• 12.4.1. Interoperability with DM3 Application Foundation Code
• 12.4.2. Getting, Using, and Closing Device Handles in a DM3 Fixed Routing Configuration
• DM3 Fixed Routing Configuration and Device-Handling Guidelines for the GlobalCall API

12.4. Operating in an R4 on DM3 Fixed Routing Configuration

All information specific to using a fixed routing configuration is provided here, including information on interoperability, device management, and guidelines and examples for implementing an application.

12.4.1. Interoperability with DM3 Application Foundation Code

The DM3 fixed routing configuration is consistent with the clustering operation used in the DM3 Application Foundation Code (AFC).

12.4.2. Getting, Using, and Closing Device Handles in a DM3 Fixed Routing Configuration

Since an R4 for DM3 application must use GlobalCall for call control on DM3 boards, the DM3 network interface devices must be opened with the gc_Open( ) or gc_OpenEx( ) function. Where call control is not required, such as with ISDN NFAS, dt_open( ) may be used to open DM3 network interface devices.

Also, since the voice device and network interface timeslot in a DM3 fixed routing configuration are permanently routed and attached to each other, SCbus routing and attaching of the devices is unnecessary with DM3 hardware. The same is true of a fax device and its network interface timeslot in the DM3 fixed routing configuration. The resource device (voice/fax) and its associated DTI network interface timeslot on the same physical port are tied together in a DM3 cluster. The resource channel is explicitly tied to the network interface timeslot; and the voice resource cannot be shared or separately routed to another network interface device. Thus, the resource device and associated network interface device are bound together in a static link, and there is no support for routing the resource independently to the SCbus. However, the DTI network interface can be routed to the SCbus, allowing access to other SCbus resources.

With the DM3 fixed routing configuration, the voice or fax resource device has no direct access to the CT Bus timeslots and it is neither necessary nor possible to attach the resource and network interface devices together from the host. Therefore, in most cases, an R4 for DM3 application does not need to open the voice channel device and/or the network interface timeslot device directly using the dx_open( ) and dt_open( ) functions, respectively. However, the fax device must explicitly be opened using fx_open( ). Although the fax device also has no direct access to the CT Bus timeslots and therefore cannot be routed over the CT Bus, it is necessary to retrieve the fax device handle to do fax operations.

DM3 Fixed Routing Configuration and Device-Handling Guidelines for the GlobalCall API

The following summary applies only to a DM3 fixed routing configuration and presents some guidelines for DM3 device-handling using the GlobalCall API.

• Use gc_Start( ) to initialize GlobalCall prior to using any devices.
• Use gc_Open( ) to open the voice resource and network interface devices; then use gc_GetVoiceH( ) to retrieve the voice device handle and gc_GetNetworkH( ) to retrieve the network interface device handle.
  
  The gc_Open( ) function internally opens the associated voice channel on DM3 boards. Do not specify the name of the voice device channel in the gc_Open( ) device string. The device name string for the gc_Open( ) function should look similar to the following (see Section 12.3.1. gc_Open( ) and gc_OpenEx( ) Restrictions (Fixed Routing) for more information):

    ":N_dtiB1T1:P_ISDN"

• Since the fax library does not support the use of a voice handle for fax commands, you cannot use the device handle from dx_open( ) to call fax API functions. You must use fx_open( ) to open a channel device for fax processing and use that fax device handle. Therefore, it is recommended that you do the following to retrieve and use the fax device handle:
  • Use ATDV_NAMEP( ) to retrieve the voice device name for the voice device handle returned by the gc_GetVoiceH( ) function.
  • Use fx_open( ) on this voice device name to open the associated fax device and retrieve the fax device handle.
• The voice device is automatically and permanently associated with and connected to the network interface line device, so the gc_Attach( ) and gc_Detach( ) functions cannot be used and are not supported for DM3 boards.
• In general, when using DM3 and earlier-generation boards, the R4 for DM3 application must use a device-discovery procedure to become "hardware-aware." To perform device discovery and identify whether a logical device belongs to a DM3 board, use the SCbus routing device information functions, such as dx_getctinfo( ) and dt_getctinfo( ), and check the CT_DEVINFO ct_devfamily field for the CT_DFDM3 value. For details see Section 3.3. CT_DEVINFO: Channel/Timeslot Device Information Data Structure and Section 12.5.2. Initializing an Application Under Different Hardware and API Scenarios (Fixed Routing).
• Application performance may be a consideration when opening and closing devices with GlobalCall. If the application uses GlobalCall to dynamically open and close devices as needed, it can impact the application's performance. One way to avoid this is to open all DM3 devices during application initialization and keep them open for the duration of the application, closing them only at the end.

Click here to contact Dialogic Customer Engineering