The Answer application
Consider the dialplan we’ve used in the previous section:
exten => 999,1,Answer() same => n,Playback(this-call-may-be-monitored-or-recorded) same => n,Hangup()
In the first line of the dialplan we are using the Answer application (exten => 999,1,Answer()). The purpose of this application is to answer a channel that is ringing, which does the initial setup for the channel. It is recommended that the channel be answered before executing any other applications.