[incoming]
exten => s,1,Answer( )
exten => s,2,Background(enter-ext-of-person)
exten => s,3,Set(TIMEOUT(digit)=3)
exten => s,4,Set(TIMEOUT(response)=15)

exten => i,1,Playback(pbx-invalid)
exten => i,2,Goto(s,1)

exten => t,1,Playback(vm-goodbye)
exten => t,2,Hangup( )

include => internal