I feel products like this - http://www.vtechphones.com/products/product_detail/1673 - (just an example) are a better solution to this problem. You dont need a land line subscription, just a cell phone with bluetooth. When my parents get home, their cell phones pair to the home phone, so when they receive a call, the home phone rings. They don't have to carry around cell phones, and they can place calls through their cell phones using the handsets. Seems complicated at first, but saved headache and $$ in the end.