 500 includes header 502 and payload 504. The accessory communication protocol, for example, can dictate the size of the header and what 25 information can be provided within header 502. In some embodiments, header 502 can include a command or byte code that can indicate what is contained in the payload and/or what is to be done with data in the payload. For example, in the embodiment shown, header 502 includes a command code for the TunnelToAcc command. Header 502 can 5 also include other information, such as information specifying the size of payload 504. In some embodiments, an optional tail 506 can be included at the end of packet 500; the tail can include information usable to detect or correct errors (e.g., a checksum) and/or other information as desired. Those skilled in the art will recognize that various packet types can be used in the accessory communication protocol. 10 [00971 FIG. 5B shows an example of an application protocol packet 510. Application protocol packet 510, in this example, includes a header 512 (App. Header), payload 514 (App. Payload), and tail 516. Various other packet types, styles, configurations, payloads, information regions, etc., can be used in an application protocol packet. Indeed, applications and/or accessories can use application protocol packet of any type, size, 15 configuration, etc., as designed, developed and/or created by application developers without limitation; in some embodiments, some or all application protocol packets may be modeled on (or even indistinguishable by content from) accessory communication protocol packets. In some embodiments, an application protocol packet may or may not include a header. In some embodiments, application protocol packet may or may not 20 include a tail. In some embodiments, an application protocol packet can include a payload 514 with a fixed or variable size. In some embodiments, commands, data, and/or other message elements can be provided within the payload and/or the header. The specific characteristics of the commands and/or data and/or other message elements can be specified by the application protocol. Further, application protocols are not required to use 25 a packet structure for messages at all; accessory protocol messages can have any format and/or structure that is capable of being correctly interpreted by the recipient. [00981 FIG. 5C shows an example an application protocol packet 510 packaged (or wrapped) within payload 504 of accessory protocol packet 520. As shown, packet 520 can include accessory protocol packet header 502 followed by application protocol packet 510. 30 In some embodiments, header 502 can include a command or byte code indicating that the payload is an application protocol packet. The application protocol packet, in this example, includes an application protocol packet header 512, application protocol packet payload 514, and application protocol packet tail 516. Application protocol packet 510 26 may or may not completely fill payload 504 of accessory protocol packet 520. More generally, an accessory protocol packet for a TunnelToA cc command can include any data bundle intended for delivery to the accessory and is not limited to carrying a single accessory protocol packet. 5 [00991 Referring again to FIG. 4, accessory 402 receives the accessory protocol TunnelToAcc command packet, e.g., at port 422. Port 422 can route the TunnelToA cc command packet to a protocol interpreter 424, which can be, e.g., a software process executing on a controller or other processor of accessory 402. Protocol interpreter 424 can read the TunnelToA cc command, extract the bundle contained therein, and forward the 1o bundle to another process 426 executing on a controller or other processor of accessory 402. Process 426 can include any process that is capable of processing received information conforming to the application protocol. For instance, process 426 can include a process that extracts instructions from the received information and generates corresponding control signals for accessory-specific hardware (e.g., accessory specific 15 hardware 275 of FIG. 2). [0100] Communication from accessory 402 to mobile computing device 400 is also supported. For example, process 426 can generate a data bundle corresponding to a message in the application protocol and provide the bundle to protocol interpreter 424 to be sent to mobile computing device 400. Protocol interpreter 424 can package the bundle 20 inside a TunnelToHost command of the accessory communication protocol (e.g., similarly to the example shown in FIGs. 5A-5C) and send the command to port 422 for transmission to mobile computing device 400. [01011 At mobile computing device 400, port 414 receives the TunnelToHost command packet and forwards it to protocol manager 410. Protocol manager 410 recognizes the 25 TunnelToHost command and in response thereto, extracts the bundle and forwards it to support layer 408, along with identification of the accessory and application protocol associated with the bundle. In some embodiments, protocol manager 410 can determine these identifiers based on which port delivered the TunnelToHost command; thus, the TunnelToHost command need not provide identification of the accessory or application 30 protocol. [0102] Support layer 408 uses the accessory and accessory protocol identifiers to direct the bundle to the input stream of session 406. Application 404 can then read the incoming 27 data from the input stream of session 406, interpret the data according to the application protocol and respond accordingly. [01031 Thus, for example, application 404 can be a thermometer application, and accessory 402 can include a thermometer. Application 404 can request a temperature 5 measurement from accessory 402 using an appropriate application protocol (e.g., a protocol named "com.temprus.thermometer1"). The application protocol, for example, can specify a GetTemp command that is sent by the application to request temperature data from the accessory. Application 404 can create an application protocol packet that includes, e.g., the GetTemp command and any preferences or variables associated with 10 the command (e.g., whether to return the temperature data in Fahrenheit or Celsius). Application 404 can create a packet with the proper header and/or tail as defined by the application protocol. Application 404 can then pass this packet as an application protocol message into the output stream of session 406. Session 406 can direct protocol manager 410 to send an accessory protocol-tunneling command, specifying that the application 15 protocol is "com.temprus.thermometerl." Protocol manager 410 can package the GetTemp command inside a TunnelToAcc command packet of the accessory communication protocol and can also look up the application protocol name and determine that this application protocol is associated with port 414. Protocol manager 410 can then route the TunnelToAcc command packet to port 414 for deliver to accessory 402. 20 101041 Accessory 402 can receive the TunnelToAcc command at port 422. Protocol interpreter 424 can extract the GetTemp command packet and deliver it to process 426, which in this example can be a process that controls a temperature sensor and receives data therefrom. Accordingly, process 426 can obtain temperature data that is to be returned to application 404. To send the data, process 426 can, for example, generate a 25 SendTemp command packet conforming to the application protocol. This packet can include the requested temperature data (e.g., using the temperature scale specified in the GetTemp command). Process 426 can provide the SendTemp command packet as a bundle to protocol interpreter 424, with an indication that it should be sent to mobile computing device 400. Protocol interpreter 424 can package the Send_Temp command 30 packet within a TunnelToHost command of the accessory communication protocol, and port 422 can communicate the TunnelToHost command to port 414 of mobile computing device 400. Port 414 can deliver the incoming TunnelToHost command to protocol manager 410, which can extract the bundle (in this case the SendTemp command packet) 28 and provide it to support layer 408, along with the information that the bundle is associated with the "com.temprus.thermometerl" protocol, as determined from port map 412. Support layer 408 can then direct the bundle to session 406, in particular to the input stream of session 406. Application 404 can read the bundle from the input stream, 5 recognize it as a SendTemp command packet conforming to the application protocol, and extract the temperature data. [01051 In some embodiments, an accessory can use both an application protocol and commands of the accessory communication protocol to communicate with an accessory. FIG. 6 illustrates a path for commands of the accessory communication protocol in the 10 embodiment of FIG. 4. In addition to sending application protocol messages via session 406, application 404 can invoke accessory-protocol commands by making appropriate API calls to support layer 406, which can instruct protocol manager 410 to send an accessory protocol command (represented here as "mobile computing deviceProtCmdOut") via port 414 to accessory 402. Similarly, an accessory-protocol command received from accessory 15 402 (represented here as "mobile computing deviceProtCmdln") can be received and processed by protocol manager 410, and protocol manager can communicate the command to support layer 406. Support layer 406, in turn, can act accordingly upon application 404. [01061 In some embodiments, an application protocol can incorporate lingoes and/or commands specified by the accessory communication protocol. For example, the 20 accessory communication protocol can define a tuner lingo, RFTuner, that allows a user to control a radio frequency tuner accessory through the mobile computing device. For instance, the RFTuner lingo can include commands to turn the receiver on and off, to change the station, etc. In some embodiments, a radio tuner application can execute at the mobile computing device, and the radio tuner application executing at the mobile 25 computing device and the radio tuner accessory can support a radio tuner application protocol that allows the radio tuner accessory to communicate with the radio tuner application. Some or all commands of the RFTuner lingo can be used with the radio tuner application protocol, and the radio tuner application protocol can include other commands as well (e.g., commands to control a preset list of stations that the user likes). Thus, the 30 radio tuner application can use the RFTuner lingo as part of the radio tuner application protocol to communicate with the radio tuner accessory, e.g., for changing the station, and can also use other commands of the radio tuner application protocol for other operations. The mobile computing device can also use the RFTuner lingo as part of the accessory 29 communication protocol to communicate with the radio tuner accessory independent of the application. Thus, the radio tuner accessory can send commands and/or messages to the mobile computing device using a single lingo within either of the two protocols. [01071 As another example, the RFTuner lingo can include an RFSetFreq command that 5 is sent from the mobile computing device (for instance, the application executing at the mobile computing device) to tune the radio tuner accessory to the frequency to a frequency included in the command. The radio tuner application can create a packet with the proper header and/or tail as defined by the application protocol, and include the RFSetFreq command and the required frequency in the packet payload. The packet can 10 then be sent to the Protocol manager which can bundle the packet into an accessory protocol packet with a command of the accessory communication protocol, e.g., a TunnelToAcc command as described above. The accessory protocol packet can then be sent to the accessory. As another example, the RFSetFreq command can be used without a radio tuner accessory and without being tunneled. The mobile computing device can 15 send a packet using the accessory communication protocol using the RFSetFreq command and the associated frequency to the accessory as a stand alone packet. [01081 As yet another example, an accessory can use the RFTuner lingo to communicate with the mobile computing device using either the application protocol and/or the accessory communication protocol. For example, the accessory can use the TunnelToHost 20 command to tunnel RFTuner commands to the mobile computing device when communicating with a specific application at the mobile computing device. As another example, the accessory can send RFTuner commands without tunneling to the mobile computing device. [01091 In another embodiment, an accessory such as a speaker dock may provide remote 25 control of media playback on the mobile computing device. The remote control functions can be implemented using commands of the accessory communication protocol; for example, the accessory communication protocol can include a ButtonStatus command that the accessory can send to identify a particular function invoked by the user (e.g., Play, Pause, Next Track, Previous Track, etc.). The mobile computing device can have a 30 playback engine for stored media that can process the ButtonStatus command and respond accordingly. An application executing on the mobile computing device can provide playback of other media sources, e.g., from an Internet data stream. It would be desirable 30 for the user to be able to remotely control the playback of the streaming content by operating the accessory in the same way that the user controls the playback of stored media. Accordingly, a "streaming control" application protocol can be defined that includes commands or other control signals to control the playback of streamed content. 5 The user can operate the accessory in exactly the same way to control playback of either stored or streamed media content. If stored content is being played, the accessory can communicate the remote control information to the playback engine using the accessory communication protocol (e.g., the ButtonStatus command). If streamed content is being played, the accessory can communicate the remote control information to the application 10 using the streaming control application protocol. In one embodiment, the ButtonStatus command of the accessory communication protocol can be incorporated into the streaming control application protocol. [0110] In still another embodiment, an accessory might send location information to the mobile computing device. Location information can include any information representing 15 the location of the accessory and/or the mobile computing device and can be determined in various ways, such as using a Global Positioning System (GPS) receiver and/or triangulating a location based on information about nearby mobile phone network access points. The accessory communication protocol may provide a "location" lingo that is usable by an accessory to transmit location information to the mobile computing device. 20 An application, however, might use location information that is not provided for in the location lingo. Such information can be transmitted by the accessory to the application using an accessory-specific protocol. Thus, depending on how the location information is to be used, the same accessory can transmit location information to the mobile computing device using either the location lingo of the accessory communication protocol or the 25 accessory-specific protocol. 10111] It will be appreciated that the communication paths described herein are illustrative and that variations and modifications are possible. For example, a path may include more or fewer layers at the accessory and/or mobile computing device side. In some embodiments, each mobile computing device tunneling packet will contain one 30 accessory protocol message, but this is not required. For example, a single accessory protocol message might be sent using multiple mobile computing device tunneling packets, provided that the recipient (the accessory or application as the case may be) is capable of reconstructing a message from multiple received data bundles. Similarly, a 31 single mobile computing device tunneling packet might be allowed to contain multiple accessory protocol messages, provided that the recipient is capable of parsing the bundle into multiple messages. [01121 In describing FIG. 4, it was assumed that application 404 had already established 5 session 406 with compatible accessory 402. Examples of techniques enabling an application to identify a compatible accessory (or vice versa) and establish a session will now be described. [0113] FIG. 7 is a flow diagram of process 700 for identifying an accessory and compatible application according to an embodiment of the present invention. Process 700 10 can start at block 702. The mobile computing device can determine whether an accessory has been connected at block 704. For example, the mobile computing device can detect whether an accessory has been physically coupled with a connector, e.g., as shown in FIG. 1A or whether an accessory has been wirelessly coupled with the mobile computing device, e.g., as shown in FIG. lB. As noted above, an accessory can be considered as 15 being connected whenever a wired or wireless communication channel between the mobile computing device and the accessory is open, and block 704 can include detecting the opening of such a channel. An application manager executing at the mobile computing device can monitor hardware connections or communication modules to determine if a communication channel between the mobile computing device and the accessory is open. 20 [01141 At block 706, the mobile computing device can receive application protocol information from the accessory. In some embodiments, this information can be communicated using packets defined by the accessory communication protocol. In other embodiments, the application protocol information can be communicated in any manner understood by either or both the accessory and the mobile computing device. For 25 instance, the application protocol information can be communicated using any industry standard communication protocol such a USB protocol, Bluetooth protocol, or WiFi protocol. For example, the accessory communication protocol can specify one or more commands and associated data formats that an accessory can send to a mobile computing device to provide information about itself and its capabilities; in some embodiments, these 30 commands can be part of the general lingo of the accessory communication protocol. The information provided by the accessory can include text strings for the name(s) of the application communication protocol(s) supported by the accessory. The names can be 32 specified, for instance, using the reverse domain name convention as described above or any other desired naming convention. The accessory can also send other identifying information. For example, the accessory can send information identifying its type; manufacturer; model name; serial number; hardware, software and/or firmware versions; 5 etc. The accessory can also send information indicating capabilities of the mobile computing device that it is capable of or intending to use. For example, the accessory can specify which lingo of the accessory communication protocol it may use, whether it receives or provides audio and/or video signals from or to the mobile computing device, preferred initial operating states of the mobile computing device (e.g., whether audio 10 and/or video signal exchange should initially be enabled or disabled, a preferred format for audio and/or video signaling), and so on. [01151 In other embodiments, the application protocol can be specified by referencing an application store or from a server over the Internet. For example, when an accessory is coupled with the mobile computing device, the mobile computing device can request 15 application protocol information from the application store and/or from a server through the Internet. In one embodiment, the mobile computing device can send accessory identifying information such as accessory manufacturer, model name, and/or serial number to the application store or other server and receive application protocol information in response. Application protocol information sent from the accessory, for 20 example, can include the application protocol name; a file specifying various application protocol commands, messages and/or packet specifications; a listing of accessories with which the application protocol is compatible; a listing of applications with which the application protocol is compatible; an indication of a network location where an application or application update can be downloaded; etc. The application protocol 25 information can be sent in a metadata format. In some embodiments, various versions of the application protocol can be made available through the application store or through the Internet. For example, different versions of an application protocol can allow various levels of functionality and can be provided for use with a mobile computing device at different prices. For example, "lite" versions, free versions, full versions, demo versions, 30 etc. can be made available. For example, a full version can define a set of commands usable by the mobile computing device and/or accessory, whereas a lite version defines a subset of the commands defined by the full version. 33 [01161 In some embodiments, application protocols can be enumerated when communicated to the mobile computing device. The accessory can identify each supported application protocol with an index number or some type of indication that relates to each application. For example, the accessory can send a message that indicates 5 that index I is application protocol 1, index 2 is application protocol 2, and index 3 is application protocol 3. Each application protocol can be indicated using any type indication such as, for example, using the reverse domain name convention. Later these protocols can be referenced using their index number. Such enumeration can be used in embodiments described throughout this disclosure. 10 101171 The mobile computing device can authenticate the accessory using authentication procedures in accordance with the accessory communication protocol at block 708. These procedures can include, for example, authentication techniques based on public-key certificates stored in the mobile computing device and private keys held by various accessories and/or other techniques. In some embodiments, the mobile computing device 15 can authenticate every accessory upon connection and identification (e.g., after block 706). In other embodiments, the mobile computing device can authenticate every accessory prior to or during identification at block 706, and in still other embodiments, authentication can occur later in the process or not at all. For example, in some embodiments, the mobile computing device permits certain features and/or operations 20 associated with the accessory communication protocol to be accessed only by authenticated accessories; such "restricted-access" features can include features related to communication of accessory protocol commands (e.g., the tunneling commands described above can be restricted-access commands). The mobile computing device can wait to authenticate an accessory until the accessory attempts to use a restricted-access feature, or 25 the mobile computing device can authenticate the accessory at any time after receiving information indicating that the accessory will or might attempt to use a restricted-access feature. [01181 The mobile computing device can then create and/or update a "connected" application protocol list at block 710 using the application protocol information supplied 30 at block 706. For example, referring to FIG. 3, port map 325 and/or accessory information table 330 can be updated to associate the newly connected accessory and its application protocol(s) with a port. Any of the accessory identifying information provided at block 706 can be stored in a connected application protocol list by the mobile computing device. 34 One example of a connected protocol list is shown in FIG. 8 as table 820. Table 820 lists each application protocol that a currently-connected accessory has identified in association with the port to which the accessory is connected. (Accordingly, table 820 can be an example of port map 325 of FIG. 3). It is understood that the format and information 5 content of table 820 can be varied as desired. [01191 Referring again to FIG. 7, at block 712, the mobile computing device can determine whether any applications are available that use the application protocol(s) associated with the accessory (such applications are also referred to herein as "compatible" applications). For example, the mobile computing device can store a table 10 of supported application protocols, with each protocol being associated with the application (or applications) that supports it. One example of a supported-application protocol table is shown in FIG. 8 as table 810. Table 810 includes a list of application protocol names, and each application protocol name is associated with an identifier of one or more applications. In some embodiments, table 810 can be implemented as a lookup 15 table that can be accessed using the name of an application protocol to return an application identifier; table 810 can also be accessible using an application identifier to return a list of application protocols associated with a particular application. [01201 In some embodiments, table 810 includes only application protocols associated with currently executing applications. For example, when an application launches, it can 20 provide a system process of the mobile computing device (e.g., support layer 315 of FIG. 3) with a list of any application protocols that it requires and/or can use. The mobile computing device system process can update table 810 accordingly. In other embodiments, table 810 can be a persistent table that is maintained for all applications installed on the mobile computing device. For example, installing (or updating) an 25 application can include notifying a system process of the mobile computing device (e.g., support layer 315) of any application protocols that the application requires and/or is capable of using; the mobile computing device can update table 810 accordingly. [01211 In some embodiments, when an accessory is coupled with the mobile computing device, the accessory can identify itself by sending identification information, for 30 example, using an accessory identification lingo associated with the accessory communication protocol. The identification information can be used by the mobile computing device to select an appropriate application communication protocol, for 35 example, by referencing table 810. In some embodiments, the mobile computing device can send accessory identifying information to an application store and/or a server through the Internet to identify an application communication protocol compatible with the accessory. In some embodiments, the application store and/or server can send a file 5 detailing an application communication protocol compatible with the accessory. In some embodiments, the accessory may not send application protocol information to the mobile computing device, rather the accessory can send accessory identification information that is then used by the mobile computing device to chose the proper application communication protocol. 10 101221 Referring again to block 712 of FIG. 7, in embodiments where a supported application protocol table (e.g., table 810 of FIG. 8) is provided, the mobile computing device can determine whether a compatible application is available by accessing the supported protocol table using the protocol name of the newly connected accessory. For example, as shown in FIG. 8, if the newly connected accessory has provided 15 protocolString{c} as its application protocol identifier, block 712 of process 700 can include looking up protocolString{c} in supported protocol table 810 and thereby determining that an application "App8" is associated with this application protocol. In this case, block 712 would result in a determination that an application is available. As further shown in FIG. 8, if the newly connected accessory has provided protocolString{x} as its 20 application protocol, no match can be found in table 810, and block 712 of process 700 would result in a determination that a compatible application is not available. [01231 If a compatible application is not available, process 700 can facilitate locating and obtaining a compatible application at block 714. For example, the mobile computing device can direct the user to an application store (e.g., the iTunes* Store provided by 25 Apple Inc.) or other resource for purchasing and/or downloading applications. Various types of assistance can be provided. For instance, in some embodiments, the accessory information provided to the mobile computing device at block 706 can include an identifier of a preferred application for use with the accessory. This identifier might be a URL (uniform resource locator, e.g., a World Wide Web page address), a unique product 30 identifier for the preferred application in a particular application store, or the like. The mobile computing device can use this information to locate the preferred application and prompt the user to purchase and/or download the application. 36 [0124] In other embodiments, the mobile computing device can use the application protocol information, with or without other accessory identifying information, to search for a compatible application, e.g., within an application store. For example, as shown in FIG. 9, the mobile computing device can formulate a query 825 using one or more of the 5 connected application protocols and/or an identifier for a preferred application provided by the accessory (represented as appCode 830). The mobile computing device can send query 825 to a URL 840 associated with searching at an application store or another destination. In the example shown, the query includes a list of all connected application protocols (linked with a logical "OR" operand), along with appCode 830 for the preferred 10 application. In the event that multiple applications match the query, preferred application 830 can be used by the application store to highlight the preferred application (assuming it is on the list of matches). Thus, even though a number of applications may be listed that support one or more of the application protocols in connected protocol list 820, preferred application 830 may be the default application and may be listed as such, e.g., at the top of 15 a results list and/or marked with an symbol, word, or logo identifying it as preferred. In some embodiments more than one version of the preferred application may be provided with a ranking, so that the user may be presented with a tiered list. For example, a pro version, a standard version and/or a free version of the preferred application can all be provided. 20 [0125] In response to a query, the application store can return a list of one or more compatible applications, and the mobile computing device can prompt the user to select a compatible application to download. In some embodiments, applications can be installed immediately upon downloading; in other embodiments, the user may be separately prompted to download and then install the application. In yet other embodiments the user 25 may be required to purchase the application. In some embodiments purchase can be made through an application store, using credit, and/or through a previously established account. [0126] In still other embodiments, a compatible application may be pre-stored on the accessory itself, and the accessory communication protocol can include commands allowing the accessory to indicate that it has a compatible application stored thereon; in 30 response to such an indication, the mobile computing device can upload the compatible application from the accessory and install it. (In some embodiments, the mobile computing device may prompt the user for approval prior to uploading and/or installing accessory-provided applications.) 37 [01271 Referring again to FIG. 7, at block 716 it is determined whether a compatible application is now available and installed. (For instance, a compatible application might not have been located or the user might have chosen not to purchase or download it.) If not, process 700 can end at block 718. 5 [0128] If, at block 716, a compatible application is available (either previously installed or just installed via block 714), then at block 720, the mobile computing device can determine whether the compatible application is already running. If not, the application can be launched at block 722. Depending on implementation, block 722 can include prompting the user to confirm that the application should be launched. 10 [01291 At block 724, the application can communicate with the accessory. In some embodiments, block 724 can include creating a session and sending and/or receiving application protocol commands via the session, e.g., as described above. Block 724 can also include sending and/or receiving commands and other information using the accessory communication protocol. Thus, the same application and accessory can use 15 functions supported by the accessory communication protocol and can also exchange other information, control signals, data, etc. using an application protocol that might or might not overlap with the functions supported by the accessory communication protocol. Communication can persist indefinitely, e.g., until the accessory becomes disconnected from the mobile computing device and/or the application exits. At that point, process 700 20 can end (block 718). [0130] Process 700 can be implemented using hardware, software and/or firmware at a mobile computing device. For example, system processes and/or applications may execute to control the functionality of the mobile computing device to perform the actions described above. 25 [01311 In some embodiments, the mobile computing device can maintain a persistent list of all or a number of application protocols supported by any accessory that has ever connected to that mobile computing device even after the accessory disconnects. When the mobile computing device communicates with an application store, the mobile computing device can provide some or all of the protocols on the persistent list to the 30 application store (e.g., as a search query to a server hosting the application store), and the application store can suggest applications that the user might be interested in based on the list. For example, the application store can identify other applications that use the same 38 application protocol(s). If the persistent list also includes information identifying particular accessories associated with each application protocol, the information provided by the application store can identify particular accessories as compatible with the identified applications. This can assist the user in selecting applications to purchase 5 and/or download. 101321 FIG. 10 is a flow diagram of a process 1000 that can be executed by an application to initiate communication with an accessory according to an embodiment of the present invention. Process 1000 can start (block 1002), e.g., when the application is launched on the mobile computing device. For example, the user can manually launch the 10 application, or the application can be launched automatically by the mobile computing device in response to an accessory connecting (e.g., as described above with reference to FIG. 7). [01331 At block 1004, the application checks to determine whether a compatible accessory is connected. (As used herein, an accessory is "compatible" with a particular 15 application if the accessory supports an application protocol that is required and/or usable by that application.) For example, in embodiments where the mobile computing device maintains a connected accessory table such as table 820 of FIG. 8, the application can query the table using the name of a desired application protocol to determine whether a compatible accessory is connected. This query can include, e.g., invoking an API function 20 call to communicate with a support layer (e.g., support layer 315 of FIG. 3). [01341 If, at block 1006, a compatible accessory is not connected, the application can wait at block 1008 for a certain amount of time and then try again. If, for example, a timeout period is reached, then process 1000 ends at block 1020. In some embodiments, while waiting at block 1008, the application can generate a message to the user prompting 25 the user to connect a compatible accessory. In some embodiments, the application can register with a mobile computing device system service and request a notification when a compatible accessory becomes available rather than repeatedly checking. In still other embodiments, the application can exit if a compatible accessory is not connected and can also notify the user that the application will not run unless a compatible accessory is 30 connected or the application can run with reduced functionality. [0135] If a compatible accessory is detected at block 1010, the application can initiate a session with that accessory. For example, the accessory can invoke an API call of support 39 layer 408 (see FIG. 4) or an application manager (see FIG. 14) to create a session that is associated with a particular accessory and application protocol (e.g., session 406 of FIG. 4). The session, represented in FIG. 10 by block 1012, can continue indefinitely. As described above, during the session the application can send and/or receive messages (e.g., 5 control signals, data, status and/or other information) using the application protocol associated with the session, and the application can also send and/or receive messages using the accessory communication protocol to the extent that desired functionality is supported within the accessory communication protocol. [0136] A session can eventually end. For example, at block 1014, the application can 10 determine that the session should be ended (e.g., in response to a user instruction such as exiting the application or indicating that the accessory is no longer to be used) and can terminate the session at block 1016 in response to such a determination. As another example, at block 1018, the application can be notified that the accessory has disconnected; this can also result in session termination at block 1016. Session 15 termination at block 1016 can include, e.g., invoking an API call to destroy or close the session object and free associated resources. For example, in embodiments where only one session at a time is permitted for a given combination of accessory and application protocol, session termination can signal the mobile computing device that the accessory and its protocol are now free to be used in another session, e.g., with a different 20 application. In some embodiments, terminating the session can result in disconnecting the accessory (e.g., the mobile computing device can close the port); in other embodiments, the accessory can remain connected after the session terminates; and in still other embodiments, the application can instruct the mobile computing device system services as to whether to disconnect the accessory when the session terminates. 25 [0137] Once the session terminates, process 1000 can end. In some embodiments, if the application is still executing after session termination process, 1000 can return to block 1004 to look for a compatible accessory and start a new session. [01381 It will be appreciated that the accessory communication protocol described herein is illustrative and that variations and modifications are possible. Acts described as 30 sequential may be executed in parallel, order of acts may be modified, and/or acts may be added, omitted or combined. 40 [01391 In some embodiments, a mobile computing device can support concurrent connections to multiple accessories and/or concurrent execution of multiple applications. Thus, a single application can be concurrently interacting with multiple accessories, or a single accessory can be concurrently interacting with multiple applications. 5 [01401 For example, FIG. 11 illustrates an application 1100 on mobile computing device 1102 concurrently interacting with accessory A 1106 and accessory B 1108 according to some embodiments of the invention. Accessories A 1106 and accessory B 1108 can be different types of accessories, or they can be similar or even identical accessories. In this example, each accessory is connected on a different port; thus, accessory A 1106 is 10 connected to port 1110 and accessory B 1106 is connected to port 1112. Application 1100 has created two sessions 1114, 1116. Session 1112 is associated with accessory 1104 and uses an application protocol A1, while session 1114 is associated with accessory A 1106 and uses an application protocol Bl. Sessions 1112 and 1114 are independent of each other; either can be initiated, used, and/or terminated without affecting the other. In some 15 embodiments, the session can be protocol specific. Port I110 can use the accessory communication protocol to provide a "tunnel" for messages conforming to protocol Al to pass between mobile computing device 1102 and accessory 1106, and port 1112 can use the (same) accessory communication protocol to provide a separate tunnel for messages conforming to protocol BI to pass between mobile computing device 1102 and accessory 20 1108. It is understood that application protocols Al and BI can be different protocols or the same protocol as desired. Further, while two accessories and two sessions are shown, any number of accessories and sessions can be connected with a particular application in the manner described herein, provided only that sufficient hardware and/or software resources (e.g., ports and/or sessions) are available on the mobile computing device. 25 [01411 FIG. 12 illustrates two applications, application 1 1200 and application 2 1202, that are executing on mobile computing device 1204 and concurrently interacting with accessory A 1206 and accessory B 1208 according to some embodiments of the invention. Accessories A 1206 and accessory B 1208 can be different types of accessories, or they can be similar or even identical accessories. In this example, each accessory is connected 30 on a different port; thus, accessory A 1206 is connected to port 1210 and accessory B 1208 is connected to port 1212. Application 1 1200 has created a session 1214 associated with accessory A 1206 and application protocol Al, and application 2 1202 has created a session 1216 associated with accessory B 1208 and application protocol B 1. Sessions 41 1212 and 1214 are independent of each other; either can be initiated, used, and/or terminated without affecting the other. Port 1210 can use the accessory communication protocol to provide a tunnel for messages conforming to application protocol Al to pass between mobile computing device 1204 and accessory 1106, and port 1212 can use the 5 (same) accessory communication protocol to provide a separate tunnel for messages conforming to application protocol BI to pass between mobile computing device 1204 and accessory 1208. As with FIG. 11, it is understood that application protocols Al and BI can be different protocols or the same protocol as desired. Further, while two accessories, two applications, and two sessions are shown, any number of accessories, sessions, and/or 10 applications can be concurrently supported in the manner described herein, provided only that sufficient hardware and/or software resources (e.g., ports and/or sessions) are available on the mobile computing device. [0142] FIG. 13 illustrates two applications, application 1 1300 and application 2 1302, executing on mobile computing device 1304 and concurrently interacting with an 15 accessory 1306 according to some embodiments of the invention. In this example, accessory 1306 supports two different application protocols (Al and A2). Protocols Al and A2 can differ in name only, or they can be two distinct and potentially incompatible protocols. Accessory 1306 is connected to mobile computing device 1304 on port 1310, which is associated with protocol Al, and is also connected to mobile computing device 20 1304 on port 1312, which is associated with protocol A2. Application 1 1300 has created a session 1314 associated with accessory 1306 and application protocol Al and can therefore communicate with accessory 1306 via port 1310. Similarly, application 2 1302 has created a session 1316 associated with accessory 1306 and application protocol A2 and can therefore communicate with accessory 1306 via port 1312. Sessions 1312 and 25 1314 are independent of each other; either can be initiated, used, and/or terminated without affecting the other. Port 1310 can use the accessory communication protocol to provide a tunnel for messages conforming to application protocol A l to pass between mobile computing device 1304 and accessory 1306, and port 1312 can use the (same) accessory communication protocol to provide a separate tunnel for messages conforming 30 to application protocol A2 to pass between mobile computing device 1304 and accessory 1306. While two applications, and two sessions are shown, any number of accessories, sessions, and/or applications can be concurrently connected to the same accessory in the 42 manner described herein, provided only that sufficient hardware and/or software resources (e.g., ports and/or sessions) are available on the mobile computing device. [01431 It will be appreciated that the system configurations of FIGs. 11-13 are illustrative and that variations and modifications are possible. For example, any number 5 of applications and any number of accessories can be connected using any number of sessions and ports. As described above, the session can be a software entity that hides the application from the details of the physical connections (e.g., ports and the like). Thus, the application does not need to know which port a compatible accessory is connected to in order to communicate with it. Further, the communication path can also include other 10 intermediate layers (e.g., a protocol manager and/or protocol daemon layer as described above). [0144] An application manager can be used to abstract a communication connection between an application and a communication port to make the particulars of a communication protocol transparent to application programs. In some embodiments, 15 when a communication connection is abstracted, an application program can communicate with an accessory by writing data to an output stream and reading data from an input stream without knowing any details of the accessory it is communicating with. This can occur using an application manager. [01451 In some embodiments, an application manager can include portions of or be 20 implemented by the support layer 408 or protocol manager 410 shown in FIG. 4. FIG. 14 illustrates an example of such an abstraction. The figure shows the flow of data between application layer 1402, application manager 1404, and hardware transport layer 1406 of a mobile computing device according to some embodiments of the invention. The application layer 1402 can be any kind of process running at the mobile computing device. 25 The hardware transport layer 1402 can include any type of hardware interface or software interface between the mobile computing device and the accessory. [0146] Application manager 1404 can provide communication interface between accessories through the hardware transport layer 1406 and through the application layer 1402. In doing so, communication can be abstracted such that application 1402 does not 30 know the specifics of the accessory with which it is communicating or the specifics of the port where the accessory is coupled. Application manager 1404 can be a background process that is part of the operating system of the mobile computing device or another 43 background process executing at the mobile computing device. Application manager 1404 can provide input and output streams to an application that can be used to communicate with an accessory. [01471 In some embodiments, application manager 1404 can manage connected 5 accessories that are coupled with the mobile computing device and can be accessed through hardware transport layer 1406. Application manager 1404 can also manage accessory communication features of applications executing or installed on the mobile computing device. In both cases, application manager 1404 can store application protocol information associated with accessories and/or applications. Figures 15 - 18 show various 1o processes that can be implemented to establish sessions and provide communication between an application and an accessory using the application manager. [01481 FIG. 15 is a flow diagram of process 1500 that can be executed by an application manager at a mobile computing device to establish and manage a session according to some embodiments of the invention. Process 1500 can start at block 1502. At block 1504, 15 the application manager monitors the communication ports to determine whether an accessory has been connected (i.e., is in communication) with the mobile computing device. In some embodiments, the application manager can monitor the hardware state of a physical connector to determine if an accessory is coupled with the mobile computing device. In some embodiments, the application manager can receive an indication from a 20 WiFi or Bluetooth module indicating that a wireless connection has been established. Regardless of the type of port, the application manager can determine whether a communication channel has been established with the accessory. At block 1506 process 1500 continues to monitor whether an accessory is coupled with the mobile computing device. 25 [01491 Once a communication channel has been established as determined at block 1506, process 1500 can then perform authentication processes at block 1508. Authentication can proceed by sending various messages between the mobile computing device and the accessory using the accessory protocol. Once the accessory is authenticated and given permission to communicate with the mobile computing device, 30 accessory capability information can be received at block 1510. The capability information can include information indicating one or more application protocols with which the accessory is compatible. Application protocols can be indicated using, for 44 example, a reverse domain name convention as described above, or any other convention to indicate the application protocol. Some or all of the information can be stored in memory at the mobile computing device at block 1512. In particular, the application protocols can be stored in a lookup table (e.g., the connected application protocol table 5 820 of FIG. 8) that associates application protocols with the communication port where the accessory is coupled. [0150] At block 1514 the application manager can determine whether to allow communication between the accessory and the mobile computing device or an application executing at the mobile computing device using an application protocol supported by the 10 accessory. In some embodiments, communication can be allowed if an application (or other process) is executing on the mobile computing device that supports an application protocol supported by the accessory. For example, the application manager can compare application protocols supported by applications executing at the mobile computing device with application protocols stored in the lookup table. Communication between the 15 accessory and application can occur using the application protocol. In some embodiments, an application protocol message can be tunneled or embedded within an accessory protocol message (e.g., by wrapping the application protocol message within an accessory protocol message). As long as the accessory is not decoupled from the mobile computing device at block 1516 and/or execution of the application is not terminated at block 1518, 20 communication can continue. Otherwise, in some embodiments, application protocols stored in the lookup table can be removed at block 1520, and process 1500 can end at block 1522. [01511 FIG. 16 is another flow diagram of a process that can be executed by an application manager at a mobile computing device to coordinate communication between 25 an accessory and an application executing at the mobile computing device according to some embodiments of the invention. Process 1600 can start at block 1605. At block 1610 application manager can receive a request for accessory information from an application executing at the mobile computing device. If an accessory is not attached at block 1615, a message can be sent to the application so indicating, and process 1600 can return to block 30 1610 and wait until an accessory is coupled with the MCD or in some embodiments process 1600 can end. If an accessory is connected with the mobile computing device then the application manager can provide the application with accessory information including an indication of any application protocols supported by each and every 45 accessory coupled with the mobile computing device at block 1620. The application manager can send any or all of the application protocol information, including the application protocols supported by the accessory as metadata, e.g. using the reverse domain name convention. Each application protocol can be associated with an application 5 protocol identifier. 101521 In some embodiments, rather than requesting accessory information, the application can send application protocol data to the application manager. And the application manager can select an application protocol from a lookup table (e.g. the connected application protocol table 820) that is compatible with the application protocol 10 data sent from the application, if one exists. [01531 At block 1625, the application can open a communication session for an application protocol and can indicate the protocol to the application manager; for example, using the application protocol identifier. In doing so, the application can make the request without specifying anything about the accessory or the port. In response to opening the 15 communication session the application manager can provide an output stream and an input stream associated with the session to the application at block 1630. In some embodiments, the communication session is opened for a particular protocol associated with a particular accessory. So multiple sessions can be created using multiple protocols for communication with one or many accessories. 20 [0154] At block 1635, the application manager can receive an application protocol message from the application using the application protocol associated with the communication session. The application protocol message can be received at the application manager using the output stream provided at block 1630. The application manager can then wrap the application protocol message with an accessory protocol 25 wrapper at block 1640. In some embodiments, this wrapping can include embedding the application protocol message within an accessory protocol message (e.g., as shown in FIGS. 5A, 5B and 5C). In some embodiments, this wrapping can tunnel the application protocol message using the accessory protocol. At block 1645 the wrapped application protocol message can be sent to the accessory. Process 1600 can then proceed to block 30 1650. Turning back to block 1635, if the application manager does not receive an application protocol message at block 1635 process 1600 can proceed to block 1650. 46 [01551 At block 1650, the application manager can receive an accessory protocol message from the accessory. The accessory protocol message can include an application protocol message wrapped within an accessory protocol message. At block 1655, the accessory protocol wrapper can be stripped from the application protocol message; and the 5 application protocol message can be sent to the application at block 1660. [01561 If either the accessory is disconnected from the mobile computing device 1670 or the application ceases to execute at the mobile computing device 1665 than process 600 can end at block 1675. Otherwise the process returns to block 1635. [01571 A process that can be performed at an accessory coupled with a mobile 10 computing device is shown in FIG. 17. Process 1700 can start at block 1702, when an accessory becomes connected with the mobile computing device. At block 1704 the accessory can send a message to the mobile computing device indicating the application protocols supported by the accessory. This message may be part of the accessory capabilities described in regard to block 1510 of FIG. 15. This message can be sent in 15 accordance with the accessory protocol. The accessory can indicate the application protocols using a reverse domain name convention (e.g., as described above). When a communication session has been established by the application manager, at block 1706, the mobile computing device can send the accessory a message, using the accessory protocol, indicating that a communication session has been created. This message, or a 20 subsequent message, can indicate the application protocol used to create the session as indicated in block 1708. In some embodiments, at block 1708 a session ID can be communicated instead of or in addition to the application protocol. At block 1710 an acknowledgement message can be sent to the mobile computing device from the accessory using the accessory protocol prior to communicating with the mobile computing device 25 using the application protocol at block 1712. Process 1700 can end at block 1714. Process 1700 can end, for example, when the application is closed by the user or the operating system, when the application or operating system closes the session, and/or when the accessory is disconnected. [01581 FIG. 18 is a flow diagram of process 1800 that can be executed by an application 30 at a mobile computing device to open a communication with an accessory according to some embodiments of the invention. Process 1800 can begin at block 1805. At block 1810 the application can request information about the connected accessories from the 47 application manager. The application manager can respond by sending accessory information to the application, which can be received by the application at block 1815. A response from the application manager can be received at block 1815 that includes accessory information. The accessory information can include information indicating the 5 accessories coupled with the mobile computing device, the application protocol(s) compatible with the accessory, and/or identifiers associated with the application protocol(s). In some embodiments, the accessory manger can direct the application to the memory location where a listing or table of the connected application protocols can be located. 10 [01591 At block 1820 the application (or mobile computing device) can determine whether any of the application protocols or a single application protocol that is compatible with an attached accessory matches an application protocol compatible with the application. If a match is found, process 1800 moves to block 1835. If there are no matches, an application that is compatible with an application protocol associated with the 15 accessory can be searched for on the internet (e.g., at an online application store) or on the mobile computing device at block 1825. In some embodiments, the accessory information can include information indicating a preferred application for use with the accessory. In some embodiments, an application can be downloaded and executed at the mobile computing device at block 1830 and process 1800 can move to block 1835. In some 20 embodiments, an application add-on or patch can be downloaded from a network location (e.g., at an online application store) that provides compatibility with an application protocol that is also compatible with the accessory. If a new application is not downloaded and there are not compatible applications found, then process 1800 can end at block 1865. 25 [0160] In some embodiments, at block 1820, in the event no compatible applications are found or available at the mobile computing device one of three options can be performed. First, the user is prompted whether they'd like to search for and/or download a compatible application from a network location or application store. The process can the proceed in accordance with the user's choice. Second, the mobile computing device can search for 30 and/or download a compatible application without prompting the user. Third, the mobile computing device may neither prompt the user nor search for a compatible application. In some embodiments, the accessory can send a message indicating which of the above three options should be followed by the mobile computing device. This message can be sent 48 prior to or at block 1810 or block 815. In other embodiments, a system setting at the mobile computing device can be set by the user indicating which of the above options should be followed for all accessories. [01611 At block 1835, the application can open a communication session that is tied to a 5 compatible application protocol. Once a session is created, the application manager can provide input and output streams to the application at block 1840. At block 1845, the application can communicate with the accessory by writing data formatted according to the application protocol to the output stream, and by reading application protocol data from the input stream. 10 [0162] As long as the accessory is coupled with the mobile computing device, as determined at block 1850, and the application does not end the session at block 1855, the application can communicate with the accessory using the input/output streams provided by the application manager. Otherwise, the session can be terminated at block 1860 and process 1800 can end at block 1855. 15 [01631 In some embodiments of the invention, when an accessory connects with a mobile computing device, the accessory can send accessory information that includes metadata specifying a preferred application. This information, for example, can be sent during an identification phase, authentication phase, or capabilities phase. In some embodiments, if preferred application is not executing on the application and is stored in 20 memory at the mobile computing device, the application can be automatically launched. In some embodiments, the mobile computing device can provide a notice to the user asking the user whether they'd like to launch the preferred application, and launch the application if the user responds affirmatively. [0164] In some embodiments of the invention, if any of the preferred applications (that 25 is, applications preferred by the accessory) are loaded on the mobile computing device, the mobile computing device can highlight an icon related to one or each of the preferred applications on a home screen of the user interface. Thus a user can more easily locate compatible applications for use with the accessory. For example, when highlighting the application icon, the mobile computing device can change the color or shade of the icon, 30 wiggle or vibrate the icon, enlarge the icon, change the shape of the icon, change the picture on icon, etc. Any aspect of the icon can be changed. 49 [01651 In other embodiments of the invention, if the preferred application is not stored or loaded on the mobile computing device, the mobile computing device can be directed to a network location, such as an application store to download the preferred application. In some embodiments, the metadata can be saved and the preferred application can be 5 downloaded from a network location at a later time. For example, the application can be downloaded when the user directs a web browser or application store to a specified network location where the preferred application can be downloaded. As another example, the application can be downloaded when the user has the proper level of wireless connectivity to download the preferred application. In some embodiments, the preferred 10 application can be loaded when the mobile computing device is coupled with a host computer. [01661 Moreover, in some embodiments, the metadata sent from the accessory to the mobile computing device can also include an indication specifying how to behave when the preferred application does not match an application loaded on the mobile computing 15 device. This indication can be part of a command or message. For example, the accessory can specify that the preferred application must match an application at the mobile computing device and the preferred application must be downloaded to interact with the accessory. As another example, the accessory can specify a preferred application, but will interoperate with any application with a compatible application protocol. In this case, the 20 mobile computing device can download the preferred application but it is not required. Moreover, in some cases the mobile computing device can request feedback from the user about whether to download the preferred application or use a compatible application. As yet another example, the accessory can specify that mobile computing device never search for or download an application from a network location or application store. Moreover, in 25 some situations, the accessory can specify that the user never be asked whether to download the application. In this scenario, the accessory can operate without interaction with an application at the mobile computing device. [0167] In yet another embodiment of the invention, an accessory can be coupled with a mobile computing device and a first application can be executing at the mobile computing 30 device. The first application can be associated with an application protocol that may or may not be compatible with accessory and the application may or may not be in communication with the accessory. The accessory can send a command to the mobile computing device specifying a second application to execute. This can be initiated in 50 response to an interaction with a user; for example, from the press of a button at the accessory from the user. The mobile computing device can then execute the second application in response to receiving the command. In some embodiments the first application can run in parallel with the second application. In some embodiments, the first 5 application can be closed and the second application loaded. In some embodiments the command can indicate the application by serial number and/or name. In some embodiments, the command can also specify a network location where the application can be downloaded and then executed. Moreover, in some embodiments the accessory can request that the second application execute when no application is executing at the mobile 10 computing device or when the operating system is executing at the mobile computing device. [01681 While the invention has been described with respect to specific embodiments, one skilled in the art will recognize that numerous modifications are possible. For example, in certain embodiments described herein, a port is associated with, at most, one 15 application protocol at any given time. In other embodiments, communications using different application protocols can be multiplexed on the same port, and/or communications with different applications using the same application protocol can be multiplexed on the same port. In such embodiments, mobile computing device-protocol commands used for tunneling accessory protocol messages (in either direction) can 20 include a session and/or application protocol identifier to facilitate proper handling of the accessory protocol messages. In one such embodiment, when an application establishes a session associated with a particular accessory and application protocol, an identifier of that session can be provided to the accessory using a command of the accessory communication protocol. Subsequent mobile computing device-protocol packets (e.g., 25 tunneling command packets) associated with that session can include the session identifier. Thus, the accessory can associate any accessory protocol messages it may send or receive with a particular session, even if multiple sessions are concurrently in progress and even if communications related to multiple sessions are multiplexed onto the same port. The accessory can then maintain separate state information for multiple sessions, 30 even if communications for multiple sessions are multiplexed onto a single port. [01691 Embodiments of the invention have been described that provide an example of how an application communication protocol can be used for communication between an application and an accessory. In many cases the mobile computing device can be agnostic 51 regarding the application communication protocol. Some embodiments describe schemes whereby the accessory and/or the application communicate information specifying the application communication protocol. Various other techniques can be used so the accessory and/or the application knows which application protocol to use. For example, 5 the mobile computing device can include a table with all the known application protocols. The accessory and/or application can specify the application protocol by pointing to the table entry. As another example, the application can request application protocol information from the accessory using any number of communication protocols. As another example, the application can specify to the accessory any protocols supported by 1o the application and the accessory can chose the application protocol to use. As yet another example, a bit mask can be used where predetermined different bitmasks can be used to represent various application protocols. Various other means for identifying the application protocol can also be used. [01701 Various other embodiments are also disclosed. For example, a method for 15 communicating between an accessory device and an application executing on a mobile computing device is disclosed that operates at the accessory device. The method can comprise communicating information specifying at least one application communication protocol to the mobile device using an accessory communication protocol; and/or communicating with an application executing at the mobile device using the accessory 20 communication protocol. In some embodiments, the method also can include also can include communicating with an operating system executing at the mobile computing device using the accessory communication protocol. [01711 In some embodiments, an application communication protocol packet can be tunneled within an accessory communication protocol packet. In some embodiments, the 25 method also can include receiving application communication protocol commands from the application executing on the mobile communication device and changing the state of the accessory in response thereto. In some embodiments, the method also can include sending data to the application executing on the mobile computing device in response to a command from the application executing on the mobile computing device, wherein the 30 data can be sent using the application communication protocol and the command can be received using the accessory communication protocol. In some embodiments, the information specifying at least one application communication protocol can be provided in a reverse domain name convention. In some embodiments, the method also can include 52 controlling functionality of the mobile computing device with the accessory using the accessory communication protocol. [01721 An accessory device is disclosed that can include a housing; a communication interface disposed at least partially within the housing and configured to exchange 5 commands and data with a mobile computing device, the communication interface having at least one port; and/or control logic disposed within the housing and communicatively coupled with the communication interface. The control logic can be configured to communicate with an operating system executing at the mobile computing device through the communication interface using an accessory communication protocol. The control 10 logic can be configured to communicate with an application executing on the mobile computing device through the communication interface using an accessory communication protocol. [01731 In some embodiments, the control logic can also be configured to communicate information specifying the application communication protocol using the accessory 15 communication protocol. In some embodiments, the control logic can also be configured to communicate information specifying the application communication protocol using a standard communication protocol other than the accessory communication protocol. In some embodiments, the application communication protocol information can be communicated to the mobile computing device using a reverse domain name convention. 20 In some embodiments, the communication interface can comprise a wireless communication interface. [0174] A method for communicating between an accessory device and an application executing at a mobile computing device, the method operating at the accessory device. The method can include communicating accessory information to the mobile computing 25 device using an accessory communication protocol; receiving at least one of a session identifier, an application protocol identifier, or an open connection command from a mobile computing device; and/or thereafter communicating with the application executing at the mobile computing device using an application communication protocol. In some embodiments, the application communication protocol can be a protocol associated with 30 the application protocol string communicated to the mobile computing device. In some embodiments, the accessory information can include at least one of an application protocol string, an application protocol index corresponding with the application protocol string, 53 preferred application information, or accessory communication protocol information. In some embodiments, the preferred application information specifies an application which supports communication using an application communication protocol associated with the application protocol strings communicated to the mobile computing device. In some 5 embodiments, the communicating can include controlling the functionality of the mobile computing device with the accessory. In some embodiments, the application communication protocol string can be in a reverse domain name convention. [0175] Another accessory device is disclosed. The accessory can include a housing; a communication interface disposed at least partially within the housing, and/or configured 10 to communicatively couple with a mobile computing device; accessory hardware; and/or control logic disposed within the housing and communicatively coupled with the communication interface and the accessory specific hardware. The control logic can be configured to communicate application communication protocol information to a mobile computing device through the communication interface using a accessory communication 15 protocol. The control logic can be configured to establish a communication session with an application executing at the mobile computing device through the communication interface, wherein the communication session uses the application communication protocol to communicate between the accessory and the application executing at the mobile computing device. The control logic can be configured to receive data from the 20 application executing at the mobile computing device using the accessory communication protocol. The control logic can be configured to control the operation of the accessory hardware in response to the data received from the application executing at the mobile computing device. [0176] In some embodiments, the communication interface can comprise a wireless 25 communication interface. In some embodiments, the control logic can be further configured to receive hardware data from the accessory hardware, and/or send the hardware data to the application executing at the mobile computing device using the application communication protocol. In some embodiments, the accessory hardware can comprise and the hardware data can comprise data collected using the sensor. In some 30 embodiments, the accessory hardware can comprise a hardware interface with an electrical device and the hardware data can comprise data received from the electrical device through the hardware interface. In some embodiments, the accessory hardware can comprise a hardware interface with an electrical device and the data from the application 54 executing at the mobile computing device comprise data to control the electrical device using the a hardware interface. In some embodiments, the accessory hardware can comprise a display and the data from the application executing at the mobile computing device can comprise displayable information. 5 101771 Another method for communicating between an accessory device and an application executing on a mobile device is disclosed. This method can operate on the mobile device. The method can include identifying an accessory device, wherein the identification uses an accessory communication protocol; receiving information from the accessory device specifying an application communication protocol, wherein the io information is received using the accessory communication protocol; executing an application at the mobile computing device; and/or communicating with the accessory device from the application using the application communication protocol. In some embodiments, the method can also include determining whether the application protocol can be listed in a protocol table at the mobile computing device, wherein the protocol table 15 can comprise protocols supported by applications at the mobile computing device. [01781 In some embodiments, the method can also include downloading an application that supports the application protocol in the event that the protocol table does not include the application protocol. In some embodiments, the information from the accessory device specifying an application communication protocol specifies the one application 20 communication protocol using a reverse domain name convention. In some embodiments, the information from the accessory device specifying the application communication protocol also can include an identifier associated with the application communication protocol. In some embodiments, the communicating with the accessory device using the application communication protocol, further can comprise encapsulating application 25 communication protocol packets within accessory communication protocol packets. In some embodiments the application communication protocol can include commands that are included within the accessory communication protocol. [0179] A mobile computing device is also disclosed that can include a housing; a communication interface disposed at least partially within the housing, and/or configured 30 to exchange commands and data with an accessory, the communication interface having at least one port; memory disposed within the housing; and/or control logic disposed within the housing, and/or communicatively coupled with the memory and the communication 55 interface. The control logic can be configured to receive an indication specifying an application communication protocol from an accessory through the communication interface using an accessory communication protocol. The control logic can be configured to execute an application stored in the memory. The control logic can be configured to 5 establish communication between the accessory and the application using the application communication protocol. In some embodiments, the at least one port can be a wired or a wireless port. In some embodiments, the control logic can be further configured to determine whether an application communication protocol specified by the application can be associated with an application communication protocol stored in memory. In some 10 embodiments, the control logic can be further configured to tunnel application communication protocol data to the accessory using the accessory communication protocol. In some embodiments, the control logic can be further configured to encapsulate an application communication protocol packet with an accessory communication protocol packet and to provide the accessory communication protocol packet to the port. 15 [01801 Another mobile computing device is disclosed that can include a housing; a communication interface disposed at least partially within the housing, and/or configured to exchange commands and data with an accessory; memory disposed within the housing; and/or control logic disposed within the housing, and/or communicatively coupled with the memory and the communication interface. The control logic can be configured to 20 receive application communication protocol information from an accessory device through the communication interface, wherein the application communication protocol information can include an identification of an application communication protocol supported by the accessory, and/or wherein the application communication protocol information can be received from the accessory using an accessory communication protocol. The control 25 logic can be configured to create encapsulated packets by encapsulating application communication protocol packets within accessory communication protocol packets. The control logic can be configured to send the encapsulated packets to the accessory via the communication interface. In some embodiments, the communication interface can be a wireless communication interface. In some embodiments, the mobile computing device 30 can include a protocol table stored in the memory, wherein the protocol table can include a listing of application protocols supported by applications installed on the mobile computing device. 56 101811 A computer-readable medium is disclosed that can contain program instructions that, when executed by a processor of a mobile computing device, cause the processor to execute a method. This method can include receiving application communication protocol information from an accessory device using an accessory communication protocol, 5 receiving data from the accessory using the application communication protocol, and/or manipulating the data received from the accessory. In some embodiments, the method can also include displaying at least a portion of the manipulated data at a display of the mobile computing device. In some embodiments, the method can also include controlling the functionality of the accessory by sending commands to the accessory using the application io communication protocol. [01821 Another method is provided for establishing a communication session between an accessory device and an application installed on a mobile device. The method can operate on the mobile device and can include comparing a list of supported application protocols with a list of collected application protocols; in the event a match is found 15 between an application protocol in the supported application protocol list and an application protocol in the collected application protocol list, communicating information specifying the matched application protocol to the accessory; and/or in the event a match is not found between an application protocol in the supported application protocol list and an application protocol in the collected application protocol list, directing a user of the 20 mobile device to an application store where an application associated with at least one application protocol within the collected application protocol list is available to be downloaded. In some embodiments, the list of supported application protocols can include one or more communication protocols supported by the application, and/or the list of collected application protocols can include one or more communication protocols 25 received from one or more accessories coupled with the mobile computing device. In some embodiments, in the event a match is found between an application protocol in the supported application protocol list and an application protocol in the collected application protocol list, requesting a communication session with the accessory. In some embodiments, in the event the communicating information specifying the matched 30 application protocol can include a session identifier. In some embodiments, when a match is found between an application protocol in the supported application protocol list and an application protocol in the collected application protocol list, communicating with the 57 accessory using the matched application protocol. In some embodiments, the application store can be an Internet-based application store. [01831 A computer-readable medium is provided that contains program instructions that, when executed by a processor of mobile computing device, cause the processor to execute 5 a method. The method can include determining whether a supported application protocol identifier in a supported protocol list matches an application protocol identifier in a collected protocol list; and/or in response to finding a match between the supported application protocol and an application protocol in the list of collected application protocols perform a sub-method. The sub-method including initiating a communication 10 session between the mobile computing device and an accessory coupled with the mobile computing device; communicating to the accessory information specifying the supported application protocol; and/or communicating with the accessory from the mobile computing device using the supported application protocol. In some embodiments, the collected protocol list can include one or more communication protocol identifiers 15 representing application protocols compatible with the accessory, and/or the supported protocol list can include one ore more communication protocol identifiers representing application protocols compatible with an application installed at the mobile computing device. In some embodiments, the supported application protocol can be different from an accessory communication protocol. In some embodiments, the program instructions can 20 further cause the processor to download an application that supports a protocol that matches an application protocol in the collected protocol list in response to not finding a match between the supported application protocol and an application protocol in the list of collected application protocols. [0184] Another method operating at a mobile computing device is provide that can 25 include receiving an application protocol identifier from an accessory device, wherein the received application protocol identifier can include a data string in reverse domain name format and can be associated with an application communication protocol; and/or determining whether the received application protocol identifier matches an application protocol identifier listed within a protocol table stored in memory at the mobile computing 30 device, thereafter communicating with the accessory using the application communication protocol. In some embodiments, the protocol table can include one or more application protocol identifiers associated with applications executable at the mobile computing device. In some embodiments, the method can also include executing the application 58 associated with an application protocol identifier in the protocol table in the event that the received application protocol identifier matches an application protocol identifier in the protocol table. In some embodiments, the method can also include downloading an application with an associated application protocol identifier that matches the received 5 application protocol identifier. [01851 A mobile computing device is also disclosed that includes a housing; a communication interface disposed at least partially within the housing, and/or configured to exchange commands and data with an accessory; memory disposed within the housing, the memory configured to maintain a supported application protocol list; and/or control io logic disposed within the housing, and/or communicatively coupled with the memory and the communication interface. In some embodiments, the control logic can be configured to receive from the accessory through the communication interface information identifying an application communication protocol supported by the accessory. In some embodiments, the control logic can be configured to determine whether application 15 communication protocol supported by the accessory corresponds with a protocol identified in a list of supported application protocols, wherein the list of supported application protocols can include one or more protocols supported by the application installed on the mobile device. In some embodiments, the control logic can be configured to communicate information specifying the matched application protocol to the accessory using a mobile 20 computing device protocol in the event a correspondence is determined between the application protocol supported by the accessory and a protocol identified in a list of supported application protocols. In some embodiments, the control logic can be configured to communicate with the accessory using the matched application protocol. [01861 Another method is also provided that can include receiving application protocol 25 information from an accessory using a mobile computing device protocol, wherein the application protocol information identifies at least one application protocol compatible with the accessory. The method can also include determining whether the application protocol matches a protocol listed within a supported protocol list, wherein the supported protocols list can include one ore more communication protocols supported at least by an 30 application installed on the mobile device, and/or wherein each protocol listed within the supported protocol list can be associated with an application. And in the event that an application protocol matches a protocol in the supported protocol list, the method can further include executing the application associated with the matched protocol in the 59 supported list. In some embodiments, in the event that an application protocol does not match a protocol in the supported protocol list, downloading an application associated with the protocol in the supported protocol list from the Internet. [01871 Another method is provide that can include receiving information at a mobile 5 computing device from an accessory, wherein the information can comprise an identification of an application protocol; comparing the application protocol with protocols listed in a supported protocol table stored in memory at a mobile computing device, wherein the supported protocol table can include at least one application protocol associated with an application; and/or in the event that the application protocol matches a 10 protocol listed in the supported protocol table, executing the application associated with the application protocol at the mobile computing device. In some embodiments, the information can comprise an identification of a preferred application that supports the application protocol, and/or in the event that the application protocol does not match a protocol listed in the supported protocol table, downloading the preferred application. In 15 some embodiments, the information identifying an application protocol identifies the application protocol using a reverse domain name format. In some embodiments, the method can also include communicating with the accessory using the application protocol. In some embodiments, the information identifying an application protocol can be formatted according to a mobile computing device protocol. 20 [01881 A mobile computing device is provided that includes a housing; a communication interface disposed at least partially within the housing, and/or configured to exchange commands and data with an accessory; memory disposed within the housing, the memory comprising a supported application protocol list that lists protocols compatible with an application, wherein a supported application protocol can include an 25 application protocol supported by an application installed on the mobile computing device; and/or control logic disposed within the housing, and/or communicatively coupled with the memory and the communication interface. The control logic being configured to receive a message from an accessory identifying an application protocol supported by the accessory; determine whether the application protocol matches a supported application 30 protocol stored within the supported application protocol list; and/or in the event a match is found, executing an application associated with the supported accessory matched with the application protocol. In some embodiments, the message can be received from the accessory identifies an Internet-based address where an application can be found that 60 supports the application protocol. In some embodiments, the method can also include downloading the application from the Internet-based address. In some embodiments, the method can also include installing the application at the mobile computing device and executing the application. 5 [01891 A mobile communication device is disclosed comprising a housing; a communication interface disposed at least partially within the housing, and/or configured to exchange commands and data with an accessory, the communication interface having a first communication port and a second communication port; memory disposed within the housing; and/or control logic disposed within the housing and communicatively coupled 10 with the memory and the communication interface. The control logic can be configured to communicate with a first accessory through the first communication port using a first application communication protocol; and/or communicate with a second accessory though the second communication port using a second application communication protocol. In some embodiments, at least one of the first communication port or the second 15 communication port can comprise a wireless communication port. In some embodiments, the first application communication protocol and the second application communication protocol are different. In some embodiments, the control logic can be further configured to communicate with the first accessory through the first communication port and the second accessory through the second accessory communication port using an accessory 20 communication protocol. In some embodiments, the control logic can be further configured to establish a first communication session for communicating with the first accessory through the first port. In some embodiments, the control logic can be further configured to establish a second communication session for communicating with the second accessory through the first port. In some embodiments, the communication 25 interface can include a third communication port and the control logic can be further configured to communicate with a third accessory through the third communication port using a third application communication protocol. [01901 A computer-readable medium comprising program instructions that, when executed by a processor of a mobile computing device, cause the processor to execute a 30 method. This method can include requesting a first communication session for communication with a first accessory; receiving a session identifier for the first communication session; communicating with the first accessory through the first communication session using a first application protocol; requesting a second 61 communication session for communication with a second accessory; receiving a session identifier for the second communication session; and/or communicating with the second accessory through the second communication session using a second application protocol. In some embodiments, the first application protocol and the second application protocol 5 are different. In some embodiments, the first application protocol and the second application protocol are the same. In some embodiments, the program instructions further cause the processor to determine whether the first accessory or the second accessory are communicatively coupled with the mobile computing device. [01911 A mobile communication device comprising a housing; a communication 10 interface disposed at least partially within the housing, and/or configured to exchange commands and data with a first accessory and a second accessory, the communication interface having a first communication port and a second communication port; memory disposed within the housing; and/or control logic disposed within the housing, and/or communicatively coupled with the memory and the communication interface. The control 15 logic being configured to establish a first communication session between the first communication port and a first application executing by the control logic; communicate with a first accessory through the first communication session using a first application protocol; establish a second communication session between the second communication port and a second application executing by the control logic; and/or communicate with a 20 second accessory through the second communication session using a second application protocol. In some embodiments, the control logic can be further configured to provide a tunnel for first application communication protocol messages using an accessory communication protocol. In some embodiments, the accessory communication protocol can be different from the first application communication protocol. In some 25 embodiments, the control logic can be further configured to provide a tunnel for second application communication protocol messages using an accessory communication protocol. In some embodiments, the accessory communication protocol can be different from the second application communication protocol. [01921 Another method executing at a mobile computing device is provide. The method 30 can include receiving an indication that an accessory can be communicatively coupled with the mobile computing device at a communication port; determining that the accessory supports communication with the mobile computing device using both an accessory protocol and an application protocol; establishing a communication session between the 62 accessory through the communication port and an application executing at the mobile computing device through the communication port; and/or sending messages from the application to the accessory using the communication session, wherein the messages are application protocol messages. In some embodiments, the accessory protocol and the 5 application protocol are different. In some embodiments, the method can include receiving an indication from the accessory that the accessory supports the application protocol. In some embodiments, the method can also include encapsulating application protocol messages within accessory protocol messages. [01931 A method for establishing a communication session between an application io executing on a mobile computing device and an accessory in communication with the mobile computing device is provided. The method can execute at the mobile computing device and can include receiving a request from the application for information related to the accessory; providing accessory information to the application, wherein the accessory information can comprise an identifier of at least one application communication protocol 15 with which the accessory can be compatible; receiving a request for a communication session between the accessory and the application for communication using the application communication protocol; receiving a message from the application, wherein the message can be formatted according to the application communication protocol; wrapping the message with an accessory communication protocol wrapper; and/or communicating the 20 message to the accessory, wherein the message can be communicated according to an accessory communication protocol that can be different from the application communication protocol. In some embodiments, the accessory communication protocol wrapper can include a tunneling command. In some embodiments, the identifier of at least an application communication protocol can comprise the identifier provided in reverse 25 domain name format. In some embodiments, the method can also include receiving a message from the accessory, wherein the message can be formatted according to an accessory communication protocol, stripping the accessory communication protocol wrapper from the message, and/or sending the message to the application, wherein the message can be communicated according to the application communication protocol. In 30 some embodiments, the method also can include monitoring a communication interface for accessory connectivity; and/or in the event an accessory can be communicatively coupled with the communication interface, receiving a capabilities message including accessory capabilities, wherein the message can include an identifier for at least one 63 application communication protocol with which the accessory can be compatible. In some embodiments, the capabilities message can be formatted according to the accessory communication protocol. [01941 A mobile computing device is can include a housing; a communication interface 5 disposed at least partially within the housing, and/or configured to exchange commands and data with an accessory using an accessory communication protocol; memory disposed within the housing; and/or control logic disposed within the housing, and/or communicatively coupled with the memory and the communication interface, the control logic being configured to execute an accessory manager as a background process and an 10 application. The control logic executing as an accessory manager can be configured to monitor the communication interface for an accessory being coupled with the communication interface; in the event an accessory becomes coupled with the communication interface, receive accessory capability information including compatible application protocols from the accessory using the accessory communication protocol; 15 receive, from the accessory, application communication protocol formatted messages wrapped with an accessory communication protocol wrapper; remove the accessory communication protocol wrapper from the messages; and/or communicate messages to the application. In some embodiments, the accessory capabilities are received using the accessory communication protocol. In some embodiments, the control logic executing as 20 an accessory manager can be further configured to establish an input data stream such that data can be read from the input data stream. In some embodiments, the control logic executing as an accessory manager communicates messages received from the accessory to the application using the input data stream. In some embodiments, the control logic executing as an accessory manager can be further configured to: receive, from the 25 application, application communication protocol formatted messages, wrap the accessory communication protocol messages with an accessory communication protocol wrapper, and/or communicate the messages to the accessory. In some embodiments, the control logic executing as an accessory manager can be further configured to establish an output data stream such that data can be written to the output data stream by the application and 30 sent to the accessory. In some embodiments, the control logic executing as an accessory manager communicates messages received from the output data stream to the accessory. [0195] Another method is provided. This method can comprise monitoring an accessory interface of the mobile computing device for an indication that an accessory has been 64 communicatively coupled with the accessory interface; in the event an accessory can be communicatively coupled with the accessory interface, receiving capabilities information from the accessory, wherein the capabilities information can be received using an accessory communication protocol, and/or the capabilities information can include 5 information indicating one or more application communication protocols compatible with the accessory; establishing an input data stream for an application executing at the mobile computing device, wherein an application message received from the accessory wrapped in an accessory communication protocol wrapper can be stripped from the accessory communication protocol wrapper and written to the application using the input data 10 stream; and/or establishing an output data stream for the application, wherein an application message written to the output data stream from the application can be wrapped in an accessory communication protocol wrapper and sent to the accessory through accessory interface. In some embodiments, the accessory interface can comprise a wireless communication interface. In some embodiments, the information indicating one 15 or more application communication protocols can be provided using a reverse domain name format. [01961 A method executing on a mobile computing device is also provided. The method can include receiving from an application executing on the mobile computing device a request for a communication session between the mobile computing device and an 20 external accessory using an application protocol; determining whether the application protocol can be supported by the accessory; in the event the application protocol can be supported by the accessory, providing an input stream and an output stream to the application for communication with the accessory using the application protocol; receiving a message from the application through the output stream wherein the message can be 25 formatted according to the application protocol; wrapping the message within an accessory protocol message; and/or sending the message to the accessory. [01971 In some embodiments, the determining further can comprise: looking up the application protocol in a lookup table. In some embodiments, the method can include receiving a message from the accessory, wherein the message can be an application 30 protocol message wrapped within an accessory protocol message; unwrapping the accessory protocol wrapper from the application protocol message; and/or writing the application protocol message to the input stream of the application. 65 101981 Another method executing on a mobile computing device is provided. The method comprising opening a first communication session between a first application and a first accessory, wherein the communication session provides communication between the first application and the first accessory using a first communication protocol; receiving 5 a first message from the first application; sending the first message to the accessory wrapped within an accessory protocol wrapper; opening a second communication session between a second application and the first accessory, wherein the communication session provides communication between the first application and the first accessory using a second communication protocol, wherein the first and second application protocols are 1o different; and/or receiving a second message from the second application and sending the second message to the accessory wrapped within the accessory protocol wrapper. [01991 A computer-readable medium containing program instructions that, when executed by a processor of a mobile computing device, cause the processor to execute a method is provided. The method can include requesting accessory information from an 15 accessory manager, wherein the accessory manager can be a background process executing at the mobile computing device and provides communication connectivity between applications executing at the mobile computing device and an accessory communicatively coupled with the mobile computing device; in the event an accessory can be communicatively coupled with the mobile computing device, receiving from the 20 accessory manager an accessory identifier and one or more protocol identifiers specifying at least one application communication protocol compatible with the accessory; determining whether the application can be compatible with the at least one application protocol; in the event the application can be compatible, opening a session for communication with the accessory through the accessory manager using the application 25 communication protocol; and/or communicating with the accessory using the application communication protocol. In some embodiments, a protocol identifier can be formatted using reverse domain naming convention. In some embodiments, the communicating with the accessory can comprise receiving an output stream from the accessory manager; and/or writing data according to the application communication protocol to the input stream. In 30 some embodiments, the communicating with the accessory can comprise receiving an input stream from the accessory manager; and/or receiving data formatted according to the application communication protocol from the input stream. 66 [02001 A method for an application to establish communication with an accessory using an application manager. The method can include receiving an indication from the application manager specifying an application protocol compatible with the accessory; receiving an input stream and an output stream from the application manger for 5 communication with the accessory using the application protocol; and/or thereafter, writing an application protocol messages for the accessory to the output stream. In some embodiments, the method can include sending application protocol information to the application manager, wherein the application protocol information can include an indication of the application protocols supported by the application. In some 10 embodiments, the application protocol compatible with the accessory can be an application protocol indicated by the application protocol information sent by the application. In some embodiments, the application protocol indicated by the application protocol information indicates an application protocol using a reverse domain name convention. 15 [02011 A method performed by an application executing on a mobile computing device is disclosed. The method including requesting accessory information from an application manager, wherein the accessory information can include information indicating one or more application protocols supported by an accessory communicatively coupled with a mobile computing device; determining whether an application protocol supported by the 20 accessory matches an application protocol supported by the application; in the event application protocols match, requesting an input stream and an output stream for communication with the accessory using the application protocol; receiving an input stream and an output stream; and/or thereafter, writing an application protocol messages for the accessory to the output stream. In some embodiments, the method can include 25 reading application protocol messages from the accessory using the input stream. In some embodiments, the accessory information indicates application protocols using the reverse domain name convention. In some embodiments, the accessory information can be stored in a table and the accessory information can be a pointer to the storage location of metadata associated with the accessory information. 30 102021 A method performed by an application executing on a mobile computing device is provided. The method including accessing a table containing information indicating an application protocol supported by an accessory coupled with the mobile computing device; determining whether an application protocol supported by the application matches the 67 application protocol in the table; in the event application protocols match, opening a communication session for communication with the accessory using the matched application; receiving an input stream and an output stream; and/or thereafter, writing an application protocol messages for the accessory to the output stream. In some 5 embodiments, the table can include a plurality of application protocols associated with the accessory, and/or the application determines whether an application protocol supported by the application matches any of the application protocol in the table. In some embodiments, the method can also can include reading an application protocol message from the accessory using the input stream. In some embodiments, the accessory 10 information indicates application protocols formatted using the reverse domain name convention. [02031 Circuits, logic modules, processors, and/or other components can be described herein as being "configured" to perform various operations. Those skilled in the art will recognize that, depending on implementation, such configuration can be accomplished 15 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. 20 [02041 While the embodiments described above can make reference to specific hardware and software components, those skilled in the art will appreciate that different combinations of hardware and/or software components can also be used and that particular operations described as being implemented in hardware might also be implemented in software or vice versa. 25 [02051 Computer programs incorporating various features of the present invention can be encoded on various computer readable storage media; suitable media include magnetic 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 can be packaged with a compatible device or provided separately from other 30 devices. In addition program code can 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. 68 [02061 While examples and/or details are described in this disclosure in relation to a single embodiment such examples or details can be used in conjunction with any embodiment described herein. [02071 Thus, although the invention has been described with respect to specific 5 embodiments, it will be appreciated that the invention is intended to cover all modifications and equivalents within the scope of the following claims. 69

Claims (5)

1. A method including: communicating, by an accessory device, with an operating system executing at a 5 mobile computing device using an accessory communication protocol, wherein the accessory communication protocol provides a global standard to enable communication between any accessory device and the mobile computing device; communicating, by the accessory device to the operating system executing on the mobile computing device, information that is usable by the mobile computing device to identify D an application communication protocol supported by the accessory device, the information being communicated using the accessory communication protocol, wherein the application communication protocol is distinct from the accessory communication protocol and is specific to a particular application on the mobile computing device; and communicating, by the accessory device, with an application executing on the mobile 5 computing device using the application communication protocol.

2. The method of claim 1 wherein the information that is usable by the mobile computing device to identify the application communication protocol includes information specifying the application communication protocol.

3. The method of claim 2 wherein the information specifying the application D communication protocol is provided in a reverse domain name convention.

4. The method of claim 1 wherein the information that is usable by the mobile computing device to identify the application communication protocol includes information identifying the accessory device.

5. The method of claim I wherein communicating with the application executing on the !5 mobile computing device using the application communication protocol includes: tunneling a first packet conforming to the application communication protocol within a second packet conforming to the accessory communication protocol. 70