call transfer or call forwarding in asterisk

call transfer or call forwarding in asterisk

[test]
exten => 1000,1,Dial(SIP/User1)
exten => 1000,n,Hangup()

exten => 2000,1,Dial(SIP/User2)
exten => 2000,n,Hangup()

exten => 3000,1,Dial(SIP/User3)
exten => 3000,n,Hangup()

;call forwarding
exten => _*21*X.,1,NoCDR
exten => _*21*X.,2,Set(DB(CFIM/${CALLERID(NUM)}=${EXTEN:4})
exten => _*21*X.,3,Playback(vm-saved)
exten => _*21*X.,4,Hangup()