For many people, a Voice over IP (VoIP) service is a good substitute for a fixed telephone line, especially if you have reasonable mobile phone coverage. However, it will not operate during a power cut – unless all of your equipment is connected to battery backup or generator. In contrast, the telephone exchange is designed to operate for an extended period on backup power, and to provide power to your handset over the telephone line, so it can continue to work in a power outage.
The majority of our network has some kind of battery backup and will continue to operate through power cuts; however batteries may fail if the interruption is lengthy.
You should weigh up your personal circumstances and decide what option is best for you; if you have a secondary way of contacting emergency services (such as good mobile reception), then it can be a much cheaper alternative to fixed line rentals.
VoIP service providers must allow you to register your address against your number for emergency calls and security systems, so if you do decide to change, then ‘999’ should still work. As VoIP numbers may be used on any internet connection, if you ever move, remember to update the address on the account for the emergency services!