ms_chgxtder( )

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Cautions | Errors | Example | See Also

Name:	int ms_chgxtder (devh, xid, cdt)
Inputs:	int devh	MSI board device handle
	int xid	extended connection identifier
	MS_CDT *cdt	pointer to descriptor table
Returns:	0 on success -1 on failure
Includes:	srllib.h dtilib.h msilib.h
Category:	Extended Connection
Mode:	synchronous
Platform:	Springware

Description

The ms_chgxtder( ) function changes the attribute of the connection extender. After an extended connection has been established, only the channel attributes of the connection extender may be changed.

The signal that the connection extender should listen to is always present on the TDM bus, irrespective of the connection extender setting of the chan_sel field in the MS_CDT data structure.

Note: There can be only one connection extender per extended connection.

Parameter	Description
devh	the MSI board device handle
xid	the extended connection identifier
cdt	pointer to the conference descriptor table. See the MS_CDT data structure page for details.

Cautions

This function fails when:

• The device handle specified is invalid
• The board is not an MSI board
• The connection ID is invalid

Errors

If this function returns -1 to indicate failure, obtain the reason for the error by calling the SRL standard attribute function ATDV_LASTERR( ) or ATDV_ERRMSGP( ) to retrieve either the error code or a pointer to the error description, respectively.

Refer to the error type tables found in Chapter 5, "Error Codes". Error defines can be found in dtilib.h or msilib.h.

Example

#include <windows.h>         /* For Windows applications only */
#include <errno.h>
#include "srllib.h"
#include "dtilib.h"
#include "msilib.h"  
int  dev1;            /* Device handle for board */
int  chdev2;          /* Station dev descriptor */
int  tsdev1,tsdev2;   /* DTI time slot device handles */
MS_CDT  cdt[3];       /* Connection descriptors */
int  xid;             /* Connection ID */
long lts;             /* listen time slot */
SC_TSINFO    tsinfo;  /* Time slot information structure */
int  rc;              /* Return Code */
int  station, ts1, ts2;  
/* Start System */  
/* Assume that there is a DTI in the system.
 * Assume two DTI transmit time slots. ts1 and
 * ts2, are identified by device handles tsdev1
 * and tsdev2, respectively.
 */  
/*
 * Continue processing
 */
/*
 * Establish connection between a station and time slot ts1
 */
if ((rc=nr_scroute(tsdev1,SC_DTI,chdev2,SC_MSI,SC_FULLDUP))== -1) {
   printf("Error making connection between DTI timeslot\n");
   printf("and MSI station. rc = 0x%x\n",rc);
   exit(1);
}  
/*
 * Now extend the connection established earlier
 */
cdt[0].chan_num = station ;      /* Use MSI station as connection identifier*/
cdt[0].chan_sel = MSPN_STATION;
cdt[0].chan_attr = MSPA_PUPIL;  
cdt[1].chan_num = ts2;           /* DTI time slot ts2 for connection extender */
cdt[1].chan_sel = MSPN_TS;
cdt[1].chan_attr = MSPA_RO;  
/* Establish extended connection. Since the extender is in receive only mode,
 * the connection will be extended without interrupting the conversation between the
 * external party and the station
 */  
if (ms_estxtdcon(dev1,cdt,&xid) == -1) {
   printf("Error Message = %s",ATDV_ERRMSGP(dev1));
   exit(1);
}  
/* Make tsdev2 listen to time slot returned by the ms_estxtdcon function  */
tsinfo.sc_numts = 1;
tsinfo.sc_tsarray = &cdt[1].chan_lts;
if (dt_listen(tsdev2,&tsinfo) == -1) {
   printf("Error Message = %s",ATDV_ERRMSGP(tsdev2));
   exit(1);
}  
/* Prepare cdt to change the attribute of the connection extender */
cdt[0].chan_num = ts2 ;        /* Required station number */
cdt[0].chan_sel = MSPN_TS;
cdt[0].chan_attr = MSPA_COACH;  
/* Change extender to coach */
if (ms_chgxtder(dev1,xid,cdt)== -1) {
    printf("Error Message = %s",ATDV_ERRMSGP(dev1));
    exit(1);
}  

See Also

• ms_delxtdcon( )
• ms_estxtdcon( )

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