Will a digital landline work during a power cut?

A digital call travels through equipment inside the home. The router needs power, and a full-fibre connection also uses an optical network terminal. If either loses power, the voice service may become unavailable even though the fibre or broadband network outside the property is still working.

Tell your provider if the landline is your only dependable way to contact emergency services, if mobile coverage is poor, or if disability, health, age or other circumstances make a mobile alternative unsuitable. Do this before migration rather than waiting for the first power cut.

Ofcom says providers must provide at least one hour of power resilience for consumers who need their landline to call emergency services during a power cut, and this should be provided free of charge to those landline-dependent customers. Providers may use different technical solutions, so ask what is available for your service and circumstances.

A backup unit normally powers specific communications equipment for a limited period. It does not keep every cordless handset, extension, Wi-Fi device or household appliance running. Check which equipment the backup supports, how long it is designed to last and how you know when the battery needs replacement.

A cordless DECT base station normally needs mains electricity. Even if the router has backup power, the cordless base may not. A provider or accessibility adviser may recommend an alternative arrangement, such as a compatible corded handset connected to the powered voice port, depending on the service design.

Keep a charged mobile where possible, know how to contact emergency services, keep provider support details somewhere accessible and test any approved backup arrangement periodically. If the household uses telecare or a personal alarm, the alarm provider should be involved in the plan as well.