B.33. Echo()

Repeats incoming audio to the caller.
Echo()
Takes any incoming audio and returns it on the same channel. This application is used primarily for troubleshooting and testing of delay (latency) and sound quality on VoIP connections. The caller can end the call by pressing "#".
Returns 0 if the caller ends the call with "#" or -1 if the caller hangs up.
exten => 123,1,Echo()
exten => 123,n,Playback(vm-goodbye)

Note

Internal help for this application in Asterisk 1.4:
  -= Info about application 'Echo' =- 

[Synopsis]
Echo audio, video, or DTMF back to the calling party

[Description]
  Echo(): This application will echo any audio, video, or DTMF frames read from
the calling channel back to itself. If the DTMF digit '#' is received, the
application will exit.
diff output to internal help in Asterisk 1.2:
5c5
< Echo audio, video, or DTMF back to the calling party
---
> Echo audio read back to the user
8,10c8,10
<   Echo(): This application will echo any audio, video, or DTMF frames read from
< the calling channel back to itself. If the DTMF digit '#' is received, the
< application will exit.
---
>   Echo():  Echo audio read from channel back to the channel. 
> User can exit the application by either pressing the '#' key, 
> or hanging up.