I have a specialty "softphone" that I have that makes VoIP calls to a "SIP compatible VoIP internet account or PBX". It's working just fine using Callcentric. The issue I have is when my Internet connection fails it can no longer make calls. I need something that will fail-over to the PSTN. I would even be okay if it gave preference to the PSTN.
So can the OBi212 do the job? I know I can set it up to use Callcentric, but how would I get it to allow a local "softphone" to connect to it and make VoIP, or just PSTN, calls? I've attached a diagram of how I was thinking of connecting things.