If it is DSL, your phone line should still be coming from a local CO or terminal that has backup power. If you lose power at your residence, sure the modem may go down, but your POTS line should still function as you should still have -48VDC on it.
Thank you and Hi, the phone part of the equasion is why I would be looking for the back up as I have done away with the POTS and now have VoIP so it would end up being back up for the phones them selves until the power came back on thank you for your response.
