[app]
; Unconditional Call Forward
exten => *21*X.,1,DBput(CFIM/${CALLERIDNUM}=${EXTEN:4})
exten => *21*X.,2,Hangup
exten => #21#,1,DBdel(CFIM/${CALLERIDNUM})
exten => #21#,2,Hangup

; Call Forward on Busy or Unavailable
exten => _*61*X.,1,DBput(CFBS/${CALLERIDNUM}=$EXTEN:4})
exten => _*61*X.,2,Hangup
exten => #61#,1,DBdel(CFBS/${CALLERIDNUM})
exten => #61#,2,Hangup