dt_listen( )

Description | Cautions | Example | Errors | See Also

Name:	int dt_listen(devh,sc_tsinfop)
Inputs:	int devh	Digital Network Interface device handle
	SC_TSINFO *sc_tsinfop	pointer to SCbus time slot information structure
Returns:	0 on success -1 if error
Includes:	srllib.h dtilib.h
Category:	SCbus Routing
Mode:	synchronous

Description

The dt_listen( ) function connects the digital listen channel to the 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) such as on a D/240SC-T1 or D/300SC-E1 board to an SCbus time slot. This function 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.

NOTE:

The SCbus convenience function nr_scroute( ) includes dt_listen( ) functionality. See the SCbus Routing Guide for more information on convenience functions.

Parameter	Description
devh:	Specifies the valid Digital Network Interface time slot device handle returned by a call to dt_open( )
sc_tsinfop:	Specifies the pointer to the SC_TSINFO data structure

The SC_TSINFO structure is declared as follows:

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

The sc_numts member of the SC_TSINFO structure must be set to 1. The sc_tsarrayp field of the SC_TSINFO structure must be initialized with a pointer to a valid array. The first element of this array must contain a valid SCbus time slot number (between 0 and 1023) which was obtained by issuing an xx_getxmitslot( ) function (xx = ag, dt, dx or fx). Upon return from the dt_listen( ) function, the digital receive channel will be connected to this time slot.

Although multiple SCbus device channels may listen (be connected) to the same SCbus time slot, a digital receive (listen) channel can connect to only one SCbus time slot.

Cautions

This function will fail under the following conditions:

• An invalid device handle is specified
• An invalid SCbus time slot number is specified

Example

#include <windows.h>         /* For Windows applications only */  
#include <srllib.h>  
#include <dtilib.h>  
#include <errno.h>  
   
main( )  
{  
   int voxh;                 /* Voice channel device handle */  
   int dtih;                 /* Digital channel (time slot) device handle */  
   SC_TSINFO  sc_tsinfo;     /* Time slot information structure */  
   long scts;                /* SCbus time slot */  
   
   /* Open board 1 channel 1 device */  
   if ((voxh = dx_open("dxxxB1C1", 0)) == -1) {  
      printf("Cannot open channel dxxxB1C1.  errno = %d", errno);  
      exit(1);  
   }  
   
   /* Fill in the SCbus time slot information */  
   sc_tsinfo.sc_numts = 1;  
   sc_tsinfo.sc_tsarrayp = &scts;  
   
   /* Get SCbus time slot connected to transmit of channel 1 on board 1 */  
   if (dx_getxmitslot(voxh, &sc_tsinfo) == -1) {  
      printf("Error message = %s", ATDV_ERRMSGP(voxh));  
      exit(1);  
   }  
   
   /* Open board 1 time slot 1 on Digital network interface device */  
   if ((dtih = dt_open("dtiB1T1", 0)) == -1) {  
      printf("Cannot open time slot dtiB1T1.  errno = %d", errno);  
      exit(1);  
   }  
   
   /* Connect the receive of digital channel (time slot) 1 on board 1 to  
    SCbus transmit time slot of voice channel 1*/  
   if (dt_listen(dtih, &sc_tsinfo) == -1) {  
      printf("Error message = %s", ATDV_ERRMSGP(dtih));  
      exit(1);  
   }  
}

Errors

If the function returns -1, use the SRL Standard Attribute function ATDV_LASTERR( ) to obtain the error code or use ATDV_ERRMSGP( ) to obtain a descriptive error message. The error codes returned by ATDV_LASTERR( ) are:

• EDT_BADBRDERR - Board missing or defective
• EDT_BADCMDERR - Invalid command parameter to driver
• EDT_FWERR - Firmware returned an error
• EDT_INVTS - Invalid time slot device handle
• EDT_INVMSG - Invalid message
• EDT_SH_BADLCLTS - Invalid local time slot number
• EDT_SH_BADEXTTS - External time slot unsupported at current clock rate
• EDT_SH_BADINDX - Invalid Switch Handler library index number
• EDT_SH_BADMODE - Invalid Switch Handler bus configuration
• EDT_SH_BADTYPE - Invalid local time slot type
• EDT_SH_LCLTSCNCT - Local time slot is already connected to SCbus
• EDT_SH_LIBBSY - Switch Handler library busy
• EDT_SH_LIBNOTINIT - Switch Handler library is uninitialized
• EDT_SH_MISSING - Switch Handler is not present
• EDT_SH_NOCLK - Switch Handler clock fallback failed
• EDT_SYSTEM - system error
• EDT_TMOERR - Timed out waiting for reply from firmware

See Also

In the SCbus Routing Function Reference:

• dt_unlisten( )
• ag_getxmitslot( )
• dx_getxmitslot( )

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