Voice API Programming Guide — June 2005 115
Speed and Volume Control
A speed/volume adjustment stays in effect until the next adjustment on that channel or until a
system reset.
The SVMT is like a 21-speed bicycle. You can select the gear ratio for each of the 21 speeds before
you go for a ride (by changing the values in the SVMT). And you can select any gear once you are
on the bike, like adjusting the current speed/volume to any setting in the SVMT.
To change the default values of the speed or volume modification table, use the dx_setsvmt()
function, which in turn uses the DX_SVMT data structure. To return the current values of a table to
the DX_SVMT structure, use dx_getsvmt( ). The DX_SVCB data structure uses this table when
setting adjustment conditions.
See the Voice API Library Reference for detailed information about these functions and data
structures.
Adjustments to speed or volume are made by dx_adjsv() and dx_setsvcond( ) according to the
speed or volume modification table settings. These functions adjust speed or volume to one of the
following:
•a specified level (that is, to a specified absolute position in the speed table or volume table)
•a change in level (that is, by a specified number of steps up or down in the speed table or
volume table)
For example, by default, each entry in the volume modification table is equivalent to 2dB from the
origin. Volume could be decreased by 2dB by specifying position 1 in the table, or by moving one
step down from the origin.