cc_AnswerCall( )

Description | Termination Events | Cautions | Example | Errors | See Also

Name:	int cc_AnswerCall(crn, rings, mode)
Inputs:	CRN crn	call reference number
	int rings	number of rings before return
	unsigned long mode	synchronous or asynchronous
Returns:	0 on success < 0 on failure
Includes:	cclib.h
Category	Call control
Mode:	synchronous or asynchronous
Technology:	BRI/2; BRI/SC; PRI (all protocols)

Description

The cc_AnswerCall( ) function accepts a connection request from the remote end and connects the call. This function is equivalent to a conventional "offhook" command in answering an incoming call. The cc_AnswerCall( ) function is used any time after:

• CCEV_OFFERED, CCEV_PROGRESSING, or CCEV_ACCEPT is received in asynchronous mode
• the successful completion of cc_WaitCall( ) in synchronous mode

In asynchronous mode, the CCEV_ANSWERED event indicates successful completion of the cc_AnswerCall( ) function. After the successful completion of the function call, the call state changes from Offered or Accepted, if cc_AcceptCall( ) was used, to Connected.

Parameter	Description
crn:	The call reference number. Each call needs a CRN.
rings:	Specifies how long the protocol handler will wait before returning to the calling entity. In ISDN systems, rings must be set to zero or an error will be returned.
Mode:	Specifies asynchronous (EV_ASYNC) or synchronous (EV_SYNC) mode.

Termination Events

• CCEV_ANSWERED - indicates that a CONNECT message has been sent to the network.
• CCEV_TASKFAIL - indicates that a request/message was rejected by the firmware. Typically, this event is triggered by an incorrect function call during the call.

Cautions

This function is called only after an inbound call has been detected.

Example

#include <windows.h>   /* For Windows applications only */  
#include <stdio.h>  
#include <errno.h>  
#include "srllib.h"  
#include "dtilib.h"  
#include "cclib.h"  
void main()  
{  
   LINEDEV   devhdl    = 0;  
   CRN       crn = 0;  
   char     *devname = "dtiB1T1";  
   if ( cc_Open( &devhdl, devname, 0 ) < 0 )   
   {  
      printf("Error opening device: errno = %d\n", errno);  
      exit(1);  
   }  
   printf("Waiting for call\n");  
   if ( cc_WaitCall(devhdl, &crn, NULL, -1, EV_SYNC) < 0 )  
        procdevfail(devhdl);  
   if ( cc_AnswerCall(crn, 0, EV_SYNC) < 0 )  
        callfail(crn);  
      .  
      .  
      .  
      .  
      .  
   /* Drop the call */  
   if ( cc_DropCall(crn, NORMAL_CLEARING, EV_SYNC) < 0 )  
        callfail(crn);  
   if ( cc_ReleaseCall(crn) < 0 )  
        callfail(crn);  
   /* Close the device */  
   if ( cc_Close( devhdl ) < 0 )   
      printf("Error closing device, errno = %d\n", errno);  
}  
int callfail(CRN crn)  
{                  
        LINEDEV ld;  
       cc_CRN2LineDev(crn,&ld);  
       procdevfail(ld);  
}  
int procdevfail(LINEDEV handle)  
{  
        int reason;  
        char *msg;  
        reason = cc_CauseValue(handle);  
        cc_ResultMsg(handle,reason,&msg);  
        printf("reason = %x - %s\n",reason,msg);  
}

Errors

If the function returns < 0 to indicate failure, use the cc_CauseValue( ) function to retrieve the reason code for the failure. The cc_ResultMsg( ) function can be used to interpret the reason code. Error codes are defined in the files ccerr.h, isdnerr.h and isdncmd.h.

Error codes from the cc_AnswerCall( ) function include the following:

Error Code	Description
ERR_ISDN_LIB | E_ISBADIF	Bad interface number
ERR_ISDN_LIB | E_ISBADCALLID	Bad call identifier
ERR_ISDN_LIB | E_ISBADTS	Bad time slot

See Also

• cc_WaitCall( )
• cc_DropCall( )

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