From a coding point of view, the UA is constructed from classes and threads.
Here is a look at some of the classes behind the VOCAL UA . These classes can be easily divided into base classes and event classes, as shown in the following diagrams. Figure 10-3 shows the UA classes.
The classes in the gray shading are base classes. Here are descriptions of the event classes:
Works with the hardware devices such as the sound card.
Receives digit input while the user is dialing and processes the digits according to the dialing plan.
The main thread that executes the state machine.
Tracks statistics when the UA is being run in Load Generation mode. This is used for bulk testing to make large numbers of calls.
Used for testing when neither a sound card nor a Quicknet card is available.
A device thread that works with Quicknet cards (http://www.quicknet.com).
Figure 10-3. UA class diagram
Keeps track of the UA’s registration with the network and its expiry.
Residential Gateway Device, a base class. Anything that was a UA that did audio would need to deal with certain operations. We derive certain devices from that, such as the Quicknet card and sound card, or if there is nothing, we derive the NullHardware class. If you have ...