They could use what is known as a Lifeline Unit. The system is connected to a telephone socket and the user has a pendant which is a personal radio alarm trigger which is designed to hang round the neck. They can summon help either by pushing the button on the pendant or by pushing a button on the Lifeline unit. When they have activated the Lifeline, details of their circumstances will appear on a computer screen at a Control Centre. The Duty Officer will then contact the nominated keyholders who in turn will be expected to call on them immediately. If the keyholders are unavailable or it is obvious that medical help is needed, either a doctor or the emergency services will be called.