lineSetCallParams

The lineSetCallParams function allows an application to change bearer mode and/or the rate parameters of an existing call.

LONG lineSetCallParams(
  HCALL hCall,                         
  DWORD dwBearerMode,                  
  DWORD dwMinRate,                     
  DWORD dwMaxRate,                     
  LPLINEDIALPARAMS const lpDialParams  
);
 

Parameters

hCall

A handle to the call whose parameters are to be changed. The application must be an owner of the call. The call state of hCall can be any state except idle or disconnected.

dwBearerMode

The new bearer mode for the call. This parameter can have only a single bit set, and it uses the following LINEBEARERMODE_ constants:

LINEBEARERMODE_VOICE

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

Corresponds to G.711 speech transmission on the call. The network can 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

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.

dwMinRate

A lower bound for the call's new data rate. The application can accept a new rate as low as this one.

dwMaxRate

An upper bound for the call's new data rate. This is the maximum data rate the application can accept. If an exact data rate is required, dwMinRate and dwMaxRate should be equal.

lpDialParams

A pointer to the new dial parameters for the call, of type LINEDIALPARAMS. This parameter can be left NULL if the call's current dialing parameters are to be used.

Return Values

Returns a positive request identifier if the function is completed asynchronously, or a negative error number if an error occurs. The dwParam2 parameter of the corresponding LINE_REPLY message is zero if the function succeeds or it is a negative error number if an error occurs. Possible return values are:

LINEERR_BEARERMODEUNAVAIL, LINEERR_NOTOWNER, LINEERR_INVALBEARERMODE, LINEERR_OPERATIONUNAVAIL, LINEERR_INVALCALLHANDLE, LINEERR_OPERATIONFAILED, LINEERR_INVALCALLSTATE, LINEERR_RATEUNAVAIL, LINEERR_INVALPOINTER, LINEERR_RESOURCEUNAVAIL, LINEERR_INVALRATE, LINEERR_UNINITIALIZED, LINEERR_NOMEM.

Remarks

This operation is used to change the parameters of an existing call. Examples of its usage include changing the bearer mode and/or the data rate of an existing call.

QuickInfo

  Version: Use TAPI version 1.4 and later.
  Header: Declared in tapi.h.
  Import Library: Link with tapi32.lib.

See Also

TAPI Reference Overview, Supplementary Line Services Functions, LINE_REPLY, LINEDIALPARAMS