Have you tried to press # from your phone? And if you hear another dial tone, then the connection to the wall jack (PSTN) might work, and try to dial a local number to see whether it works or not.
Additionally, make a call into that landline (PSTN) and see if your OBi rings or not?
Last to check, unplug the power to the OBi, and pick up the phone, if you hear dial tone, that means your connection to the landline is correct. There is a relay on the OBi that would force a direct connection from the phone to the landline when the power is not applied.