You don't need to register your OBi110 to OBiTalk and I recommend that you don't.
Connect the OBi110 to your router, connect the Line port to your landline and connect a phone to the Phone port. Make sure everything is connected correctly by placing a call from the phone connected to the OBi110. Does it work?
You need to know the IP address of the OBi110. Dial ***1 from the phone attached to the OBi110 and it will say the IP address.
Key the IP address into a browser and press Enter.
The OBi110 username and password are both admin
To make a configuration change, the box to the right of the value must be unchecked.
Service Providers -> ITSP Profile A -> SIP
Click Service Providers on the left column then ITSP Profile A then SIP
Make the following config changes:
ProxyServer:
callcentric.comRegistrationPeriod: 1800
Click Submit at the bottom of the page.
Voice Services -> SP1 Service
X_InboundCallRoute: {>1777xxxxxxx:aa}
AuthUserName: 1777xxxxxxx
AuthPassword: your_callcentric_pw
Replace 1777xxxxxxx with your Callcentric account number
Submit
Click Reboot on the top right.
Wait for the OBi110 to reboot.
Status -> System Status
Scroll down to SP1
It should show Registered
Dial 100 from your mobile app
You should get connected to the OBi110's Auto Attendant
After the Prompt, enter 2 for make a new call
After the 2nd prompt enter a number followed by a #
Does it work?