<p>Asterisk is a powerful and flexible open source framework for building feature-rich telephony systems. As a Private Branch Exchange (PBX) which connects one or more telephones, and usually connects to one or more telephone lines, Asterisk offers very advanced features, including station-to-station calls, line trunking, call distribution, call detail rerecords, and call recording.<br /> <br /> Asterisk can be used to provide Interactive Voice Response (IVR). The power and flexibility of a programmable phone system gives us the ability to respond to our customers in meaningful ways. <br /> <br /> Asterisk has also a fully-functional voicemail system included. It supports voicemail contexts so that multiple organizations can be hosted from the same server.&nbsp; It supports different time zones so that users can track when their phone calls come in.&nbsp; It even provides the option to notify the recipient of new messages via email.&nbsp; In fact, we can even attach the message in audio!<br /> <br /> Finally, Asterisk is a Voice Over IP (VoIP) system. The benefits of VoIP are numerous. For instance, we can have multiple users using the same Asterisk service from a variety of locations; we can have users in the local office using PSTN phones or IP phones; we can have remote VoIP users; we can even have entire Asterisk systems operated and run completely separately but with integrated routing; We can have an extension anywhere we have a reasonably fast Internet connection, which means employees can have an extension on the phone system at home if they have a broadband connection. The benefits are too many to list.<br /> <br /> Flexibility often means complexity, and this is true in the case of Asterisk. This book is all you need to understand and use Asterisk to build the telephony system that meets your need. You will learn how to use the many features that Asterisk provides you with.</p>