[incoming]
exten => s,1,Answer
exten => s,2,DigitTimeout,5
exten => s,3,ResponseTimeout,10
exten => s,4,PlayTones(ring)

exten => t,1,Dial(SIP/1000,15,r)
exten => t,2,Hangup

exten => 2,1,Dial(SIP/1002,15,r)
exten => 2,2,Hangup