All the OBi ATAs have 8 Voice Gateway accounts that can be used to set up other providers that allows outgoing calls without registration. This Voice Gateway cannot accept incoming calls, only outgoing!
said by sofakng3:
That sounds similar to what I'm thinking as well...
...but how is she using three providers with the OBi110? (GV, Anveo, and CallCentric?) I think it only supports 2 providers.