Inside Macintosh: Telephony /

Chapter 5 - Telephone Manager Messages

About Telephone Manager Messages

The Telephone Manager sends messages to your application when terminal, directory number, and call appearance activities occur. These messages are originated by telephone tools, which send them to the Telephone Manager. For example, when a telephone tool detects an incoming call appearance, it sends a telCAAlertingMsg message to the Telephone Manager, which then relays that message to your application. Because there is a standard set of messages used by all telephone tools, using the Telephone Manager ensures that your application will work with a variety of telephone terminals.

In order to process messages passed by the Telephone Manager, you must create one or more message handlers. For each category of messages (terminal, directory number, and call appearance), you register one or more message handlers with the Telephone Manager. For each message handler, you specify which messages you want to receive. After you're through processing messages (or when you want to modify the list of messages to be received), you must deactivate your message handler.

Telephone tools send messages at interrupt time, but the Telephone Manager calls your message handler at system task time for all messages except the digits immediate message (telCADigitsImmMsg).