Wanted to share this ....was getting phantom calls all day and at night -urghhh
this is what fixed my problem
Change the config on the Obi100:
Voice Service->SP1 Service->X_InboundCallRoute
{(?|x|xx|xxx|xxxx|xxxxx|xxxxxx|un@@.|anon@@.):},{(x.):ph}
This will block calls that have no caller id, numeric calls less than 7 digits, unknown number calls, anonymous calls, and any non-numeric calls.