Chapter 10. Asterisk for the Über-Geek

The first ninety percent of the task takes ninety percent of the time, and the last ten percent takes the other ninety percent.

—The Ninety:Ten Rule

The toughest part of writing this book was not finding things to write about, but rather deciding what we would not be able to write about. Now that we’ve covered the basics, you are ready to be told the truth: we have not taught you anywhere near all that there is to know about Asterisk. Well, okay, perhaps five percent, but likely less.

Now please understand, this is not because we didn’t want to give you our very best; it’s merely because Asterisk is, well, limitless (or so we believe).

In this chapter, we want to give you a taste of some of the wonders Asterisk holds in store for you. Pretty nearly every section in this chapter could become a book in itself (and they will become books, if Asterisk succeeds in the way we think it is going to).


Festival is a popular open source text-to-speech engine. The basic premise of using Festival with Asterisk is that your dialplan can pass a body of text to Festival, which will then “speak” the text to the caller. Probably the most obvious use for Festival would be to have it read your email to you when you are on the road.

Getting Festival Set Up and Ready for Asterisk

There are currently two ways to use Festival with Asterisk. The first (and easiest) method—without having to patch and recompile Festival—is to add the following text to Festival’s configuration ...

Get Asterisk: The Future of Telephony now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.