Emergency Numbers

000 is the official Australian emergency number
112 is a standard number for mobile phones that originated in Europe following an inquest.
106 if for TTY landline phones only (text to speech equipment for people with disabilities)

It is not possible to contact emergency services using the Short Message Service (SMS) on your mobile telephone.

112 arose because a young German fella died in Belgium when his mates couldn't get help because they had no provider coverage.
The Euro mob agreed that all providers and manuf would program their cells and phones so that 112 would link to that country's emergency services regardless of who the caller used as a provider or if the phone had credit or where the phone came from etc etc.
It was originally only on Euro manuf phones IE Nokia etc and in EU countries and it took many years for other countries and manuf to adopt.

Now that the Japs, Koreans etc have integrated 112 into their phone firmware you can pick up almost any phone in almost any country around the world (assuming same technology) and dial 112 and get help... no credit required, no international roaming required... just a live cell tower of any provider within range.

Edit: Copied The Evil Twin's reply to your original post here as it was more accurate

Thankyou, note that 112 CAN NOT be used on a land line.

An important note to this is in NSW they brought in a rule (I don't know if it got thrown out again or if it went Australia wide) where a Triple Zero call that came in as a NO SIM call (i.e. via '112' where no sim card is in the phone and '112' where the phone has a SIM card, but roams over to another network) can be abandonded essentially without answering the call at all. I left the cops about 6 months before this was brought in kicked up a huge stink at the time about the responsibility to answer ALL calls made to a 000 centre and cited a number of examples of genuine calls where overseas tourists with their overseas SIM cards (global roaming) were making emergency calls because they were lost in the bush, broken legs etc. but under the new rules these calls would be automatically abandonded. I got a reply to say my message had been forwarded on to the powers that be, but they had apparently already made their decision and it was going ahead (this was early 2008).

This all came about as a result of a number of statistics to show that only something like 5% of '000' calls were genuine and that something like 20% of '000' calls were coming in with no CLI details attached to them (i.e. no SIM card or roaming between competitors networks). Of the 20% no SIM calls something like 99.99999% of these were idiot teenagers ringing up to order pork pizzas and the like. I actually had some stupid little local theif prosecuted for this, because he was stupid enough to do it seven times and used his home phone to do so!

So basically (unless the rules have changed at the Police call centres) 112 is good so long as your call is connected via your home network and you CLI (Call Line Indicator) details come up on the screen. If they don't you may find yourself at the end of a dead line. Hence I suppose why it ALWAYS pays to have a back up emergency communications system (HF, Sat Phone, EPIRB etc.).

It is also important that if you need to ring 112 or 000 for assistance that you know and can tell them exactly where you are. Your generally not talking to your local Police station and you could end up getting an operator anywhere in Australia, especially if dialling from a Sat Phone as there are only a couple of downlinks in Australia. I have been sitting in Sydney and taken sat phone calls from truck drivers in the middle of nowhere somewhere in WA. I've also taken 000 overflow calls for almost every state of Australia because their call centres were overflowing and busy. Obviously back in the days of limited mapping resources this made it a bit hard to pin point where people were sometimes ad direct the details back to the right people to attend.

Cheers

Brian.

I also think 911 diverts to 000.

There was some talk a while ago about Telstra creating a network short cut so 911 would divert to 000 but I don't think it ever happened. Essentiall though if you in Australia just remember 000 from a landline and 112 from a mobile and you'll always get through (if there is service available) and you wont go wrong.

Sad, but too many bogans watch US program's and think 911 is for emergency services!!!