1. Create a user and create add a "Phone" without any phone information to create a "Phone" profile to edit which will provide the following information
2. Remote or log into the Sumowifi/Calix router admin
3. On left bar, locate the path: Support > Voice > VoIP Gateway Settings and enter/choose the following
a) Select Protocol: SIP
b) Select WAN Interface: wan
c) Enter Primary Proxy Server: (from whatever is listed as "Outbound Proxy" from PBX softphone credentials)
d) Enable "Options Timer".
UPDATED DO NOT ENABLE OPTIONS TIMER
e) Enter in Domain: (the domain name listed in "Domain/Proxy" from PBX softphone credentials)
4. On left bar, locate the path: Support > Voice > Line Features and enter/choose the following:
a) Select Line: Choose line 1 (choose line 2 after if enabling both ports)
b) Select VoIP Profile: Voice_Profile_Default (or a different name if renamed)
c) Enter the username and password as listed on PBX softphone credentials
d) Enable Msg Waiting Indicator
5. Save all configurations and reboot the router/voice port and it should be registered.