The dialplan is the heart of Asterisk, and everything it does begins here.

Two important files in /etc/asterisk make up the dialplan in 1.4. The first is extensions.conf, which uses the original and still recommended priority model; the second is extensions.ael, which uses the newer Asterisk Extensions Language; we'll look at that in more detail in a separate chapter. For now, we'll use the traditional priority model, since even in 1.4, extensions.ael is converted into priority format and added to extensions.conf when Asterisk is started.