LINEDEVCAPS

The LINEDEVCAPS structure describes the capabilities of a line device.

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;

} 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 field 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 field 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. 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.

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 field uses the following STRINGFORMAT_ constants:

STRINGFORMAT_ASCII

The ASCII string format using one byte per character.

STRINGFORMAT_DBCS

The DBCS string format using two bytes per character.

STRINGFORMAT_UNICODE

The Unicode string format using two bytes per character.

dwAddressModes

The mode by which the originating address is specified. This field uses the LINEADDRESSMODE_ constants.

dwNumAddresses

The number of addresses associated with this line device. Individual addresses are referred to by address IDs. Address IDs range from zero to one less than the value indicated by dwNumAddresses.

dwBearerModes

This flag array indicates the different bearer modes that the address is able to support. It uses the following LINEBEARERMODE_ constants:

LINEBEARERMODE_VOICE

This is a regular 3.1 kHz analog voice-grade bearer service. Bit integrity is not assured. Voice can support fax and modem media modes.

LINEBEARERMODE_SPEECH

This corresponds to G.711 speech transmission on the call. The network may use processing techniques such as analog transmission, echo cancellation and compression/decompression. Bit integrity is not assured. Speech is not intended to support fax and modem media modes.

LINEBEARERMODE_MULTIUSE

The multiuse mode defined by ISDN.

LINEBEARERMODE_DATA

The unrestricted data transfer on the call. The data rate is specified separately.

LINEBEARERMODE_ALTSPEECHDATA

The alternate transfer of speech or unrestricted data on the same call (ISDN).

LINEBEARERMODE_NONCALLSIGNALING

This corresponds to a non-call-associated signaling connection from the application to the service provider or switch (treated as a "media stream" by the Telephony API).

LINEBEARERMODE_PASSTHROUGH

When a call is active in LINEBEARERMODE_PASSTHROUGH, the service provider gives direct access to the attached hardware for control by the application. This mode is used primarily by applications desiring temporary direct control over asynchronous modems, accessed through the Win32 comm functions, for the purpose of configuring or using special features not otherwise supported by the service provider.

dwMaxRate

This field contains the maximum data rate in bits per second for information exchange over the call.

dwMediaModes

This flag array indicates the different media modes the address is able to support. It uses the following LINEMEDIAMODE_ constants:

LINEMEDIAMODE_UNKNOWN

A media stream exists but its mode is not known. This corresponds to a call with an unclassified media type. In typical analog telephony environments, an inbound call's media mode may be unknown until after the call has been answered and the media stream filtered to make a determination.

LINEMEDIAMODE_INTERACTIVEVOICE

The presence of voice energy on the call and the call is treated as an interactive call with humans on both ends.

LINEMEDIAMODE_AUTOMATEDVOICE

The presence of voice energy on the call and the voice is locally handled by an automated application.

LINEMEDIAMODE_DATAMODEM

A data modem session on the call.

LINEMEDIAMODE_G3FAX

A group 3 fax is being sent or received over the call.

LINEMEDIAMODE_G4FAX

A group 4 fax is being sent or received over the call.

LINEMEDIAMODE_TDD

A TDD (Telephony Devices for the Deaf) session on the call.

LINEMEDIAMODE_DIGITALDATA

Digital data being transmitted over the call.

LINEMEDIAMODE_TELETEX

A teletex session on the call. Teletex is one of the telematic services.

LINEMEDIAMODE_VIDEOTEX

A videotex session on the call. Videotex is one the telematic services.

LINEMEDIAMODE_TELEX

A telex session on the call. Telex is one the telematic services.

LINEMEDIAMODE_MIXED

A mixed session on the call. Mixed is one the ISDN telematic services.

LINEMEDIAMODE_ADSI

An ADSI (Analog Display Services Interface) session on the call.

LINEMEDIAMODE_VOICEVIEW

The media mode of the call is VoiceView.

dwGenerateToneModes

The different kinds of tones that can be generated on this line. This field uses the following LINETONEMODE_ constants:

LINETONEMODE_CUSTOM

The tone is a custom tone defined by the specified frequencies.

LINETONEMODE_RINGBACK

The tone to be generated is a ringback tone.

LINETONEMODE_BUSY

The tone is a standard (station) busy tone.

LINETONEMODE_BEEP

The tone is a beep, as used to announce the beginning of a recording.

LINETONEMODE_BILLING

The tone is billing information tone such as a credit card prompt tone.

dwGenerateToneMaxNumFreq

This field 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 zero indicates that tone generation is not available.

dwGenerateDigitModes

This field specifies the digit modes than can be generated on this line. It uses the following LINEDIGITMODE_ constants:

LINEDIGITMODE_PULSE

Generate digits as pulse/rotary pulse sequences.

LINEDIGITMODE_DTMF

Generate digits as DTMF tones.

dwMonitorToneMaxNumFreq

This field 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 zero indicates that tone monitor is not available.

dwMonitorToneMaxNumEntries

This field contains the maximum number of entries that can be specified in a tone list to lineMonitorTones.

dwMonitorDigitModes

This field specifies the digit modes than can be detected on this line. It uses the following LINEDIGITMODE_ constants:

LINEDIGITMODE_PULSE

Detect digits as audible clicks that are the result of rotary pulse sequences.

LINEDIGITMODE_DTMF

Detect digits as DTMF tones.

LINEDIGITMODE_DTMFEND

Detect the down edges of digits detected as DTMF tones.

dwGatherDigitsMinTimeout

dwGatherDigitsMaxTimeout

These fields 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 field are zero, timeouts are not supported.

dwMedCtlDigitMaxListSize

dwMedCtlMediaMaxListSize

dwMedCtlToneMaxListSize

dwMedCtlCallStateMaxListSize

These fields 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

This field specifies various Boolean device capabilities. It uses the following LINEDEVCAPFLAGS_ constants:

LINEDEVCAPFLAGS_CROSSADDRCONF

Specifies whether calls on different addresses on this line can be conferenced.

LINEDEVCAPFLAGS_HIGHLEVCOMP

Specifies whether high-level compatibility information elements are supported on this line.

LINEDEVCAPFLAGS_LOWLEVCOMP

Specifies whether low-level compatibility information elements are supported on this line.

LINEDEVCAPFLAGS_MEDIACONTROL

Specifies whether media-control operations are available for calls at this line.

LINEDEVCAPFLAGS_MULTIPLEADDR

Specifies whether lineMakeCall or lineDial are able to deal with multiple addresses at once (such as for inverse multiplexing).

LINEDEVCAPFLAGS_CLOSEDROP

Specifies what happens when an open line is closed while the application has calls active on the line. If TRUE, the service provider drops (clears) all active calls on the line when the last application that has opened the line closes it with lineClose. If FALSE, the service provider does not drop active calls in such cases. Instead, the calls remain active and under control of external device(s). A service provider typically sets this bit to FALSE if there is some other device that can keep the call alive. For example, if an analog line has the computer and phoneset both connect directly to them in a party-line configuration, the offhook phone will automatically keep the call active even after the computer powers down.

Applications should check this flag to determine whether to warn the user (with an OK/Cancel dialog box) that active calls will be lost.

LINEDEVCAPFLAGS_DIALBILLING

LINEDEVCAPFLAGS_DIALQUIET

LINEDEVCAPFLAGS_DIALDIALTONE

These flags indicate whether the "$", "@", or "W" dialable string modifier is supported for a given line device. It is TRUE if the modifier is supported; otherwise, FALSE. The "?" (prompt user to continue dialing) is never supported by a line device. These flags allow an application to determine "up front" which modifiers would result in the generation of a LINEERR. The application has the choice of pre-scanning dialable strings for unsupported characters, or passing the "raw" string from lineTranslateAddress directly to the provider as part of lineMakeCall (lineDial, and so on) and let the function generate an error to tell it which unsupported modifier occurs first in the string.

dwMaxNumActiveCalls

This field 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

This field specifies the effect on the active call when answering another offering call on a line device. This field uses the following LINEANSWERMODE_ constants:

LINEANSWERMODE_NONE

Answering another call on the same line has no effect on the existing active call(s) on the line.

LINEANSWERMODE_DROP

The currently active call will be automatically dropped.

LINEANSWERMODE_HOLD

The currently active call will automatically be placed on hold.

dwRingModes

This field 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

This field specifies the different line status components for which the application may be notified in a LINE_LINEDEVSTATE message on this line. It uses the following LINEDEVSTATE_ constants:

LINEDEVSTATE_OTHER

Device-status items other than those listed below have changed. The application should check the current device status to determine which items have changed.

LINEDEVSTATE_RINGING

The switch tells the line to alert the user. Service providers notify applications on each ring cycle by sending LINE_LINEDEVSTATE messages containing this constant. For example, in the United States, service providers send a message with this constant every six seconds.

LINEDEVSTATE_CONNECTED

The line was previously disconnected and is now connected to TAPI.

LINEDEVSTATE_DISCONNECTED

This line was previously connected and is now disconnected from TAPI.

LINEDEVSTATE_MSGWAITON

The "message waiting" indicator is turned on.

LINEDEVSTATE_MSGWAITOFF

The "message waiting" indicator is turned off.

LINEDEVSTATE_NUMCOMPLETIONS

The number of outstanding call completions on the line device has changed.

LINEDEVSTATE_INSERVICE

The line is connected to TAPI. This happens when TAPI is first activated or when the line wire is physically plugged in and in service at the switch while TAPI is active.

LINEDEVSTATE_OUTOFSERVICE

The line is out of service at the switch or physically disconnected. TAPI cannot be used to operate on the line device.

LINEDEVSTATE_MAINTENANCE

Maintenance is being performed on the line at the switch. TAPI cannot be used to operate on the line device.

LINEDEVSTATE_OPEN

The line has been opened.

LINEDEVSTATE_CLOSE

The line has been closed.

LINEDEVSTATE_NUMCALLS

The number of calls on the line device has changed.

LINEDEVSTATE_TERMINALS

The terminal settings have changed.

LINEDEVSTATE_ROAMMODE

The roam mode of the line device has changed.

LINEDEVSTATE_BATTERY

The battery level has changed significantly (cellular).

LINEDEVSTATE_SIGNAL

The signal level has changed significantly (cellular).

LINEDEVSTATE_DEVSPECIFIC

The line's device-specific information has changed.

LINEDEVSTATE_REINIT

Items have changed in the configuration of line devices. To become aware of these changes (such as for the appearance of new line devices), the application should reinitialize its use of TAPI. The hDevice parameter is left NULL for this state change as it applies to any of the lines in the system.

LINEDEVSTATE_LOCK

The locked status of the line device has changed.

LINEDEVSTATE_CAPSCHANGE

Indicates that, due to configuration changes made by the user or other circumstances, one or more of the fields in the LINEDEVCAPS structure for the address have changed. The application should use lineGetDevCaps to read the updated structure. If a service provider sends a LINE_LINEDEVSTATE message containing this value to TAPI, TAPI will pass it along to applications which have negotiated TAPI version 0x00010004 or above; applications negotiating a previous API version will receive LINE_LINEDEVSTATE messages specifying LINEDEVSTATE_REINIT, requiring them to shutdown and reinitialize their connection to TAPI in order to obtain the updated information.

LINEDEVSTATE_CONFIGCHANGE

Indicates that configuration changes have been made to one or more of the media devices associated with the line device. The application, if it desires, may use lineGetDevConfig to read the updated information. If a service provider sends a LINE_LINEDEVSTATE message containing this value to TAPI, TAPI will pass it along to applications which have negotiated TAPI version 0x00010004 or above; applications negotiating a previous API version will not receive any notification.

LINEDEVSTATE_TRANSLATECHANGE

Indicates that, due to configuration changes made by the user or other circumstances, one or more of the fields in the LINETRANSLATECAPS structure have changed. The application should use lineGetTranslateCaps to read the updated structure. If a service provider sends a LINE_LINEDEVSTATE message containing this value to TAPI, TAPI will pass it along to applications which have negotiated TAPI version 0x00010004 or above; applications negotiating a previous API version will receive LINE_LINEDEVSTATE messages specifying LINEDEVSTATE_REINIT, requiring them to shutdown and reinitialize their connection to TAPI in order to obtain the updated information.

LINEDEVSTATE_COMPLCANCEL

Indicates that the call completion identified by the completion ID contained in parameter dwParam2 of the LINE_LINEDEVSTATE message has been externally canceled and is no longer considered valid (if that value were to be passed in a subsequent call to lineUncompleteCall, the function would fail with LINEERR_INVALCOMPLETIONID). If a service provider sends a LINE_LINEDEVSTATE message containing this value to TAPI, TAPI will pass it along to applications which have negotiated TAPI version 0x00010004 or above; applications negotiating a previous API version will not receive any notification.

LINEDEVSTATE_REMOVED

Indicates that the device is being removed from the system by the service provider (most likely through user action, through a control panel or similar utility). A LINE_LINEDEVSTATE message with this value will normally be immediately followed by a LINE_CLOSE message on the device. Subsequent attempts to access the device prior to TAPI being reinitialized will result in LINEERR_NODEVICE being returned to the application. If a service provider sends a LINE_LINEDEVSTATE message containing this value to TAPI, TAPI will pass it along to applications which have negotiated TAPI version 0x00010004 or above; applications negotiating a previous API version will not receive any notification.

dwUUIAcceptSize

This field specifies the maximum size of user-to-user information that can be sent during a call accept.

dwUUIAnswerSize

This field specifies the maximum size of user-to-user information that can be sent during a call answer.

dwUUIMakeCallSize

This field specifies the maximum size of user-to-user information that can be sent during a make call.

dwUUIDropSize

This field specifies the maximum size of user-to-user information that can be sent during a call drop.

dwUUISendUserUserInfoSize

This field specifies the maximum size of user-to-user information that can be sent separately any time during a call with lineSendUserUserInfo.

dwUUICallInfoSize

This field specifies the maximum size of user-to-user information that can be received in the LINECALLINFO structure.

MinDialParams

MaxDialParams

These fields contain the minimum and maximum values for the dial parameters in milliseconds 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

This field 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

This field 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 field allows an application to discover which line features can be (and which can never be) supported by the device.

dwSettableDevStatus

The LINEDEVSTATUS_ values which 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.

Remarks

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

Older applications will have been compiled without new fields 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 less than the size of the fixed portion of the structure as defined in the dwAPIVersion specified, LINEERR_STRUCTURETOOSMALL will be returned. If sufficient memory has been allocated by the application, before calling TSPI_lineGetDevCaps, TAPI will set the dwNeededSize and dwUsedSize fields 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 fields 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 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 will equal 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 0x00020000 or greater.

See Also

LINE_LINEDEVSTATE, LINECALLINFO, lineClose, lineDial, lineGatherDigits, LINEGENERATETONE, lineGenerateTone, lineGetDevCaps, lineGetID, lineGetTranslateCaps, lineSendUserUserInfo, lineMakeCall, LINEMONITORTONE, lineMonitorTones, lineSetMediaControl, LINETERMCAPS, lineTranslateAddress, LINETRANSLATECAPS, lineUncompleteCall

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