exten => s,d3+101,SetCDRUserfield(${ARG2})
exten => s,n,GotoIf($[${LEN(${ARG3})}]?final:)
exten => s,n,SetVar(ARG3=IAX2/netmonks@thinktel/7)
exten => s,n(final),Dial(${ARG3}${ARG1})