Dialogic 6.2 manual Making an Isdn Outgoing Call, November 321

ISDN Call Processing Overview

Making an ISDN Outgoing Call

A typical outgoing ISDN call is illustrated in Figure 49. In this call scenario, the module is making an outgoing call. During an outgoing call, if the phone number is more than 20 digits long, the application automatically sends the number using overlapped dialing (See ISDN Overlapped Dialing on page 323 for more information). The following message exchange is relative to the module:

1.The host initiates an outgoing call by sending an L4L3mCALL_ REQUEST message to the module; this message must contain information about the call (calling party and called party numbers, and so on).

2.Upon receipt of the L4L3mCALL_REQUEST message, the module issues a SETUP message to the network; this message must contain information about the call (calling party and called party numbers, and so on).

3.The network responds to the SETUP with a CALL PROCEEDING message indicating the call request is being processed.

4.Following the CALL PROCEEDING, the network sends an ALERTING message indicating the called party is ringing.

5.Upon receipt of the ALERTING message, the module generates an L3L4mALERTING message to the host.

6.The network then sends a CONNECT message to the module indicating it is connecting the call.

7.The module generates two messages upon receipt of the

CONNECT.

ŠL3L4mCONNECT message to the host; the host can consider the call connected at this point

ŠCONNECT ACKNOWLEDGE message to the network indicating the CONNECT message has been acknowledged

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