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 on error
Includes:	srllib.h
	dtilib.h
Category:	SCbus Routing
Mode:	Synchronous

Description

The dt_listen( ) function connects digital receive channel to 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.

NOTE:

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

Parameter	Description
devh:	Specifies a 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 field 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 when:

• An invalid device handle is specified.
• An invalid SCbus time slot number is specified.
• A PEB time slot is requested.

Example

#include <windows.h>  
#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 voice 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 interface device */  
   if ((dtih = dt_open("dtiB1T1", 0)) == -1) {  
      printf("Cannot open time slot dtiB1T1.  errno = %d", errno);  
      xit(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:

Equate	Returned When
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	Windows system error
EDT_TMOERR	Timed out waiting for reply from firmware

See also

• dt_unlisten( )
• ag_getxmitslot( )
• dx_getxmitslot( )
• fx_getxmitslot( )
• ms_getxmitslot( )

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