Do not use the phone. As in all disasters, the lines will probably be tied up. One more call only contributes to clogging the system. Keep the ringer on the lowest setting (or vibrate). If a call does come through, by all means answer it, but do so quietly. Plan an alternate escape. you may be safe from zombies but not from fire. If a gas line bursts, or some fool down the street goes crazy with a Molotov, you may have to abandon your home. Find a bag or other means of carrying essentials and keep it at the ready.