Even though I have an AT&T landline I activated my ooma without the landline integration and I got the temporary phone #. I connected the ooma hub to the wall jack in one room and I plugged in the scout to the wall jack in the other room. I was kind of surprised to see that everything works perfect even though I left a regular phone attached to the wall jack in the third room. We don't have separate wiring, all the phone jacks are connected to the same landline. So I wanted to push the envelope further so I put a splitter to the wall jack, attached scout to one port and another regular phone to the second port. It works! I can even call ooma from that regular phone and pick up the call from phone attached to scout.
Is this configuration sustainable? Is ti some kind of undocumented feature that may not be supported in the future? I like this configuration and I'd liek to keep it as it is. Again, I activated ooma without the landline integration.
In my case my scout worked fine in the other room, but as soon as I connected a second scout next to the hub, the scout in the other room went red. It wasn't until I removed the landline from the picture did all Scouts go blue.
Like we all say here in the forum, Your Mileage May Very.