ms_listen( )

Description | Cautions | Example | Errors | See Also

Name:	int ms_listen(devh,tsinfop)
Inputs:	int devh	station handle
	SC_TSINFO *tsinfop	pointer to the SCbus time slot information structure
Returns:	0 on success
	-1 on failure
Includes:	srllib.h
	dtilib.h
	msilib.h
Category:	SCbus Routing
Mode:	asynchronous

Description

The ms_listen( ) function connects the receive of a station to an SCbus time slot. This function uses the information stored in the SC_TSINFO structure to connect the digital receive (listen) channel (T-1/E-1 time slot) to an SCbus time slot. This functon sets up a half-duplex connection. For a full-duplex connection, the receive (listen) channel of the other device must be connected to the digital transmit channel.

Parameter	Description
devh:	The board device handle.
tsinfop:	The pointer to the SCbus time slot information structure.

A pointer to the SC_TSINFO structure is passed to the function. It contains two fields: the first field specifies the total number of SCbus time slots to which the connection is to be made, and the second is a pointer to an array which contains the SCbus time slots (between 0 and 1023) to be connected to the receive of the station device. The SC_TSINFO structure is declared as follows:

     typedef struct {  
          unsigned long   sc_numts;  
          long           *sc_tsarrayp;  
     } SC_TSINFO;

For MSI/SC station devices, the sc_numts element of the SC_TSINFO array should be set to 1. The sc_tsarrayp must point to an array of type long. The first element of the array will contain a valid SCbus time slot number (0 to 1023) which was obtained by issuing the appropriate xx_getxmitslot( ) function call (xx = ag, dt, dx or fx).

NOTES:

1. An MSI/SC station device can listen to only one time slot at a time. However, multiple devices may listen to a time slot at the same time.

2. Dialogic recommends that you unlisten before invoking this function.

Cautions

This function fails when:

• An invalid station handle is specified.
• The SCbus time slot number is invalid.
• The device is operating in PEB mode.

Example

#include "srllib.h"  
#include "dtilib.h"  
#include "msilib.h"  
#include "errno.h"  
int     chdev1, tsdev4;    /* Chan dev descriptor variables */  
SC_TSINFO     tsinfo;      /* Time slot information structure */  
long     scts;             /* SCbus time slot */  
/* Open board 1, channel 1 device */  
if ((chdev1 = ms_open("msiB1C1",0)) == -1) {  
     printf( "Cannot open MSI B1, C1: errno=%d", errno);  
     exit(1);  
}  
/* Open board 1, time slot 4 device */  
if ((tsdev1 = dt_open("dtiB1T4",0)) == -1) {  
     printf( "Cannot open DTI B1, T4: errno=%d", errno);  
     exit(1);  
}  
/* Set up SC_TSINFO structure */  
tsinfo.sc_numts = 1;  
tsinfo.sc_tsarray = &scts;  
/* Get time slot on which DTI board 1, time slot 4 is xmitting */  
if (dt_getxmitslot(tsdev4,&tsinfo) == -1) {  
     printf("Error message = %s", ATDV_ERRMSGP(chdev));  
     exit(1);  
}  
/* Make MSI board 1, station 1 listen to transmit time slot  
     of DTI Board 1 time slot 4 on SCbus */  
if (ms_listen(chdev1,&tsinfo) == -1) {  
     printf("Error Message = %s",ATDV_ERRMSGP(tsdev4));  
     exit(1);  
}

Errors

If the function returns a -1 indicating an error, the error code may be retrieved by calling the SRL standard attribute function ATDV_LASTERR( ). A more descriptive error message may be retrieved by using the function ATDV_ERRMSGP( ).

See Also

• ms_getxmitslot( )
• ms_unlisten( )

Click here to contact Dialogic Customer Engineering