Question

I have an example asterisk dial plan below.It just the main (no extension or start) and it has 3 priorities.In the first priority of our extension, we’ll answer the call. In the second, we’ll play a sound file named hello-world.gsm, and in the third we’ll hang up the call

One example on the web seem to suggest the below format

[incoming]
exten => s,1,Answer()
exten => s,n,Playback(hello-world)
exten => s,n,Hangup()

instead of

[incoming]
exten => s,1,Answer()
exten => s,2,Playback(hello-world)
exten => s,3,Hangup()

why is that? what exactly is a priority ? and what does ‘n’ signify

Answer 1

Asterisk executes each priority in numerical order,
and like in BASIC, you can jump to those Priorities with Goto.

Since Asterisk 1.2 you have the ability to use the n priority.

The n priority adds 1 to the previous Prioritiy.

That makes you more flexible, you could add a Line, without the need to care about the Priorities.

Another Benefit of the n priority is that you can use the n Priority with optional Labels and jump to that Label, instead of messing arround with the priorities Counter.

[incoming]
exten => s,1,Answer()
exten => s,n(Start),Background(hello-world)
exten => s,n,Goto(Start)
exten => s,n,Hangup()

See GotoIf for more examples.