On Sun, 2 Jan 2005 08:17:13 +0000, Roland Perry
wrote:

In message , at
14:57:34 on Sat, 1 Jan 2005, Martin Underwood remarked:
Nowadays no buttons
are needed because the coin is automatically consumed if the call is
answered (equivalent to pressing A) and automatically returned (if not used)
when the handset is replaced (equivalent to pressing B). I'm not sure why
this functionality wasn't included in old callboxes: surely it wasn't
difficult even in valve-amplifier and relay days.

Almost certainly because the button A/B callboxes weren't powered. All
the work was done by pressing the buttons very hard.

That explains a lot. My experience of A/B boxes is limited: they were
on their way out in London at least by the time that I was old enough
to use phone boxes, though I came across them in significant numbers
in Ireland as late as 1985, and at least one in a remote spot in the
north of Scotland even later than that. But I always had the sense of
buttons that were extremely heavy to use and some chunky thumb-powered
mechanisms within the box.

Incidentally http://www.bt.com/archives/history/19241931.htm and
scroll down to 1925 reveals that the A/B button system was introduced
in 1935 and the very last ones in the UK weren't discontinued until
1992

Martin