I use my ObiHai 110 with GV. Everything works well except DTMF signaling.
If I use factory defaults, I can interact with GV voice mail; for example, pressing 7 during listening to voice mail will archive it, pressing 0 will go to "more options" etc. However I seem to have trouble with dialing into conference calls or use international calling cards where you have to punch in a lot of digits. It seems like some digits are lost or duplicated.
If I customize it as suggested in other threads (Service Providers > ITSP Profile X > General > X_UseFixedDurationRFC2833DTMF: Checked, Service Providers > ITSP Profile X > General > DTMFMethod = InBand, Physical Interfaces > PHONE Port > Port Settings > ChannelRxGain = 5), I can dial into conference calls or use my international calling cards with ease. But every interaction with GV ceases to be working. i.e. pressing 7 or 9 or 0 during listening to voice message does nothing.
I want an ideal DTMF setting where both the above scenario would work. I should not be made to choose between the two as both functionalities are of equal importance to me.