exten => _1NXXNXXXXXX,1,SetCallerID(6045823333)
exten => _1NXXNXXXXXX,2,NoOp(IAX2/secret@sixtel/${EXTEN}) 
exten => _1NXXNXXXXXX,3,Dial(IAX2/secret@sixtel/${EXTEN}) 
exten => _91NXXNXXXXXX,104,Dial(${LOCALTRUNK}/${EXTEN:1})


Should be:


exten => _1NXXNXXXXXX,1,SetCallerID(6045823333); Sets caller Id
exten => _1NXXNXXXXXX,2,NoOp(IAX2/secret@sixtel/${EXTEN}) 
exten => _1NXXNXXXXXX,3,Dial(IAX2/secret@sixtel/${EXTEN}) 
exten => _1NXXNXXXXXX,104,Dial(${LOCALTRUNK}/${EXTEN:1})