How to Make an Echo Test in Asterisk (Echo() Application)

Question: How do I make an echo test in Asterisk?
Answer: to play back what the caller says (the echo), Asterisk has the Echo() application.

Echo() plays what the caller says back into the channel.

Return codes
0 — the user left by pressing the ‘#’ key;
-1 — the user hung up.

Attach the echo test to extension 600

Add this to extensions.conf:

; Create extension 600 to test the echo delay.
exten => 600,1,Playback(demo-echotest) ; Greeting
exten => 600,2,Echo ; Run the echo test
exten => 600,3,Playback(demo-echodone) ; Say that the test is finished

Then reload the dialplan so the new extension is picked up:

asterisk -rx "dialplan reload"

Dial 600 from any phone: you will hear the greeting, then your own voice with a slight delay — a quick way to check call delay and audio quality.