I remember having a wired system in my old Junior (Elementary) school in the 1970s, which I would say was probably installed when the school was built in the 1950s.
I have no idea what system was employed, but I would guess it was the standard 100V PA line. My memories are somewhat vague now, but I know for certain they piped BBC Radio 4 VHF/FM around the school (as that was used for school broadcasts at the time). As for PA announcements originating from the principal's office, I can't say I ever remember any, but the feature probably existed.
** FM on cable. Done in North America too, at least until the mid 1990s. You could often hook cable up to your regualr stero system receiver. Many had a 75 ohm or 300 ohm input.
Not directly related to cable radio, but the following link has a good article explaining the development of cable TV systems in the United States:
http://www.sbe24.org/archive/c24sep97.asp (Scroll down about halfway to the section titled "BROADBAND NETWORKS, PART 14 - Bandwidth Allocation").
[This message has been edited by pauluk (edited 12-21-2004).]
