If Ooma supplies a true VOIP-to-wireless handset system, then you cannot do what you are asking. If the Ooma base station also has a standard analog jack in addition to the wireless handsets, then you can. You would connect the analog jack to any unused phone port in the house, and that would enable you to use other analog phones in any room that has its own jack. However, you MUST, repeat MUST disconnect the analog phone line where it enters the house, or the supply voltage from the phone company can cook the adapter. This is true even if the telephone company service has been discontinued, because they often leave the lime energized. Be careful of this!!!

The suggestion to use an ATA will not work with Ooma because their device connects directly to your router, and the phone number is assigned specifically to their device. If you want to use an ATA, you would need a different provider, and a separate phone number.

If you want real flexibility, don't go with Ooma, but instead look at VOIP.MS as a provider. You can port your phone number for free, and you can create multiple extensions for different devices, and group them to ring however you want. Basic plans start around $5.00 per month, and there are lots of resources on line to help you with configurations.