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Comment by zw123456 | Hacker News Reader

One other fun fact about numbering, the most frequently dialed exchanges, those for big cities would use the lowest numbers, e.g. downtown would be 223 for the exchange and big cities area codes 212 and so on. The reason was not for the convenience of the dialer, remember it was rotary dial way back when a lot of those first got assigned, it was because the signaling was in band so the longer it took for the dialing to happen the longer the trunk was seized. If you have ever used a rotary phone, you'll notice it takes forever to dial 909 for example. So to optimize for the network they made the most frequently used numbers, most populated places, have the lower digits.

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That also explains why European emergency numbers are often 11X, including 112 which is the universal emergency number in the EU and the GSM standard (so it will work on your mobile phone too).

It doesn't explain Britain using 999 or Australia using 000.

Maybe the thinking was that you can easily slip with your finger or mindlessly dial something, then accidentally dialing a 1 or 2 is much more likely than doing the same with 9 or 0 which needs ten times the pulses (and the time) needed for a 1. Having grown up with rotary phones, that would make sense to me.

The UK originally considered using 111, but there were problems in that on windy days, trees etc brushing the lines could generate momentary disconnections = a pulse = digit 1. So false calls.

999 was choosen because it was easy to find the number 9 on the dial in the dark.

On a rotary dial 9 is hard to find, 0 or 1 would be much easier. Was the UK early with button dials?

It's not that difficult -- you find the metal fingerstop, and then move two around from it (0 and then 9). 000 would be easier, but it seems like that was already taken for other purposes.

I believe this was a plot point in one of the original stories about Paddington bear. Something about his fat finger.

000 makes lot of sense to me. It is the last digit available, so it can be quickly dialled.

Whether 0 comes before 1 or after 9 has been the matter of some debate!

But by the time typewriters started cementing the order of things, 0 came last, and on all the rotary phones I see on google images, 0 would take the longest to dial.

Do rotary phones in Australia flow backwards? xP

> Do rotary phones in Australia flow backwards? xP

They rotate the same direction as water circles when you flush a toilet.

They do in NZ: https://en.wikipedia.org/wiki/Rotary_dial#/media/File:New_Ze...

This wasn't a problem until direct international dialing became a thing, and then all of a sudden pulse converters had to be installed.

The emergency number there is 111.

With pulse dialing "1" is one click, "3" is 3 clicks, "9" is 9 clicks

You can't have zero clicks, so "0" would have to be 10 clicks

Yes, dialing 0 sends 10 pulses.

In which case it needs to be after 9

Sorry for the offtopicness but can you please email hn@ycombinator.com? I want to send you a repost invite.

This is not universal. E.g in Sweden we used one pulse for 0, two for 1, etc

My understanding of 999 was in order to stop accidental signalling of the intent to dial the emergency number by way of noise on the line being intepreted as dial click, which this article on BBC news seems to corroborate [1].

Having said that, that doesn't really then line up with 112 for mainland European countries, unless that is a relatively modern occurrence and they historically had different emergency numbers?

[1] http://news.bbc.co.uk/local/london/hi/people_and_places/hist...

112 didn't really start getting widespread support until after pulse dialing had mostly faded away.

Indeed, 999 is rather old, and many other European countries had different short codes such as 15, 17 or 110 and often they were different for police, ambulance and fire fighters, and some countries had no central emergency number at all. The coordination on 112 as a common Europe-wide number (including the UK) happened somewhere in the 1990s. Pulse dialing was on its way out by then, although it is the reason why it ends in a 2 and not a 1.

Here in Croatia they still have different numbers available for the different services, alongside the 112 "catch all".

112 – general emergency line

192 – police

193 – firefighters

194 – emergency medical assistance

195 – search and rescue at sea

There is also this:

1987 – road assistance

Emergency numbers would rarely go onto trunk lines though, so in that case, I suppose speed of dialing was actually the main concern.

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