@Setanta,
You've reminded me of an interesting phenomenon I experienced a couple of weeks ago.
I was drift fishing, in a boat, on a small local lake with a friend, after dark. It happened that another friend was fishing from the bank, within earshot.
Rather than shout, the friend on the bank called my friend's cell phone. So I had the rather unique experience of hearing his voice, on the phone, well before I heard his actual voice across the water.
Gave a whole new dimension to the term, real time.