Audio Gateway Service

Other versions of this page are also available for the following:
Windows Mobile Not SupportedWindows Embedded CE Supported
8/28/2008

Windows Embedded CE supports Headset Profile and the Hands-Free Profile by providing the Audio Gateway (AG) service that links Bluetooth devices by using the Winsock interface to the Bluetooth Protocol Stack. This service provides the functionality to interface with TAPI to control a cellular phone and route audio to the Bluetooth chip.

The AG service is implemented as a DLL, Btagsvc.dll that resides in Services.exe and can be controlled by external modules through IOCTLs provided by Services.exe.

The AG service supports audio routing by using the audio driver message, WODM_BT_SCO_AUDIO_CONTROL, that routes audio to the Bluetooth chip. For more information about routing audio, see Routing Audio to the Bluetooth Hardware.

The following image map shows the the AG service architecture for Windows Embedded CE. To link to topics that provide information about the elements in the image map, move your pointer over the element, and then choose the element. The table following the illustration describes each module in the architecture.

The following table shows each module in alphabetic order, describes the module's functionality, and links to the module's main programming topic.

Module Description

AT Command Extension Module

This module enables you to extend the default command parsing and handling provided by the Audio Gateway Core component.

Audio Gateway Core Component

This component registers the headset and the hands-free SDP records, listens for incoming connections, and initializes the Network component. It also parsers AT commands and sends appropriate unsolicited result codes to the headset and the hands-free device.

Network Component

This module interfaces between the AG service and the cellular phone network. It handles all phone call related tasks.

Phone-Extension Component

For Windows Embedded CE: This module queries the phone for call information such as caller ID and prompts the user when incoming calls arrive and outgoing calls and placed.

You can configure the AG service through the registry. For information about the registry settings for the service, see Audio Gateway Registry Settings.

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