I asked this question because a friend was telling me she had some wind damage earlier this winter, and a tree came down on her phone line, ripping it completely loose from her house. The power was already out. Her cell phone had had an unfortunate 'death by toilet' due to a toddler who is big on flushing. She knew her immediate neighbors only had electronic phones, but they did have useful phone jacks.
Sue
In that case, sure, I have a POTS phone sitting around. I just don't have the service. Any old POTS phone will work with my Vonage device.