exten => s,n,Dial(IAX2/provider1/1${ARG1}|100|t)
exten => s,n,GotoIf($["${DIALSTATUS}"="ANSWERED"||"${DIALSTATUS}" = "BUSY"||"${DIALSTATUS}" = "NOANSWER"]?end)
exten => s,n,Dial(IAX2/provider2/1${ARG1}|100|t)
exten => s,n,GotoIf($["${DIALSTATUS}"="ANSWERED"||"${DIALSTATUS}" = "BUSY"||"${DIALSTATUS}" = "NOANSWER"]?end)
exten => s,n,Dial(IAX2/provider3/1${ARG1}|100|t)
exten => s,n,GotoIf($["${DIALSTATUS}"="ANSWERED"||"${DIALSTATUS}" = "BUSY"||"${DIALSTATUS}" = "NOANSWER"]?end)

exten => s,n,NoOp(Call could not be completed through any trunk)
exten => s,n,Goto(s-${DIALSTATUS},1)