exten => 657,1,Answer
exten => 657,2,Playback(transfer)       ; some dummy voice
exten => 657,3,Wait(1)
exten => 657,4,Hangup
exten => h,1,Wait(3)
exten => h,2,Dial(SIP/mobile)
exten => H,1,Wait(3)
exten => H,2,Dial(SIP/mobile)