Thanks for putting me straight on that "Signal down a wire thing" if your info is correct, which I assume it is, then I have changed my mind again now.
Personally I think that most people today think the Modern Era started at the begging of 1900 exactly, though probably alot think your idea 1970 too, and I am split between 1900 and the end of WW2.
I think the first telephone (none mobile) is a good bet too.
PS
Don't tell me too: "Make up your mind!" It's a hard question!
PPS
How do you make a pole?
PPPS
How do you change the thing under your screen name that, for me at the moment I save this says Chieftain?