I have configured my Obi110 to work with Google Voice. If I don't answer an incoming call with 4-5 rings, the call rolls over to Google Voicemail. The same thing happens on an incoming call while the phone on the Obi110 is in use.
Is there any way to disable Google Voicemail? Can you adjust the number of rings before the call rolls over to voicemail? Is there any way to have the caller hear a busy signal when the Obi110 phone is in use?
It looks like there is no way to turn off the GoogleVoice voicemail if you don't answer the phone.
Perhaps something you might want to ask Google?
Check this out:
http://michigantelephone.wordpress.com/2010/10/21/how-to-stop-people-from-leaving-messages-in-your-google-voice-voicemail-box/
:)