Platform SDK: TAPI

LINEDEVCAPS

The LINEDEVCAPS structure describes the capabilities of a line device. The lineGetDevCaps function and the TSPI_lineGetDevCaps function return the LINEDEVCAPS structure.

typedef struct linedevcaps_tag {
  DWORD  dwTotalSize;
  DWORD  dwNeededSize;
  DWORD  dwUsedSize;

  DWORD  dwProviderInfoSize;
  DWORD  dwProviderInfoOffset;

  DWORD  dwSwitchInfoSize;
  DWORD  dwSwitchInfoOffset;

  DWORD  dwPermanentLineID;
  DWORD  dwLineNameSize;
  DWORD  dwLineNameOffset;
  DWORD  dwStringFormat; 
  DWORD  dwAddressModes;
  DWORD  dwNumAddresses;
  DWORD  dwBearerModes;
  DWORD  dwMaxRate;
  DWORD  dwMediaModes;

  DWORD  dwGenerateToneModes;
  DWORD  dwGenerateToneMaxNumFreq;
  DWORD  dwGenerateDigitModes;
  DWORD  dwMonitorToneMaxNumFreq;
  DWORD  dwMonitorToneMaxNumEntries;
  DWORD  dwMonitorDigitModes;
  DWORD  dwGatherDigitsMinTimeout;
  DWORD  dwGatherDigitsMaxTimeout;

  DWORD  dwMedCtlDigitMaxListSize;
  DWORD  dwMedCtlMediaMaxListSize;
  DWORD  dwMedCtlToneMaxListSize;
  DWORD  dwMedCtlCallStateMaxListSize;

  DWORD  dwDevCapFlags;
  DWORD  dwMaxNumActiveCalls;
  DWORD  dwAnswerMode;
  DWORD  dwRingModes;
  DWORD  dwLineStates;

  DWORD  dwUUIAcceptSize;
  DWORD  dwUUIAnswerSize;
  DWORD  dwUUIMakeCallSize;
  DWORD  dwUUIDropSize;
  DWORD  dwUUISendUserUserInfoSize;
  DWORD  dwUUICallInfoSize;

  LINEDIALPARAMS  MinDialParams;
  LINEDIALPARAMS  MaxDialParams;
  LINEDIALPARAMS  DefaultDialParams;

  DWORD  dwNumTerminals;
  DWORD  dwTerminalCapsSize;
  DWORD  dwTerminalCapsOffset;
  DWORD  dwTerminalTextEntrySize;
  DWORD  dwTerminalTextSize;
  DWORD  dwTerminalTextOffset;

  DWORD  dwDevSpecificSize;
  DWORD  dwDevSpecificOffset;

  DWORD  dwLineFeatures;

  DWORD  dwSettableDevStatus;
  DWORD  dwDeviceClassesSize;
  DWORD  dwDeviceClassesOffset;
  GUID   PermanentLineGuid;      //TAPI Version 2.2
  DWORD  dwAddressTypes;         //TAPI Version 3.0
  GUID   ProtocolGuid;           //TAPI Version 3.0
  DWORD  dwAvailableTracking;    //TAPI Version 3.0
} LINEDEVCAPS, FAR *LPLINEDEVCAPS;

Members

dwTotalSize: The total size, in bytes, allocated to this data structure.
dwNeededSize: The size, in bytes, for this data structure that is needed to hold all the returned information.
dwUsedSize: The size, in bytes, of the portion of this data structure that contains useful information.
dwProviderInfoSize
dwProviderInfoOffset: The size, in bytes, of the variably sized field containing service provider information, and the offset, in bytes, from the beginning of this data structure. The dwProviderInfoSize/Offset member is intended to provide information about the provider hardware and/or software, such as the vendor name and version numbers of hardware and software. This information can be useful when a user needs to call customer service with problems regarding the provider.
dwSwitchInfoSize
dwSwitchInfoOffset: The size, in bytes, of the variably sized device field containing switch information, and the offset, in bytes, from the beginning of this data structure. The dwSwitchInfoSize/Offset member is intended to provide information about the switch to which the line device is connected, such as the switch manufacturer, the model name, the software version, and so on. This information can be useful when a user needs to call customer service with problems regarding the switch.
dwPermanentLineID: The permanent DWORD identifier by which the line device is known in the system's configuration. It is a permanent name for the line device. This permanent name (as opposed to dwDevice ID) does not change as lines are added or removed from the system, and persists through operating system upgrades. It can therefore be used to link line-specific information in .ini files (or other files) in a way that is not affected by adding or removing other lines or by changing the operating system.
dwLineNameSize
dwLineNameOffset: The size, in bytes, of the variably sized device field containing a user configurable name for this line device, and the offset, in bytes, from the beginning of this data structure. This name can be configured by the user when configuring the line device's service provider, and is provided for the user's convenience.
dwStringFormat: The string format used with this line device. This member uses one of the STRINGFORMAT_ Constants.
dwAddressModes: The mode by which the originating address is specified. This member uses the LINEADDRESSMODE_ Constants.
dwNumAddresses: The number of addresses associated with this line device. Individual addresses are referred to by address identifiers. Address identifiers range from zero to one less than the value indicated by dwNumAddresses.
dwBearerModes: Flag array that indicates the different bearer modes that the address is able to support. This member uses one or more of the LINEBEARERMODE_ Constants.
dwMaxRate: Contains the maximum data rate, in bits per second, for information exchange over the call.
dwMediaModes: Flag array that indicates the different media types the address is able to support. This member uses one or more of the LINEMEDIAMODE_ Constants.
dwGenerateToneModes: The different kinds of tones that can be generated on this line. This member uses one or more of the LINETONEMODE_ Constants.
dwGenerateToneMaxNumFreq: Contains the maximum number of frequencies that can be specified in describing a general tone using the LINEGENERATETONE data structure when generating a tone using lineGenerateTone. A value of 0 indicates that tone generation is not available.
dwGenerateDigitModes: Specifies the digit modes than can be generated on this line. This member uses one or more of the LINEDIGITMODE_ Constants.
dwMonitorToneMaxNumFreq: Contains the maximum number of frequencies that can be specified in describing a general tone using the LINEMONITORTONE data structure when monitoring a general tone using lineMonitorTones. A value of 0 indicates that tone monitor is not available.
dwMonitorToneMaxNumEntries: Contains the maximum number of entries that can be specified in a tone list to lineMonitorTones.
dwMonitorDigitModes: Specifies the digit modes than can be detected on this line. This member uses one or more of the LINEDIGITMODE_ Constants.
dwGatherDigitsMinTimeout
dwGatherDigitsMaxTimeout: These members contain the minimum and maximum values, in milliseconds, that can be specified for both the first digit and inter-digit timeout values used by lineGatherDigits. If both these members are zero, timeouts are not supported.
dwMedCtlDigitMaxListSize
dwMedCtlMediaMaxListSize
dwMedCtlToneMaxListSize
dwMedCtlCallStateMaxListSize: These members contain the maximum number of entries that can be specified in the digit list, the media list, the tone list, and the call state list parameters of lineSetMediaControl respectively.
dwDevCapFlags: Specifies various Boolean device capabilities. This member uses one or more of the LINEDEVCAPFLAGS_ Constants.
dwMaxNumActiveCalls: Provides the maximum number of (minimum bandwidth) calls that can be active (connected) on the line at any one time. The actual number of active calls may be lower if higher bandwidth calls have been established on the line.
dwAnswerMode: Specifies the effect on the active call when answering another offering call on a line device. This member uses one of the LINEANSWERMODE_ Constants.
dwRingModes: Contains the number of different ring modes that can be reported in the LINE_LINEDEVSTATE message with the ringing indication. Different ring modes range from one to dwRingModes. Zero indicates no ring.
dwLineStates: Specifies the different line status components for which the application may be notified in a LINE_LINEDEVSTATE message on this line. This member uses one or more of the LINEDEVSTATE_ Constants.
dwUUIAcceptSize: Specifies the maximum size of user-user information that can be sent during a call accept.
dwUUIAnswerSize: Specifies the maximum size of user-user information that can be sent during a call answer.
dwUUIMakeCallSize: Specifies the maximum size of user-user information that can be sent during a make call.
dwUUIDropSize: Specifies the maximum size of user-user information that can be sent during a call drop.
dwUUISendUserUserInfoSize: Specifies the maximum size of user-user information that can be sent separately any time during a call with lineSendUserUserInfo.
dwUUICallInfoSize: Specifies the maximum size of user-user information that can be received in the LINECALLINFO structure.
MinDialParams
MaxDialParams: These members contain the minimum and maximum values, in milliseconds, for the dial parameters that can be set for calls on this line. Dialing parameters can be set to values in this range. The granularity of the actual settings is service provider-specific.
DefaultDialParams: Contains the default dial parameters used for calls on this line. These parameter values can be overridden on a per-call basis.
dwNumTerminals: The number of terminals that can be set for this line device, its addresses, or its calls. Individual terminals are referred to by terminal IDs and range from zero to one less than the value indicated by dwNumTerminals.
dwTerminalCapsSize
dwTerminalCapsOffset: The size, in bytes, and the offset, in bytes, from the beginning of this data structure of the variably sized device field containing an array with entries of type LINETERMCAPS. This array is indexed by terminal IDs, in the range from zero to dwNumTerminals minus one. Each entry in the array specifies the terminal device capabilities of the corresponding terminal.
dwTerminalTextEntrySize: The size, in bytes, of each of the terminal text descriptions pointed at by dwTerminalTextSize/Offset.
dwTerminalTextSize
dwTerminalTextOffset: The size, in bytes, of the variably sized field containing descriptive text about each of the line's available terminals, and the offset, in bytes, from the beginning of this data structure. Each message is dwTerminalTextEntrySize bytes long. The string format of these textual descriptions is indicated by dwStringFormat in the line's device capabilities.
dwDevSpecificSize
dwDevSpecificOffset: The size, in bytes, of the variably sized device-specific field, and the offset, in bytes, from the beginning of this data structure.
dwLineFeatures: Specifies the features available for this line using the LINEFEATURE_ Constants. Invoking a supported feature requires the line to be in the proper state and the underlying line device to be opened in a compatible mode. A zero in a bit position indicates that the corresponding feature is never available. A one indicates that the corresponding feature may be available if the line is in the appropriate state for the operation to be meaningful. This member allows an application to discover which line features can be (and which can never be) supported by the device.
dwSettableDevStatus: The LINEDEVSTATUS values that can be modified using lineSetLineDevStatus.
dwDeviceClassesSize
dwDeviceClassesOffset: Length, in bytes, and offset from the beginning of LINEDEVCAPS of a string consisting of the device class identifiers supported on one or more addresses on this line for use with lineGetID, separated by NULLs; the last identifier in the list is followed by two NULLs.
PermanentLineGuid: The GUID permanently associated with the line device.
dwAddressTypes: The address type used for the call. This member of the structure is available only if the negotiated TAPI version is 3.0 or higher.
ProtocolGuid: The current TAPI Protocol. This member of the structure is available only if the negotiated TAPI version is 3.0 or higher. The protocols are declared in tapi3.h.
dwAvailableTracking: Available tracking, as represented by a LINECALLHUBTRACKING.constant. This member of the structure is available only if the negotiated TAPI version is 3.0 or higher.

Remarks

Device-specific extensions should use the DevSpecific (dwDevSpecificSize and dwDevSpecificOffset) variably sized area of this data structure.

Older applications are compiled without new members in the LINEDEVCAPS structure, and using a SIZEOF LINEDEVCAPS smaller than the new size. The application passes in a dwAPIVersion parameter with the lineGetDevCaps function, which can be used for guidance by TAPI in handling this situation. If the application passes in a dwTotalSize member less than the size of the fixed portion of the structure as defined in the specified dwAPIVersion, LINEERR_STRUCTURETOOSMALL is returned. If sufficient memory has been allocated by the application, before calling TSPI_lineGetDevCaps, TAPI sets the dwNeededSize and dwUsedSize members to the fixed size of the structure as it existed in the specified API version.

New applications must be cognizant of the API version negotiated, and not examine the contents of members in the fixed portion beyond the original end of the fixed portion of the structure for the negotiated API version.

If the LINEBEARERMODE_DATA bit is set in the dwBearerModes member, the dwMaxRate member indicates the maximum rate of digital transmission on the bearer channel. The dwMaxRate member of the LINEDEVCAPS structure can contain valid values even if the dwBearerModes member of the LINEDEVCAPS structure is not set to LINEBEARERMODE_DATA.

If LINEBEARERMODE_DATA is not set in dwBearerModes, but the LINEBEARERMODE_VOICE value is set and the LINEMEDIAMODE_DATAMODEM value is set in the dwMediaModes member, the dwMaxRate member indicates the maximum SYNCHRONOUS (DCE) bit rate on the phone line for the attached modem or functional equivalent. For example, if the modem's fastest modulation speed is V.32bis at 14,400bps, dwMaxRate equals 14400. This is not the fastest DTE port rate (which would most likely be 38400, 57600, or 115200), but the fastest bit rate the modem supports on the phone line.

The application must be careful to check to see that LINEBEARERMODE_DATA is not set, to avoid misinterpreting the dwMaxRate member. It is likely to be 64000 or higher if LINEBEARERMODE_DATA is set.

It should also be noted that if the modem has not been specifically identified (for example, it is a "generic" modem), the figure indicated is a "best guess" based on examination of the modem.

The members dwSettableDevStatus through dwDeviceClassesOffset are available only to applications that open the line device with an API version of 2.0 or later.

Requirements

  Windows NT/2000: Requires Windows NT 4.0 SP3 or later.
  Windows 95/98: Requires Windows 95 or later.
  Version: Requires TAPI 1.4 or later.
  Header: Declared in Tapi.h.

LINEDEVCAPS

Members

Remarks

Requirements

See Also