dx_TxRxIottData( )

Description | Cautions | Example | Errors | See Also

Name:	int dx_TxRxIottData(chdev, lpTxIott, lpTxTerminations, lpRxIott, lpRxTerminations. wType, lpParams, mode)
Inputs:	int chdev	valid channel device handle
	DX_IOTT *lpTxIott	pointer to I/O transfer table
	DV_TPT *lpTxTerminations	pointer to termination parameter table
	DX_IOTT *lpRxIott	pointer to I/O transfer table
	DV_TPT *lpRxTerminations	pointer to termination parameter table
	int wType	data type
	LPVOID lpParams	pointer to data type-specific information
	USHORT mode	function mode
Returns:	0 if successful -1 if error
Includes:	dxxxlib.h srllib.h
Mode:	Synchronous/asynchronous

Description

The dx_TxRxIottData( ) function is used to start a transmit-initiated reception of data (two-way ADSI), where faster remote terminal device (CPE) turnaround occurs, typically within 100 msec. Faster turnaround is required for two-way FSK so that the receive data is not missed while the application turns the channel around after the last sample of FSK transmission is sent.

The wType parameter specifies the type of data that is to be transmitted and received, i.e., two-way ADSI. The transmitted data may come from, and the received data may be directed to, any combination of data files, memory, or custom devices. The data is transmitted and received on a specified channel.

The lpTxIott parameter specifies the location of the messages to be transmitted. The destination for the retrieved messages is specified by lpRxIott.

The transmit portion of the dx_TxRxIottData( ) function continues until one of the following occurs:

• all data specified in DX_IOTT has been transmitted
• dx_stopch( ) is issued on the channel
• one of the conditions specified in DV_TPT is satisfied

The receive portion of the dx_TxRxIottData( ) function continues until one of the following occurs:

• dx_stopch( ) is called
• the data requirements specified in the DX_IOTT are fulfilled
• the channel detects end of FSK data
• one of the conditions in the DV_TPT is satisfied

If the channel detects end of FSK data during the receive portion, the function is terminated. Use ATDX_TERMMSK( ) to return the cause of termination. Possible return values are:

TM_MAXTIME	Maximum function time exceeded
TM_USRSTOP	Function stopped by user
TM_EOD	End of FSK data detected on receive
TM_MAXDATA	Maximum data reached
TM_ERROR	I/O device error

Upon asynchronous completion of the transmit portion of the function, a TDX_TXDATA event is generated. Upon asynchronous completion of the receive portion of the function, a TDX_RXDATA event is generated.

Parameter	Description
chdev	The valid Dialogic channel device handle.
lpTxIott	The pointer to the I/O Transfer Table. lpTxIott specifies the source of the messages to be transmitted. This is the same DX_IOTT structure used in dx_playiottdata( ) and dx_reciottdata( ).
lpTxTerminations	The pointer to the DV_TPT Termination Parameter Table that sets the termination conditions for the device handle. Supported values are:   DX_MAXTIME. For more information, see the DV_TPT structure in the Voice Software Reference.   DX_MAXDATA. Specify a valid value in the tp_length field of the DV_TPT structure. Valid values are 1 through 65535.
lpRxIott	The pointer to the I/O Transfer Table structure. lpRxIott specifies the destination of the messages to be received. This is the same DX_IOTT structure used in dx_playiottdata( ) and dx_reciottdata( ).
lpRxTerminations	The pointer to the DV_TPT Termination Parameter Table that sets the termination conditions for the device handle. Supported values are:   DX_MAXTIME. For more information, see the DV_TPT structure in the Voice Software Reference.   DX_MAXDATA. Specify a valid value in the tp_length field of the DV_TPT structure. Valid values are 1 through 65535.
wType	Specifies the type of data to be transmitted and received. To transmit and receive ADSI data, set wType to DT_ADSI.
lpParams	The pointer to a structure that specifies additional information about the data that is to be sent and received. The structure type is determined by the data type (ADSI) specified by wType. For ADSI data, set lpParams to point to an ADSI_XFERSTRUC parameter block structure.
mode	Specifies how the function should execute, either EV_ASYNC (asynchronous) or EV_SYNC (synchronous).

Cautions

Library level data is buffered when it is received. The buffer size is 255, which is the default buffer size used by the library.

Example

// Synchronous transmit initiated receive ADSI data  
DX_IOTT TxIott = {0};  
DX_IOTT RxIott = {0};  
DV_TPT tpt;  
char *devnamep = "dxxxB1C1";  
char buffer[16];  
ADSI_XFERSTRUC adsimode;  
int chdev;  
         .  
         .  
         .  
    sprintf(buffer, "MENU.ADSI");  
    if ((TxIott.io_fhandle = dx_fileopen(buffer, _O_RDONLY|O_BINARY)) == -1) {  
         /* Perform system error processing */  
         exit(1);  
    }  
    sprintf(buffer, "RECEIVE.ADSI");  
    if ((RxIott.io_fhandle = dx_fileopen(buffer, O_BINARY)) == -1) {  
         /* Perform system error processing */  
         dx_fileclose(TxIott.io_fhandle);  
         exit(2);  
    }  
    if ((chdev = dx_open(devnamep, 0)) == -1) {  
         fprintf(stderr, "Error opening channel %s\n",devnamep);  
         dx_fileclose(TxIott.io_fhandle);  
         dx_fileclose(RxIott.io_fhandle);  
         exit(1);  
    }  
         .  
         .  
         .
  
    // source is a file  
    TxIott.io_type = IO_DEV|IO_EOT;  
    TxIott.io_bufp = 0;  
    TxIott.io_offset = 0;  
    TxIott.io_length = -1;
  
    // destination is a file  
    RxIott.io_type = IO_DEV|IO_EOT;  
    RxIott.io_bufp = 0;  
    RxIott.io_offset = 0;  
    RxIott.io_length = -1;  
    adsimode.cbSize = sizeof(adsimode);  
    adsimode.dwTxDataMode = ADSI_ALERT;  
    adsimode.dwRxDataMode = ADSI_NOALERT;  
    // Specify maximum time termination condition in the TPT for the  
    // receive portion of the function.  Application specific value is  
    // used to terminate dx_TxRxIottData( ) if end of data is not  
    // detected over a specified duration.  
    tpt.tp_type = IO_EOT;  
    if (dx_clrtpt(&tpt, 1) == -1) {  
       // Process error  
    }  
    tpt.tp_termno = DX_MAXTIME;  
    tpt.tp_length = 1000;  
    tpt.tp_flags = TF_MAXTIME;  
    // Wait for inbound call  
    if (dx_TxRxIottData(chdev, &TxIott, NULL, &RxIott, &tpt, DT_ADSI,   
         &adsimode, EV_SYNC) < 0) {  
         fprintf(stderr, "ERROR: dx_TxRxIottData failed on Channel %s; "  
                "error: %s\n", ATDV_NAMEP(chdev), ATDV_ERRMSGP(chdev));  
    }

Errors

If the function returns -1 to indicate an error, use the SRL Standard Attribute function ATDV_LASTERR( ) to obtain the error code or you can use ATDV_ERRMSGP( ) to obtain a descriptive error message.

Possible error codes from the dx_TxRxIottData( ) function include the following:

Error Code	Description
EDX_BADPARM	Invalid data mode
EDX_BADIOTT	Invalid DX_IOTT (pointer to I/O transfer table)
EDX_BUSY	Channel already executing I/O function
EDX_SYSTEM	Error from operating system; use dx_fileerrno( ) to obtain error value

See Also

• dx_TxIottData( )
• dx_RxIottData( )

Click here to contact Dialogic Customer Engineering