Yes, I canceled my phone service with Comcast. I still used my AT&T base unit with 3 other wireless phones. It works perfect. That was one of my concerns also. I thought I might have to buy some VOIP phones. Not so.
I tried using the wi-fi connection with the Ooma 2 but I didn’t like the connection. It’s been almost a year so I can’t recall how bad it was but I connected my router to the Ooma using an Ethernet cable and it works great. So all you need to do is then connect your phone to the Ooma 2 using a phone cable. Follow the setup procedures. I moved my original phone number to my new Ooma service. It took about a week so don’t cancel your phone service until it switches over. I hope this helps.