The dialplan is the heart of your Asterisk system. It defines how calls flow into and out of the system. A form of scripting language, the dialplan contains instructions that Asterisk follows in response to external triggers. In contrast to traditional phone systems, Asterisk’s dialplan is fully customizable.

This chapter introduces the essential concepts of the dialplan. The information presented here is critical to your understanding of dialplan code and will form the basis of any dialplan you write. The examples have been designed to build upon one another, and we recommend that you do not skip too much of this chapter, since it is so fundamentally important to Asterisk. Please also note that this chapter is by no means an exhaustive survey of all the possible things dialplans can do; our aim is to cover just the essentials. We’ll cover more advanced dialplan topics in later chapters. You are encouraged to experiment.