[default]
exten => _91NXXNXXXXXX,1,Macro(callerid-fixup,5042743301)
exten => _91NXXNXXXXXX,2,Dial(Zap/g1/${EXTEN:1})

exten => 2101,1,Macro(callerid-fixup)
exten => 2101,2,Dial(SIP/2101)

[macro-callerid-fixup]
;
; This macro assumes the following:
;   Extensions without a DID number have a CallerID number that is 4 digits
;   Extensions with a DID number have their CallerID number set to their 10 digit DID
;   The last 4 digits of a DID number is the same as the extension number
;
; This macro does the following if it is called without any parameters:
;   If the Caller*ID number is 4 digits, do nothing
;   If the Caller*ID number is not 4 digits, strip off the first 6 digits
;
; This macro does the following if it is called with a parameter
;   If the Caller*ID number is 4 digits, reset the Caller*ID number to be the value of the parameter
;   If the Caller*ID number is not 4 digits, do nothing
;
exten => s,1,NoOp(Entering Macro "callerid-fixup")
exten => s,2,NoOp(Variable CALLERIDNUM is equal to ${CALLERIDNUM})
exten => s,3,GoToIf($["${ARG1}" != ""]?external,1)
exten => s,4,GoToIf($["${ARG1}" = ""]?internal,1)
                                                                                                                              
exten => internal,1,GoToIf($[${LEN(${CALLERIDNUM})} = 4]?e,1)
exten => internal,2,SetCIDNum(${CALLERIDNUM:6})
exten => internal,3,GoTo(e,1)
                                                                                                                              
exten => external,1,GoToIf($[${LEN(${CALLERIDNUM})} = 4]?e,1)
exten => external,2,SetCIDNum(${ARG1},a)
exten => external,3,GoTo(e,1)
                                                                                                                              
exten => e,1,NoOp(Variable CALLERIDNUM is equal to ${CALLERIDNUM})
exten => e,2,NoOp(Leaving Macro "callerid-fixup")