Billion BiPAC 74xx series Quick Install Manual page 5

5) On the 'General Settings' page you will need to enable SIP if it is not already enabled, and input the
settings as shown below. Usually the only field you will need to complete is the Registrar Address
field (in this case: sip.voipuser.org). Scroll down and click on 'Apply' at the bottom.
6) Next click on 'Phone Port' on the left hand side menu bar.