General overview

The event system is the nerve center of FreeSWITCH, allowing both internal and external software to subscribe to a stream of activity happening inside the switching system. In FreeSWITCH, almost everything that happens generates (or "fires") an event. Receiving a new phone call results in an event. Ending a call results in an event. Committing a log entry to disk results in an event. Even speaking or going silent can generate an event. Each event becomes part of an event stream, tagged with an event type, event category, and various other details about the event. Other pieces of software can then listen for these events and act on them in any way they wish, such as streaming them to you via a TCP socket connection in plain text.

Events provide yet another way to extend functionality within FreeSWITCH. Events are different from hooks or modules (which can affect the actual processing and handling of calls in real-time). Events provide an asynchronous (or non-blocking/queued...