OBi202 suddenly started ringing and showed 3 digits no one on other line. Even when I pulled out cord and had it self start after a short while the rings started again need to disconnect device
Unless you have a good reason, don't use Port Forwarding or DMZ in your router.
If above doesn't help, see:
http://www.obitalk.com/forum/index.php?topic=13870.msg89095#msg89095