Retrieving Stored Bluetooth Device Data

10/16/2008

This topic describes how to retrieve detailed information about a paired device from the system registry using the Bluetooth Pairing Service API.

About Device Attributes

After a Bluetooth–enabled device has paired successfully to Windows Embedded CE, information about the paired device is available in the Windows Embedded CE system registry.

Each paired device has a corresponding registry entry under [HKEY_LOCAL_MACHINE\Drivers\BuiltIn\BTPairSvc\Devices]. This registry key contains sub–keys for each Bluetooth profile supported, and a sub–key named \Attributes which contains device attributes.

Note

When the Windows Embedded CE system is cold booted, the registry will be cleaned and the paired device list will be empty.

The following is a list of device attributes available under the \Attributes sub–key:

Sub–key	Value	Description
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\RingtoneOption]	DWORD	Indicates whether ring-tone option is present for notification of incoming calls.
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\AccessOrder_HFP]	DWORD	Indicates order in which paired phones are accessed for Hands-Free Profile (HFP).
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\SupportsATCOPS]	DWORD	Indicates whether device supports AT+COPS command, which is used to indicate whether the phone is connected to a network, or to change the GSM network.
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\ListCurrCalls]	DWORD	Indicates list of current calls.
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\HFPSMSSupport]	DWORD	Indicates whether device supports Hands-Free Profile (HFP) Short Message Service (SMS).
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\HFPPBSupport]	DWORD	Indicates whether device supports Hands-Free Profile (HFP) Phone Book (PB).
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\CHLDFeatures]	DWORD	Indicates CHLD features.
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\Manuf]	String	Indicates manufacturer of the paired device.
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\Model]	String	Indicates model of the paired device.
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\BatteryCINDIndex]	DWORD	AT+CIND command that indicates cell-indicator status for "battery".
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\CallheldCINDIndex]	DWORD	AT+CIND command that indicates cell-indicator status for "callheld".
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\SignalCINDIndex]	DWORD	AT+CIND command that indicates cell-indicator status for "signal".
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\Call_StatusCINDIndex]	DWORD	AT+CIND command that indicates cell-indicator status for "call_status".
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\RoamCINDIndex]	DWORD	AT+CIND command that indicates cell-indicator status for "roaming".
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\CallSetupCINDIndex]	DWORD	AT+CIND commands indicates cell-indicator status for "callsetup".
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\ServiceCINDIndex]	DWORD	AT+CIND command indicates cell-indicator status for "service".
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\CallCINDIndex]	DWORD	AT+CIND command indicates cell-indicator status for "call".
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\CINDCount]	DWORD	AT+CIND command indicates cell-indicator status for "count".
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\CINDData]	BLOB	AT+CIND command indicates cell-indicator status for "data".
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\BRSFeatures]	DWORD	Indicates Broadband Radio Service (BRS) features. BRS provides high-speed and high-capacity broadband service.
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\IsHFP10]	DWORD	Indicates support for HFP 1.0 spec.
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\PhoneCAP]	BLOB	Indicates phone capabilities.
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\ContactAdded]	DWORD	Indicates whether a new contact has been added.
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\Exclusive]	DWORD	Indicates exclusive attribute value.
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\AccessOrder_BTAV]	DWORD	Indicates order in which paired devices are accessed for Bluetooth Audio/Video.
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn \BTPairSvc\Devices\<UniqueDeviceID>\Attributes\AccessOrder_PAIR]	DWORD	Indicates order in which paired devices are accessed.

Retrieving Device Attributes

To retrieve device attribute values stored in the registry, you can use the GetBTDeviceAttribute functions.

Attributes can be retrieved or set in the form of a DWORD, a BYTE array (BLOB), or a WCHAR.

The functions that retrieve device attributes are GetBTDeviceAttributeDWORD, GetBTDeviceAttributeBLOB, and GetBTDeviceAttributeWCHAR. The functions that set device attributes are SetBTDeviceAttributeDWORD, SetBTDeviceAttributeBLOB, and SetBTDeviceAttributeWCHAR.

For example, the following code example gets the value for the Manufacturer sub–key belonging to a Bluetooth–enabled device which has already been discovered and paired to:

TCHAR szPhoneType[1000] = {0};
DWORD dwPhoneTypeLen = 1000;
dwResult = GetBTDeviceAttributeWCHAR(csDeviceInfo.m_btAddr, 
               L"Manuf", 
               szPhoneType,
               &dwPhoneTypeLen 
              );

Another type of device attribute exists that is general to the Bluetooth Pairing Service. For example, the BTPAIR_ATTRNAME_ACCESSORDER attribute (defined in btpairapi.h) indicates the independent access order for each device type. One of the GetBTDeviceAttribute functions can be used to read or write this value.

For example:

BTDeviceAttributeDWORD(arPairedDevices[ nNdx ]->m_diDeviceInfo.m_btAddr, 
     BTPAIR_ATTRNAME_ACCESSORDER,
     arPairedDevices[ nNdx ]->m_dwAccessOrderCur
     );

See Also

Other Resources

How to Create and Manage Bluetooth Pairing Relationships