I'd like to get some kind of very brief sound or whisper to let me know the outbound voip "line" is being used. My Obi110 was falling back to the PSTN line because the Obi's power got unplugged. By the time I noticed, I'd spent too many $$$ making calls at Verizon's full rates. I realize there'd be no whisper if the Obi were powered off, but I'd notice something was missing.
Alternately, maybe some kind of modification to the Obi's dialtone so I can tell when it's alive, though that might not work for some people if their phone's autodialer mutes audio during dialing.
You can change the default dialtone for the OBi at:
Tone Settings -> Tone Profile A -> Dial Tone -> TonePattern
Page 95 of the OBi Device Administration Guide describes the format.
For example, changing the default value from 350-18,440-18;20 to 300-18,440-18;20 makes a recognizably different dialtone. With a little experimentation, you should be able to come up with something you like that lets you know you're hearing OBi dialtone vs PSTN dialtone.