User access layer is constituted by user terminal devices including PC, set-top box, mobile phone, videoconferencing terminal, Voip terminal, etc. With such devices, users can gain access to services provided by the system.
It is unlikely to be a coincidence that the new advice comes on the day that a combined BBC Newsnight and British Medical Journal investigation reports that problems withsuchdevices have been long known, but no action taken to block their use.