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If you happened to find yourself in an emergency situation, it’s quite possible that you, or someone with you has a mobile phone to call for help. But many people do not know that with GSM phones it is a little more complicated than dialing 000. In fact, there is another number which may succeed where 000 may not.

In this post I explain this mess of a situation we have, as well as cover the details on another widely publicized topic – the reason for the increased number of false 000 calls from mobiles.

Mobile phones used in Australia

There are two families of mobile system used in Australia. The first, and most common, is GSM/3GSM. This includes Telstra GSM, Telstra Next-G (UMT850), Telstra 3G (UMTS2100), Optus GSM, Optus UMTS, Vodafone, Vodafone UMTS and Three.

The other type, CDMA, includes Telstra CDMA (which is planned to be shutdown).

Chances are you are using a GSM/3GSM handset. If you are unsure, you can check if your phone has a SIM card (often located under the battery). If it does, then it’s a GSM/3GSM phone.

Emergency numbers used in Australia

There are 2 main emergency numbers used in Australia. The first you are almost certainly aware of – 000. This is the standard emergency number from landlines.

You can also call this number from all types of mobile phone, at no charge.

The second number is the international GSM emergency number – 112. This works from GSM phones as well.

You may now be interested to know why bother with the added confusion of dialing 112 on a GSM phone when you can use 000. The short answer is 112 has a greater chance of succeeding than 000. Read on to find out why.

Emergency calls on GSM/3GSM phones

The GSM specifications make provisions for a special type of call, the emergency call. All GSM handsets are aware of the GSM emergency number, 112.

If you dial 112, the handset will always recognize this number as an emergency number. Regardless of whether the phone is keypad locked, security coded, blocked (because it is stolen or you haven’t paid your bill), or even if it doesn’t have a SIM card, the phone will still attempt an emergency call on the available network(s).

Even if your home network is not available, but another is, the phone will try that network instead. For example, if you are with Vodafone and your phone shows no service, but there is Telstra or Optus service, dialing 112 will use one of those networks to make the call.

What about 000? Does the phone understand this is an emergency number also? Unfortunately, this is a more complex question to answer. The GSM specifications make provisions for the SIM card to be programmed with up to 5 additional emergency numbers in the EFECC file. In the older days of GSM in Australia, this function was not used. In more recent years, it is, and most SIM cards issued today have ‘000’ programmed in. This means for such SIM cards, the behavior with 000 will be the same as with 112 described above – in other words, any available network will be used, keypad locks will be overridden, etc.

You may be able to tell if your SIM card has 000 programmed in by locking the keypad and entering 000 (do not call). If this number suddenly appears on screen (i.e. backlights come on), then your SIM most likely recognizes 000.

If your SIM does not recognize 000, it doesn’t mean you won’t be able to make emergency calls. What it does mean is that the phone and the radio-link side of the network will treat it as if it were a regular call, and not prioritize it on the radio link. You would also have to be within a service area of your home network. However, using 112 avoids these potential problems.

Finally, there has been a lot of discussion in the press about false mobile calls to 000, as a result of the phone being knocked around and dialing 000. This is quite easy to do, and with newer SIMs there is nothing you can do to stop it. So don’t feel bad about it.

Emergency calls on CDMA
With CDMA it’s simple - emergency calls on CDMA are made with the standard 000 number.

Tips with emergency calls

• Remember, if the phone shows no service, try to make a call anyway. If a GSM phone has ‘lost’ its home network, it monitors other networks, but does not always show it (some phones do show they are, by saying ‘Emergency calls only’ or similar). Try dialing anyway.
• Try dialing both emergency numbers, 112 and 000, in that order.
• Remember, a mobile phone should not be relied upon as the only source of communication in an emergency. If you are traveling in isolated areas, always let someone know of your plans. Also consider taking an EPIRB and possibly a satellite phone

Links

Telstra’s Mobile Emergency page

Vodafone’s Customer Service

References

• ETSI GSM 03.22
• ETSI GSM 04.08
• ETSI GSM 11.11