Voice API Programming Guide — June 2005 39
Application Development Guidelines
6.4.3 DM3 Media Loads
Different configurations for DM3 products are supported in the form of media loads. For instance,
a specific media load is available for users who need to implement continuous speech processing
(CSP) and conferencing in their applications. See the appropriate Configuration Guide for specific
media loads that are available.
6.4.4 Device Discovery for DM3 and Springware
Applications that use both Springware and DM3 devices must have a way of differentiating what
type of device is to be opened. The TDM bus routing functions such as dx_getctinfo() provide a
programming solution. DM3 hardware is identified by the CT_DFDM3 value in the ct_devfamily
field of the CT_DEVINFO structure. Only DM3 devices will have this field set to CT_DFDM3.
For more information on the dx_getctinfo( ) function and the CT_DEVINFO structure, see the
Voice API Library Reference.
Note: Use SRL device mapper functions to return information about the structure of the system. For
information on these functions, see the Standard Runtime Library API Library Reference.
The following procedure shows how to initialize an application and perform device discovery when
the application supports both DM3 and Springware boards.
1. Open the first voice channel device on the first voice board in the system with dx_open( ).
2. Call dx_getctinfo( ) and check the CT_DEVINFO.ct_devfamily value.
3. If ct_devfamily is CT_DFDM3, then flag all the voice channel devices associated with the
board as DM3 type.
4. Close the voice channel with dx_close( ).
5. Repeat steps 1 to 4 for each voice board.
For information on initializing the Global Call API on DM3 devices, see the Global Call API
Programming Guide.
6.4.5 Device Initialization Hint
The xx_open( ) functions for the voice (dx), Global Call (gc), network (dt), and fax (fx) APIs are
asynchronous on DM3 boards, unlike the standard Springware versions, which are synchronous.
This should usually have no impact on an application, except in cases where a subsequent function
calls on a device that is still initializing, that is, is in the process of opening. In such cases, the
initialization must be finished before the follow-up function can work. The function won’t return
an error, but it is blocked until the device is initialized.
For instance, if your application calls dx_open( ) followed by dx_getfeaturelist(), the
dx_getfeaturelist() function is blocked until the initialization of the device is completed
internally, even though dx_open() has already returned success. In other words, the initialization
(dx_open()) may appear to be complete, but, in truth, it is still going on in parallel.