dx_listen( )

Description | Cautions | Example | Errors | See Also

Name:	int dx_listen(chdev, sc_tsinfop)
Inputs:	int chdev	voice channel handle
	SC_TSINFO *sc_tsinfop	pointer to SCbus time slot information structure
Returns:	0 on success
	-1 on error
Includes:	dxxxlib.h
Category:	SCbus Routing
Mode:	Synchronous

Description

The dx_listen( ) function connects voice receive channel to SCbus time slot. This function uses the information stored in the SC_INFO structure to connect the voice receive (listen) channel 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 voice transmit channel.

NOTE:

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

Parameter	Description
chdev:	Specifies the voice channel handle obtained when the channel was opened using dx_open( ).
sc_tsinfop:	Specifies a pointer to the data structure SC_TSINFO.

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 dx_listen( ) function, the voice receive channel will be connected to the SCbus time slot.

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

Cautions

This function will fail when:

• An invalid channel 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 <dxxxlib.h>  
#include <errno.h>
  
   
main( )  
{  
   int chdev;                        /* Channel device handle */  
   SC_TSINFO  sc_tsinfo;             /* Time slot information structure */  
   long scts;                        /* SCbus time slot */  
   
   /* Open board 1 channel 1 device */  
   if ((chdev = 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 analog channel 1 on board ...1 */  
   if (ag_getxmitslot(chdev, &sc_tsinfo) == -1) {  
       printf("Error message = %s", ATDV_ERRMSGP(chdev));  
       exit(1);  
   }  
   
   /* Connect the receive of voice channel 1 on board 1 to SCbus time slot ...of analog   
      channel 1 */  
   if (dx_listen(chdev, &sc_tsinfo) == -1) {  
       printf("Error message = %s", ATDV_ERRMSGP(chdev));  
      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. One of the following error codes may be returned:

Equate	Returned When
EDX_BADPARM	Parameter error
EDX_SH_BADCMD	Command is not supported in current bus configuration
EDX_SH_BADEXTTS	SCbus time slot is not supported at current clock rate
EDX_SH_BADINDX	Invalid Switch Handler index number
EDX_SH_BADLCLTS	Invalid channel number
EDX_SH_BADMODE	Function not supported in current bus configuration
EDX_SH_CMDBLOCK	Blocking command is in progress
EDX_SH_LCLTSCNCT	Channel is already connected to SCbus
EDX_SH_LIBBSY	Switch Handler library busy
EDX_SH_LIBNOTINIT	Switch Handler library uninitialized
EDX_SH_MISSING	Switch Handler is not present
EDX_SH_NOCLK	Switch Handler clock fallback failed
EDX_SYSTEM	Windows System Error

See Also

• ag_getxmitslot( )
• dt_getxmitslot( )
• fx_getxmitslot( )
• dx_unlisten( )

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