Simply dial 911, same as ever! This means your emergency calls will be routed over the Internet with whatever service address and phone number you've registered with Ooma. For this reason, we urge customers to keep contact information up to date. If you're using your Ooma system with a landline back-up, your 911 calls will be routed over through your landline provider, same as ever. Just pick up the phone and dial. If Internet service is unavailable, non-landline customers will need to call from a mobile or working phone.