8. Application Guidelines
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Each BRI structure is composed of one D channel and two B (bearer) channels. A
BRI board device, such as briS1, is defined as a station and controls the D channel
the same way as a PRI board device. A BRI time slot device, such as briS1T1, is
defined as a bearer channel under a station and is handled the same way as a PRI
line device.
NOTE:
For BRI, the protocol must be configured at initialization using the
cc_SetDChanCfg( ) function. See Section 8.4.1. BRI/SC Configuration
below and the cc_SetDChanCfg( ) function description in Chapter
5. ISDN Function Reference for more information.
8.3.2. MAKECALL Block Initialization and Settings
Because ISDN services vary with switches and provisioning plans, a set of default
standards cannot be set for the MAKECALL_BLK. Therefore, it is up to the user
application to fill in the applicable MAKECALL_BLK values that apply to the
particular provisioning.
The current ISDN Call Control library will check for the ISDN_NOTUSED
(0xFF) define to determine
• which Information Elements (IEs) to send down to the firmware
• the length of each IE to be sent
All of the bearer capability elements in the MAKECALL_BLK structure must be
specified or the ISDN library will not properly fill in the ISDN_CMD messages to
pass down to the firmware. It is suggested that the application first initialize the
MAKECALL_BLK structure with a set of defaults prior to filling in settings
pertaining to the particular ISDN service.
A sample MAKECALL_BLK initialization is shown below:
/* Initialize the MAKECALL block */
makecall_blk.isdn.BC_xfer_cap = BEAR_CAP_SPEECH;
makecall_blk.isdn.BC_xfer_mode = ISDN_ITM_CIRCUIT;
makecall_blk.isdn.BC_xfer_rate = BEAR_RATE_64KBPS;
makecall_blk.isdn.usrinfo_layer1_protocol = 0xFF;
makecall_blk.isdn.usr_rate = 0xFF;
makecall_blk.isdn.destination_number_type = 0xFF;
makecall_blk.isdn.destination_number_plan =0xFF;
makecall_blk.isdn.destination_sub_number_type = 0xFF;
makecall_blk.isdn.destination_sub_phone_number[0] = NULL;
makecall_blk.isdn.origination_number_type = 0xFF;
makecall_blk.isdn.origination_number_plan = 0xFF;