exten=> 701,s,Dial(SIP/gf,15)
exten => t,1,Goto(s-${DIALSTATUS},1)

exten => s-NOANSWER,1,Playing(vm-rec-busy)
exten => s-NOANSWER,2,Hangup()

exten => s-BUSY,1,Playing(tt-allbusy); play caller is busy talking to someone else
exten => s-BUSY,2,Hangup()

exten => s-CHANUNAVAIL,1,Dial(SIP/070232333@outgoing-isp,30,r) ;dial this number if gf's sip phone does not ring
exten => s-CHANUNAVAIL,2,Hangup()

exten => _s-.,1,Hangup()