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396 Voice API for Windows Operating Systems Library Reference — November 2003
dx_setparm( ) — set physical parameters of a channel or board device
!
!!
! Cautions
• A constant cannot be used in place of valuep. The value of the parameter to be set must be
placed in a variable and the address of the variable cast as void * must be passed to the
function.
• When setting channel parameters, the channel must be open and in the idle state.
• When setting board parameters, all channels on that board must be idle.
DXCH_T_IDD 2 R/W 5 Specifies DTMF Interdigit delay (time between digits in DTMF
dialing)
DXCH_TTDATA 1 R/W 10 Specifies DTMF length (duration) for dialing.
DXCH_TXDATABUFSIZE 4 R/W 32
kbytes
Sets the size of the play buffers only that are used to transfer
data between the application on the host and the driver. The
minimum buffer size is 128 bytes. The largest available buffer
size is 32 kbytes (must be in multiples of 128). If play and
record buffers are the same size, use DXCH_XFERBUFSIZE.
DXCH_VARNUMBUFFERS 4 R/W 0 Allows you to use more than two play or record buffers when
set to 1. This parameter is used in conjunction with
DXCH_XFERBUFSIZE, DXCH_RXDATABUFSIZE,
DXCH_TXDATABUFSIZE, DXCH_NUMRXBUFFERS and
DXCH_NUMTXBUFFERS. Valid parameter values are:
• 1 (True) – more than 2 buffers
• 0 (False) – 2 buffers
DXCH_WINKDLY 1 R/W 15 Wink Delay. Specifies the delay after a ring is received before
issuing a wink (10 msec units)
DXCH_WINKLEN 1 R/W 15 Wink Length. Specifies the duration of a wink in the off-hook
state (10 msec units)
DXCH_XFERBUFSIZE 4 R/W 32
kbytes
Sets the size of both the play and record buffers used to
transfer data between the application on the host and the
driver. These buffers are also called driver buffers. The
minimum buffer size is 128 bytes. The largest available buffer
size is 32 kbytes (must be in multiples of 128).This parm can be
used with the dx_getparm( ) function. The dx_setchxfercnt( )
function sets the bulk queue buffer size for the channel. This
function can change the size of the buffer used to transfer voice
data between a user application and the hardware. The
dx_setchxfercnt( ) function allows a smaller driver data
transfer buffer size. The minimum buffer size is now 1KB. The
largest available buffer size is 32 kbytes. In general, this
function is used in conjunction with the User I/O feature; for
more information, see the dx_setuio( ) function. This function
sets up the frequency with which the application-registered
read or write functions are called by the voice dll. For
applications requiring more frequent access to voice data in
smaller chunks, you can use this function on a per channel
basis to lower the buffer size.
Table 15. Voice Channel Parameters (Springware) (Continued)
Define Bytes
Read/
Write
Default Description