!Connect your old AT&T-Lucent-Avaya Definity to an ITSP
!This example uses ITSP voip.ms
!
version 15.7
!
hostname c2901
!
card type t1 0 0
!
network-clock-participate wic 0 
network-clock-select 1 T1 0/0/0
!
no ip domain lookup
!
isdn switch-type primary-ni
!
voice service voip
 ip address trusted list
  ipv4 <voip.ms-reg-server>
 allow-connections sip to sip
!
voice class codec 1
 codec preference 1 g711ulaw
!
hw-module pvdm 0/0
!
username cisco privilege 15 password 0 cisco
!
controller T1 0/0/0
 cablelength short 110
 pri-group timeslots 1-15,24
!
interface GigabitEthernet0/0
 ip address 172.16.0.100 255.255.0.0
 duplex auto
 speed auto
!
interface Serial0/0/0:23
 no ip address
 encapsulation hdlc
 no cdp enable
 isdn switch-type primary-ni
 isdn protocol-emulate network
 isdn incoming-voice voice
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
ip nat inside source static 172.16.0.100 <my-public-ip>
ip route 0.0.0.0 0.0.0.0 172.16.0.1
!
voice-port 0/0/0:23
!
dial-peer voice 1 pots
 destination-pattern [2-9]..[2-9]......
 port 0/0/0:23
 forward-digits all
 no sip-register
!
dial-peer voice 2 pots
 incoming called-number .
 direct-inward-dial
 port 0/0/0:23
 no sip-register
!
dial-peer voice 3 voip
 destination-pattern 1[2-9]..[2-9]......
 session protocol sipv2
 session target sip-server
 voice-class codec 1  
 no vad
!
dial-peer voice 4 voip
 session protocol sipv2
 incoming called-number .
 voice-class codec 1  
 no vad
!
sip-ua 
 credentials username <voip.ms-account> password <passwd> realm <voip.ms-reg-server>
 authentication username <voip.ms-account> password <passwd> realm <voip.ms-reg-server>
 registrar ipv4:<voip.ms-reg-server> expires 300
 sip-server ipv4:<voip.ms-reg-server>
!
line vty 0 4
 exec-timeout 120 0
 privilege level 15
 login local
 transport input telnet
!
scheduler allocate 20000 1000
ntp server 205.233.73.201
!
end