David FitzGerald:
112 is the international standard emergency number. It works almost
anywhere in the world. ...

My understanding is that it is only a European standard. I'm confident
enough that it doesn't work here to try it -- and I've just confirmed
that it doesn't. If you can cite anything official saying that it is
a world standard, I'd be interested to see it.

Martin Underwood:
Has Europe always just had 112?

Certainly not. I think it was a new innovation about 10-15 years ago.

As I understand it, 999 was chosen in the UK partly because it consisted of
high digits and there fore was unlikely to be dialled by accident using old
pulse-dial phones.

Also, the 9 hole could be easily found in the dark -- an advantage of
your 999 over our 911.

In North American in pre-911 days, if you didn't know the local police
(or fire, etc.) emergency number, what you did was dial the operator
and say which service you wanted. The number is just 0 (also easy to
find in the dark, althought I don't know if that was a consideration),
and back then it was always answered by a human operator directly.

112 is much easier to dial this way by accident - eg random shorting
or make/break of the phone line. So how come it wasn't an issue for
Europe if it was for the UK?

Random shorting is much less of an issue now than it was in the early
days when 999 was adopted, particularly now that calls are transmitted
in digital format over much of their length. I don't know if there are
places where pulse dialing is no longer accepted at all, though.
--
Mark Brader | (Monosyllables being forbidden to doctors of philosophy,
Toronto | such truths are called "invariants" in the trade.)
| -- Jeff Prothero

My text in this article is in the public domain.