This unit became the standard viewdata terminal provided by UK banks to their better-off clientele. It was given to me with the words 'you might as well have it, I'm only going to toss it otherwise' and it came in supremely handy several years later when I was troubleshooting the first STC Executel phone system I got - itself a viewdata terminal.

Sadly the Prestel servers were turned off many years ago and their TV broadcast compatriots from the BBC and ITV, Ceefax and Oracle, were turned off in 2012. This of course means that there's nothing for this set-top-box to dial into which is a shame.