exten => s,n,GotoIf($["${CALLERID(num)}" = ""]?fix:ok)
exten => s,n(fix),NoOP(FIXING EMPTY CALLERID)
exten => s,n,Set(CALLERID(num)=00000000000)
exten => s,n(ok),MixMonitor(incoming_to_${EXTEN}_from_${CALLERID(num)}_on_${STRFTIME(${EPOCH},,%Y%m%d-%H%M%S)}CET.wav)
exten => s,n,Macro(stdexten,${EXTEN},SCCP/${EXTEN})
exten => s,n,StopMonitor
exten => s,n,Hangup()