Intel 05-2409-003 5.3.3 Handling Multiple Call Objects Per Channel in a Glare Condition

Global Call API for HMP on Windows Programming Guide — August 2006 83

Application Development Guidelines

In some applications, when xx_open() fun ctions (Global Call, Voice, Fax) are issued

asynchronously, it may cause slow device-initialization performance. Fortunately, you can avoid

this particular problem quite simply by reorganizing the way the application opens and then

configures devices. The recommendation is to do all xx_open( ) functions for all channels before

proceeding with the next function. For example, you would have one loop through the system

devices to do all the xx_open() functions first, and then start a second loop through the devices to

configure them, instead of doing one single loop where an xx_open( ) is immediately followed by

other API functions on the same device. With this method, by the time all xx_open() commands

are completed, the first channel will be initialized, so you won’t experience problems.

This change is not necessary for all applications, but if you experience poor initialization

performance, you can gain back speed by using this hint.

For ISDN protocols, the protocol to use is determined at board initialization time and not when

opening a Global Call device. Protocol parameters are configured in the CONFIG file before the

firmware is downloaded to the board. If a protocol is specified in the devicename parameter of the

gc_OpenEx( ) function when opening a device, it is ignored.

For T1/E1 CAS/R2MF protocols, the protocol to use for a trunk is selected using the “Trunk

Configurator” feature of the configuration manager (DCM). Protocol files are provided with the

system software in the \data directory under the Dialogic home directory. A protocol can be

configured by changing the parameter values in the corresponding Country Dependent Parameter

(CDP) file located in the \data directory. See the Global Call Country Dependent Parameters

(CDP) for PDK Protocols Configuration Guide for details on the parameters that can be changed

for each protocol. If a protocol is specified in the devicename parameter of the gc_OpenEx( )

function when opening a device, it is ignored.

5.3.3 Handling Multiple Call Objects Per Channel in a Glare Condition

When using Digital Network Interface boards, Global Call supports the handling of multiple call

objects per channel in a glare condition. An application running on bi-directional circuits is capable

of handling two CRNs on a single line device, where one call can be in an Idle state, while the other

call is in Active state. For example, a glare condition occurs when a call has been dropped but not

released and an inbound call is detected as indicated in Table10. In order to avoid a long delay in

processing the inbound call, the Global Call library does not wait for the outbound call to be

released before notifying the application of the inbound call.

Table10. Handling Glare

Application Global Call Library

gc_MakeCall(CRN1) -->

<-- GCEV_DISCONNECTED(CRN1)

gc_DropCall(CRN1) -->