[root@www asterisk]# cat extensions.conf
[general]

static=yes       ; These two lines prevent the command-line interface
writeprotect=yes ; from overwriting the config file. Leave them here.

[default]

exten => _2XXX,1,Dial(SIP/${EXTEN},20)
exten => _2XXX,2,Voicemail(u${EXTEN})
exten => _2XXX,102,Voicemail(b${EXTEN})
exten => _2XXX,103,Hangup

exten => 2999,1,VoicemailMain(${CALLERIDNUM})

include => dualtalk
include => to-fwd
include => special
include => international

[dualtalk]

exten => _11XXXX,1,Dial(SIP/${EXTEN},20)
exten => _11XXXX,2,Voicemail(u${EXTEN})
exten => _11XXXX,102,Voicemail(b${EXTEN})
exten => _11XXXX,103,Hangup

[fromfwd-111790]
exten => 414197,1,Dial(SIP/111790,30,Tt) 
exten => 414197,2,Voicemail(u111790) 
exten => 414197,3,Hangup 
exten => 414197,102,Voicemail(b111790) 
exten => 414197,103,Hangup 

[to-fwd]
exten => _7.,1,SetVar(THECALLER=${CALLERIDNUM})
exten => _7.,2,DBGet(FWDUSERID1=FWDUSERID/${CALLERIDNUM})
exten => _7.,3,SetCIDNum(${FWDUSERID1})
exten => _7.,4,DBGet(FWDUSERID1=FWDUSERNAME/${CALLERIDNUM}) 
exten => _7.,5,SetCIDName(${FWDUSERNAME1})
exten => _7.,6,Dial(SIP/${EXTEN:1}@fwd-${THECALLER})
exten => _7.,7,Playback(invalid)
exten => _7.,8,Hangup

[special]
exten => _0018.,1,Dial(SIP/*${EXTEN:2}@fwd-111790) ;usa

[international]
exten => _00.,1,Dial(SIP/${CALLERIDNUM}${EXTEN:2}@dualtalk)