Very helpful advice - thanks again.

The bottom line is, as I expected, that I must not have the VOIPO box connected to my home's telco wiring if the telco wiring is also connected to the ONT box. So that means I need to disconnect the ONT from my home telco wiring somehow or other.

My guess is Verizon is not going not be too willing to send a guy out here to do that. What I'll probably do instead is just take the cover off the ONT and disconnect the telco wire myself. I was here when the ONT was installed a number of years ago and as I recall it's pretty obvious what connections do what. So it should not be a big deal to take out the appropriate connection.

So now I have to call Verizon and find out what happens when I request cancelling my phone service. That should be a fun conversation.

Thanks again for all your help on this. I wonder why VOIPO doesn't put up some web pages that details stuff like this; my guess is there are lots of people out there who will be switching from major carriers and I don't think my situation is all that unique.