Intel IP Gateway (Global Call) for Linux and Windows ユーザーズマニュアル

Once the destination gateway has answered the H.323 call, the IP Gateway
(Global Call) demo connects the PSTN call to the IP call. An audio path is now
established between the PSTN call and the destination IP station. For more details
see section 6.5.  Event Mechanism .

A call that arrives from the IP network needs to be routed to a PSTN number.
That number may arrive as part of the call establishment procedure (if the call
was originated by another IP Gateway for example). If the destination number
arrived during call establishment, then the IP Gateway (Global Call) demo uses
that number to call the PSTN. If no destination number was included in the call
establishment procedure, then the IP Gateway (Global Call) demo uses the
gateway_r4.cfg file to determine the destination number to call (local phone
number). Once the IP Gateway (Global Call) demo answers and connects the call
on the IP network, it initiates (dial out) a call on the PSTN line and connects the
two calls. This allows the calling party to hear the call progress tones on the local
PSTN. For more details see section 6.5.  Event Mechanism .

The IP Gateway (Global Call) Object Oriented demo operates with two threads,
as shown in Figure 4.

Keyboard

Main Thread

SRL

Sub-Thread

IP

R4/GC