=========== sip.conf ============

[pstn] ; this is the PSTN bit on SPA 3000
type=friend
host=dynamic
secret=foo
call-limit=2
disallow=all
allow=ulaw
allow=alaw
allow=g729
allow=gsm
context=incoming

[05] ; this is the sip client on SPA 3000
type=friend
username=05
secret=secret
host=dynamic
mailbox=05
context=intern
canreinvite=yes
dtmfmode=rfc2833
nat=yes
accountcode=fserto


===========  extensions.conf ===============
[incoming]
;include => local

exten => s,1,Dial(SIP/05,30,rtT)
exten => s,2,Voicemail(u05)
exten => s,n,Hangup()

[outgoing]
exten => 000,1,Dial(SIP/000@engin,60,rtT)
exten => 000,2,Dial(SIP/000@pstn,60,rtT)

exten => _XXX.,1,Dial(SIP/${EXTEN}@engin,60,rtT)
exten => _XXX.,2,Dial(SIP/${EXTEN}@pstn,60,rtT)

[intern]
include => outgoing
include => local

[local]
exten => 05,1,Dial(SIP/05,30,rt)
exten => 05,2,Voicemail(u05)
exten => 05,4,Hangup
exten => 05,102,Voicemail(u05)
exten => 05,103,Hangup