For old school wired communication then go to nearby Porthcurno - see the hut there where the cables from all over the empire came ashore in the UK and there is an interesting museum there as well (plus non techies can go to see the Minnack theatre at the same time!)
Also there used to be a visitor centre at Goonhilly to cover the wizzy new satelite comms which I remember occupying a wet day on a family holiday a few years ago but that subsequently closed.
Biting the hand that feeds IT
