If you have a native GV definition on the OBi100 SP1 or when the GVGW stops working, replace it with this definition:
Service Providers -> ITSP Profile A -> SIP -> ProxyServer: 127.0.0.1
Voice Services -> SP1 Service -> AuthUserName: OBi100
Voice Services -> SP1 Service -> X_RegisterEnable: (unchecked)
If SP4 is open on the OBi200, define a dummy trunk:
Service Providers -> ITSP Profile D -> SIP -> ProxyServer: 127.0.0.1
Service Providers -> ITSP Profile D -> SIP -> X_SpoofCallerID: Checked
Voice Services -> SP4 Service -> X_ServProvProfile: D
Voice Services -> SP4 Service -> AuthUserName: OBi200
Voice Services -> SP4 Service -> X_RegisterEnable: (unchecked)
You will have audio problems when routing calls to another OBi device and the receiving SP trunk is registered to a provider. That is why I unregister those trunks. If you need the trunk registered, making the following change on the receiving trunk will fix the problem:
Service Providers -> ITSP Profile ? -> SIP -> X_DiscoverPublicAddress: unchecked
Edit:
Blocking SIP scanners might also block calls between the 2 OBi devices.
If you have an OBi202 running in router mode, you might need changes to your network.
Edit2:
I found a couple typos and corrected them. Hopefully, I didn't make any more errors.