Вот Вам рабочий конфиг, немного под-редактируйте, и все заработает.
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voice rtp send-recvvoice class codec 1
codec preference 1 g729r8
codec preference 2 g729br8
codec preference 3 g726r32
codec preference 4 g726r24
codec preference 5 g726r16
codec preference 6 g723r53
codec preference 7 g723ar53
codec preference 8 g723ar63
codec preference 9 g711alaw
codec preference 10 g711ulaw
application
service dsapp param
param callWaiting TRUE
voice-port ????
cptone ES
caller-id alerting pre-ring
dial-peer voice (SIP_ID) voip
service session
destination-pattern ????????
voice-class codec 1
session protocol sipv2
session target dns:sipnet.ru
session transport udp
dtmf-relay rtp-nte
!
dial-peer voice 1 pots
answer-address (SIP_ID)
destination-pattern ????????
port 1
sip-ua
authentication username (SIP_ID) password ??????????
nat symmetric check-media-src
max-forwards 10
registrar dns:sipnet.ru:5060 expires 3600
sip-server dns:sipnet.ru
no suspend-resume
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С Уважением Андрей.
sip:220000@lviv-ua.com